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Sample records for based zno film

  1. ZnO based transparent conductive oxide films with controlled type of conduction

    Energy Technology Data Exchange (ETDEWEB)

    Zaharescu, M., E-mail: mzaharescu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Mihaiu, S., E-mail: smihaiu@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Toader, A. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Atkinson, I., E-mail: irinaatkinson@yahoo.com [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Calderon-Moreno, J.; Anastasescu, M.; Nicolescu, M.; Duta, M.; Gartner, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Vojisavljevic, K.; Malic, B. [Institute Jožef Stefan, Ljubljana (Slovenia); Ivanov, V.A.; Zaretskaya, E.P. [State Scientific and Production Association “Scientific-Practical Materials Research Center of the National Academy of Science Belarus, P. Brovska str.19, 220072, Minsk (Belarus)

    2014-11-28

    The transparent conductive oxide films with controlled type of conduction are of great importance and their preparation is intensively studied. In our work, the preparation of such films based on doped ZnO was realized in order to achieve controlled type of conduction and high concentration of the charge carriers. Sol–gel method was used for films preparation and several dopants were tested (Sn, Li, Ni). Multilayer deposition was performed on several substrates: SiO{sub 2}/Si wafers, silica-soda-lime and/or silica glasses. The structural and morphological characterization of the obtained films were done by scanning electron microscopy, X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy and atomic force microscopy respectively, while spectroscopic ellipsometry and transmittance measurements were done for determination of optical properties. The selected samples with the best structural, morphological and optical properties were subjected to electrical measurement (Hall and Seebeck effect). In all studied cases, samples with good adherence and homogeneous morphology as well as monophasic wurtzite type structure were obtained. The optical constants (refractive index and extinction coefficient) were calculated from spectroscopic ellipsometry data using Cauchy model. Films with n- or p-type conduction were obtained depending on the composition, number of deposition and thermal treatment temperature. - Highlights: • Transparent conductive ZnO based thin films were prepared by the sol–gel method. • Controlled type of conduction is obtained in (Sn, Li) doped and Li-Ni co-doped ZnO films. • Hall and Seebeck measurements proved the p-type conductivity for Li-Ni co-doped ZnO films. • The p-type conductivity was maintained even after 4-months of storage. • Influence of dopant- and substrate-type on the ZnO films properties was established.

  2. Development and surface characterization of a glucose biosensor based on a nanocolumnar ZnO film

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, A., E-mail: adriana.rodrigues@partner.kit.edu [Instituto de Física − UFRGS, P.O. Box 15051, 91501-970 Porto Alegre, RS (Brazil); Castegnaro, M.V. [Instituto de Física − UFRGS, P.O. Box 15051, 91501-970 Porto Alegre, RS (Brazil); Arguello, J.; Alves, M.C.M. [Instituto de Química − UFRGS, P.O. Box 15003, 91501-970 Porto Alegre, RS (Brazil); Morais, J., E-mail: jonder@if.ufrgs.br [Instituto de Física − UFRGS, P.O. Box 15051, 91501-970 Porto Alegre, RS (Brazil)

    2017-04-30

    Highlights: • Glucose biosensor based on self-assembled nanocolumnar ZnO deposited on stainless steel. • XPS applied to investigate the GOx immobilization on the ZnO nanocolumns surface. • Observable chemical shifts on O1s and Zn2p corroborates enzime immobilization. - Abstract: Highly oriented nanostructured ZnO films were grown on the surface of stainless steel plates (ZnO/SS) by chemical bath deposition (CBD). The films consisted of vertically aligned ZnO nanocolumns, ∼1 μm long and ∼80 nm wide, as observed by SEM (scanning electron microscopy) and FIB (focused ion beam). XRD (X-ray diffraction) confirmed the c-axis preferred orientation of the ZnO columns, which were functionalized with the glucose oxidase (GOx) enzyme into a biosensor of glucose. The electrochemical response studied by CV (cyclic voltammetry) proved that the biosensor was capable of detecting glucose from 1.5 up to 16 mM concentration range. XPS (X-ray photoelectron spectroscopy) analysis, excited with synchrotron radiation, probed the atom specific chemical environment at the electrode’s surface and shed some light on the nature of the ZnO-GOx interaction.

  3. Disposable urea biosensor based on nanoporous ZnO film fabricated from omissible polymeric substrate

    Energy Technology Data Exchange (ETDEWEB)

    Rahmanian, Reza; Mozaffari, Sayed Ahmad, E-mail: mozaffari@irost.ir; Abedi, Mohammad

    2015-12-01

    In the present study, a facile and simple fabrication method of a semiconductor based urea biosensor was reported via three steps: (i) producing a ZnO–PVA composite film by means of a polymer assisted electrodeposition of zinc oxide (ZnO) on the F-doped SnO{sub 2} conducting glass (FTO) using water soluble polyvinyl alcohol (PVA), (ii) obtaining a nanoporous ZnO film by PVA omission via a subsequent post-treatment by annealing of the ZnO–PVA film, and (iii) preparation of a FTO/ZnO/Urs biosensor by exploiting a nanoporous ZnO film as an efficient and excellent platform area for electrostatic immobilization of urease enzyme (Urs) which was forced by the difference in their isoelectric point (IEP). The characterization techniques focused on the analysis of the ZnO–PVA film surfaces before and after annealing, which had a prominent effect on the porosity of the prepared ZnO film. The surface characterization of the nanostructured ZnO film by a field emission-scanning electron microscopy (FE–SEM), exhibited a film surface area as an effective bio-sensing matrix for enzyme immobilization. The structural characterization and monitoring of the biosensor fabrication was performed using UV–Vis, Fourier Transform Infrared (FT-IR), Raman Spectroscopy, Thermogravimetric Analysis (TGA), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) techniques. The impedimetric results of the FTO/ZnO/Urs biosensor showed a high sensitivity for urea detection within 8.0–110.0 mg dL{sup −1} with the limit of detection as 5.0 mg dL{sup −1}. - Highlights: • Novel disposable impedimetric urea biosensor fabrication based on ZnO–nanoporous transducer • Exploiting omissible PVA polymer as a simple strategy for ZnO–nanoporous film preparation • ZnO–nanoporous film as a good pore framework with large surface area/volume for enzyme immobilization • Application of impedimetric measurement for urea monitoring due to its rapidity, sensitivity, and

  4. Physical properties of fish gelatin-based bio-nanocomposite films incorporated with ZnO nanorods.

    Science.gov (United States)

    Rouhi, Jalal; Mahmud, Shahrom; Naderi, Nima; Ooi, Ch Raymond; Mahmood, Mohamad Rusop

    2013-08-27

    Well-dispersed fish gelatin-based nanocomposites were prepared by adding ZnO nanorods (NRs) as fillers to aqueous gelatin. The effects of ZnO NR fillers on the mechanical, optical, and electrical properties of fish gelatin bio-nanocomposite films were investigated. Results showed an increase in Young's modulus and tensile strength of 42% and 25% for nanocomposites incorporated with 5% ZnO NRs, respectively, compared with unfilled gelatin-based films. UV transmission decreased to zero with the addition of a small amount of ZnO NRs in the biopolymer matrix. X-ray diffraction showed an increase in the intensity of the crystal facets of (10ī1) and (0002) with the addition of ZnO NRs in the biocomposite matrix. The surface topography of the fish gelatin films indicated an increase in surface roughness with increasing ZnO NR concentrations. The conductivity of the films also significantly increased with the addition of ZnO NRs. These results indicated that bio-nanocomposites based on ZnO NRs had great potentials for applications in packaging technology, food preservation, and UV-shielding systems.

  5. Physical properties of fish gelatin-based bio-nanocomposite films incorporated with ZnO nanorods

    Science.gov (United States)

    Rouhi, Jalal; Mahmud, Shahrom; Naderi, Nima; Ooi, CH Raymond; Mahmood, Mohamad Rusop

    2013-08-01

    Well-dispersed fish gelatin-based nanocomposites were prepared by adding ZnO nanorods (NRs) as fillers to aqueous gelatin. The effects of ZnO NR fillers on the mechanical, optical, and electrical properties of fish gelatin bio-nanocomposite films were investigated. Results showed an increase in Young's modulus and tensile strength of 42% and 25% for nanocomposites incorporated with 5% ZnO NRs, respectively, compared with unfilled gelatin-based films. UV transmission decreased to zero with the addition of a small amount of ZnO NRs in the biopolymer matrix. X-ray diffraction showed an increase in the intensity of the crystal facets of (10ī1) and (0002) with the addition of ZnO NRs in the biocomposite matrix. The surface topography of the fish gelatin films indicated an increase in surface roughness with increasing ZnO NR concentrations. The conductivity of the films also significantly increased with the addition of ZnO NRs. These results indicated that bio-nanocomposites based on ZnO NRs had great potentials for applications in packaging technology, food preservation, and UV-shielding systems.

  6. Physical properties of fish gelatin-based bio-nanocomposite films incorporated with ZnO nanorods

    OpenAIRE

    Rouhi, Jalal; Mahmud, Shahrom; Naderi, Nima; Ooi, CH Raymond; Mahmood, Mohamad Rusop

    2013-01-01

    Well-dispersed fish gelatin-based nanocomposites were prepared by adding ZnO nanorods (NRs) as fillers to aqueous gelatin. The effects of ZnO NR fillers on the mechanical, optical, and electrical properties of fish gelatin bio-nanocomposite films were investigated. Results showed an increase in Young's modulus and tensile strength of 42% and 25% for nanocomposites incorporated with 5% ZnO NRs, respectively, compared with unfilled gelatin-based films. UV transmission decreased to zero with the...

  7. ZnO Film Photocatalysts

    Directory of Open Access Journals (Sweden)

    Bosi Yin

    2014-01-01

    Full Text Available We have synthesized high-quality, nanoscale ultrathin ZnO films at relatively low temperature using a facile and effective hydrothermal approach. ZnO films were characterized by scanning electron microscope (SEM, X-ray diffraction (XRD, Raman spectroscopy, photoluminescence spectra (PL, and UV-vis absorption spectroscopy. The products demonstrated 95% photodegradation efficiency with Congo red (CR after 40 min irradiation. The photocatalytic degradation experiments of methyl orange (MO and eosin red also were carried out. The results indicate that the as-obtained ZnO films might be promising candidates as the excellent photocatalysts for elimination of waste water.

  8. Ultrasonic vibration imposed on nanoparticle-based ZnO film improves the performance of the ensuing perovskite solar cell

    Science.gov (United States)

    Miao, Yihe; Du, Peng; Wang, Zhiyu; Chen, Qianli; Eslamian, Morteza

    2018-02-01

    This work focuses on the development of nearly annealing-free ZnO-based perovskite solar cells (PSCs), suitable for low-cost manufacturing of PSCs on flexible substrates. To this end, thin film of ZnO nanoparticles is employed as the electron transporting layer (ETL), because of its low-temperature solution-processability and high electron mobility. In order to remove the structural and surface defects, ultrasonic vibration is imposed on the substrate of the as-spun wet ZnO films for a short duration of 3 min. It is shown that the ultrasonic excitation bridges the ZnO nanoparticles (cold sintering), and brings about significant improvement in the ZnO film nanostructure and functionality. In addition, ethyl acetate (EA), as an emerging volatile anti-solvent, is employed to deposit the methylammonium (MA) lead halide perovskite thin film atop the ZnO ETL, in order to prepare perovskite layers that only need an annealing time of 30 s. The ZnO-based PSCs, with a simple structure and free of additional treatments, except for the ultrasonic vibration, exhibit a promising performance with a power conversion efficiency (PCE) of over 11%, 40% higher than that of the control device. The ultrasonic vibration treatment is facile, low-cost, environmentally friendly, and compatible with the scalable coating and printing techniques, such as spray and blade coating.

  9. Development of Antibacterial Composite Films Based on Isotactic Polypropylene and Coated ZnO Particles for Active Food Packaging

    Directory of Open Access Journals (Sweden)

    Clara Silvestre

    2016-01-01

    Full Text Available This study was aimed at developing new films based on isotactic polypropylene (iPP for food packaging applications using zinc oxide (ZnO with submicron dimension particles obtained by spray pyrolysis. To improve compatibility with iPP, the ZnO particles were coated with stearic acid (ZnOc. Composites based on iPP with 2 wt % and 5 wt % of ZnOc were prepared in a twin-screw extruder and then filmed by a calender. The effect of ZnOc on the properties of iPP were assessed and compared with those obtained in previous study on iPP/ZnO and iPP/iPPgMA/ZnO. For all composites, a homogeneous distribution and dispersion of ZnOc was obtained indicating that the coating with stearic acid of the ZnO particles reduces the surface polarity mismatch between iPP and ZnO. The iPP/ZnOc composite films have relevant zinc oxide with respect to E. coli, higher thermal stability and improved mechanical and impact properties than the pure polymer and the composites iPP/ZnO and iPP/iPPgMA/ZnO. This study demonstrated that iPP/ZnOc films are suitable materials for potential application in the active packaging field.

  10. Development and surface characterization of a glucose biosensor based on a nanocolumnar ZnO film

    Science.gov (United States)

    Rodrigues, A.; Castegnaro, M. V.; Arguello, J.; Alves, M. C. M.; Morais, J.

    2017-04-01

    Highly oriented nanostructured ZnO films were grown on the surface of stainless steel plates (ZnO/SS) by chemical bath deposition (CBD). The films consisted of vertically aligned ZnO nanocolumns, ∼1 μm long and ∼80 nm wide, as observed by SEM (scanning electron microscopy) and FIB (focused ion beam). XRD (X-ray diffraction) confirmed the c-axis preferred orientation of the ZnO columns, which were functionalized with the glucose oxidase (GOx) enzyme into a biosensor of glucose. The electrochemical response studied by CV (cyclic voltammetry) proved that the biosensor was capable of detecting glucose from 1.5 up to 16 mM concentration range. XPS (X-ray photoelectron spectroscopy) analysis, excited with synchrotron radiation, probed the atom specific chemical environment at the electrode's surface and shed some light on the nature of the ZnO-GOx interaction.

  11. Blue electroluminescence nanodevice prototype based on vertical ZnO nanowire/polymer film on silicon substrate

    International Nuclear Information System (INIS)

    He Ying; Wang Junan; Chen Xiaoban; Zhang Wenfei; Zeng Xuyu; Gu Qiuwen

    2010-01-01

    We present a polymer-complexing soft template technique to construct the ZnO-nanowire/polymer light emitting device prototype that exhibits blue electrically driven emission with a relatively low-threshold voltage at room temperature in ambient atmosphere, and the ZnO-nanowire-based LED's emission wavelength is easily tuned by controlling the applied-excitation voltage. The nearly vertically aligned ZnO-nanowires with polymer film were used as emissive layers in the devices. The method uses polymer as binder in the LED device and dispersion medium in the luminescence layer, which stabilizes the quasi-arrays of ZnO nanowires embedding in a thin polymer film on silicon substrate and passivates the surface of ZnO nanocrystals, to prevent the quenching of luminescence. Additionally, the measurements of electrical properties showed that ZnO-nanowire/polymer film could significantly improve the conductivity of the film, which could be attributed to an increase in both Hall mobility and carrier concentration. The results indicated that the novel technique is a low-cost process for ZnO-based UV or blue light emission and reduces the requirement for achieving robust p-doping of ZnO film. It suggests that such ZnO-nanowire/polymer-based LEDs will be suitable for the electro-optical application.

  12. Perovskite solar cells based on nanocolumnar plasma-deposited ZnO thin films.

    Science.gov (United States)

    Ramos, F Javier; López-Santos, Maria C; Guillén, Elena; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Gonzalez-Elipe, Agustin R; Ahmad, Shahzada

    2014-04-14

    ZnO thin films having a nanocolumnar microstructure are grown by plasma-enhanced chemical vapor deposition at 423 K on pre-treated fluorine-doped tin oxide (FTO) substrates. The films consist of c-axis-oriented wurtzite ZnO nanocolumns with well-defined microstructure and crystallinity. By sensitizing CH3NH3PbI3 on these photoanodes a power conversion of 4.8% is obtained for solid-state solar cells. Poly(triarylamine) is found to be less effective when used as the hole-transport material, compared to 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), while the higher annealing temperature of the perovskite leads to a better infiltration in the nanocolumnar structure and an enhancement of the cell efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. doped ZnO thick film resistors

    Indian Academy of Sciences (India)

    The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ...

  14. Field Effect Transistors Based on Composite Films of Poly(4-vinylphenol) with ZnO Nanoparticles

    Science.gov (United States)

    Boughias, Ouiza; Belkaid, Mohammed Said; Zirmi, Rachid; Trigaud, Thierry; Ratier, Bernard; Ayoub, Nouh

    2018-01-01

    In order to adjust the characteristic of pentacene thin film transistor, we modified the dielectric properties of the gate insulator, poly(4-vinylphenol), or PVP. PVP is an organic polymer with a low dielectric constant, limiting the performance of organic thin film transistors (OTFTs). To increase the dielectric constant of PVP, a controlled amount of ZnO nanoparticles was homogeneously dispersed in a dielectric layer. The effect of the concentration of ZnO on the relative permittivity of PVP was measured using impedance spectroscopy and it has been demonstrated that the permittivity increases from 3.6 to 5.5 with no percolation phenomenon even at a concentration of 50 vol.%. The performance of OTFTs in terms of charge carrier mobility, threshold voltage and linkage current was evaluated. The results indicate a dramatic increase in both the field effect mobility and the linkage current by a factor of 10. It has been demonstrated that the threshold voltage can be adjusted. It shifts from 8 to 0 when the volume concentration of ZnO varied from 0 vol.% to 50 vol.%.

  15. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications.

    Science.gov (United States)

    Vidor, Fábio F; Meyers, Thorsten; Hilleringmann, Ulrich

    2016-08-23

    Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs) are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high- k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the I ON / I OFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V / V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  16. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications

    Directory of Open Access Journals (Sweden)

    Fábio F. Vidor

    2016-08-01

    Full Text Available Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high-k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the ION/IOFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V/V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  17. Nanostructured porous ZnO film with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Wang Lina; Zheng Yingying; Li Xiaoyun; Dong Wenjun; Tang Weihua; Chen Benyong; Li Chaorong; Li Xiao; Zhang Tierui

    2011-01-01

    Well-defined ZnO nanostructured films have been fabricated directly on Zn foil via hydrothermal synthesis. During the fabrication of the ZnO nanostructured films, the Zn foil serves as the Zn source and also the substrate. Porous nanosheet-based, nanotube-based and nanoflower-based ZnO films can all be easily prepared by adjusting the alkali type, reaction time and reaction temperature. The composition, morphology and structure of ZnO films are characterized by X-ray diffraction, scanning electron microscope and high-resolution transmission electron microscope. The porous ZnO nanosheet-based film exhibits enhanced photocatalytic activity in the degradation of Rhodamine B under UV light irradiation. This can be attributed to the high surface area of the ZnO nanosheet and the large percentage of the exposed [001] facet. Moreover, the self-supporting, recyclable and stable ZnO photocatalytic film can be readily recovered and potentially applied for pollution disposal.

  18. Resistive Switching Characteristics in Electrochemically Synthesized ZnO Films

    Directory of Open Access Journals (Sweden)

    Shuhan Jing

    2015-04-01

    Full Text Available The semiconductor industry has long been seeking a new kind of non-volatile memory technology with high-density, high-speed, and low-power consumption. This study demonstrated the electrochemical synthesis of ZnO films without adding any soft or hard templates. The effect of deposition temperatures on crystal structure, surface morphology and resistive switching characteristics were investigated. Our findings reveal that the crystallinity, surface morphology and resistive switching characteristics of ZnO thin films can be well tuned by controlling deposition temperature. A conducting filament based model is proposed to explain the switching mechanism in ZnO thin films.

  19. Effect of initialization time on application potentiality of a ZnO thin film based LPG sensor

    Directory of Open Access Journals (Sweden)

    Parta Mitra

    2009-09-01

    Full Text Available A prototype electronic LPG (Liquid Petroleum Gas sensor based on zinc oxide (ZnO film has been fabricated. The objective of the present work was to investigate the importance of initialization time (also called warm-up time on the application potentiality of the ZnO based alarm. The role of sensor geometry on initialization time is presented. The electronic circuitry of the prototype LPG device alarm is discussed. It is shown that that the initialization time depends on the switch off time (or the time for which the sensor was kept idle. The resistive mode sensors can be fixed at 40% LEL (Lower Explosive Limit of LPG for safe operation.

  20. Random laser based on Rhodamine 6G (Rh6G doped poly(methyl methacrylate (PMMA films coating on ZnO nanorods synthesized by hydrothermal oxidation

    Directory of Open Access Journals (Sweden)

    Hua Zhang

    Full Text Available Random laser based on Rh6G doped PMMA thin films coating on ZnO nanorods synthesized by a simple hydrothermal oxidation method has been demonstrated. This kind of random laser medium is based on waveguide structure consisting of ZnO nanorods, Rh6G doped PMMA film and air. By controlling the time of hydrothermal oxidation reaction, wheat-like and hexagonal prism ZnO nanorods have been successfully fabricated. The emission spectra of these gain mediums based on different ZnO nanorods are different. The one based on wheat-like ZnO nanorods mainly exhibits amplified spontaneous emission, and the other one based on hexagonal prism ZnO nanorods shows random laser emission. The threshold of the random laser medium is about 73.8 μJ/pulse, and the full width at half maximum (FWHM is around 2.1 nm. The emission spectra measured at different detecting angles reveal that the output direction is strongly confined in ±30° by the waveguide effect. Our experiments demonstrate a promising method to achieve organic random laser medium. Keywords: Random laser, ZnO nanorods, Hydrothermal oxidation, Rhodamine 6G (Rh6G, Poly(methyl methacrylate (PMMA

  1. Nanocomposite films based on CMC, okra mucilage and ZnO nanoparticles: Physico mechanical and antibacterial properties.

    Science.gov (United States)

    Mohammadi, Hamid; Kamkar, Abolfazl; Misaghi, Ali

    2018-02-01

    This work examined the physico mechanical parameters and antibacterial activity of CMC/okra mucilage (OM) blend films containing ZnO nanoparticles (NPs). Different proportions of CMC and okra mucilage (100/0; 70/30; 60/40 and 50/50 respectively), were mixed and casted to posterior analysis of formed films. The more colored films were obtained by higher contents of okra mucilage and adding ZnO nanoparticles. The incorporation of ZnO NPs into CMC film decreased the elongation at the break (EB) value of the films and increased the tensile strength (TS) value of the film. With increase in CMC concentration in the films, higher water vapor permeability and higher solubility in water were achieved. Microstructure analysis using SEM showed a smooth and compact surface morphology, homogeneous structure, and a rough surface for CMC, CMC+ZnO, and CMC/OM30%+ZnO, respectively. Nanocomposite films presented antibacterial activity against tested bacteria. Films contained okra mucilage showed more antibacterial activity. The inhibitory activities of resultant films were stronger against S. aureus than E. coli. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. An economic approach to fabricate photo sensor based on nanostructured ZnO thin films

    Science.gov (United States)

    Huse, Nanasaheb; Upadhye, Deepak; Sharma, Ramphal

    2016-05-01

    Nanostructural ZnO Thin Films have been synthesized by simple and economic Chemical Bath Deposition technique onto glass substrate with bath temperature at 60°C for 1 hour. Structural, Optical, Electrical and topographical properties of the prepared Thin Films were investigated by GIXRD, I-V Measurement System, UV-Visible Spectrophotometer and AFM respectively. Calculated lattice parameters are in good agreement with the standard JCPDS card (36-1451) values, exhibits Hexagonal Wurtzite crystal structure. I-V Measurement curve has shown ohmic nature in dark condition and responds to light illumination which reveals Photo sensor properties. After illumination of 60W light, decrease in resistance was observed from 110.9 KΩ to 104.4 KΩ. The change in current and calculated Photo sensitivity was found to be 3.51 µA and 6.3% respectively. Optical band gap was found to be 3.24 eV. AFM images revealed uniform deposition over entire glass substrate with 32.27 nm average roughness of the film.

  3. Development of Room Temperature Excitonic Lasing From ZnO and MgZnO Thin Film Based Metal-Semiconductor-Metal Devices

    Science.gov (United States)

    Suja, Mohammad Zahir Uddin

    Room temperature excitonic lasing is demonstrated and developed by utilizing metal-semiconductor-metal devices based on ZnO and MgZnO materials. At first, Cu-doped p-type ZnO films are grown on c-sapphire substrates by plasma-assisted molecular beam epitaxy. Photoluminescence (PL) experiments reveal a shallow acceptor state at 0.15 eV above the valence band edge. Hall effect results indicate that a growth condition window is found for the formation of p-type ZnO thin films and the best conductivity is achieved with a high hole concentration of 1.54x1018 cm-3, a low resistivity of 0.6 O cm and a moderate mobility of 6.65 cm2 V -1 s-1 at room temperature. Metal oxide semiconductor (MOS) capacitor devices have been fabricated on the Cu-doped ZnO films and the characteristics of capacitance-voltage measurements demonstrate that the Cu-doped ZnO thin films under proper growth conditions are p-type. Seebeck measurements on these Cu-doped ZnO samples lead to positive Seebeck coefficients and further confirm the p-type conductivity. Other measurements such as XRD, XPS, Raman and absorption are also performed to elucidate the structural and optical characteristics of the Cu-doped p-type ZnO films. The p-type conductivity is explained to originate from Cu substitution of Zn with a valency of +1 state. However, all p-type samples are converted to n-type over time, which is mostly due to the carrier compensation from extrinsic defects of ZnO. To overcome the stability issue of p-type ZnO film, alternate devices other than p-n junction has been developed. Electrically driven plasmon-exciton coupled random lasing is demonstrated by incorporating Ag nanoparticles on Cu-doped ZnO metal-semiconductor-metal (MSM) devices. Both photoluminescence and electroluminescence studies show that emission efficiencies have been enhanced significantly due to coupling between ZnO excitons and Ag surface plasmons. With the incorporation of Ag nanoparticles on ZnO MSM structures, internal quantum

  4. Surface Engineering of ZnO Thin Film for High Efficiency Planar Perovskite Solar Cells

    Science.gov (United States)

    Tseng, Zong-Liang; Chiang, Chien-Hung; Wu, Chun-Guey

    2015-09-01

    Sputtering made ZnO thin film was used as an electron-transport layer in a regular planar perovskite solar cell based on high quality CH3NH3PbI3 absorber prepared with a two-step spin-coating. An efficiency up to 15.9% under AM 1.5G irradiation is achieved for the cell based on ZnO film fabricated under Ar working gas. The atmosphere of the sputtering chamber can tune the surface electronic properties (band structure) of the resulting ZnO thin film and therefore the photovoltaic performance of the corresponding perovskite solar cell. Precise surface engineering of ZnO thin film was found to be one of the key steps to fabricate ZnO based regular planar perovskite solar cell with high power conversion efficiency. Sputtering method is proved to be one of the excellent techniques to prepare ZnO thin film with controllable properties.

  5. Electrical characteristics and density of states of thin-film transistors based on sol-gel derived ZnO channel layers with different annealing temperatures

    Science.gov (United States)

    Wang, S.; Mirkhani, V.; Yapabandara, K.; Cheng, R.; Hernandez, G.; Khanal, M. P.; Sultan, M. S.; Uprety, S.; Shen, L.; Zou, S.; Xu, P.; Ellis, C. D.; Sellers, J. A.; Hamilton, M. C.; Niu, G.; Sk, M. H.; Park, M.

    2018-04-01

    We report on the fabrication and electrical characterization of bottom gate thin-film transistors (TFTs) based on a sol-gel derived ZnO channel layer. The effect of annealing of ZnO active channel layers on the electrical characteristics of the ZnO TFTs was systematically investigated. Photoluminescence (PL) spectra indicate that the crystal quality of the ZnO improves with increasing annealing temperature. Both the device turn-on voltage (Von) and threshold voltage (VT) shift to a positive voltage with increasing annealing temperature. As the annealing temperature is increased, both the subthreshold slope and the interfacial defect density (Dit) decrease. The field effect mobility (μFET) increases with annealing temperature, peaking at 800 °C and decreases upon further temperature increase. An improvement in transfer and output characteristics was observed with increasing annealing temperature. However, when the annealing temperature reaches 900 °C, the TFTs demonstrate a large degradation in both transfer and output characteristics, which is possibly produced by non-continuous coverage of the film. By using the temperature-dependent field effect measurements, the localized sub-gap density of states (DOSs) for ZnO TFTs with different annealing temperatures were determined. The DOSs for the subthreshold regime decrease with increasing annealing temperature from 600 °C to 800 °C and no substantial change was observed with further temperature increase to 900 °C.

  6. Nanostructured ZnO films on stainless steel are highly safe and effective for antimicrobial applications.

    Science.gov (United States)

    Shim, Kyudae; Abdellatif, Mohamed; Choi, Eunsoo; Kim, Dongkyun

    2017-04-01

    The safety and effectiveness of antimicrobial ZnO films must be established for general applications. In this study, the antimicrobial activity, skin irritation, elution behavior, and mechanical properties of nanostructured ZnO films on stainless steel were evaluated. ZnO nanoparticle (NP) and ZnO nanowall (NW) structures were prepared with different surface roughnesses, wettability, and concentrations using an RF magnetron sputtering system. The thicknesses of ZnO NP and ZnO NW were approximately 300 and 620 nm, respectively, and ZnO NW had two diffraction directions of [0002] and [01-10] based on high-resolution transmission electron microscopy. The ZnO NW structure demonstrated 99.9% antimicrobial inhibition against Escherichia coli, Staphylococcus aureus, and Penicillium funiculosum, and no skin irritation was detected using experimental rabbits. Approximately 27.2 ± 3.0 μg L -1 Zn ions were eluted from the ZnO NW film at 100 °C for 24 h, which satisfies the WHO guidelines for drinking water quality. Furthermore, the Vickers hardness and fracture toughness of ZnO NW films on stainless steel were enhanced by 11 and 14% compared to those of the parent stainless steel. Based on these results, ZnO NW films on STS316L sheets are useful for household supplies, such as water pipes, faucets, and stainless steel containers.

  7. PMMA–SiO{sub 2} hybrid films as gate dielectric for ZnO based thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, M.D. [Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, Apdo. Postal 1-798, Querétaro, Qro. 76001 (Mexico); Quevedo-López, M.A. [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75083 (United States); Ramírez-Bon, R., E-mail: rrbon@qro.cinvestav.mx [Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, Apdo. Postal 1-798, Querétaro, Qro. 76001 (Mexico)

    2014-08-01

    In this paper we report a low temperature sol–gel deposition process of PMMA–SiO{sub 2} hybrid films, with variable dielectric properties depending on the composition of the precursor solution, for applications to gate dielectric layers in field-effect thin film transistors (FE-TFT). The hybrid layers were processed by a modified sol–gel route using as precursors Tetraethyl orthosilicate (TEOS) and Methyl methacrylate (MMA), and 3-(Trimethoxysilyl)propyl methacrylate (TMSPM) as the coupling agent. Three types of hybrid films were processed with molar ratios of the precursors in the initial solution 1.0: 0.25, 0.50, 0.75: 1.0 for TEOS: TMSPM: MMA, respectively. The hybrid films were deposited by spin coating of the hybrid precursor solutions onto p-type Si (100) substrates and heat-treated at 90 °C for 24 h. The chemical bonding in the hybrid films was analyzed by Fourier Transform Infrared Spectroscopy to confirm their hybrid nature. The refractive index of the hybrid films as a function of the TMSPM coupling agent concentration, were determined from a simultaneous analysis of optical reflectance and spectroscopic ellipsometry experimental data. The PMMA–SiO{sub 2} hybrid films were studied as dielectric films using metal-insulator-metal structures. Capacitance–Voltage (C–V) and current–voltage (I–V) electrical methods were used to extract the dielectric properties of the different hybrid layers. The three types of hybrid films were tested as gate dielectric layers in thin film transistors with structure ZnO/PMMA–SiO{sub 2}/p-Si with a common bottom gate and patterned Al source/drain contacts, with different channel lengths. We analyzed the output electrical responses of the ZnO-based TFTs to determine their performance parameters as a function of channel length and hybrid gate dielectric layer. - Highlights: • PMMA–SiO{sub 2} hybrid films as dielectric material synthesized by sol–gel process at low temperature. • PMMA–SiO{sub 2

  8. Nanostructured hybrid ZnO thin films for energy conversion

    Directory of Open Access Journals (Sweden)

    Samantilleke Anura

    2011-01-01

    Full Text Available Abstract We report on hybrid films based on ZnO/organic dye prepared by electrodeposition using tetrasulfonated copper phthalocyanines (TS-CuPc and Eosin-Y (EoY. Both the morphology and porosity of hybrid ZnO films are highly dependent on the type of dyes used in the synthesis. High photosensitivity was observed for ZnO/EoY films, while a very weak photoresponse was obtained for ZnO/TS-CuPc films. Despite a higher absorption coefficient of TS-CuPc than EoY, in ZnO/EoY hybrid films, the excited photoelectrons between the EoY levels can be extracted through ZnO, and the porosity of ZnO/EoY can also be controlled.

  9. Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode

    Science.gov (United States)

    Gallay, P.; Tosi, E.; Madrid, R.; Tirado, M.; Comedi, D.

    2016-10-01

    We present a glucose biosensor based on ZnO nanowire self-sustained films grown on compacted graphite flakes by the vapor transport method. Nanowire/graphite films were fragmented in water, filtered to form a colloidal suspension, subsequently functionalized with glucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices were evaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical responses of the devices were determined in buffer solutions with successive glucose aggregates using a tripolar electrode system. The nanostructured biosensors showed excellent analytical performance, with linear response to glucose concentrations, high sensitivity of up to ≈17 μA cm-2 mM-1 in the 0.03-1.52 mM glucose concentration range, relatively low Michaelis-Menten constant, excellent reproducibility and a fast response. The detection limits are more than an order of magnitude lower than those achievable in commercial biosensors for glucose control, which is promising for the development of glucose monitoring methods that do not require blood extraction from potentially diabetic patients. The strong detection enhancements provided by the functionalized nanostructures are much larger than the electrode surface-area increase and are discussed in terms of the physical and chemical mechanisms involved in the detection and transduction processes.

  10. ZnO Thin Film Electronics for More than Displays

    Science.gov (United States)

    Ramirez, Jose Israel

    Zinc oxide thin film transistors (TFTs) are investigated in this work for large-area electronic applications outside of display technology. A constant pressure, constant flow, showerhead, plasma-enhanced atomic layer deposition (PEALD) process has been developed to fabricate high mobility TFTs and circuits on rigid and flexible substrates at 200 °C. ZnO films and resulting devices prepared by PEALD and pulsed laser deposition (PLD) have been compared. Both PEALD and PLD ZnO films result in densely packed, polycrystalline ZnO thin films that were used to make high performance devices. PEALD ZnO TFTs deposited at 300 °C have a field-effect mobility of ˜ 40 cm2/V-s (and > 20 cm2/V-S deposited at 200 °C). PLD ZnO TFTs, annealed at 400 °C, have a field-effect mobility of > 60 cm2/V-s (and up to 100 cm2/V-s). Devices, prepared by either technique, show high gamma-ray radiation tolerance of up to 100 Mrad(SiO2) with only a small radiation-induced threshold voltage shift (VT ˜ -1.5 V). Electrical biasing during irradiation showed no enhanced radiation-induced effects. The study of the radiation effects as a function of material stack thicknesses revealed the majority of the radiation-induced charge collection happens at the semiconductor-passivation interface. A simple sheet-charge model at that interface can describe the radiation-induced charge in ZnO TFTs. By taking advantage of the substrate-agnostic process provided by PEALD, due to its low-temperature and excellent conformal coatings, ZnO electronics were monolithically integrated with thin-film complex oxides. Application-based examples where ZnO electronics provide added functionality to complex oxide-based devices are presented. In particular, the integration of arrayed lead zirconate titanate (Pb(Zr, Ti)O3 or PZT) thin films with ZnO electronics for microelectromechanical systems (MEMs) and deformable mirrors is demonstrated. ZnO switches can provide voltage to PZT capacitors with fast charging and slow

  11. Oxidant-Dependent Thermoelectric Properties of Undoped ZnO Films by Atomic Layer Deposition

    KAUST Repository

    Kim, Hyunho

    2017-02-27

    Extraordinary oxidant-dependent changes in the thermoelectric properties of undoped ZnO thin films deposited by atomic layer deposition (ALD) have been observed. Specifically, deionized water and ozone oxidants are used in the growth of ZnO by ALD using diethylzinc as a zinc precursor. No substitutional atoms have been added to the ZnO films. By using ozone as an oxidant instead of water, a thermoelectric power factor (σS) of 5.76 × 10 W m K is obtained at 705 K for undoped ZnO films. In contrast, the maximum power factor for the water-based ZnO film is only 2.89 × 10 W m K at 746 K. Materials analysis results indicate that the oxygen vacancy levels in the water- and ozone-grown ZnO films are essentially the same, but the difference comes from Zn-related defects present in the ZnO films. The data suggest that the strong oxidant effect on thermoelectric performance can be explained by a mechanism involving point defect-induced differences in carrier concentration between these two oxides and a self-compensation effect in water-based ZnO due to the competitive formations of both oxygen and zinc vacancies. This strong oxidant effect on the thermoelectric properties of undoped ZnO films provides a pathway to improve the thermoelectric performance of this important material.

  12. Admittance spectroscopy of spray-pyrolyzed ZnO film

    International Nuclear Information System (INIS)

    Kavasoglu, Nese; Kavasoglu, A. Sertap

    2008-01-01

    A ZnO film was deposited using the spray pyrolysis method. The admittance spectroscopy method was used to establish the contributions to electrical behavior from grains, grain boundaries, and electrodes of film. Proper equivalent electrical circuit of a ZnO film composed of a single parallel resistor, capacitor, and inductor network connected with a series resistance was proposed. Moreover, we displayed metal-semiconductor transition (MST) in the ZnO film via admittance spectroscopy

  13. Simulation, fabrication and characterization of ZnO based thin film transistors grown by radio frequency magnetron sputtering.

    Science.gov (United States)

    Singh, Shaivalini; Chakrabarti, P

    2012-03-01

    We report the performance of the thin film transistors (TFTs) using ZnO as an active channel layer grown by radio frequency (RF) magnetron sputtering technique. The bottom gate type TFT, consists of a conventional thermally grown SiO2 as gate insulator onto p-type Si substrates. The X-ray diffraction patterns reveal that the ZnO films are preferentially orientated in the (002) plane, with the c-axis perpendicular to the substrate. A typical ZnO TFT fabricated by this method exhibits saturation field effect mobility of about 0.6134 cm2/V s, an on to off ratio of 102, an off current of 2.0 x 10(-7) A, and a threshold voltage of 3.1 V at room temperature. Simulation of this TFT is also carried out by using the commercial software modeling tool ATLAS from Silvaco-International. The simulated global characteristics of the device were compared and contrasted with those measured experimentally. The experimental results are in fairly good agreement with those obtained from simulation.

  14. Surface Engineering of ZnO Thin Film for High Efficiency Planar Perovskite Solar Cells

    OpenAIRE

    Tseng, Zong-Liang; Chiang, Chien-Hung; Wu, Chun-Guey

    2015-01-01

    Sputtering made ZnO thin film was used as an electron-transport layer in a regular planar perovskite solar cell based on high quality CH3NH3PbI3 absorber prepared with a two-step spin-coating. An efficiency up to 15.9% under AM 1.5G irradiation is achieved for the cell based on ZnO film fabricated under Ar working gas. The atmosphere of the sputtering chamber can tune the surface electronic properties (band structure) of the resulting ZnO thin film and therefore the photovoltaic performance o...

  15. Fabrication and characterization of novel semolina-based antimicrobial films derived from the combination of ZnO nanorods and nanokaolin.

    Science.gov (United States)

    Jafarzadeh, Shima; Alias, Abd Karim; Ariffin, Fazilah; Mahmud, Shahrom; Najafi, Ali; Ahmad, Mehraj

    2017-01-01

    This study aimed to provide novel biopolymer-based antimicrobial films as food packaging that may assist in reducing environmental pollution caused by the accumulation of synthetic food packaging. The blend of ZnO nanorods (ZnO-nr) and nanokaolin in different ratios (1:4, 2:3, 3:2 and 4:1) was incorporated into semolina, and nanocomposite films were prepared using solvent casting. The resulting films were characterized through field-emission scanning electron microscopy and X-ray diffraction. The mechanical, optical, physical, and antimicrobial properties of the films were also analyzed. The water vapor permeability of the films decreased with increasing ZnO-nr percentage, but their tensile strength and modulus of elasticity increased with increasing nanokaolin percentage. The UV transmittance of the semolina films were greatly influenced by an increase in the amount of ZnO-nr. The addition of ZnO-nr: nanokaolin at all ratios (except 1:4) into semolina reduced UV transmission to almost 0%. Furthermore, the ZnO-nr/nanokaolin/semolina films exhibited a strong antimicrobial activity against Staphylococcus aureus . These properties suggest that the combination of ZnO-nr and nanokaolin are potential fillers in semolina-based films to be used as active packaging for food and pharmaceuticals.

  16. EPD-deposited ZnO thin films: a review

    Directory of Open Access Journals (Sweden)

    Verde, M.

    2014-08-01

    Full Text Available ZnO-based materials and specifically ZnO films with tailored morphology have been subjected to extensive research in the past few years due to their high potential for multiple prospective applications, mainly in electronics. Electrophoretic Deposition (EPD constitutes an economical, ecofriendly, low energy consuming and easily scalable alternative to the high energy consuming evaporative techniques which are commonly used for the obtaining of these ZnO films. For its application, however, the use of stable, well dispersed suspensions is a necessary requirement, and thus a thorough study of their colloidal chemistry is essential. In this work the main contributions to the study of colloidal chemistry of ZnO nanoparticle suspensions and their shaping into ZnO films by EPD are summarized.Los materiales basados en ZnO y en particular las láminas de ZnO con morfología controlada han sido objeto en los últimos años de numerosas investigaciones debido al elevado potencial que presentan para múltiples aplicaciones emergentes, principalmente en electrónica. La deposición electroforética (EPD constituye un método alternativo económico, ecológico, de bajo coste energético y elevada escalabilidad para la producción de éstas láminas de ZnO, en contraste con las técnicas evaporativas empleadas habitualmente, las cuales presentan un elevado impacto energético, así como una escalabilidad complicada. Para su aplicación, sin embargo, y puesto que el principal requisito es el uso de suspensiones estables y bien dispersas, es necesario un detallado estudio de la coloidequímica de las mismas. En este trabajo se resumen las aportaciones más relevantes relativas al estudio de los distintos parámetros que afectan a la estabilidad coloidal de las suspensiones de nanopartículas de ZnO y al proceso de obtención de las láminas mediante EPD a partir de las mismas.

  17. Manufacturing of patterned ZnO films with application for ...

    Indian Academy of Sciences (India)

    Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol–gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with hexagonal crystal structure, are characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction.

  18. Manufacturing of patterned ZnO films with application for ...

    Indian Academy of Sciences (India)

    Administrator

    Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., 1164 Sofia, Bulgaria. MS received 30 December 2008; revised 11 July 2009. Abstract. Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol–gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with ...

  19. Reliable thermal processing of organic perovskite films deposited on ZnO

    Science.gov (United States)

    Zakhidov, Alex; Manspeaker, Chris; Lyashenko, Dmitry; Alex Zakhidov Team

    Zinc oxide (ZnO) is a promising semiconducting material to serve as an electron transport layer (ETL) for solar cell devices based on organo-halide lead perovskites. ZnO ETL for perovskite photovoltaics has a combination of attractive electronic and optical properties: i) the electron affinity of ZnO is well aligned with valence band edge of the CH3NH3PbI3, ii) electron mobility of ZnO is >1 cm2/(Vs), which is a few orders of magnitude higher than that of TiO2 (another popular choice of ETL for perovskite photovoltaic devices), and iii) ZnO has a large of band gap of 3.3 eV, which ensures optical transparency and large barrier for the hole injection. Moreover, ZnO nanostructures can be printed on flexible substrates at room temperatures in cost effective manner. However, it was recently found that organic perovskites deposited on ZnO are unstable and readily decompose at >90°C. In this work, we further investigate the mechanism of decomposition of CH3NH3PbI3 film deposited on ZnO and reveal the role of the solvent in the film during the annealing process. We also develop a restricted volume solvent annealing (RVSA) process for post annealing of the perovskite film on ZnO without decomposition. We demonstrate that RVSA enables reliable perovskite solar cell fabrication.

  20. Growth of vertically aligned ZnO nanorods using textured ZnO films

    Directory of Open Access Journals (Sweden)

    Meléndrez Manuel

    2011-01-01

    Full Text Available Abstract A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100 substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells. PACS 61.46.Hk, Nanocrystals; 61.46.Km, Structure of nanowires and nanorods; 81.07.Gf, Nanowires; 81.15.Gh, Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.

  1. Growth of vertically aligned ZnO nanorods using textured ZnO films

    Science.gov (United States)

    Solís-Pomar, Francisco; Martínez, Eduardo; Meléndrez, Manuel F.; Pérez-Tijerina, Eduardo

    2011-09-01

    A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD) is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100) substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells.

  2. Significant room-temperature ferromagnetism in porous ZnO films: The role of oxygen vacancies

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xue; Liu, Huiyuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Sun, Huiyuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Liu, Lihu; Jia, Xiaoxuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China)

    2015-10-15

    Graphical abstract: - Highlights: • Porous ZnO films were deposited on porous anodic alumina substrates. • Significant ferromagnetism (FM) has been observed in porous ZnO films (110 emu/cm{sup 3}). • The strong magnetic anisotropy was observed in the porous ZnO films. • The origin of FM is attributed to the oxygen vacancy with a local magnetic moment. - Abstract: Pure porous ZnO films were prepared by direct current reactive magnetron sputtering on porous anodic alumina substrates. Remarkably large room-temperature ferromagnetism was observed in the films. The highest saturation moment along the out-of-plane direction was about 110 emu/cm{sup 3}. Experimental and theoretical results suggested that the oxygen vacancies and the unique porous structure of the films are responsible for the large ferromagnetism. There are two modes of coupling between oxygen vacancies in the porous ZnO films: (i) exchange interactions directly between the oxygen vacancies and (ii) with the mediation of conduction electrons. In addition, it was found that the magnetic moment of ZnO films can be changed by tuning the concentration of oxygen vacancies. These observations may be useful in the development of ZnO-based spintronics devices.

  3. Photosensitivity of nanocrystalline ZnO films grown by PLD

    International Nuclear Information System (INIS)

    Ayouchi, R.; Bentes, L.; Casteleiro, C.; Conde, O.; Marques, C.P.; Alves, E.; Moutinho, A.M.C.; Marques, H.P.; Teodoro, O.; Schwarz, R.

    2009-01-01

    We have studied the properties of ZnO thin films grown by laser ablation of ZnO targets on (0 0 0 1) sapphire (Al 2 O 3 ), under substrate temperatures around 400 deg. C. The films were characterized by different methods including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atomic force microscopy (AFM). XPS analysis revealed that the films are oxygen deficient, and XRD analysis with θ-2θ scans and rocking curves indicate that the ZnO thin films are highly c-axis oriented. All the films are ultraviolet (UV) sensitive. Sensitivity is maximum for the films deposited at lower temperature. The films deposited at higher temperatures show crystallite sizes of typically 500 nm, a high dark current and minimum photoresponse. In all films we observe persistent photoconductivity decay. More densely packed crystallites and a faster decay in photocurrent is observed for films deposited at lower temperature

  4. Wound Healing Bionanocomposites Based on Castor Oil Polymeric Films Reinforced with Chitosan-Modified ZnO Nanoparticles.

    Science.gov (United States)

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2015-09-14

    Castor oil (CO), which is a readily available, relatively inexpensive, and environmentally benign nonedible oil, has been successfully used as matrix material to prepare biocompatible and biodegradable nanocomposite films filled with chitosan (CS)-modified ZnO nanoparticles. The biocomposites were synthesized via a simple and versatile solution mixing and casting method. The morphology, structure, thermal stability, water absorption, biodegradability, cytocompatibility, barrier, mechanical, viscoelastic, antibacterial, and wound healing properties of the films have been analyzed. FT-IR spectra were used to obtain information about the nanoparticle-matrix interactions. The thermal stability, hydrophilicity, degree of porosity, water absorption, water vapor transmission rate (WVTR), oxygen permeability (Dk), and biodegradability of the films increased with the CS-ZnO loading. The WVTR and Dk data obtained are within the range of values reported for commercial wound dressings. Tensile tests demonstrated that the nanocomposites displayed a good balance between elasticity, strength, and flexibility under both dry and simulated body fluid (SBF) environments. The flexibility increased in a moist atmosphere due to the plasticization effect of absorbed water. The nanocomposites also exhibited significantly enhanced dynamic mechanical performance (storage modulus and glass transition temperature) than neat CO under different humidity conditions. The antibacterial activity of the films against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus bacteria was investigated in the presence and the absence of UV light. The biocide effect increased progressively with the CS-ZnO content and was systematically stronger against Gram-positive cells. Composites with nanoparticle loading ≤5.0 wt % exhibited very good in vitro cytocompatibility and enabled a faster wound healing than neat CO and control gauze, hence showing great potential to be applied as antibacterial

  5. Recent advances in ZnO nanostructures and thin films for biosensor applications: Review

    International Nuclear Information System (INIS)

    Arya, Sunil K.; Saha, Shibu; Ramirez-Vick, Jaime E.; Gupta, Vinay; Bhansali, Shekhar; Singh, Surinder P.

    2012-01-01

    Graphical abstract: ZnO nanostructures have shown binding of biomolecules in desired orientation with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, their compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes them suitable candidate for future small integrated biosensor devices. This review highlights various approaches to synthesize ZnO nanostructures and thin films, and their applications in biosensor technology. Highlights: ► This review highlights various approaches to synthesize ZnO nanostructures and thin films. ► Article highlights the importance of ZnO nanostructures as biosensor matrix. ► Article highlights the advances in various biosensors based on ZnO nanostructures. ► Article describes the potential of ZnO based biosensor for new generation healthcare devices. - Abstract: Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review

  6. Polyelectrolyte-assisted preparation and characterization of nanostructured ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Shijun

    2005-05-15

    The present work focuses on the synthesis and characterization of nanostructured ZnO thin films onto silicon wafers modified by self-assembled-monolayers via chemical bath deposition. Two precursor solutions were designed and used for the film deposition, in which two different polymers were introduced respectively to control the growth of the ZnO colloidal particles in solution. ZnO films were deposited from an aqueous solution containing zinc salt and hexamethylenetetramine (HMTA) in the presence of a graft-copolymer (P (MAA{sub 0.50}-co(MAA-EO{sub 20}){sub 0.50}){sub 70}). A film-formation-diagram was established based on the results obtained by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which describes the influence of the concentration of HMTA and copolymer on the ZnO film formation. According to the film morphology, film formation can be classified into three categories: (a) island-like films, (b) uniform films and (c) canyon-like films. The ZnO films annealed at temperatures of 450 C, 500 C, 600 C and 700 C were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). After annealing, the films are polycrystalline ZnO with wurtzite structure. XRD measurements indicate that with increasing annealing temperature, the average grain size increases accordingly and the crystallinity of the films is improved. Upon heating to 600 C, the ZnO films exhibit preferred orientation with c-axis normal to substrate, whereas the films annealed at 700 C even show a more explicit texture. By annealing at temperatures above 600 C the ZnO film reacts with the substrate to form an interfacial layer of Zn{sub 2}SiO{sub 4}, which grows thicker at elevated annealing temperatures. The ZnO films annealed at 600 C and 700 C show strong UV emission. Another non-aqueous solution system for ZnO thin film deposition was established, in which 2- propanol was used as a solvent and Zn(CH3COO){sub 2}.2H{sub 2}O as well as NaOH as reactants

  7. Superhydrophobic Ag decorated ZnO nanostructured thin film as effective surface enhanced Raman scattering substrates

    Science.gov (United States)

    Jayram, Naidu Dhanpal; Sonia, S.; Poongodi, S.; Kumar, P. Suresh; Masuda, Yoshitake; Mangalaraj, D.; Ponpandian, N.; Viswanathan, C.

    2015-11-01

    The present work is an attempt to overcome the challenges in the fabrication of super hydrophobic silver decorated zinc oxide (ZnO) nanostructure thin films via thermal evaporation process. The ZnO nanowire thin films are prepared without any surface modification and show super hydrophobic nature with a contact angle of 163°. Silver is further deposited onto the ZnO nanowire to obtain nanoworm morphology. Silver decorated ZnO (Ag@ZnO) thin films are used as substrates for surface enhanced Raman spectroscopy (SERS) studies. The formation of randomly arranged nanowire and silver decorated nanoworm structure is confirmed using FESEM, HR-TEM and AFM analysis. Crystallinity and existence of Ag on ZnO are confirmed using XRD and XPS studies. A detailed growth mechanism is discussed for the formation of the nanowires from nanobeads based on various deposition times. The prepared SERS substrate reveals a reproducible enhancement of 3.082 × 107 M for Rhodamine 6G dye (R6G) for 10-10 molar concentration per liter. A higher order of SERS spectra is obtained for a contact angle of 155°. Thus the obtained thin films show the superhydrophobic nature with a highly enhanced Raman spectrum and act as SERS substrates. The present nanoworm morphology shows a new pathway for the construction of semiconductor thin films for plasmonic studies and challenges the orderly arranged ZnO nanorods, wires and other nano structure substrates used in SERS studies.

  8. Morphology and Structure of ZnO Films Synthesized by Off-Axis Sputtering Deposition

    Science.gov (United States)

    Zhu, Shen; Su, C.-H.; Lehoczky, S. L.

    1999-01-01

    ZnO is a wide-band-gap oxide material that has many applications. A new potential application of ZnO material is for light emitting devices since its structure and electrical properties are similar to that of the GaN material (a blue laser candidate). It also is a good substrate for fabricating GaN-based devices. Off-axis sputtering technique has revealed great potential in synthesizing excellent oxide materials because the negative ion bombardment is greatly reduced when adatoms condense on substrates. The surface of films grown by off-axis sputtering will be much smoother than that produced in a regular sputtering configuration. A growth mechanism is studied by investigating the morphology and structure of ZnO films under different growth conditions and orientations. ZnO films are deposited on (0001) sapphire and quartz substrates by off- axis sputtering deposition at various oxygen/argon mixture ratios and pressures and at different temperatures. All films reveal highly textured structures on quartz substrates and epitaxial growth on sapphire substrates. Two off-axis configurations, vertical and horizontal orientations are conducted to study the process of film growth, surface morphology, and film structure. X-ray diffraction, scanning probe microscopy, and electrical measurements are used to characterize these films. Detailed results will be discussed in the presentation. Keywords: ZnO, Photonic material, Off-axis sputtering, Growth mechanism

  9. Preparation and characterization of ALD deposited ZnO thin films studied for gas sensors

    International Nuclear Information System (INIS)

    Boyadjiev, S.I.; Georgieva, V.; Yordanov, R.; Raicheva, Z.; Szilágyi, I.M.

    2016-01-01

    Highlights: • For the first time the gas sensing towards NO 2 of very thin ALD ZnO films is studied. • The very thin ALD ZnO films showed excellent sensitivity to NO 2 at room temperature. • These very thin film ZnO-based QCM sensors very well register even low concentrations. • The sensors have fully reversible sorption and are able to be recovered in short time. • Described fast and cost-effective ALD deposition of ZnO thin films for QCM gas sensor. - Abstract: Applying atomic layer deposition (ALD), very thin zinc oxide (ZnO) films were deposited on quartz resonators, and their gas sensing properties were studied using the quartz crystal microbalance (QCM) method. The gas sensing of the ZnO films to NO 2 was tested in the concentration interval between 10 and 5000 ppm. On the basis of registered frequency change of the QCM, for each concentration the sorbed mass was calculated. Further characterization of the films was carried out by various techniques, i.e. by SEM-EDS, XRD, ellipsometry, and FTIR spectroscopy. Although being very thin, the films were gas sensitive to NO 2 already at room temperature and could register very well as low concentrations as 100 ppm, while the sorption was fully reversible. Our results for very thin ALD ZnO films show that the described fast, simple and cost-effective technology could be implemented for producing gas sensors working at room temperature and being capable to detect in real time low concentrations of NO 2 .

  10. Preparation and characterization of ALD deposited ZnO thin films studied for gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyadjiev, S.I., E-mail: boiajiev@gmail.com [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Georgieva, V. [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Yordanov, R. [Department of Microelectronics, Technical University of Sofia, 8 Kliment Ohridski Blvd., 1756 Sofia (Bulgaria); Raicheva, Z. [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Szilágyi, I.M. [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary)

    2016-11-30

    Highlights: • For the first time the gas sensing towards NO{sub 2} of very thin ALD ZnO films is studied. • The very thin ALD ZnO films showed excellent sensitivity to NO{sub 2} at room temperature. • These very thin film ZnO-based QCM sensors very well register even low concentrations. • The sensors have fully reversible sorption and are able to be recovered in short time. • Described fast and cost-effective ALD deposition of ZnO thin films for QCM gas sensor. - Abstract: Applying atomic layer deposition (ALD), very thin zinc oxide (ZnO) films were deposited on quartz resonators, and their gas sensing properties were studied using the quartz crystal microbalance (QCM) method. The gas sensing of the ZnO films to NO{sub 2} was tested in the concentration interval between 10 and 5000 ppm. On the basis of registered frequency change of the QCM, for each concentration the sorbed mass was calculated. Further characterization of the films was carried out by various techniques, i.e. by SEM-EDS, XRD, ellipsometry, and FTIR spectroscopy. Although being very thin, the films were gas sensitive to NO{sub 2} already at room temperature and could register very well as low concentrations as 100 ppm, while the sorption was fully reversible. Our results for very thin ALD ZnO films show that the described fast, simple and cost-effective technology could be implemented for producing gas sensors working at room temperature and being capable to detect in real time low concentrations of NO{sub 2}.

  11. Easy Formation of Nanodisk-Dendritic ZnO Film via Controlled Electrodeposition Process

    Directory of Open Access Journals (Sweden)

    Nur Azimah Abd Samad

    2015-01-01

    Full Text Available A facile electrodeposition synthesis was introduced to prepare the nanodisk-dendritic ZnO film using a mixture solution of zinc chloride (ZnCl2 with potassium chloride (KCl that acted as a directing agent. This study aims to determine the best photoelectrochemical response for solar-induced water splitting. Based on our results obtained, it was found that an average diagonal of nanodisk was approximately 1.70 µm with the thickness of ≈150 nm that was successfully grown on the surface of substrate. The photocatalytic and photoelectrochemical responses of the resultant wurtzite type based-nanodisk-dendrite ZnO film as compared to the as-prepared ZnO film were monitored and evaluated. A photocurrent density of 19.87 mA/cm2 under ultraviolet rays and 14.05 mA/cm2 under visible light (500 nm was recorded for the newly developed nanodisk-dendritic ZnO thin film. It was believed that nanodisk-dendritic ZnO film can harvest more incident photons from the illumination to generate more photoinduced charge carriers to trigger the photocatalytic and photoelectrochemical reactions. Moreover, strong light scattering effects and high specific surface area of 2D nanostructures aid in the incident light absorption from any direction.

  12. DFT calculations on electronic properties of ZnO thin films deposited by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Cordeiro, J.M.; Reynoso, V.C.; Azevedo, D.H.M. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil)

    2016-07-01

    Full text: Introduction - Thin films of Zinc oxide (ZnO) has a wide range of technological applications, as transparent conducting electrodes in solar cells, flat panel displays, and sensors, for example. More recently applications in optoelectronics, like light emitter diodes and laser diodes, due to its large band gap, are been explored. Studies of ZnO thin films are important for these applications. Methodology - In this study thin films of ZnO have been deposited by spray pyrolysis on glass substrate. The films were characterized by XRD and UV-VIS techniques and the electronic properties as a function of the film thickness have been investigated by DFT calculations with B3LYP hybrid potential implemented in the CRYSTAL09 code. Results - The diffractograms obtained for the ZnO thin films as a function of the thickness are shown. The films exhibit a hexagonal wurtzite structure with preferred c-axis orientation in (002) direction of ZnO crystal. A quantum mechanical approach based on the periodic Density Functional Theory (DFT), with B3LYP hybrid potential was used to investigate the electronic structure of the films as a function of the thickness. The CRYSTAL09 code has been used for the calculations on the wurtzite hexagonal structure of ZnO - spatial group P63mc. For optimizing the geometry of the pure ZnO crystal, the experimental lattice parameters were got as follows: a= 0.325 nm, b= 0.325 nm, c= 0.5207 nm with c/a= 1.602. Considering to the calculations of the band structure, it is suggested that the semiconducting properties of ZnO arises from the overlapping of the 4s orbital of the conducting band of Zn and the 2p orbital of the top of valence band of O. Conclusions - The structure of ZnO thin film deposited on glass substrate present preferential orientation in (002) direction. Variation in the optical properties as a function of the film thickness was observed. The band gap energy was determined from optical analysis to be ∼ 3.27 eV. The refractive

  13. Properties and characterization of bionanocomposite films prepared with various biopolymers and ZnO nanoparticles.

    Science.gov (United States)

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-06-15

    This study was aimed to develop biopolymer based antimicrobial films for active food packaging and to reduce environmental pollution caused by accumulation of synthetic packaging. The ZnO NPs were incorporated as antimicrobials into different biopolymers such as agar, carrageenan and CMC. Solvent casting method was performed to prepare active nanocomposite films. Methods such as FE-SEM, FT-IR and XRD were used to characterize resulting films. Physical, mechanical, thermal and antimicrobial properties were also examined. Remarkable surface morphological differences were observed between control and nanocomposite films. The crystallinity of ZnO was confirmed by XRD analysis. The addition of ZnO NPs increased color, UV barrier, moisture content, hydrophobicity, elongation and thermal stability of the films, while decreased WVP, tensile strength and elastic modulus. ZnO NPs impregnated films inhibited growth of L. monocytogenes and E. coli. So these newly prepared nanocomposite films can be used as active packaging film to extend shelf-life of food. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. The effect of post-annealing on surface acoustic wave devices based on ZnO thin films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Phan, Duy-Thach; Chung, Gwiy-Sang

    2011-01-01

    Zinc oxide (ZnO) thin films were deposited on unheated silicon substrates via radio frequency (RF) magnetron sputtering, and the post-deposition annealing of the ZnO thin films was performed at 400 deg. C, 600 deg. C, 800 deg. C, and 1000 deg. C. The characteristics of the thin films were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The films were then used to fabricate surface acoustic wave (SAW) resonators. The effects of post-annealing on the SAW devices are discussed in this work. Resulting in the 600 deg. C is determined as optimal annealing temperature for SAW devices. At 400 deg. C, the microvoids exit between the grains yield large root mean square (RMS) surface roughness and higher insertion losses in SAW devices. The highest RMS surface roughness, crack and residual stress cause a reduction of surface velocity (about 40 m/s) and increase dramatically insertion loss at 1000 deg. C. The SAW devices response becomes very weak at this temperature, the electromechanical coupling coefficient (k 2 ) of ZnO film decrease from 3.8% at 600 deg. C to 1.49% at 1000 deg. C.

  15. Analysis of Li-related defects in ZnO thin films influenced by ...

    Indian Academy of Sciences (India)

    Li-doped ZnO thin films were grown on quartz substrates by radio frequency magnetron sputtering and in situ annealing under O2 or Ar ambient. Li-related defects in ZnO films strongly depend on the annealing ambient. AFM and XRD indicated that ZnO films possessed a good crystallinity with -axis orientation, uniform ...

  16. An Enhanced UV-Vis-NIR an d Flexible Photodetector Based on Electrospun ZnO Nanowire Array/PbS Quantum Dots Film Heterostructure.

    Science.gov (United States)

    Zheng, Zhi; Gan, Lin; Zhang, Jianbing; Zhuge, Fuwei; Zhai, Tianyou

    2017-03-01

    ZnO nanostructure-based photodetectors have a wide applications in many aspects, however, the response range of which are mainly restricted in the UV region dictated by its bandgap. Herein, UV-vis-NIR sensitive ZnO photodetectors consisting of ZnO nanowires (NW) array/PbS quantum dots (QDs) heterostructures are fabricated through modified electrospining method and an exchanging process. Besides wider response region compared to pure ZnO NWs based photodetectors, the heterostructures based photodetectors have faster response and recovery speed in UV range. Moreover, such photodetectors demonstrate good flexibility as well, which maintain almost constant performances under extreme (up to 180°) and repeat (up to 200 cycles) bending conditions in UV-vis-NIR range. Finally, this strategy is further verified on other kinds of 1D nanowires and 0D QDs, and similar enhancement on the performance of corresponding photodetecetors can be acquired, evidencing the universality of this strategy.

  17. An integrated optic ethanol vapor sensor based on a silicon-on-insulator microring resonator coated with a porous ZnO film.

    Science.gov (United States)

    Yebo, Nebiyu A; Lommens, Petra; Hens, Zeger; Baets, Roel

    2010-05-24

    Optical structures fabricated on silicon-on-insulator technology provide a convenient platform for the implementation of highly compact, versatile and low cost devices. In this work, we demonstrate the promise of this technology for integrated low power and low cost optical gas sensing. A room temperature ethanol vapor sensor is demonstrated using a ZnO nanoparticle film as a coating on an SOI micro-ring resonator of 5 microm in radius. The local coating on the ring resonators is prepared from colloidal suspensions of ZnO nanoparticles of around 3 nm diameter. The porous nature of the coating provides a large surface area for gas adsorption. The ZnO refractive index change upon vapor adsorption shifts the microring resonance through evanescent field interaction. Ethanol vapor concentrations down to 100 ppm are detected with this sensing configuration and a detection limit below 25 ppm is estimated.

  18. Properties of ZnO thin films deposited by chemical bath deposition and post annealed

    International Nuclear Information System (INIS)

    Ouerfelli, J; Regragui, M; Morsli, M; Djeteli, G; Jondo, K; Amory, C; Tchangbedji, G; Napo, K; Bernede, J C

    2006-01-01

    ZnO thin films deposited by chemical bath deposition (CBD) have been studied using x-ray diffraction, scanning electron microscopy, electron microprobe analysis and electrical measurements. The optimum CBD conditions for achieving structured, but adherent, ZnO films are as follows. Zinc acetate (0.0188 mol l -1 ) and ethylenediamine (0.03 mol l -1 ) are mixed. The pH of the bath is raised by addition of a base (0.5 mol l -1 , NaOH). The solution is maintained at a temperature between 60 deg. C and 65 0 C, while the bath is continuously stirred. We proceeded to anneal in room air for 30 min at 300 deg. C and under vacuum for 2 h at 300 deg. C. All the films obtained are nearly stoichiometric ZnO films crystallized in the usual hexagonal structure. As expected the films are rough and porous. The main difference between the two ZnO film families is their conductivity. The conductivity of the films annealed under vacuum is five orders of magnitude higher than that of those annealed in room air

  19. A high power ZnO thin film piezoelectric generator

    Science.gov (United States)

    Qin, Weiwei; Li, Tao; Li, Yutong; Qiu, Junwen; Ma, Xianjun; Chen, Xiaoqiang; Hu, Xuefeng; Zhang, Wei

    2016-02-01

    A highly efficient and large area piezoelectric ZnO thin film nanogenerator (NG) was fabricated. The ZnO thin film was deposited onto a Si substrate by pulsed laser ablation at a substrate temperature of 500 °C. The deposited ZnO film exhibited a preferred c-axis orientation and a high piezoelectric value of 49.7 pm/V characterized using Piezoelectric Force Microscopy (PFM). Thin films of ZnO were patterned into rectangular power sources with dimensions of 0.5 × 0.5 cm2 with metallic top and bottom electrodes constructed via conventional semiconductor lithographic patterning processes. The NG units were subjected to periodic bending/unbending motions produced by mechanical impingement at a fixed frequency of 100 Hz at a pressure of 0.4 kg/cm2. The output electrical voltage, current density, and power density generated by one ZnO NG were recorded. Values of ∼95 mV, 35 μA cm-2 and 5.1 mW cm-2 were recorded. The level of power density is typical to that produced by a PZT NG on a flexible substrate. Higher energy NG sources can be easily created by adding more power units either in parallel or in series. The thin film ZnO NG technique is highly adaptable with current semiconductor processes, and as such, is easily integrated with signal collecting circuits that are compatible with mass production. A typical application would be using the power harvested from irregular human foot motions to either to operate blue LEDs directly or to drive a sensor network node in mille-power level without any external electric source and circuits.

  20. Transient behaviors of ZnO thin films on a transparent, flexible polyethylene terephthalate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Jun [Department of Nano-Physics, Gachon University, 1342 Seongnamdaero, Sujeong-gu, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of); Lee, Ho Seok [Department of Materials Science and Engineering, Korea University, 5-1 Anam-dong, Seongbuk-gu, Seoul 136-713 (Korea, Republic of); Noh, Jin-Seo, E-mail: jinseonoh@gachon.ac.kr [Department of Nano-Physics, Gachon University, 1342 Seongnamdaero, Sujeong-gu, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)

    2016-03-31

    Thickness-dependent electrical, structural, and optical properties of zinc oxide (ZnO) thin films on polyethylene terephthalate (PET) substrates have been investigated in the very thin thickness range of 20 to 120 nm. In this thickness range, the electrical resistance of ZnO film increased with an increase in film thickness. This unusual transition behavior was explained in terms of structural evolution from Zn-phase-incorporating non-crystalline ZnO to hexagonal-structured ZnO. A critical thickness for the full development of hexagonal ZnO crystal was estimated at approximately 80 nm in this study. ZnO thin films on PET substrates exhibit a high optical transmittance of > 70% and good endurance to bending cycles over the measured thickness range. The results of this study indicate that a trade-off should be sought between structural, electrical, optical, and mechanical properties for practical applications of very thin ZnO films on organic substrates. - Highlights: • Very thin ZnO films were sputter-deposited on the PET substrate. • The ZnO film resistance increases with an increase in film thickness until saturation. • Hexagonal crystal structures gradually develop with increasing film thickness. • A Zn phase appears in a 20-nm-thick ZnO film. • ZnO films show high optical transmittance of > 80% and good endurance to bending.

  1. Transient behaviors of ZnO thin films on a transparent, flexible polyethylene terephthalate substrate

    International Nuclear Information System (INIS)

    Kim, Yong Jun; Lee, Ho Seok; Noh, Jin-Seo

    2016-01-01

    Thickness-dependent electrical, structural, and optical properties of zinc oxide (ZnO) thin films on polyethylene terephthalate (PET) substrates have been investigated in the very thin thickness range of 20 to 120 nm. In this thickness range, the electrical resistance of ZnO film increased with an increase in film thickness. This unusual transition behavior was explained in terms of structural evolution from Zn-phase-incorporating non-crystalline ZnO to hexagonal-structured ZnO. A critical thickness for the full development of hexagonal ZnO crystal was estimated at approximately 80 nm in this study. ZnO thin films on PET substrates exhibit a high optical transmittance of > 70% and good endurance to bending cycles over the measured thickness range. The results of this study indicate that a trade-off should be sought between structural, electrical, optical, and mechanical properties for practical applications of very thin ZnO films on organic substrates. - Highlights: • Very thin ZnO films were sputter-deposited on the PET substrate. • The ZnO film resistance increases with an increase in film thickness until saturation. • Hexagonal crystal structures gradually develop with increasing film thickness. • A Zn phase appears in a 20-nm-thick ZnO film. • ZnO films show high optical transmittance of > 80% and good endurance to bending.

  2. Single-Crystal Mesoporous ZnO Thin Films Composed of Nanowalls

    KAUST Repository

    Wang, Xudong

    2009-02-05

    This paper presents a controlled, large scale fabrication of mesoporous ZnO thin films. The entire ZnO mesoporous film is one piece of a single crystal, while high porosity made of nanowalls is present. The growth mechanism was proposed in comparison with the growth of ZnO nanowires. The ZnO mesoporous film was successfully applied as a gas sensor. The fabrication and growth analysis of the mesoporous ZnO thin film gi ve general guidance for the controlled growth of nanostructures. It also pro vides a unique structure with a superhigh surface-to-volume ratio for surface-related applications. © 2009 American Chemical Society.

  3. Nanostructured ZnO films: A study of molecular influence on transport properties by impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sappia, Luciano D.; Trujillo, Matias R. [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Lorite, Israel [Division of Superconductivity and Magnetism, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig (Germany); Madrid, Rossana E., E-mail: rmadrid@herrera.unt.edu.ar [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Tirado, Monica [NanoProject and Laboratorio de Nanomateriales y Propiedades Dieléctricas, Departamento de Física, Universidad Nacional de Tucumán, Avenida Independencia 1800, Tucumán (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); and others

    2015-10-15

    Graphical abstract: - Highlights: • We study electrical transport in nanostructured ZnO films by impedance spectroscopy. • Bioaggregates on the surface produce strong changes in film transport properties. • This behavior is explained by modeling data with RC parallel circuits. • Electrical responses of ZnO films to aggregates are promising for biosensing. - Abstract: Nanomaterials based on ZnO have been used to build glucose sensors due to its high isoelectric point, which is important when a protein like Glucose Oxidase (GOx) is attached to a surface. It also creates a biologically friendly environment to preserve the activity of the enzyme. In this work we study the electrical transport properties of ZnO thin films (TFs) and single crystals (SC) in contact with different solutions by using impedance spectroscopy. We have found that the composition of the liquid, by means of the charge of the ions, produces strong changes in the transport properties of the TF. The enzyme GOx and phosphate buffer solutions have the major effect in the conduction through the films, which can be explained by the entrapment of carriers at the grain boundaries of the TFs. These results can help to design a new concept in glucose biosensing.

  4. Mott-Schottky analysis of thin ZnO films

    International Nuclear Information System (INIS)

    Windisch, Charles F. Jr.; Exarhos, Gregory J.

    2000-01-01

    Thin ZnO films, both native and doped with secondary metal ions, have been prepared by sputter deposition and also by casting from solutions containing a range of precursor salts. The conductivity and infrared reflectivity of these films are subsequently enhanced chemically following treatment in H 2 gas at 400 degree sign C or by cathodic electrochemical treatment in a neutral (pH=7) phosphate buffer solution. While Hall-type measurements usually are used to evaluate the electrical properties of such films, the present study investigated whether a conventional Mott-Schottky analysis could be used to monitor the change in concentration of free carriers in these films before and after chemical and electrochemical reduction. The Mott-Schottky approach would be particularly appropriate for electrochemically modified films since the measurements could be made in the same electrolyte used for the post-deposition electrochemical processing. Results of studies on sputtered pure ZnO films in ferricyanide solution were promising. Mott-Schottky plots were linear and gave free carrier concentrations typical for undoped semiconductors. Film thicknesses estimated from the Mott-Schottky data were also reasonably close to thicknesses calculated from reflectance measurements. Studies on solution-deposited films were less successful. Mott-Schottky plots were nonlinear, apparently due to film porosity. A combination of dc polarization and atomic force microscopy measurements confirmed this conclusion. The results suggest that Mott-Schottky analysis would be suitable for characterizing solution-deposited ZnO films only after extensive modeling was performed to incorporate the effects of film porosity on the characteristics of the space-charge region of the semiconductor. (c) 2000 American Vacuum Society

  5. Hydrothermal Growth of Quasi-Monocrystal ZnO Thin Films and Their Application in Ultraviolet Photodetectors

    Directory of Open Access Journals (Sweden)

    Yung-Chun Tu

    2015-01-01

    Full Text Available Quasi-monocrystal ZnO film grown using the hydrothermal growth method is used for the fabrication of Cu2O/ZnO heterojunction (HJ ultraviolet photodetectors (UV-PDs. The HJ was formed via the sputtering deposition of p-type Cu2O onto hydrothermally grown ZnO film (HTG-ZnO-film. The effect of annealing temperature in the nitrogen ambient on the photoluminescence spectra of the synthesized ZnO film was studied. The optoelectronic properties of Cu2O/ZnO film with various Cu2O thicknesses (250–750 nm under UV light (365 nm; intensity: 3 mW/cm2 were determined. The UV sensitivity of the HTG-ZnO-film-based UV-PDs and the sputtered ZnO-film-based UV-PDs were 55.6-fold (SHTG and 8.8-fold (Ssputter, respectively. The significant gain in sensitivity (SHTG/Ssputter = 630% of the proposed ZnO-film-based device compared to that for the device based on sputtered film can be attributed to the improved photoelectric properties of quasi-monocrystal ZnO film.

  6. Effect of Al doping on performance of ZnO thin film transistors

    Science.gov (United States)

    Dong, Junchen; Han, Dedong; Li, Huijin; Yu, Wen; Zhang, Shendong; Zhang, Xing; Wang, Yi

    2018-03-01

    In this work, we investigate the Aluminum-doped Zinc Oxide (AZO) thin films and their feasibility as the active layer for thin film transistors (TFTs). A comparison on performance is made between the AZO TFTs and ZnO TFTs. The electrical properties such as saturation mobility, subthreshold swing, and on-to-off current ratio are improved when AZO is utilized as the active layer. Oxygen component of the thin film materials indicates that Al is the suppressor for oxygen defect in active layer, which improves the subthreshold swing. Moreover, based on band structure analyzation, we observe that the carrier concentration of AZO is higher than ZnO, leading to the enhancement of saturation mobility. The microstructure of the thin films convey that the AZO films exhibit much smaller grain boundaries than ZnO films, which results in the lower off-state current and higher on-to-off current ratio of AZO TFTs. The AZO thin films show huge potential to be the active layer of TFTs.

  7. Hydrothermal Growth and Application of ZnO Nanowire Films with ZnO and TiO2Buffer Layers in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jiang Chunhua

    2009-01-01

    Full Text Available Abstract This paper reports the effects of the seed layers prepared by spin-coating and dip-coating methods on the morphology and density of ZnO nanowire arrays, thus on the performance of ZnO nanowire-based dye-sensitized solar cells (DSSCs. The nanowire films with the thick ZnO buffer layer (~0.8–1 μm thick can improve the open circuit voltage of the DSSCs through suppressing carrier recombination, however, and cause the decrease of dye loading absorbed on ZnO nanowires. In order to further investigate the effect of TiO2buffer layer on the performance of ZnO nanowire-based DSSCs, compared with the ZnO nanowire-based DSSCs without a compact TiO2buffer layer, the photovoltaic conversion efficiency and open circuit voltage of the ZnO DSSCs with the compact TiO2layer (~50 nm thick were improved by 3.9–12.5 and 2.4–41.7%, respectively. This can be attributed to the introduction of the compact TiO2layer prepared by sputtering method, which effectively suppressed carrier recombination occurring across both the film–electrolyte interface and the substrate–electrolyte interface.

  8. Development of novel control system to grow ZnO thin films by reactive evaporation

    Directory of Open Access Journals (Sweden)

    Gerardo Gordillo

    2016-07-01

    Full Text Available This work describes a novel system implemented to grow ZnO thin films by plasma assisted reactive evaporation with adequate properties to be used in the fabrication of photovoltaic devices with different architectures. The innovative aspect includes both an improved design of the reactor used to activate the chemical reaction that leads to the formation of the ZnO compound as an electronic system developed using the virtual instrumentation concept. ZnO thin films with excellent opto-electrical properties were prepared in a reproducible way, controlling the deposition system through a virtual instrument (VI with facilities to control the amount of evaporated zinc involved in the process that gives rise to the formation of ZnO, by means of the incorporation of PID (proportional integral differential and PWM (pulse width modulation control algorithms. The effectiveness and reliability of the developed system was verified by obtaining with good reproducibility thin films of n+-ZnO and i-ZnO grown sequentially in situ with thicknesses and resistivities suitable for use as window layers in chalcopyrite based thin film solar cells.

  9. Structural, optical, and LED characteristics of ZnO and Al doped ZnO thin films

    Science.gov (United States)

    Sandeep, K. M.; Bhat, Shreesha; Dharmaprakash, S. M.

    2017-05-01

    ZnO (pristine) and Al doped ZnO (AZO) films were prepared using sol-gel spin coating method. The XRD analysis showed the enhanced compressive stress in AZO film. The presence of extended states below the conduction band edge in AZO accounts for the redshift in optical bandgap. The PL spectra of AZO showed significant blue emission due to the carrier recombination from defect states. The TRPL curves showed the dominant DAP recombination in ZnO film, whereas defect related recombination in Al doped ZnO film. Color parameters viz: the dominant wavelength, color coordinates (x,y), color purity, luminous efficiency and correlated color temperature (CCT) of ZnO and AZO films are calculated using 1931 (CIE) diagram. Further, a strong blue emission with color purity more than 96% is observed in both the films. The enhanced blue emission in AZO significantly increased the luminous efficiency (22.8%) compared to ZnO film (10.8%). The prepared films may be used as blue phosphors in white light generation.

  10. Ethanol gas sensing properties of Al2 O3-doped ZnO thick film ...

    Indian Academy of Sciences (India)

    The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ...

  11. Influence of pH on ZnO nanocrystalline thin films prepared by sol ...

    Indian Academy of Sciences (India)

    Abstract. ZnO nanocrystalline thin films have been prepared on glass substrates by sol–gel dip coating method. ZnO thin films have been coated at room temperature and at four different pH values of 4, 6, 8 and 10. The. X-ray diffraction pattern showed that ZnO nanocrystalline thin films are of hexagonal structure and the ...

  12. Growth of ZnO thin films on GaAs by pulsed laser deposition

    NARCIS (Netherlands)

    Craciun, V.; Elders, J.; Gardeniers, Johannes G.E.; Geretovsky, J.; Boyd, Ian W.

    1995-01-01

    ZnO thin films have been grown on GaAs substrates using the pulsed laser deposition technique with or without a photodeposited SiO2 buffer layer. The presence of the SiO2 layer has a beneficial effect on the crystalline quality of the grown ZnO films. Highly c-axis oriented ZnO films having a full

  13. Optoelectronic properties of doped hydrothermal ZnO thin films

    KAUST Repository

    Mughal, Asad J.

    2017-03-10

    Group III impurity doped ZnO thin films were deposited on MgAl2O3 substrates using a simple low temperature two-step deposition method involving atomic layer deposition and hydrothermal epitaxy. Films with varying concentrations of either Al, Ga, or In were evaluated for their optoelectronic properties. Inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of dopants within the ZnO films. While Al and Ga-doped films showed linear incorporation rates with the addition of precursors salts in the hydrothermal growth solution, In-doped films were shown to saturate at relatively low concentrations. It was found that Ga-doped films showed the best performance in terms of electrical resistivity and optical absorbance when compared to those doped with In or Al, with a resistivity as low as 1.9 mΩ cm and an optical absorption coefficient of 441 cm−1 at 450 nm.

  14. Some physical properties of ZnO thin films prepared by RF sputtering technique

    Energy Technology Data Exchange (ETDEWEB)

    Ekem, N.; Korkmaz, S.; Pat, S.; Cetin, E.N.; Ozmumcu, M. [Eskisehir Osmangazi University, Physics Department, 26480 Meselik, Eskisehir (Turkey); Balbag, M.Z. [Eskisehir Osmangazi University, Education Faculty, Physics Education, 26480 Meselik, Eskisehir (Turkey)

    2009-06-15

    ZnO thin films were deposited with RF sputtering using pure Zn target. In order to generate oxidation process of Zn, Ar:O{sub 2} gas mixing in (9:1), (7:3) and (5:5) ratios of Ar:O{sub 2} was used. To characterize ZnO thin films thickness and transparency were measured using optical method, and refractive index and band gap energies were calculated. Electrical conductivity of the ZnO thin films was also determined. AFM images were used to determine surface morphology of produced ZnO thin films. (author)

  15. Development of glucose biosensor based on ZnO nanoparticles film and glucose oxidase-immobilized eggshell membrane

    Directory of Open Access Journals (Sweden)

    Bohari Noor Aini

    2015-06-01

    Full Text Available A novel electrochemical glucose biosensor was developed by depositing an ionic liquid (IL (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; [EMIM][Otf], ZnO nanoparticles (ZnONPs and eggshell membrane (ESM on a modified glassy carbon electrode (GCE for determination of glucose. Glucose oxidase (GOx was covalently immobilized on eggshell membrane with glutaraldehyde as a cross-linker. Methylene blue was used as a redox indicator to enhance the electron transfer capacity and to ensure stability of both the oxidized and reduced forms in the reaction of enzyme and substrate. The morphological characteristics of microstructures eggshell membranes, chitosan, GOx/ESM, GOx/ZnONPs/IL/ESM and GOx/ZnONPs-IL/CHIT were observed using scanning electron microscopy (SEM. The effects of scan rate, time and pH on the response of glucose biosensors were studied in detail. Under optimal conditions (pH 6.5, 50 s, cyclic voltammetry showed different glucose concentrations on the range of 1 × 10−12 to 0.6 M, with a detection limit of 1 × 10−13 M. The GOx/ZnONPs/IL/ESM was found to be more sensitive as compared to GOx/ZnONPs-IL/CHIT. This developed glucose biosensor detection approach has several advantages such as fast, simple and convenient method, sensitivity, low cost, eco-friendly, low concentrations and remarkable catalytic activities of current signals during glucose reaction.

  16. Structural and optical properties of ZnO thin films prepared by laser ...

    Indian Academy of Sciences (India)

    2017-06-09

    Jun 9, 2017 ... Abstract. ZnO thin films were deposited on ITO/glass substrates by pulsed laser deposition (PLD) using two different kinds of targets. One of the targets was made of pure ZnO powder and the other one consisted of a mixture of ZnO powder with cyanoacrylate glue. The structural and morphological ...

  17. Efficient solution route to transparent ZnO semiconductor films using colloidal nanocrystals

    Directory of Open Access Journals (Sweden)

    Satoshi Suehiro

    2016-09-01

    Full Text Available ZnO nanocrystals (NCs were synthesized by heating Zn (II acetylacetonate in oleic acid/oleylamine in the presence of 1,2-hexadecanediol at 220 °C. Transmission electron microscopy (TEM and dynamic light scattering (DLS measurements revealed the formation of monodispersed ZnO NCs of ca. 7 nm. ZnO NC assembled films were fabricated on a glass substrate by deposition with the colloidal ZnO NCs dispersed in toluene. The film composed of the NCs showed good optical transparency in the visible to near-infrared region. A device coupling the ZnO NC film with a p-type Cu2ZnSnS4 (CZTS NC film exhibited an obvious diode-like current–voltage behavior. The results suggest that the transparent ZnO film has a potentiality to be used for an n-type window layer in some optoelectronic applications.

  18. Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reeja-Jayan, B. [Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States); De la Rosa, E. [Centro de Investigacion en Optica, Loma del Bosque 115 Col. Lomas del Campestre C.P. 37150 Leon, Gto. Mexico (Mexico); Ortiz-Mendez, U. [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reyes-Betanzo, C. [Instituto Nacional de Astrofisica Optica y Electronica, Calle Luis Enrique Erro No. 1, Santa Maria Tonanzintla, Puebla. Apdo. Postal 51 y 216, C.P. 72000 Puebla (Mexico); Cruz-Silva, R. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, UAEM. Av. Universidad 1001, Col. Chamilpa, CP 62210 Cuernavaca, Mor. (Mexico); Jose-Yacaman, M. [Physics and Astronomy Department University of Texas at San Antonio 1604 campus San Antonio, TX 78249 (United States)

    2010-03-15

    In this work patterned ZnO films were prepared at room-temperature by deposition of {approx}5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation ({lambda} = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

  19. Characterization of photovoltage evolution of ZnO films using a scanning Kelvin probe system

    International Nuclear Information System (INIS)

    Li, W.; Wu, C.W.; Qin, W.G.; Wang, G.C.; Lu, S.Q.; Dong, X.J.; Dong, H.B.; Sun, Q.L.

    2009-01-01

    Work function (WF) and surface photovoltage evolution of films can be measured using the Kelvin probe technique, and further analysis of the photoelectronic behavior can provide information on the energy level structure. In this paper, a theoretical analysis to measure surface photovoltage using Kelvin probe technique is presented. Based on this analysis, the surface photovoltage and its time-resolved evolution process as well as the energy level structure of ZnO films are determined using a scanning Kelvin probe. The present study therefore provides a simple and practical methodology for the characterization of the electronic behavior of films.

  20. Direct current magnetron sputter-deposited ZnO thin films

    International Nuclear Information System (INIS)

    Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong; Knipp, Dietmar

    2011-01-01

    Zinc oxide (ZnO) is a very promising electronic material for emerging transparent large-area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 150 nm to 750 nm were deposited on glass substrates. The deposition pressure and the substrate temperature were varied from 12 mTorr to 25 mTorr, and from room temperature to 450 deg. C, respectively. The influence of the film thickness, deposition pressure and the substrate temperature on structural and optical properties of the ZnO films was investigated using atomic force microscopy (AFM) and ultraviolet-visible (UV-Vis) spectrometer. The experimental results reveal that the film thickness, deposition pressure and the substrate temperature play significant role in the structural formation and the optical properties of the deposited ZnO thin films.

  1. Growth of homoepitaxial ZnO film on ZnO nanorods and light emitting diode applications

    International Nuclear Information System (INIS)

    Park, Sun-Hong; Kim, Seon-Hyo; Han, Sang-Wook

    2007-01-01

    Vertically aligned ZnO nanorod arrays with a diameter of 40-150 nm were fabricated on Al 2 O 3 substrates with and without GaN interlayers, and consequently covered with a ZnO film in situ by a catalyst-free metal-organic vapour phase epitaxy method. X-ray diffraction and transmission electron microscopy measurements demonstrated that the ZnO film/nanorods hybrid structures had a well-ordered wurtzite structure with no lattice mismatch between the film and nanorods, and that the film was homoepitaxially grown horizontally as well as vertically on the pre-grown nanorods. From n-ZnO film/nanorods/p-GaN heterojunctions, we observed a blue light emission with a wavelength of about 440 nm

  2. Effect of substrate temperature on the structure, electrical and optical properties of Mo doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guifeng; Zhao, Xiaoli; Zhang, Hui; Wang, He; Liu, Feifei; Zhang, Xiaoqiang [Key Lab. for New Type of Functional Materials in Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Gao, Jianbo [China Institute of Atomic Energy, Beijing 102413 (China); Zhao, Yanmin; Zhang, Chao [No. 18TH Research Institute, China Electronics Technology Group Corporation, Tianjin 300384 (China); Tao, Junguang, E-mail: taojunguang@163.com [Key Lab. for New Type of Functional Materials in Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China)

    2016-09-15

    Highlights: • MZO thin films were prepared by RF magnetron sputtering from ZnO target and DC magnetron sputtering from Mo target. • All films are polycrystalline with preferential c-axis growth. • The various properties of films fabricated at varied substrate temperature have been studied. • The valence of the Mo ions in the ZnO matrix is mixture of +5 and +6. - Abstract: Mo-doped ZnO (MZO) transparent conductive thin films were prepared on glass substrate under various substrate temperature from 50 °C to 200 °C. The microstructural, electrical and optical properties of the MZO films were investigated by X-ray diffraction (XRD), Hall effect and UV–vis spectrophotometer. Based on XRD measurements, all films are polycrystalline with preferential c-axis growth. The lowest resistivity was obtained to be 2.8 × 10{sup −3} Ω·cm. According to X-ray photoelectron spectroscopy (XPS) measurement, the valence of the Mo ions in the ZnO matrix is a mixture of +5 and +6. In addition, the transmittance of the film is ∼80% throughout the visible light region. Our results indicate that the MZO films are suitable for potential transparent optoelectronic applications.

  3. Two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films

    International Nuclear Information System (INIS)

    Xu, Linhua; Zheng, Gaige; Zhao, Lilong; Pei, Shixin

    2015-01-01

    Ag-doped ZnO thin films were prepared by a sol–gel method. The structural, morphological and optical properties of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis and photoluminescence spectra. The results show that the Ag in the ZnO thin films annealed at 500 °C for 1 h substitutes for Zn and exists in the form of Ag + ion (Ag Zn ) while the Ag in the ZnO thin films without a post-annealing mainly exists in the form of simple substance (Ag 0 ). The incorporation of Ag indeed can improve the ultraviolet emission of ZnO thin films and suppress the visible emissions at the same time. However, the mechanisms on the ultraviolet emission enhancement in the annealed and unannealed Ag-doped ZnO thin films are very different. As for the post-annealed Ag-doped ZnO thin films, the UV emission enhancement maybe mainly results from more electron–hole pairs (excitons) due to Ag-doping while for the unannealed Ag-doped ZnO thin films; the UV emission enhancement is attributed to the resonant coupling between exciton emission in ZnO and localized surface plasmon in Ag nanoparticles. - Highlights: • Ag-doped ZnO thin films have been prepared by the sol–gel method. • Ag-doping can enhance ultraviolet emission of ZnO thin films and depress the visible emissions at the same time. • There are two different mechanisms on UV emission enhancement in Ag-doped ZnO thin films. • The UV emission enhancement from the resonant coupling between excitonic emissions and localized surface plasmon in Ag nanoparticle is very attractive

  4. Textured ZnO thin films by RF magnetron sputtering

    CERN Document Server

    Ginting, M; Kang, K H; Kim, S K; Yoon, K H; Park, I J; Song, J S

    1999-01-01

    Textured thin films ZnO has been successfully grown by rf magnetron sputtering method using a special technique of introducing a small amount of water and methanol on the deposition chamber. The grain size of the textured surface is highly dependent on the argon pressure during the deposition. The pressure in this experiment was varied from 50 mTorr down to 5 mTorr and the highest grain size of the film is obtained at 5 mTorr. The total transmittance of the films are more than 85% in the wavelength of 400 to 800 nm, and haze ratio of about 14% is obtained at 400 nm wavelength. Beside the textured surface, these films also have very low resistivity, which is lower than 1.4x10 sup - sup 3 OMEGA centre dot cm. X-ray analysis shows that the films with textured surface have four diffraction peaks on the direction of (110), (002), (101) and (112), while the non-textured films have only (110) and (002) peaks. Due to the excellent characteristics of this film, it will make the film very good TCO alternatives for the ...

  5. Investigation of sensitivity and selectivity of ZnO thin film to volatile organic compounds

    Science.gov (United States)

    Teimoori, F.; Khojier, K.; Dehnavi, N. Z.

    2017-06-01

    This research addresses a detailed study on the sensitivity and selectivity of ZnO thin film to volatile organic compound (VOC) vapors that can be used for the development of VOC sensors. The ZnO thin film of 100 nm thickness was prepared by post-annealing of e-beam evaporated Zn thin film. The sample was structurally, morphologically, and chemically characterized by X-ray diffraction and field emission scanning electron microscopy analyses. The sensitivity, selectivity, and detection limit of the sample were tested with respect to a wide range of common VOC vapors, including acetone, formaldehyde, acetic acid, formic acid, acetylene, toluene, benzene, ethanol, methanol, and isopropanol in the temperature range of 200-400 °C. The results show that the best sensitivity and detection limit of the sample are related to acetone vapor in the studied temperature range. The ZnO thin film-based acetone sensor also shows a good reproducibility and stability at the operating temperature of 280 °C.

  6. Structural, optical and electrical properties of ZnO thin films prepared ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. ZnO thin films have been prepared using zinc acetate precursor by spray pyrolytic decomposition of zinc acetate on glass substrates at 450 °C. Effect of precursor concentration on structural and optical pro- perties has been investigated. ZnO films are polycrystalline with (002) plane as preferential orientation. The.

  7. ZnO thin films prepared by surfatron produced discharge

    Czech Academy of Sciences Publication Activity Database

    Olejníček, Jiří; Šmíd, Jiří; Čada, Martin; Kment, Š.; Churpita, Olexandr; Kšírová, Petra; Brunclíková, Michaela; Adámek, Petr; Kohout, Michal; Valvoda, V.; Chvostová, Dagmar; Zlámal, M.; Hubička, Zdeněk

    2014-01-01

    Roč. 230, Jul (2014), s. 119-124 ISSN 0920-5861 R&D Projects: GA TA ČR TA01011740; GA MŠk LH12045; GA ČR GAP108/12/1941; GA ČR(CZ) GAP205/11/0386 Grant - others:GACR(CZ) GP13-29241P Institutional support: RVO:68378271 Keywords : ZnO * surfatron * thin films * Langmuir probe * plasma density Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.893, year: 2014

  8. Fabrication and Photo-Detecting Performance of 2D ZnO Inverse Opal Films

    Directory of Open Access Journals (Sweden)

    Xin Lin

    2016-09-01

    Full Text Available Two-dimensional (2D ZnO inverse opal (IO films were fabricated by co-assembly of sacrificed polystyrene (PS microspheres and citric acid/zinc acetate (CA/ZA aqueous solution at an oil–water interface followed by calcination. Their morphologies could be controlled by the surface property of polymer templates and CA/ZA molar ratio. Moreover, photo-detecting devices based on such films were constructed, which showed high photocurrent (up to 4.6 μA, excellent spectral selectivity, and reversible response to optical switch.

  9. Synthesis, microstructural characterization and optical properties of undoped, V and Sc doped ZnO thin films

    International Nuclear Information System (INIS)

    Amezaga-Madrid, P.; Antunez-Flores, W.; Ledezma-Sillas, J.E.; Murillo-Ramirez, J.G.; Solis-Canto, O.; Vega-Becerra, O.E.; Martinez-Sanchez, R.; Miki-Yoshida, M.

    2011-01-01

    Research highlights: → Undoped, V and Sc doped ZnO thin films by Aerosol Assisted Chemical Vapour Deposition. → Optimum substrate temperatures of 673 K and 623 K for Sc and V doped films. → Around one third of the dopants in solution were deposited into the films. → Crystallite and grain size decreased with the increase of dopant concentration. → Optical band gap increased from 3.29 to 3.32 eV for undoped to 7 Sc/Zn at. %. - Abstract: Many semiconductor oxides (ZnO, TiO 2 , SnO 2 ) when doped with a low percentage of non-magnetic (V, Sc) or magnetic 3d (Co, Mn, Ni, Fe) cation behave ferromagnetically. They have attracted a great deal of interest due to the integration of semiconducting and magnetic properties in a material. ZnO is one of the most promising materials to carry out these tasks in view of the fact that it is optically transparent and has n or p type conductivity. Here, we report the synthesis, microstructural characterization and optical properties of undoped, V and Sc doped zinc oxide thin films. ZnO based thin films with additions of V and Sc were deposited by the Aerosol Assisted Chemical Vapour Deposition method. V and Sc were incorporated separately in the precursor solution. The films were uniform, transparent and non-light scattering. The microstructure of the films was characterized by Grazing Incidence X-ray Diffraction, Scanning Electron Microscopy, and Scanning Probe Microscopy. Average grain size and surface rms roughness were estimated by the measurement of Atomic Force Microscopy. The microstructure of doped ZnO thin films depended on the type and amount of dopant material incorporated. The optical properties were determined from specular reflectance and transmittance spectra. Results were analyzed to determine the optical constant and band gap of the films. An increase in the optical band gap with the content of Sc dopant was obtained.

  10. Selective growth of ZnO thin film nanostructures: Structure, morphology and tunable optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Krishnakanth, Katturi Naga; Sunandana, C. S. [School of Physics, University of Hyderabad, Hyderabad-50046 (India); Rajesh, Desapogu, E-mail: rajesh.esapogu@gmail.com, E-mail: mperd@nus.edu.sg [School of Physics, University of Hyderabad, Hyderabad-50046 (India); Dept. of Mechanical Engineering, National University of Singapore (Singapore)

    2016-05-23

    The ZnO nanostructures (spherical, rod shape) have been successfully fabricated via a thermal evaporation followed by dip coating method. The pure, doped ZnO thin films were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy, respectively. A possible growth mechanism of the spherical, rod shape ZnO nanostructures are discussed. XRD patterns revealed that all films consist of pure ZnO phase and were well crystallized with preferential orientation towards (002) direction. Doping by PVA, PVA+Cu has effective role in the enhancement of the crystalline quality and increases in the band gap.

  11. Piezoelectric Response Evaluation of ZnO Thin Film Prepared by RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Cheng Da-Long

    2017-01-01

    Full Text Available The most important parameter of piezoelectric materials is piezoelectric coefficient (d33. In this study, the piezoelectric ZnO thin films were deposited on the SiNx/Si substrate. The 4 inches substrate is diced into 8 cm× 8 cm piece. During the deposition process, a zinc target (99.999 wt% of 2 inches diameter was used. The vertical distance between the target and the substrate holder was fixed at 5 cm. The piezoelectric response of zinc oxide (ZnO thin films were obtained by using a direct measurement system. The system adopts a mini impact tip to generate an impulsive force and read out the piezoelectric signals immediately. Experimentally, a servo motor is used to produce a fixed quantity of force, for giving an impact against to the piezoelectric film. The ZnO thin films were deposited using the reactive radio frequency (RF magnetron sputtering method. The electric charges should be generated because of the material’s extrusion. This phenomenon was investigated through the oscilloscope by one shot trigger. It was apparent that all ZnO films exhibit piezoelectric responses evaluated by our measurement system, however, its exhibit a significant discrepancy. The piezoelectric responses of ZnO thin film at various deposition positions were measured and the crystal structures of the sputtering pressure were also discussed. The crystalline characteristics of ZnO thin films are investigated through the XRD and SEM. The results show the ZnO thin film exhibits good crystalline pattern and surface morphology with controlled sputtering condition. The ZnO thin films sputtered using 2 inches target present various piezoelectric responses. With the exactly related position, a best piezoelectric response of ZnO thin film can be achieved.

  12. Fabrication of nanostructured Al-doped ZnO thin film for methane sensing applications

    International Nuclear Information System (INIS)

    Shafura, A. K.; Azhar, N. E. I.; Uzer, M.; Mamat, M. H.; Sin, N. D. Md.; Saurdi, I.; Shuhaimi, A.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-01-01

    CH 4 gas sensor was fabricated using spin-coating method of the nanostructured ZnO thin film. Effect of annealing temperature on the electrical and structural properties of the film was investigated. Dense nanostructured ZnO film are obtained at higher annealing temperature. The optimal condition of annealing temperature is 500°C which has conductivity and sensitivity value of 3.3 × 10 −3 S/cm and 11.5%, respectively.

  13. Fabrication of nanostructured Al-doped ZnO thin film for methane sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Shafura, A. K., E-mail: shafura@ymail.com; Azhar, N. E. I.; Uzer, M.; Mamat, M. H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Sin, N. D. Md. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA Cawangan Johor, Kampus Pasir Gudang, 81750 Masai, Johor (Malaysia); Saurdi, I. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA Sarawak, Kampus Kota Samarahan Jalan Meranek, Sarawak (Malaysia); Shuhaimi, A. [Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University ofMalaya, 50603 Kuala Lumpur (Malaysia); Alrokayan, Salman A. H.; Khan, Haseeb A. [Research Chair of Targeting and Treatment Cancer Using Nanoparticles, Department Of Biochemistry, College Of Science, King Saud University, P.O: 2454 Riyadh 11451 (Saudi Arabia); Rusop, M., E-mail: nanouitm@gmail.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    CH{sub 4} gas sensor was fabricated using spin-coating method of the nanostructured ZnO thin film. Effect of annealing temperature on the electrical and structural properties of the film was investigated. Dense nanostructured ZnO film are obtained at higher annealing temperature. The optimal condition of annealing temperature is 500°C which has conductivity and sensitivity value of 3.3 × 10{sup −3} S/cm and 11.5%, respectively.

  14. Comparison on electrically pumped random laser actions of hydrothermal and sputtered ZnO films

    International Nuclear Information System (INIS)

    Wang, Canxing; Jiang, Haotian; Li, Yunpeng; Ma, Xiangyang; Yang, Deren

    2013-01-01

    Random lasing (RL) in polycrystalline ZnO films is an intriguing research subject. Here, we have comparatively investigated electrically pumped RL behaviors of two metal-insulator-semiconductor structured devices using the hydrothermal and sputtered ZnO films as the semiconductor components, i.e., the light-emitting layers, respectively. It is demonstrated that the device using the hydrothermal ZnO film exhibits smaller threshold current and larger output optical power of the electrically pumped RL. The morphological characterization shows that the hydrothermal ZnO film is somewhat porous and is much rougher than the sputtered one, suggesting that in the former stronger multiple light scattering can occur. Moreover, the photoluminescence characterization indicates that there are fewer defects in the hydrothermal ZnO film than in the sputtered one, which means that the photons can pick up larger optical gain through stimulated emission in the hydrothermal ZnO film. Therefore, it is believed that the stronger multiple light scattering and larger optical gain contribute to the improved performance of the electrically pumped RL from the device using the hydrothermal ZnO film

  15. Mn{sup 2+} ions distribution in doped sol–gel deposited ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Stefan, Mariana, E-mail: mstefan@infim.ro [National Institute of Materials Physics, P.O. Box MG-7, 077125 Magurele (Romania); Ghica, Daniela; Nistor, Sergiu V.; Maraloiu, Adrian V. [National Institute of Materials Physics, P.O. Box MG-7, 077125 Magurele (Romania); Plugaru, Rodica [National Institute for R & D in Microtechnologies (IMT), Erou Iancu Nicolae Str. 126A, 077190 Bucharest (Romania)

    2017-02-28

    Highlights: • Several Mn{sup 2+} centers observed by EPR in sol–gel ZnO films. • Mn{sup 2+} ions localized at Zn{sup 2+} sites in ZnO grains and disordered ZnO phase. • Sixfold coordinated Mn{sup 2+} ions localized in inter-grain region. • Aggregated Mn in insular-like regions between ZnO grains in the ZnO:5%Mn film. • Aggregated Mn phase presence and distribution observed by EPR and EDX-STEM. - Abstract: The localization and distribution of the Mn{sup 2+} ions in two sol–gel deposited ZnO films doped with different manganese concentrations were investigated by electron paramagnetic resonance spectroscopy and analytical transmission electron microscopy. In the lightly doped sample the Mn{sup 2+} ions are mainly localized substitutionally at isolated tetrahedrally coordinated Zn{sup 2+} sites in both crystalline ZnO nanograins (34%) and surrounding disordered ZnO (52%). In the highly doped ZnO film, a much smaller proportion of manganese substitutes Zn{sup 2+} in the crystalline and disordered ZnO (10%). The main amount (85%) of manganese aggregates in a secondary phase as an insular-like distribution between the ZnO nanograins. The remaining Mn{sup 2+} ions (14% and 5% at low and high doping levels, respectively) are localized at isolated, six-fold coordinated sites, very likely in the disordered intergrain region. Annealing at 600 °C induced changes in the Mn{sup 2+} ions distribution, reflecting the increase of the ZnO crystallization degree, better observed in the lightly doped sample.

  16. Microstructures and photocatalytic properties of porous ZnO films synthesized by chemical bath deposition method

    International Nuclear Information System (INIS)

    Wang Huihu; Dong, Shijie; Chang Ying; Zhou Xiaoping; Hu Xinbin

    2012-01-01

    Different porous ZnO film structures on the surface of alumina substrates were prepared through a simple chemical bath deposition method in the methanolic zinc acetate solution. The surface morphology and phase structure of porous ZnO film were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Both initial zinc acetate concentration and sintering temperature have great impact on the final film structures. With the increase of initial zinc acetate concentration, the porous structures can be finely tuned from circular nest like assemblies composed film into successive nest like film, and finally to globular aggregates composed film. By increasing the sintering temperature, the porous structure of successive nest like film can be further controlled. Furthermore, the crystallinity of photocatalysts also can be greatly improved. The photodegradation results of Methyl Orange revealed that porous ZnO film with successive nest like structure sintered at 500 °C exhibited the highest photocatalytic activity under UV illumination.

  17. Electrical properties of ZnO thin films grown by MOCVD

    International Nuclear Information System (INIS)

    Pagni, O.; Somhlahlo, N.N.; Weichsel, C.; Leitch, A.W.R.

    2006-01-01

    We report on the electrical characterization of ZnO films grown by MOCVD on glass and sapphire substrates. After correcting our temperature variable Hall measurements by applying the standard two-layer model, which takes into account an interfacial layer, scattering mechanisms in the ZnO films were studied as well as donor activation energies determined. ZnO films grown at different oxygen partial pressures indicated the importance of growth conditions on the defect structure by means of their conductivities and conductivity activation energies

  18. Electrical properties of ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Pagni, O. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Somhlahlo, N.N. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Weichsel, C. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)]. E-mail: andrew.leitch@nmmu.ac.za

    2006-04-01

    We report on the electrical characterization of ZnO films grown by MOCVD on glass and sapphire substrates. After correcting our temperature variable Hall measurements by applying the standard two-layer model, which takes into account an interfacial layer, scattering mechanisms in the ZnO films were studied as well as donor activation energies determined. ZnO films grown at different oxygen partial pressures indicated the importance of growth conditions on the defect structure by means of their conductivities and conductivity activation energies.

  19. Effect of ZnO Nanostructured Thin Films on Pseudomonas Putida Cell Division

    Science.gov (United States)

    Ivanova, I.; Lukanov, A.; Angelov, O.; Popova, R.; Nichev, H.; Mikli, V.; Dimova-Malinovska, Doriana; Dushkin, C.

    In this report we study the interaction between the bacteria Pseudomonas putida and nanostructured ZnO and ZnO:H thin films prepared by magnetron sputtering of a ZnO target. The nanostructured ZnO and ZnO:H thin films possess some biological-active properties when in contact with bacteria. Our experimental data show that these films have no destructive effect on the cell division of Pseudomonas putida in poor liquid medium and can be applied in biosensor devices.

  20. Characteristics of strontium-doped ZnO films on love wave filter applications

    International Nuclear Information System (INIS)

    Water, Walter; Yan, Y.-S.

    2007-01-01

    The effect of dopant concentrations in strontium-doped ZnO films on Love wave filter characteristics was investigated. Strontium-doped ZnO films with a c-axis preferred orientation were grown on ST-cut quartz by radio frequency magnetron sputtering. The crystalline structures and surface morphology of films were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy. The electromechanical coupling coefficient, dielectric constant, and temperature coefficient of frequency of filters were then determined using a network analyzer. A uniform crystalline structure and smooth surface of the ZnO films were obtained at the 1-2 mol% strontium dopant level. The electromechanical coupling coefficient of the 1 mol% strontium-doped ZnO film reaches a maximum of 0.61%, and the temperature coefficient of frequency declines to + 12.87 ppm/deg. C at a 1.5 mol% strontium dopant level

  1. ZnO film for application in surface acoustic wave device

    International Nuclear Information System (INIS)

    Du, X Y; Fu, Y Q; Tan, S C; Luo, J K; Flewitt, A J; Maeng, S; Kim, S H; Choi, Y J; Lee, D S; Park, N M; Park, J; Milne, W I

    2007-01-01

    High quality, c-axis oriented zinc oxide (ZnO) thin films were grown on silicon substrate using RF magnetron sputtering. Surface acoustic wave (SAW) devices were fabricated with different thickness of ZnO ranging from 1.2 to 5.5 μmUm and the frequency responses were characterized using a network analyzer. Thick ZnO films produce the strongest transmission and reflection signals from the SAW devices. The SAW propagation velocity is also strongly dependent on ZnO film thickness. The performance of the ZnO SAW devices could be improved with addition of a SiO 2 layer, in name of reflection signal amplitude and phase velocity of Rayleigh wave

  2. Studies on nonvolatile resistance memory switching in ZnO thin films

    Indian Academy of Sciences (India)

    Six decades of research on ZnO has recently sprouted a new branch in the domain of resistive random access memories. Highly resistive and c-axis oriented ZnO thin films were grown by us using d.c. discharge assisted pulsed laser deposition on Pt/Ti/SiO2/Si substrates at room temperature. The resistive switching ...

  3. Heavy lithium-doped ZnO thin films prepared by spray pyrolysis ...

    Indian Academy of Sciences (India)

    Lithium-doped ZnO thin films (ZnO : Li) were prepared by spray pyrolysis method on the glass substrates for ( = [Li]/[Zn]) value varied between 5 and 70%. Structural, electrical and optical properties of the samples were studied by X-ray diffraction (XRD), UV–Vis–NIR spectroscopy, scanning electron microscopy (SEM), ...

  4. Analysis of Li-related defects in ZnO thin films influenced by ...

    Indian Academy of Sciences (India)

    et al 2008) and electrical measurements (Look and Claflin. 2004; Mohamed et al 2005). Here, we report the effects of annealing ambient on Li-related defects in ZnO films. For- mation mechanism of Li-related defects in ZnO was stud- ied by calculating formation energies of Li-related defects structure. 2. Experimental.

  5. Defect studies of thin ZnO films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Vlček, M; Čížek, J; Procházka, I; Novotný, M; Bulíř, J; Lančok, J; Anwand, W; Brauer, G; Mosnier, J-P

    2014-01-01

    Thin ZnO films were grown by pulsed laser deposition on four different substrates: sapphire (0 0 0 1), MgO (1 0 0), fused silica and nanocrystalline synthetic diamond. Defect studies by slow positron implantation spectroscopy (SPIS) revealed significantly higher concentration of defects in the studied films when compared to a bulk ZnO single crystal. The concentration of defects in the films deposited on single crystal sapphire and MgO substrates is higher than in the films deposited on amorphous fused silica substrate and nanocrystalline synthetic diamond. Furthermore, the effect of deposition temperature on film quality was investigated in ZnO films deposited on synthetic diamond substrates. Defect studies performed by SPIS revealed that the concentration of defects firstly decreases with increasing deposition temperature, but at too high deposition temperatures it increases again. The lowest concentration of defects was found in the film deposited at 450° C.

  6. ZnO Coated Nanospring-Based Gas Sensors

    Science.gov (United States)

    Bakharev, Pavel Viktorovich

    . The experimental and computational analyses of the sensing properties of the 3-D (nanospring-based) and flat thin films structures show that the complexity and periodic boundary conditions of the nanospring-based devices result in a lower detection limit, while flat thin films exhibit higher sensitivity to small analyte concentration fluctuations. Our analysis shows that the productive approach to fabrication of integrated sensors (electronic noses) is to use both the structures (3D and flat geometries) as the receptors for a prompt and reliable detection and recognition of the target chemical compounds. Analog lock-in amplifier (LIA) AC measurements of the electrical response have been performed to significantly improve the signal-to-noise ratio (SNR) and reduce the detection limit of the single ZnO coated nanospring chemiresistor from the ppm to the ppb analyte concentration ranges. The LIA-based sensor signal recognition technique has shown to extend the capabilities of the gas sensor array for a linear discrimination analysis (LDA), an independent component analysis (ICA), a principal component analysis (PCA) and other multiple odor recognition methods.

  7. Photovoltaic Properties of Co-doped ZnO Thin Film on Glass Substrate

    International Nuclear Information System (INIS)

    Sabia Aye; Zin Ma Ma; May Nwe Oo; Than Than Win; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    Cobalt (Co) 0.4 mol doped zinc oxide (ZnO) fine powder was prepared by solid state mixed oxide route. Phase formation and crystal structure of Co-doped ZnO (CZO) powder were examined by X-ray diffraction (XRD). Scanning Electron Microscopy (SEM) was used to observe the micro structure of Co doped ZnO powder. Energy Dispersive X-ray Fluorescent (EDXRF) technique gave the elemental content of cobalt and zinc. Co-doped ZnO film was formed on glass substrate by spin coating technique. Photovoltaic properties of CZO/glass cell were measured.

  8. Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique

    Directory of Open Access Journals (Sweden)

    M.I. Khan

    Full Text Available In this work, zinc oxide (ZnO multilayer thin films are deposited on glass substrate using sol-gel spin coating technique and the effect of these multilayer films on optical, electrical and structural properties are investigated. It is observed that these multilayer films have great impact on the properties of ZnO. X-ray Diffraction (XRD confirms that ZnO has hexagonal wurtzite structure. Scanning Electron Microscopy (SEM showed the crack-free films which have uniformly distributed grains structures. Both micro and nano particles of ZnO are present on thin films. Four point probe measured the electrical properties showed the decreasing trend between the average resistivity and the number of layers. The optical absorption spectra measured using UV–Vis. showed the average transmittance in the visible region of all films is 80% which is good for solar spectra. The performance of the multilayer as transparent conducting material is better than the single layer of ZnO. This work provides a low cost, environment friendly and well abandoned material for solar cells applications. Keywords: Multilayer films, Semiconductor, ZnO, XRD, SEM, Optoelectronic properties

  9. Enhanced photocurrent and photocatalytic properties of porous ZnO thin film by Ag nanoparticles

    Science.gov (United States)

    Lv, Jianguo; Zhu, Qianqian; Zeng, Zheng; Zhang, Miao; Yang, Jin; Zhao, Min; Wang, Wenhao; Cheng, Yuebing; He, Gang; Sun, Zhaoqi

    2017-12-01

    ZnO thin films were deposited using an electrodeposition method and porous morphologies could be achieved by annealing treatment. A variety of Ag nanoparticles were loaded on the surface of the ZnO thin films. Surface morphology, chemical composition, crystal phase and optical properties were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV-vis spectrophotometer and micro-Raman spectroscopy. Evidence of Ag nanoparticles on the Ag-4/ZnO thin film was be verified by the SEM and XPS measurements. The XRD results indicated that the Ag nanoparticles had little effect on crystallinity of the thin films. The photoresponse and photocatalytic results indicated that the photocurrent and photocatalytic performance could be enhanced by moderate Ag nanoparticles modification on the surface of the ZnO thin film. The best photoresponse and photocatalytic activity in Ag-4/ZnO thin film results from the moderate Ag nanoparticles on the surface of ZnO thin film, which could enhanced separation and suppressed recombination of photogenerated electron-hole pairs.

  10. Controlled morphologies and optical properties of ZnO films and their photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Duan Jingjing [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Liu Xiaoheng, E-mail: xhliu@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Han Qiaofeng [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Wang Xin, E-mail: wangx@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China)

    2011-09-15

    Highlights: > Gelatin acts as a capping reagent in the morphology synthesis of ZnO films. > The microstructures of ZnO films are hexagonal prisms, plates and rose-like crystals. > The hexagonal prisms and rose-like films exhibit excellent photocatalytic activities. - Abstract: ZnO films with three different microstructures including hexagonal prisms, plates and rose-like twinned crystals were fabricated using chemical bath deposition with different concentration of gelatin. The growth mechanisms of ZnO films were discussed, and the gelatin played a vital role as a polyelectrolyte capping the formation of microstructures. The photoluminescence and Raman properties were found sensitive to the crystal morphologies of ZnO films. Significantly, the photodegradation efficiencies of methylene blue under UV light irradiation in the presence of ZnO films consisted of hexagonal prisms and rose-like twinned crystals were 95% and 96%, respectively. The excellent photocatalytic activities can be ascribed to the high oxygen vacancies concentration and high percentage of polar planes, and this result was important in addressing the origin of high photocatalytic activity.

  11. Synthesis, structural and optical characterization of undoped, N-doped ZnO and co-doped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Trilok Kumar, E-mail: tpathak01@gmail.com; Kumar, R.; Purohit, L. P., E-mail: proflppurohitphys@gmail.com [Semiconductor Research Lab., Department of Physics, Gurukula Kangri University, Haridwar (India)

    2015-05-15

    ZnO, N-doped ZnO and Al-N co-doped ZnO thin films were deposited on ITO coated corning glass by spin coater using sol-gel method. The films were annealed in air at 450°C for one hour. The crystallographic structure and morphology of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The X-ray diffraction results confirm that the thin films are of wurtzite hexagonal with a very small distortion. The optical properties were investigated by transmission spectra of different films using spectrophotometer (Shimadzu UV-VIS-NIR 3600). The results indicate that the N doped ZnO thin films have obviously enhanced transmittance in visible region. Moreover, the thickness of the films has strong influences on the optical constants.

  12. Smoothing of ZnO films by gas cluster ion beam

    International Nuclear Information System (INIS)

    Chen, H.; Liu, S.W.; Wang, X.M.; Iliev, M.N.; Chen, C.L.; Yu, X.K.; Liu, J.R.; Ma, K.; Chu, W.K.

    2005-01-01

    Planarization of wide-band-gap semiconductor ZnO surface is crucial for thin-film device performance. In this study, the rough initial surfaces of ZnO films deposited by r.f. magnetron sputtering on Si substrates were smoothed by gas cluster ion beams. AFM measurements show that the average surface roughness (R a ) of the ZnO films could be reduced considerably from 16.1 nm to 0.9 nm. Raman spectroscopy was used to monitor the structure of both the as-grown and the smoothed ZnO films. Rutherford back-scattering in combination with channeling effect was used to study the damage production induced by the cluster bombardment

  13. Electrodeposited Mesoporous ZnO Thin Films as Efficient Photocatalysts for the degradation of dye pollutants

    Czech Academy of Sciences Publication Activity Database

    Pauporté, T.; Rathouský, Jiří

    2007-01-01

    Roč. 111, č. 21 (2007), s. 7639-7644 ISSN 1932-7447 Institutional research plan: CEZ:AV0Z40400503 Keywords : ZnO films * photocatalysis * pollutants Subject RIV: CF - Physical ; Theoretical Chemistry

  14. Investigation of ZnO Thin Film Synthesized by Spray Pyrolysis Method as a Toxic Gases Sensor

    Science.gov (United States)

    Khojier, K.

    2017-10-01

    In recent years, environmental pollution, particularly toxic gases and vapors, have greatly increased; hence, their detection has become increasingly important. This paper investigates ZnO thin films fabricated by the spray pyrolysis method to fabricate a toxic gases sensor. A ZnO thin film of 100 nm thickness was deposited on a glass substrate at 100°C. The crystallographic structure was characterized by x-ray diffraction and a field-emission scanning electron microscope was employed to investigate the surface physical morphology and chemical composition. Sensitivity and selectivity of the sample were tested with respect to different toxic gases and vapors including carbon monoxide, ammonia, hydrogen sulfide, chlorine, nitrogen dioxide, benzene, formaldehyde and toluene in the temperature range of 100-300°C. The results showed that the ZnO thin film is more selective to NO2 gas than the other toxic gases and vapors in the studied temperature range. The ZnO thin film-based NO2 gas sensor also showed a good reproducibility, stability, and detection limit of 10 ppm at the operating temperature of 200°C.

  15. Mango core inner shell membrane template-directed synthesis of porous ZnO films and their application for enzymatic glucose biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yu; Wang, Lei [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Ye, Zhizhen [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University (China); Zhao, Minggang; Cai, Hui [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Huang, Jingyun, E-mail: huangjy@zju.edu.cn [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University (China)

    2013-11-15

    Micro/nano-porous ZnO films were synthesized through a simple biotemplate-directed method using mango core inner shell membranes as templates. The achieved ZnO films with wrinkles on the surface are combined of large holes and small pores in the bulk. High specific surface area, numerous microspaces, and small channels for fluid circulation provided by this unique structure along with the good biocompatibility and electron communication features of ZnO material make the product an ideal platform for the immobilization of enzymes The fabricated glucose biosensor based on the porous ZnO films exhibits good selective detection ability of analyte with good stability, high sensitivity of 50.58 μA cm{sup −2} mM{sup −1} and a wide linear range of 0.2–5.6 mM along with a low detection limit of 10 μM.

  16. Mango core inner shell membrane template-directed synthesis of porous ZnO films and their application for enzymatic glucose biosensor

    Science.gov (United States)

    Zhou, Yu; Wang, Lei; Ye, Zhizhen; Zhao, Minggang; Cai, Hui; Huang, Jingyun

    2013-11-01

    Micro/nano-porous ZnO films were synthesized through a simple biotemplate-directed method using mango core inner shell membranes as templates. The achieved ZnO films with wrinkles on the surface are combined of large holes and small pores in the bulk. High specific surface area, numerous microspaces, and small channels for fluid circulation provided by this unique structure along with the good biocompatibility and electron communication features of ZnO material make the product an ideal platform for the immobilization of enzymes The fabricated glucose biosensor based on the porous ZnO films exhibits good selective detection ability of analyte with good stability, high sensitivity of 50.58 μA cm-2 mM-1 and a wide linear range of 0.2-5.6 mM along with a low detection limit of 10 μM.

  17. Pure and Sn-doped ZnO films produced by pulsed laser deposition

    DEFF Research Database (Denmark)

    Holmelund, E.; Schou, Jørgen; Tougaard, S.

    2002-01-01

    A new technique, metronome doping, has been used for doping of films during pulsed laser deposition (PLD). This technique makes it possible to dope continuously during film growth with different concentrations of a dopant in one deposition sequence. Films of pure and doped ZnO have been produced...

  18. Radio-frequency magnetron sputtering and wet thermal oxidation of ZnO thin film

    International Nuclear Information System (INIS)

    Liu, H. F.; Chua, S. J.; Hu, G. X.; Gong, H.; Xiang, N.

    2007-01-01

    The authors studied the growth and wet thermal oxidation (WTO) of ZnO thin films using a radio-frequency magnetron sputtering technique. X-ray diffraction reveals a preferred orientation of [1010]ZnO(0002)//[1120]Al 2 O 3 (0002) coexisted with a small amount of ZnO (1011) and ZnO (1013) crystals on the Al 2 O 3 (0001) substrate. The ZnO (1011) and ZnO (1013) crystals, as well as the in-plane preferred orientation, are absent from the growth of ZnO on the GaAs(001) substrate. WTO at 550 deg. C improves the crystalline and the photoluminescence more significantly than annealing in air, N 2 and O 2 ambient; it also tends to convert the crystal from ZnO (1011) and ZnO (1013) to ZnO (0002). The evolution of the photoluminescence upon WTO and annealing reveals that the green and orange emissions, centered at 520 and 650 nm, are likely originated from oxygen vacancies and oxygen interstitials, respectively; while the 420 nm emission, which is very sensitive to the postgrowth thermal processing regardless of the substrate and the ambient gas, is likely originated from the surface-state related defects

  19. ZnO thin film synthesis by reactive radio frequency magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Şenay, Volkan, E-mail: vsenay@bayburt.edu.tr [Bayburt University, Primary Science Education Department, Bayburt, 69000 (Turkey); Pat, Suat; Korkmaz, Şadan; Aydoğmuş, Tuna; Elmas, Saliha; Özen, Soner; Ekem, Naci [Eskisehir Osmangazi University, Physics Department, Eskisehir, 26480 (Turkey); Balbağ, M. Zafer [Eskisehir Osmangazi University, Education Faculty, Eskisehir, 26480 (Turkey)

    2014-11-01

    Highlights: • Band gaps of the layer are affected by the film thickness. • Nano structured ZnO deposited. • Spectral dependence of reflectance of deposited ZnO thin films. - Abstract: In this study, ZnO thin films were deposited on glass substrates by reactive RF magnetron sputtering method at argon–oxygen gas mixing (1:1) atmosphere. Some properties of the synthesized films were investigated by interferometry, UV–vis spectrophotometer, atomic force microscopy, and tensiometer. Tauc method was adopted to estimate the optical band gaps. The band gaps of the deposited films were affected by film thickness. We concluded that the surface composition plays a substantial role in the values of the band gaps. Nanocrystalline structures were detected in all produced samples.

  20. ZnO thin film synthesis by reactive radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Şenay, Volkan; Pat, Suat; Korkmaz, Şadan; Aydoğmuş, Tuna; Elmas, Saliha; Özen, Soner; Ekem, Naci; Balbağ, M. Zafer

    2014-01-01

    Highlights: • Band gaps of the layer are affected by the film thickness. • Nano structured ZnO deposited. • Spectral dependence of reflectance of deposited ZnO thin films. - Abstract: In this study, ZnO thin films were deposited on glass substrates by reactive RF magnetron sputtering method at argon–oxygen gas mixing (1:1) atmosphere. Some properties of the synthesized films were investigated by interferometry, UV–vis spectrophotometer, atomic force microscopy, and tensiometer. Tauc method was adopted to estimate the optical band gaps. The band gaps of the deposited films were affected by film thickness. We concluded that the surface composition plays a substantial role in the values of the band gaps. Nanocrystalline structures were detected in all produced samples

  1. Synthesis and characterization of ZnO thin film by low cost modified SILAR technique

    Directory of Open Access Journals (Sweden)

    Haridas D. Dhaygude

    2016-03-01

    Full Text Available The ZnO thin film is prepared on Fluorine Tin Oxide (FTO coated glass substrate by using SILAR deposition technique containing ZnSO4.7H2O and NaOH as precursor solution with 150 deeping cycles at 70 °C temperature. Nanocrystalline diamond like ZnO thin film is characterized by different characterization techniques such as X-ray diffraction (XRD, Fourier transform (FT Raman spectrometer, Field Emission Scanning Electron Microscopy (FE-SEM with Energy dispersive X-Ray Analysis (EDAX, optical absorption, surface wettability and photoelectrochemical cell performance measurement. The X-ray diffraction analysis shows that the ZnO thin film is polycrystalline in nature having hexagonal crystal structure. The FT-Raman scattering exhibits a sharp and strong mode at 383 cm−1 which confirms hexagonal ZnO nanostructure. The surface morphology study reveals that deposited ZnO film consists of nanocrystalline diamond like morphology all over the substrate. The synthesized thin film exhibited absorption wavelength around 309 nm. Optical study predicted the direct band gap and band gap energy of this film is found to be 3.66 eV. The photoelectrochemical cell (PEC parameter measurement study shows that ZnO sample confirmed the highest values of, short circuit current (Isc - 629 mAcm−2, open circuit voltage (Voc - 878 mV, fill factor (FF - 0.48, and maximum efficiency (η - 0.89%, respectively.

  2. Growth of cluster assembled ZnO film by nanocluster beam deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Halder, Nilanjan [Department of Physics, Manipal University Jaipur, Jaipur-303007 (India)

    2015-06-24

    ZnO is considered as one of the most promising material for optoelectronic devices. The present work emphasizes production of cluster assembled ZnO films by a UHV nanocluster beam deposition technique where the nanoclusters were produced in a laser vaporization cluster source. The microstructural and the optical properties of the ZnO nanocluster film deposited were investigated. As the wet chemical processes are not compatible with current solid state methods of device fabrication, therefore alternative UHV technique described in the paper is the need of the hour.

  3. Photoluminescence of ZnO thin films deposited at various substrate temperatures

    International Nuclear Information System (INIS)

    Kao, Kuo-Sheng; Shih, Wei-Che; Ye, Wei-Tsuen; Cheng, Da-Long

    2016-01-01

    This study investigated surface acoustic wave devices with an Al/ZnO/Si structure for use in ultraviolet sensors. ZnO thin films were fabricated using a reactive radio frequency magnetron sputtering system. The substrate temperature of ZnO thin films can be varied to obtain highly crystalline properties. The surface morphologies and c-axis preferred orientation of the ZnO thin films were determined using scanning electron microscopy and X-ray diffraction. In addition, bright-field images of ZnO crystallization were investigated using a transmission electron microscope. From photoluminescence analysis, four peaks were obtained at 377.8, 384.9, 391.4, and 403.4 nm. Interdigital transducers of an aluminum electrode were fabricated on the ZnO/Si structure by using a direct current sputtering system and photolithography, combined with the lift-off method, thereby obtaining a surface acoustic wave device. Finally, frequency responses were measured using a network analyzer, and an illuminating test was adopted for the ultraviolet sensor, using a wavelength of 355 nm from a light-emitting diode. The sensitivities of the ultraviolet sensor were also discussed. - Highlights: • The ZnO/Si SAW devices exhibit the Rayleigh and Sezawa modes. • The crystalline of ZnO affects the EHP recombination and generation. • The PL spectrum of ZnO shows Gaussian fitting distributions. • The CTD UV is influenced by SAW types and ZnO film characteristics.

  4. The dissimilar resistive switching properties in ZnO-Co and ZnO films

    Science.gov (United States)

    Li, Xiaoli; Shi, Yana; Li, Jie; Bai, Yuhao; Jia, Juan; Li, Yanchun; Xu, Xiaohong

    2017-03-01

    Nanostructured ZnO-Co and ZnO films with Pt, Cu, and Co as top electrodes, and Pt as bottom electrodes were grown by magnetron sputtering. Both ZnO-Co and ZnO films show bipolar resistive switching characteristics. The resistive switching properties of ZnO films are strongly dependent on the top electrode materials. The effect of top electrodes on resistive switching of ZnO-Co films is weakened due to the dominant roles of Co particles in the films. It is different with ZnO films that the ZnO-Co film shows a forming-free process. The calculation from the classical electromagnetism theory indicates that the existence of Co nanoparticles in the ZnO switching matrix can enhance the local electrical field to some extent, and decrease the operating voltages. So the device with a ZnO-Co film as a switching matrix can significantly reduce power consumption, weaken the dependence of the electrode materials, and optimize the resistive switching performance.

  5. Optical and structural properties of nanostructured ZnO thin films deposited onto FTO/glass substrate by a solution-based technique

    CSIR Research Space (South Africa)

    Berruet, M

    2013-10-01

    Full Text Available Nanostructured zinc oxide thin films were spin coated on conductive glass substrates via a sol–gel based technique using zinc acetate dihydrate as precursor. The pH of the alkalis used as catalytic agents in the hydrolysis step is shown to have a...

  6. Ga-doped ZnO thin film surface characterization by wavelet and fractal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Chenlei; Tang, Wu, E-mail: tang@uestc.edu.cn

    2016-02-28

    Graphical abstract: - Highlights: • Multi-resolution signal decomposition of wavelet transform is applied to Ga-doped ZnO thin films with various thicknesses. • Fractal properties of GZO thin films are investigated by box counting method. • Fractal dimension is not in conformity with original RMS roughness. • Fractal dimension mainly depends on the underside diameter (grain size) and distance between adjacent grains. - Abstract: The change in roughness of various thicknesses Ga-doped ZnO (GZO) thin films deposited by magnetron reactive sputtering on glass substrates at room temperature was measured by atomic force microscopy (AFM). Multi-resolution signal decomposition based on wavelet transform and fractal geometry was applied to process surface profiles, to evaluate the roughness trend of relevant frequency resolution. The results give a six-level decomposition and the results change with deposited time and surface morphology. Also, it is found that fractal dimension is closely connected to the underside diameter (grain size) and the distance between adjacent grains that affect the change rate of surface and the increase of the defects such as abrupt changes lead to a larger value of fractal dimension.

  7. Atomic layer deposition of Al-doped ZnO thin films

    International Nuclear Information System (INIS)

    Tynell, Tommi; Yamauchi, Hisao; Karppinen, Maarit; Okazaki, Ryuji; Terasaki, Ichiro

    2013-01-01

    Atomic layer deposition has been used to fabricate thin films of aluminum-doped ZnO by depositing interspersed layers of ZnO and Al 2 O 3 on borosilicate glass substrates. The growth characteristics of the films have been investigated through x-ray diffraction, x-ray reflection, and x-ray fluorescence measurements, and the efficacy of the Al doping has been evaluated through optical reflectivity and Seebeck coefficient measurements. The Al doping is found to affect the carrier density of ZnO up to a nominal Al dopant content of 5 at. %. At nominal Al doping levels of 10 at. % and higher, the structure of the films is found to be strongly affected by the Al 2 O 3 phase and no further carrier doping of ZnO is observed.

  8. Textured surface boron-doped ZnO transparent conductive oxides on polyethylene terephthalate substrates for Si-based thin film solar cells

    International Nuclear Information System (INIS)

    Chen Xinliang; Lin Quan; Ni Jian; Zhang Dekun; Sun Jian; Zhao Ying; Geng Xinhua

    2011-01-01

    Textured surface boron-doped zinc oxide (ZnO:B) thin films were directly grown via low pressure metal organic chemical vapor deposition (LP-MOCVD) on polyethylene terephthalate (PET) flexible substrates at low temperatures and high-efficiency flexible polymer silicon (Si) based thin film solar cells were obtained. High purity diethylzinc and water vapors were used as source materials, and diborane was used as an n-type dopant gas. P-i-n silicon layers were fabricated at ∼ 398 K by plasma enhanced chemical vapor deposition. These textured surface ZnO:B thin films on PET substrates (PET/ZnO:B) exhibit rough pyramid-like morphology with high transparencies (T ∼ 80%) and excellent electrical properties (Rs ∼ 10 Ω at d ∼ 1500 nm). Finally, the PET/ZnO:B thin films were applied in flexible p-i-n type silicon thin film solar cells (device structure: PET/ZnO:B/p-i-n a-Si:H/Al) with a high conversion efficiency of 6.32% (short-circuit current density J SC = 10.62 mA/cm 2 , open-circuit voltage V OC = 0.93 V and fill factor = 64%).

  9. Luminescence and structural properties of ZnO thin films annealing in air

    Energy Technology Data Exchange (ETDEWEB)

    Baca, R; Martinez, J [Centro de Investigacion de Dispositivos Semiconductores, BUAP, Puebla, Pue. C.P. 72570 (Mexico); Esparza, A [Centro de Ciencias Aplicadas y Desarrollo de TecnologIa - UNAM. C.P. 04510, Mexico D.F (Mexico); Kryshtab, T [Departamento de Ciencias de Materiales, ESFM - IPN, Mexico D.F (Mexico); Juarez, G; Solache, H; Andraca, J; Pena, R, E-mail: rbaca02006@yahoo.com.mx

    2010-02-15

    All ZnO thin films deposited on (001) silicon substrates by DC reactive magnetron sputtering were annealed in air atmosphere with different times at 800deg. C. The samples were studied by X-ray diffraction technique (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD investigation showed that ZnO phase was hexagonal wurtzite structure growing along the (002) direction. The as grown ZnO films presented macrostrain and microstrain caused a shift of the line diffraction (002) and a broadening respectively. However after 1 hour annealing these strains disappear. The grain size of ZnO films increased with an increase of annealing time. The as-deposited reactive sputtering ZnO films resulted semi-insulating with poor PL response. After high temperature annealing in air, the crystallinity and the PL response considerably improved, but their semi-insulating property also increased. The PL spectra of the annealed samples showed well defined transitions close to the near-band-edge and a wide visible deep-level band emission (430-640 nm). The main interest of this work was to enhance the PL response and to identify the origin of deep-level luminescence bands. The AFM, PL and XRD results indicated that the ZnO films annealing have potential applications in optoelectronic devices.

  10. Crystallinity Improvement of ZnO Thin Film on Different Buffer Layers Grown by MBE

    Directory of Open Access Journals (Sweden)

    Shao-Ying Ting

    2012-01-01

    Full Text Available The material and optical properties of ZnO thin film samples grown on different buffer layers on sapphire substrates through a two-step temperature variation growth by molecular beam epitaxy were investigated. The thin buffer layer between the ZnO layer and the sapphire substrate decreased the lattice mismatch to achieve higher quality ZnO thin film growth. A GaN buffer layer slightly increased the quality of the ZnO thin film, but the threading dislocations still stretched along the c-axis of the GaN layer. The use of MgO as the buffer layer decreased the surface roughness of the ZnO thin film by 58.8% due to the suppression of surface cracks through strain transfer of the sample. From deep level emission and rocking curve measurements it was found that the threading dislocations play a more important role than oxygen vacancies for high-quality ZnO thin film growth.

  11. Highly doped ZnO films deposited by spray-pyrolysis. Design parameters for optoelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcés, F.A., E-mail: felipe.garces@santafe-conicet.gov.ar [Instituto de Física del Litoral (UNL-CONICET), Güemes 3450, Santa Fe S3000GLN (Argentina); Budini, N. [Instituto de Física del Litoral (UNL-CONICET), Güemes 3450, Santa Fe S3000GLN (Argentina); Schmidt, J.A.; Arce, R.D. [Instituto de Física del Litoral (UNL-CONICET), Güemes 3450, Santa Fe S3000GLN (Argentina); Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe S3000AOM (Argentina)

    2016-04-30

    Synthesis and preparation of ZnO films are relevant subjects for obtaining transparent and conducting layers with interesting applications in optoelectronics and photovoltaics. Optimization of parameters such as dopant type and concentration, deposition time and substrate temperature is important for obtaining ZnO layers with optimal properties. In this work we present a study about the induced effects of deposition time on optical and electrical properties of ZnO thin films. These films were deposited by spray pyrolysis of a suitable Zn precursor, obtained through the sol–gel method. The deposition time has direct incidence on internal stress in the crystal structure, generating defects that may affect transparency and electrical transport into the layers. We performed mosaicity measurements, through X-ray diffraction, and used it as a tool to get an insight on structural characteristics and homogeneity of ZnO layers. Also, through this technique, we analyzed thickness and doping effects on crystallinity and carrier transport properties. - Highlights: • Al-doped ZnO films with high conductivity and moderate Hall mobility were obtained. • Mosaicity between crystalline domains increased with film thickness. • Lattice parameters a and c diminished linearly as a function of Al concentration. • First steps for developing porous silicon/doped ZnO heterojunctions were presented.

  12. Highly doped ZnO films deposited by spray-pyrolysis. Design parameters for optoelectronic applications

    International Nuclear Information System (INIS)

    Garcés, F.A.; Budini, N.; Schmidt, J.A.; Arce, R.D.

    2016-01-01

    Synthesis and preparation of ZnO films are relevant subjects for obtaining transparent and conducting layers with interesting applications in optoelectronics and photovoltaics. Optimization of parameters such as dopant type and concentration, deposition time and substrate temperature is important for obtaining ZnO layers with optimal properties. In this work we present a study about the induced effects of deposition time on optical and electrical properties of ZnO thin films. These films were deposited by spray pyrolysis of a suitable Zn precursor, obtained through the sol–gel method. The deposition time has direct incidence on internal stress in the crystal structure, generating defects that may affect transparency and electrical transport into the layers. We performed mosaicity measurements, through X-ray diffraction, and used it as a tool to get an insight on structural characteristics and homogeneity of ZnO layers. Also, through this technique, we analyzed thickness and doping effects on crystallinity and carrier transport properties. - Highlights: • Al-doped ZnO films with high conductivity and moderate Hall mobility were obtained. • Mosaicity between crystalline domains increased with film thickness. • Lattice parameters a and c diminished linearly as a function of Al concentration. • First steps for developing porous silicon/doped ZnO heterojunctions were presented.

  13. Luminescence and structural properties of ZnO thin films annealing in air

    Science.gov (United States)

    Baca, R.; Juárez, G.; Solache, H.; Andraca, J.; Martinez, J.; Esparza, A.; Kryshtab, T.; Peña, R.

    2010-02-01

    All ZnO thin films deposited on (001) silicon substrates by DC reactive magnetron sputtering were annealed in air atmosphere with different times at 800°C. The samples were studied by X-ray diffraction technique (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD investigation showed that ZnO phase was hexagonal wurtzite structure growing along the (002) direction. The as grown ZnO films presented macrostrain and microstrain caused a shift of the line diffraction (002) and a broadening respectively. However after 1 hour annealing these strains disappear. The grain size of ZnO films increased with an increase of annealing time. The as-deposited reactive sputtering ZnO films resulted semi-insulating with poor PL response. After high temperature annealing in air, the crystallinity and the PL response considerably improved, but their semi-insulating property also increased. The PL spectra of the annealed samples showed well defined transitions close to the near-band-edge and a wide visible deep-level band emission (430-640 nm). The main interest of this work was to enhance the PL response and to identify the origin of deep-level luminescence bands. The AFM, PL and XRD results indicated that the ZnO films annealing have potential applications in optoelectronic devices.

  14. Impact of nanostructured thin ZnO film in ultraviolet protection.

    Science.gov (United States)

    Sasani Ghamsari, Morteza; Alamdari, Sanaz; Han, Wooje; Park, Hyung-Ho

    2017-01-01

    Nanoscale ZnO is one of the best choices for ultraviolet (UV) protection, not only because of its antimicrobial properties but also due to its potential application for UV preservation. However, the behavior of nanostructured thin ZnO films and long-term effects of UV-radiation exposure have not been studied yet. In this study, we investigated the UV-protection ability of sol gel-derived thin ZnO films after different exposure times. Scanning electron microscopy, atomic force microscopy, and UV-visible optical spectroscopy were carried out to study the structure and optical properties of the ZnO films as a function of the UV-irradiation time. The results obtained showed that the prepared thin ZnO films were somewhat transparent under the visible wavelength region and protective against UV radiation. The UV-protection factor was 50+ for the prepared samples, indicating that they were excellent UV protectors. The deposited thin ZnO films demonstrated promising antibacterial potential and significant light absorbance in the UV range. The experimental results suggest that the synthesized samples have potential for applications in the health care field.

  15. Improvement of physical properties of ZnO thin films by tellurium doping

    Energy Technology Data Exchange (ETDEWEB)

    Sönmezoğlu, Savaş, E-mail: svssonmezoglu@kmu.edu.tr; Akman, Erdi

    2014-11-01

    Highlights: • We report the synthesis of tellurium-doped zinc oxide (Te–ZnO) thin films using sol–gel method. • Highly c-axis oriented Te-doped ZnO thin films were grown on FTO glasses as substrate. • 1.5% Te-doping ratio could improve the physical properties of ZnO thin films. - Abstract: This investigation addressed the structural, optical and morphological properties of tellurium incorporated zinc oxide (Te–ZnO) thin films. The obtained results indicated that Te-doped ZnO thin films exhibit an enhancement of band gap energy and crystallinity compared with non-doped films. The optical transmission spectra revealed a shift in the absorption edge toward lower wavelengths. X-ray diffraction measurement demonstrated that the film was crystallized in the hexagonal (wurtzite) phase and presented a preferential orientation along the c-axis. The XRD obtained patterns indicate that the crystallite size of the thin films, ranging from 23.9 to 49.1 nm, changed with the Te doping level. The scanning electron microscopy and atomic force microscopy results demonstrated that the grain size and surface roughness of the thin films increased as the Te concentration increased. Most significantly, we demonstrate that it is possible to control the structural, optical and morphological properties of ZnO thin films with the isoelectronic Te-incorporation level.

  16. Structure and morphology of magnetron sputter deposited ultrathin ZnO films on confined polymeric template

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ajaib [Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology Indore, Indore 453552 (India); Schipmann, Susanne [II. Insatitute of Physics and JARA-FIT, RWTH Aachen University, 52056 Aachen (Germany); Mathur, Aakash; Pal, Dipayan [Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology Indore, Indore 453552 (India); Sengupta, Amartya [Department of Physics, Indian Institute of Technology Delhi, Delhi 110016 (India); Klemradt, Uwe [II. Insatitute of Physics and JARA-FIT, RWTH Aachen University, 52056 Aachen (Germany); Chattopadhyay, Sudeshna, E-mail: sudeshna@iiti.ac.in [Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology Indore, Indore 453552 (India); Discipline of Physics, Indian Institute of Technology Indore, Indore 453552 (India); Centre for Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore 453552 (India)

    2017-08-31

    Highlights: • Ultra-thin ZnO films grown on confined polymeric (polystyrene, PS) template. • XRR and GISAXS explore the surface/interfaces structure and morphology of ZnO/PS. • Insights into the growth mechanism of magnetron sputtered ZnO thin film on PS template. • Nucleated disk-like cylindrical particles are the basis of the formation of ZnO layers. • Effect of ZnO film thickness on room temperature PL spectra in ZnO/PS systems. - Abstract: The structure and morphology of ultra-thin zinc oxide (ZnO) films with different film thicknesses on confined polymer template were studied through X-ray reflectivity (XRR) and grazing incidence small angle X-ray scattering (GISAXS). Using magnetron sputter deposition technique ZnO thin films with different film thicknesses (<10 nm) were grown on confined polystyrene with ∼2R{sub g} film thickness, where R{sub g} ∼ 20 nm (R{sub g} is the unperturbed radius of gyration of polystyrene, defined by R{sub g} = 0.272 √M{sub 0}, and M{sub 0} is the molecular weight of polystyrene). The detailed internal structure, along the surface/interfaces and the growth direction of the system were explored in this study, which provides insight into the growth procedure of ZnO on confined polymer and reveals that a thin layer of ZnO, with very low surface and interface roughness, can be grown by DC magnetron sputtering technique, with approximately full coverage (with bulk like electron density) even in nm order of thickness, in 2–7 nm range on confined polymer template, without disturbing the structure of the underneath template. The resulting ZnO-polystyrene hybrid systems show strong ZnO near band edge (NBE) and deep-level (DLE) emissions in their room temperature photoluminescence spectra, where the contribution of DLE gets relatively stronger with decreasing ZnO film thickness, indicating a significant enhancement of surface defects because of the greater surface to volume ratio in thinner films.

  17. Study of (1 0 0) orientated ZnO films by APCVD system

    Energy Technology Data Exchange (ETDEWEB)

    Pacio, M. [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur and Av. San Claudio, San Manuel 72000, Puebla (Mexico); Juarez, H., E-mail: hjuarez@cs.buap.mx [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur and Av. San Claudio, San Manuel 72000, Puebla (Mexico); Escalante, G.; Garcia, G.; Diaz, T.; Rosendo, E. [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur and Av. San Claudio, San Manuel 72000, Puebla (Mexico)

    2010-10-25

    ZnO thin films were grown on glass substrate by Atmospheric Pressure Chemical Vapor Deposition system (APCVD), using zinc acetate (Zn(CH{sub 3}COO){sub 2}) as precursor of Zn. The solution was prepared with zinc acetate in ammonium hydroxide (NH{sub 4}OH). Ozone was used as an oxidant agent to obtain ZnO films. The aqueous solution of zinc acetate was bubbled with nitrogen flow into the reaction chamber. The structural and optical properties of ZnO films were investigated in different deposition temperatures (300-375 deg. C in steps of 25 deg. C). X-ray diffraction results show that all deposited films were polycrystallined in (1 0 0) preferred orientation. Our samples showed a transmittance bigger or similar to 80% in the visible region. Preliminary studies show that the room-temperature photoluminescence spectrum of all films exhibits a strong peak in visible region at 492.31 nm.

  18. Study of (1 0 0) orientated ZnO films by APCVD system

    International Nuclear Information System (INIS)

    Pacio, M.; Juarez, H.; Escalante, G.; Garcia, G.; Diaz, T.; Rosendo, E.

    2010-01-01

    ZnO thin films were grown on glass substrate by Atmospheric Pressure Chemical Vapor Deposition system (APCVD), using zinc acetate (Zn(CH 3 COO) 2 ) as precursor of Zn. The solution was prepared with zinc acetate in ammonium hydroxide (NH 4 OH). Ozone was used as an oxidant agent to obtain ZnO films. The aqueous solution of zinc acetate was bubbled with nitrogen flow into the reaction chamber. The structural and optical properties of ZnO films were investigated in different deposition temperatures (300-375 deg. C in steps of 25 deg. C). X-ray diffraction results show that all deposited films were polycrystallined in (1 0 0) preferred orientation. Our samples showed a transmittance bigger or similar to 80% in the visible region. Preliminary studies show that the room-temperature photoluminescence spectrum of all films exhibits a strong peak in visible region at 492.31 nm.

  19. Zinc Vacancy induced magnetism in ZnO thin films and nanowires

    Science.gov (United States)

    Wang, Qian; Sun, Qiang; Jena, Puru

    2008-03-01

    Extensive theoretical studies based on first-principles have been carried out for the mechanism of magnetism in ZnO thin films and nanowires. It has been identified that the observed magnetism is introduced by Zn vacancy and is affected by its concentration. The main source of the magnetic moment comes from the unpaired 2p- electrons in oxygen sites around the Zn vacancy, instead of Zn 3d electrons. Moreover, Zn vacancy is more energetically favorable to reside on the surface, and its formation energy is found to be less than that of oxygen vacancy that does not introduce any magnetism. These findings suggest that the main vacancy species is Zn vacancy as expected by experiments. The present theoretical study not only provides some deep understandings for the experimentally observed magnetism in un-doped ZnO samples, but also suggests that introducing Zn vacancy is a natural and an effective way to fabricate magnetic ZnO structure for bio-magnetic applications.

  20. ZnO thin films fabricated by chemical bath deposition, used as buffer layer in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lare, Y. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); Godoy, A. [Facultad Ciencias de la Salud, Universidad Diego Portales, Ejercito 141, Santiago de Chile (Chile); Cattin, L. [Universite de Nantes, Nantes Atlantique Universites, IMN, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France); Jondo, K. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); Abachi, T. [Ecole Normale Superieure, Kouba, Alger (Algeria); Diaz, F.R. [Laboratorio de Polimeros, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Correo 22, Santiago (Chile); Morsli, M. [Universite de Nantes, Nantes Atlantique Universites, LAMP, EA 3825, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France); Napo, K. [Laboratoire sue l' Energie Solaire, Universite de Lome, Lome (Togo); del Valle, M.A. [Laboratorio de Polimeros, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Casilla 306, Correo 22, Santiago (Chile); Bernede, J.C., E-mail: jean-christian.bernede@univ-nantes.fr [Universite de Nantes, Nantes Atlantique Universites, LAMP, EA 3825, Faculte des Sciences et des Techniques, 2 rue de la Houssiniere, BP 92208, Nantes, F-44000 France (France)

    2009-04-15

    ZnO thin films synthetized by chemical bath deposition are used as buffer layer between the anode and the organic electron donor in organic solar cells. Films deposited from zinc nitrate solutions are annealed in room air at 300 deg. C for half an hour. The X-ray diffraction and microanalysis studies show that ZnO polycrystalline thin films are obtained. The solar cells used are based on the couple copper phthalocyanine as electron donor and (N,N-diheptyl-3,4,9,10-perylenetetracarboxylicdiimide-PTCDI-C7) as electron acceptor. It is shown that the presence of the ZnO buffer layer improves the energy conversion efficiency of the cells. Such improvement could be attributed to a better energy level alignment at the anode/electron donor interface. The anode roughness induced by the ZnO buffer layer can also transform the planar interface organic electron donor/electron acceptor into roughen topography. This increases the interface area, where carrier separation takes place, which improves solar cells performances.

  1. 7-Octenyltrichrolosilane/trimethyaluminum hybrid dielectrics fabricated by molecular-atomic layer deposition on ZnO thin film transistors

    Science.gov (United States)

    Huang, Jie; Lee, Mingun; Lucero, Antonio T.; Cheng, Lanxia; Ha, Min-Woo; Kim, Jiyoung

    2016-06-01

    We demonstrate the fabrication of 7-octenytrichlorosilane (7-OTS)/trimethylaluminum (TMA) organic-inorganic hybrid films using molecular-atomic layer deposition (MALD). The properties of 7-OTS/TMA hybrid films are extensively investigated using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and electrical measurements. Our results suggest that uniform and smooth amorphous hybrid thin films with excellent insulating properties are obtained using the MALD process. Films have a relatively high dielectric constant of approximately 5.0 and low leakage current density. We fabricate zinc oxide (ZnO) based thin film transistors (TFTs) using 7-OTS/TMA hybrid material as a back gate dielectric with the top ZnO channel layer deposited in-situ via MALD. The ZnO TFTs exhibit a field effect mobility of approximately 0.43 cm2 V-1 s-1, a threshold voltage of approximately 1 V, and an on/off ratio of approximately 103 under low voltage operation (from -3 to 9 V). This work demonstrates an organic-inorganic hybrid gate dielectric material potentially useful in flexible electronics application.

  2. Light extraction efficiency enhancement of GaN-based light emitting diodes by a ZnO current spreading layer

    Science.gov (United States)

    Hua, Yang; Xiaofeng, Wang; Jun, Ruan; Zhicong, Li; Xiaoyan, Yi; Yao, Duan; Yiping, Zeng; Guohong, Wang

    2009-09-01

    Gallium nitride (GaN) based light emitting diodes (LEDs) with a thick and high quality ZnO film as a current spreading layer grown by metal-source vapor phase epitaxy (MVPE) are fabricated successfully. Compared with GaN-based LEDs employing a Ni/Au or an indium tin oxide transparent current spreading layer, these LEDs show an enhancement of the external quantum efficiency of 93% and 35% at a forward current of 20 mA, respectively. The full width at half maximum of the ZnO (002) ω-scan rocking curve is 93 arcsec, which corresponds to a high crystal quality of the ZnO film. Optical microscopy and atomic force microscopy are used to observe the surface morphology of the ZnO film, and many regular hexagonal features are found. A spectrophotometer is used to study the different absorption properties between the ZnO film and the indium tin oxide film of the GaN LED. The mechanisms of the extraction quantum efficiency increase and the series resistance change of the GaN-based LEDs with ZnO transparent current spreading layers are analyzed.

  3. Annealing effect on optical properties of ZnO films fabricated by cathodic electrodeposition

    International Nuclear Information System (INIS)

    Wang Qingtao; Wang Guanzhong; Jie Jiansheng; Han Xinhai; Xu Bo; Hou, J.G.

    2005-01-01

    (001)-oriented ZnO films on Zn substrates were synthesized by cathodic electrodeposition from an aqueous solution composed only of 0.05 M zinc nitrate at 65 deg. C. A bound exciton emission band around 3.34 eV along with three longitudinal optical (LO) phonon replicas and an intensive broad emission band around 2.17 eV were observed from the photoluminescence (PL) spectra of ZnO films prepared at more positive potential (- 0.6∼- 0.8 V). When more negative potential (- 1.0∼- 1.4 V) was applied, the ultraviolet emission band disappeared. These results indicate that more positive electrodeposition potential favors the high quality ZnO film growth. The PL spectra of the annealed ZnO films prepared at more positive electrodeposition potentials - 0.6∼- 1.0 V exhibit the ultraviolet emission at 3.35 eV and a negligibly weak emission from defects. Annealing resulted in the enhancement and sharpening of the excitonic emission band and decrease of the deep level emission. The bandgap (E g ) of the ZnO film prepared at - 1.0 V on indium tin oxide (ITO) substrate decreased from 3.56 to 3.29 eV due to the removing of Zn(OH) 2 from the film after annealing

  4. ZnO thin films on single carbon fibres fabricated by Pulsed Laser Deposition (PLD)

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, André; Engel, Sebastian [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Sangiorgi, Nicola [Institute of Science and Technology for Ceramics – National Research Council of Italy (CNR-ISTEC), via Granarolo 64, 48018 Faenza, RA (Italy); Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica, 00133 Rome (Italy); Sanson, Alessandra [Institute of Science and Technology for Ceramics – National Research Council of Italy (CNR-ISTEC), via Granarolo 64, 48018 Faenza, RA (Italy); Bartolomé, Jose F. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); Gräf, Stephan, E-mail: stephan.graef@uni-jena.de [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Müller, Frank A. [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena (Germany)

    2017-03-31

    Highlights: • Carbon fibres were entirely coated with thin films consisting of aligned ZnO crystals. • A Q-switched CO2 laser was utilised as radiation source. • Suitability of ZnO thin films on carbon fibres as photo anodes for DSSC was studied. - Abstract: Single carbon fibres were 360° coated with zinc oxide (ZnO) thin films by pulsed laser deposition using a Q-switched CO{sub 2} laser with a pulse duration τ ≈ 300 ns, a wavelength λ = 10.59 μm, a repetition frequency f{sub rep} = 800 Hz and a peak power P{sub peak} = 15 kW in combination with a 3-step-deposition technique. In a first set of experiments, the deposition process was optimised by investigating the crystallinity of ZnO films on silicon and polished stainless steel substrates. Here, the influence of the substrate temperature and of the oxygen partial pressure of the background gas were characterised by scanning electron microscopy and X-ray diffraction analyses. ZnO coated carbon fibres and conductive glass sheets were used to prepare photo anodes for dye-sensitised solar cells in order to investigate their suitability for energy conversion devices. To obtain a deeper insight of the electronic behaviour at the interface between ZnO and substrate I–V measurements were performed.

  5. The structural and optical properties of Y (Y  =  Al, B, Si and Ti)-doped ZnO nano thin films from the first principles calculations

    Science.gov (United States)

    Zhang, Wenshu; Hu, Huijun; Zhang, Caili; Li, Jianguo; Li, Yuping; Ling, Lixia; Han, Peide

    2017-12-01

    Based on the density functional theory, the structural stability and optical properties of undoped and Y (Y  =  Al, B, Si and Ti)-doped ZnO nano thin films are investigated. The good stability of the films based on the ZnO (0 0 0 1) can be obtained when the layer is larger than 12. Moreover, the dielectric function, refractive index, absorption, and reflectivity of doped ZnO nano thin films have been analyzed in detail. In the visible light range, the values of ZnO films from 12 to 24 layers are all smaller than those of the bulk. And with the augment of the layers, the values keep increasing. All the results signify that the nano film of 12 layers possesses the lowest reflectivity and weakest absorption. In addition, there is an evident impact of some doped element on the properties of nano films. The absorption and reflectivity of Ti, Si-doped ZnO nano thin films are higher than those of the clean films, while Al, B-doped are lower, especially B-doped. Moreover, the conductivity of the doped structure is better than that of the bulk. Thus, the B-doped ZnO nano thin films could be potential candidate materials of transparent conductive films.

  6. Evidence of Negative Capacitance in Piezoelectric ZnO Thin Films Sputtered on Interdigital Electrodes.

    Science.gov (United States)

    Laurenti, Marco; Verna, Alessio; Chiolerio, Alessandro

    2015-11-11

    The scaling paradigm known as Moore's Law, with the shrinking of transistors and their doubling on a chip every two years, is going to reach a painful end. Another less-known paradigm, the so-called Koomey's Law, stating that the computing efficiency doubles every 1.57 years, poses other important challenges, since the efficiency of rechargeable energy sources is substantially constant, and any other evolution is based on device architecture only. How can we still increase the computational power/reduce the power consumption of our electronic environments? A first answer to this question comes from the quest for new functionalities. Within this aim, negative capacitance (NC) is becoming one of the most intriguing and studied phenomena since it can be exploited for reducing the aforementioned limiting effects in the downscaling of electronic devices. Here we report the evidence of negative capacitance in 80 nm thick ZnO thin films sputtered on Au interdigital electrodes (IDEs). Highly (002)-oriented ZnO thin films, with a fine-grained surface nanostructure and the desired chemical composition, are deposited at room temperature on different IDEs structures. Direct-current electrical measurements highlighted the semiconducting nature of ZnO (current density in the order of 1 × 10(-3) A/cm(2)). When turned into the alternating current regime (from 20 Hz to 2 MHz) the presence of NC values is observed in the low-frequency range (20-120 Hz). The loss of metal/semiconductor interface charge states under forward bias conditions, together with the presence of oxygen vacancies and piezoelectric/electrostriction effects, is believed to be at the basis of the observed negative behavior, suggesting that ZnO thin-film-based field-effect transistors can be a powerful instrument to go beyond the Boltzmann limit and the downscaling of integrated circuit elements required for the fabrication of portable and miniaturized electronic devices, especially for electric household

  7. Scintillation characteristic of In, Ga-doped ZnO thin films with different dopant concentrations

    International Nuclear Information System (INIS)

    Fujimoto, Yutaka; Yanagida, Takayuki; Yokota, Yuui; Chani, Valery; Yoshikawa, Akira; Sekiwa, Hideyuki

    2011-01-01

    The present study describes the first detailed evaluation of the rise and the decay time of scintillation phenomenon in In 3+ - and Ga 3+ -doped ZnO thin films with different dopant concentrations. In 3+ -(25, 55, and 141 ppm) and Ga 3+ -(33, 67, 333, and 1374 ppm) doped ZnO films were grown by the Liquid Phase Epitaxy (LPE) method. The characterization was performed using the pulse X-ray equipped streak camera system. Both the rise and the decay times were shortened considerably with increasing content of In 3+ and Ga 3+ in the films. However, the scintillation light yield under 241 Am α-ray excitation reduced when concentration of In 3+ and Ga 3+ in the ZnO films was high. (author)

  8. Optical and photoelectrical properties of nanostructured thin ZnO films for UV-sensors

    Science.gov (United States)

    Grigoryev, L. V.; Kulakov, S. V.; Nefedov, V. G.; Shakin, O. V.; Grigoryeva, M. L.; Moskalenko, S. D.

    2017-05-01

    The article presents the results investigations of the optical and photoelectric properties thin films zinc oxide obtained by the reactive ion-plasma method. It is shown that the optical and photoelectric properties of thin ZnO films has equivalent characteristics to the properties of single crystal zinc oxide and can be used to create UV-photoresistors.

  9. Preparation and characterization of nanostructured ZnO thin films for ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Nanostructured zinc oxide thin films (ZnO) were prepared on conducting glass support (SnO2: F overlayer) via sol–gel starting from colloidal solution of zinc acetate 2-hydrate in ethanol and 2-methoxy ethanol. Films were obtained by spin coating at 1500 rpm under room conditions (temperature, 28–35°C) and.

  10. Pulsed laser deposition of aluminum-doped ZnO films at 355 nm

    DEFF Research Database (Denmark)

    Holmelund, E.; Schou, Jørgen; Thestrup Nielsen, Birgitte

    2004-01-01

    Conducting, transparent films of aluminium-doped ZnO (AZO) have been produced at the laser wavelength 355 nm. The most critical property, the electric resistivity, is up to a factor of 8 above that for films produced at shorter wavelengths. In contrast, the transmission of visible light through...

  11. Formation of p-type ZnO thin film through co-implantation.

    Science.gov (United States)

    Chuang, Yao-Teng; Liou, Jhe-Wei; Woon, Wei-Yen

    2017-01-20

    We present a study on the formation of p-type ZnO thin film through ion implantation. Group V dopants (N, P) with different ionic radii are implanted into chemical vapor deposition grown ZnO thin film on GaN/sapphire substrates prior to thermal activation. It is found that mono-doped ZnO by N + implantation results in n-type conductivity under thermal activation. Dual-doped ZnO film with a N:P ion implantation dose ratio of 4:1 is found to be p-type under certain thermal activation conditions. Higher p-type activation levels (10 19 cm -3 ) under a wider thermal activation range are found for the N/P dual-doped ZnO film co-implanted by additional oxygen ions. From high resolution x-ray diffraction and x-ray photoelectron spectroscopy it is concluded that the observed p-type conductivities are a result of the promoted formation of P Zn -4N O complex defects via the concurrent substitution of nitrogen at oxygen sites and phosphorus at zinc sites. The enhanced solubility and stability of acceptor defects in oxygen co-implanted dual-doped ZnO film are related to the reduction of oxygen vacancy defects at the surface. Our study demonstrates the prospect of the formation of stable p-type ZnO film through co-implantation.

  12. Photocatalytic efficiency of reusable ZnO thin films deposited by sputtering technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahumada-Lazo, R.; Torres-Martínez, L.M. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ecomateriales y Energía, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Ruíz-Gómez, M.A. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, Departamento de Ecomateriales y Energía, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Departmento de Física Aplicada, CINVESTAV-IPN, Antigua Carretera a Progreso km 6, Mérida, Yucatán 97310, México (Mexico); Vega-Becerra, O.E. [Centro de Investigación en Materiales Avanzados S.C, Alianza norte 202, Parque de Investigación e Innovación Tecnológica, C.P. 66600 Apodaca Nuevo León, México (Mexico); and others

    2014-12-15

    Graphical abstract: - Highlights: • Decolorization of Orange G dye using highly c-axis-oriented ZnO thin films. • The flake-shaped film shows superior and stable photoactivity at a wide range of pH. • The highest photodecolorization was achieved at pH of 7. • The exposure of (101) and (100) facets enhanced the photoactivity. • ZnO thin films exhibit a promising performance as recyclable photocatalysts. - Abstract: The photocatalytic activity of ZnO thin films with different physicochemical characteristics deposited by RF magnetron sputtering on glass substrate was tested for the decolorization of orange G dye aqueous solution (OG). The crystalline phase, surface morphology, surface roughness and the optical properties of these ZnO films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV–visible spectroscopy (UV–Vis), respectively. The dye photodecolorization process was studied at acid, neutral and basic pH media under UV irradiation of 365 nm. Results showed that ZnO films grow with an orientation along the c-axis of the substrate and exhibit a wurtzite crystal structure with a (002) preferential crystalline orientation. A clear relationship between surface morphology and photocatalytic activity was observed for ZnO films. Additionally, the recycling photocatalytic abilities of the films were also evaluated. A promising photocatalytic performance has been found with a very low variation of the decolorization degree after five consecutive cycles at a wide range of pH media.

  13. ZnO nanostructures as electron extraction layers for hybrid perovskite thin films

    Science.gov (United States)

    Nikolaidou, Katerina; Sarang, Som; Tung, Vincent; Lu, Jennifer; Ghosh, Sayantani

    Optimum interaction between light harvesting media and electron transport layers is critical for the efficient operation of photovoltaic devices. In this work, ZnO layers of different morphologies are implemented as electron extraction and transport layers for hybrid perovskite CH3NH3PbI3 thin films. These include nanowires, nanoparticles, and single crystalline film. Charge transfer at the ZnO/perovskite interface is investigated and compared through ultra-fast characterization techniques, including temperature and power dependent spectroscopy, and time-resolved photoluminescence. The nanowires cause an enhancement in perovskite emission, which may be attributed to increased scattering and grain boundary formation. However, the ZnO layers with decreasing surface roughness exhibit better electron extraction, as inferred from photoluminescence quenching, reduction in the number of bound excitons, and reduced exciton lifetime in CH3NH3PbI3 samples. This systematic study is expected to provide an understanding of the fundamental processes occurring at the ZnO-CH3NH3PbI3 interface and ultimately, provide guidelines for the ideal configuration of ZnO-based hybrid Perovskite devices. This research was supported by National Aeronautics and Space administration (NASA) Grant No: NNX15AQ01A.

  14. Effects of seed layers on controlling of the morphology of ZnO nanostructures and superhydrophobicity of ZnO nanostructure/stearic acid composite films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Liu, Zhihua, E-mail: sdwfliu@163.com; Liu, Junqi; E, Lei; Liu, Zhifeng, E-mail: tjulzf@163.com

    2016-11-01

    Hydrophobic ZnO self-cleaning thin films with the nanobundles and nanocarpets structures fabricated on indium tin oxides (ITO) glass substrate are reported. The water contact angle of ZnO nanobundles and nanocarpets structures (79° and 67° respectively) is higher than that of unmodified ZnO nanorods. A subsequent chemical treatment with stearic acid (SA) contributed to a superhydrophobic surface with a water contact angle of 159°. Its superhydrophobic property is originated from the nanobundles or nanocarpets structures and surface energy of SA/ZnO nanobundles and SA/ZnO nanocarpets composite nanostructures. Moreover, this promising ZnO nanostructured materials show an important application in self-cleaning smart coatings. - Highlights: • PEG and CTAB are firstly introduced to modify the morphology of ZnO seed layers. • ZnO nanobundles and nanocarpets obtained from different seed layers. • Superhydrophobic surfaces obtained by chemcial treatment using SA.

  15. Boron doped nanostructure ZnO films deposited by ultrasonic spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Karakaya, Seniye, E-mail: seniyek@ogu.edu.tr; Ozbas, Omer

    2015-02-15

    Highlights: • Nanostructure undoped and boron doped ZnO films were deposited by USP technique. • Influences of doping on the surface and optical properties of the ZnO films were investigated. • XRD spectra of the films exhibited a variation in crystalline quality depending on the B content. - Abstract: ZnO is an II–VI compound semiconductor with a wide direct band gap of 3.3 eV at room temperature. Doped with group III elements (B, Al or Ga), it becomes an attractive candidate to replace tin oxide (SnO{sub 2}) or indium tin oxide (ITO) as transparent conducting electrodes in solar cell devices and flat panel display due to competitive electrical and optical properties. In this work, ZnO and boron doped ZnO (ZnO:B) films have been deposited onto glass substrates at 350 ± 5 °C by a cost-efficient ultrasonic spray pyrolysis technique. The optical, structural, morphological and electrical properties of nanostructure undoped and ZnO:B films have been investigated. Electrical resistivity of films has been analyzed by four-probe technique. Optical properties and thicknesses of the films have been examined in the wavelength range 1200–1600 nm by using spectroscopic ellipsometry (SE) measurements. The optical constants (refractive index (n) and extinction coefficient (k)) and the thicknesses of the films have been fitted according to Cauchy model. The optical method has been used to determine the band gap value of the films. Transmission spectra have been taken by UV spectrophotometer. It is found that both ZnO and ZnO:B films have high average optical transmission (≥80%). X-ray diffraction (XRD) patterns indicate that the obtained ZnO has a hexagonal wurtzite type structure. The morphological properties of the films were studied by atomic force microscopy (AFM). The surface morphology of the nanostructure films is found to depend on the concentration of B. As a result, ZnO:B films are promising contender for their potential use as transparent window layer and

  16. Growth and characterization of ZnO thin films prepared by electrodeposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Fahoume, M.; Maghfoul, O.; Aggour, M. [L.P.M.C., Faculte des Sciences, Universite Ibn Tofail, BP. 133-14000 Kenitra (Morocco); Hartiti, B. [L.P.M.A.E.R., Faculte des Sciences et Techniques, B.P. 146 Mohammedia (Morocco); Chraibi, F.; Ennaoui, A. [L.P.M., Faculte des Sciences, Universite Mohammed V, BP.1014 Rabat (Morocco)

    2006-06-15

    ZnO thin films were deposited on either indium tin oxide-coated glass or copper substrate by the electrodeposition process, using zinc chloride and flowing air as precursors. The effect of pH on the structural and morphological ZnO films was studied and the optimum deposition conditions have been outlined. The kinetics of the growth of the films have been investigated. We note that the rate of deposition of ZnO in an acidic solution was larger than in a basic solution. The structure of the films was studied using X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The surface morphology and thickness of the films were determined using scanning electron microscopy. The X-ray diffraction analysis shows that the films are polycrystalline with hexagonal crystal structure (zincite) at pH 4. The optical transmittance of ZnO decreases with varying film thickness. The optical energy bandgap was found to be 3.26eV. (author)

  17. Enhanced luminescence properties of hybrid Alq{sub 3}/ZnO (organic/inorganic) composite films

    Energy Technology Data Exchange (ETDEWEB)

    Cuba, M.; Muralidharan, G., E-mail: muraligru@gmail.com

    2014-12-15

    Pristine tris-(8-hydroxyquionoline)aluminum(Alq{sub 3}) and (Alq{sub 3}/ZnO hybrid) composites containing different weight percentages (5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt%) of ZnO in Alq{sub 3} were synthesized and coated on to a glass substrate using the dip coating method. The optimum concentration of ZnO in Alq{sub 3} films to get the best luminescence yield has been identified. XRD pattern reveals the amorphous nature of pure Alq{sub 3} film. The Alq{sub 3} films containing different weight percentages of ZnO show the presence of crystalline ZnO in Alq{sub 3}/ZnO composite films. The FTIR spectrum confirms the formation of quinoline with absorption in the region 600−800 cm{sup −1}. The hybrid Alq{sub 3}/ZnO composite films indicate the presence of Zn−O vibration band along with the corresponding Alq{sub 3} band. The band gap (HOMO–LUMO) of Alq{sub 3} film was calculated using absorption spectra and it is 2.87 eV for pristine films while it is 3.26 eV, 3.21 eV, 3.14 eV, 3.10 eV, 3.13 eV and 3.20 eV for the composite films containing 5–50 wt% of ZnO. The photoluminescence (PL) spectra of Alq{sub 3} films show a maximum PL intensity at 514 nm when excited at 390 nm. The ZnO incorporated composite films (Alq{sub 3}/ZnO) exhibit an emission in 485 nm and 514 nm. The composite films containing 30 wt% of ZnO exhibit maximum luminescence yield. - Highlights: • The pure Alq{sub 3} and Alq{sub 3}/ZnO composite were synthesized and coated on to a glass substrate using dip coating method. • Alq{sub 3}/ZnO composite film containing 30 wt% of ZnO exhibits two fold increases in luminescence intensity. • The shielding effect of ZnO on the Alq{sub 3} material suppresses the interactions among the host molecules in the excited state. • This leads to enhance the luminescence intensity in composite films.

  18. Elaboration and Characterization of Sprayed Tb-Doped ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Amina ELFAKIR

    2014-05-01

    Full Text Available ZnO and Tb-doped ZnO (TZO thin films were deposited on glass substrate at 350 °C by spray pyrolysis technique. Structural, optical and electrical properties of the films were investigated as a function of dopant concentration, which was varied between 0 and 5 at % of terbium. TZO films were polycrystalline and exhibit hexagonal quartzite crystal structure with a preferential orientation along 2 direction. The AFM measurements show that the roughness of the films increased with Tb doping. All the TZO films exhibit a transmittance between 70 and 80 % in the visible range. The TZO films were n-type degenerate semiconductor with a lowest electrical resistivity of about 6.0´10- 2 W.cm.

  19. Chitosan/poly (vinyl alcohol) films containing ZnO nanoparticles and plasticizers

    Energy Technology Data Exchange (ETDEWEB)

    Vicentini, Denice S. [Mechanical Engineering Department, Federal University of Santa Catarina, University Campus, 88040-900 Florianopolis, Santa Catarina (Brazil); Smania, Arthur [Microbiology and Parasitology Department, Federal University of Santa Catarina, University Campus, 88040-900 Florianopolis, Santa Catarina (Brazil); Laranjeira, Mauro C.M., E-mail: mauro@qmc.ufsc.br [Mechanical Engineering Department, Federal University of Santa Catarina, University Campus, 88040-900 Florianopolis, Santa Catarina (Brazil); Chemistry Department, QUITECH, Federal University of Santa Catarina, University Campus, 88040-900 Florianopolis, Santa Catarina (Brazil)

    2010-05-10

    In this study ZnO nanoparticles were prepared by the Pechini method from a polyester by reacting citric acid with ethylene glycol in which the metal ions are dissolved, and incorporated into blend films of chitosan (CS) and poly (vinyl alcohol) (PVA) with different concentrations of polyoxyethylene sorbitan monooleate, Tween 80 (T80). These films were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), swelling degree, degradation of films in Hank's solution and the mechanical properties. Besides these characterizations, the antibacterial activity of the films was tested, and the films containing ZnO nanoparticles showed antibacterial activity toward the bacterial species Staphylococcus aureus. The observed antibacterial activity in the composite films prepared in this work suggests that they may be used as hydrophilic wound and burn dressings.

  20. ZnO Films with Very High Haze Value for Use as Front Transparent Conductive Oxide Films in Thin-Film Silicon Solar Cells

    Science.gov (United States)

    Hongsingthong, Aswin; Krajangsang, Taweewat; Afdi Yunaz, Ihsanul; Miyajima, Shinsuke; Konagai, Makoto

    2010-05-01

    We successfully increased the haze value of zinc oxide (ZnO) films fabricated using metal-organic chemical vapor deposition (MOCVD) by conducting glass-substrate etching before film deposition. It was found that with increasing the glass treatment time, the surface morphology of ZnO films changed from conventional pyramid-like single texture to greater cauliflower-like multi texture. Further, the rms roughness and the haze value of the films increased remarkably. Using ZnO films with a high haze value as front transparent conductive oxide (TCO) films in hydrogenated microcrystalline silicon (µc-Si:H) solar cells, we improved the quantum efficiency of these cells particularly in the long-wavelength region.

  1. A novel hierarchical ZnO disordered/ordered bilayer nanostructured film for dye sensitized solar cells

    International Nuclear Information System (INIS)

    Feng, Yamin; Wu, Fei; Jiang, Jian; Zhu, Jianhui; Fodjouong, Ghislain Joel; Meng, Gaoxiang; Xing, Yanmin; Wang, Wenwu; Huang, Xintang

    2013-01-01

    Graphical abstract: A novel hierarchical disordered/ordered bilayer ZnO nanostructured film in the length of 18 μm have been successfully synthesized on the FTO substrate; the hierarchical ZnO nanostructured film electrodes applied in DSSCs exhibit photoelectric conversion efficiency as high as 5.16%. Highlights: •A novel hierarchical ZnO structure film was fabricated on a FTO substrate. •Hierarchical ZnO film is applied as the electrodes for dye sensitized solar cells. •The film possess high specific surface area and fast electron transport effect. •The light-scattering effect of the hierarchical film is pronounced. •The energy conversion efficiency of hierarchical ZnO electrode reaches to 5.16%. -- Abstract: A novel hierarchical ZnO nanostructured film is synthesized via a chemical bath deposition (CBD) method followed by a treatment of thermal decomposition onto a fluorine-doped tin oxide (FTO) substrate. This hierarchical film is composed of disordered ZnO nanorods (NRs) (top layer) and ordered ZnO nanowires (NWs) (bottom layer). The products possess the following features such as high specific surface area, fast electron transport, and pronounced light-scattering effect, which are quite suitable for dye sensitized solar cells (DSSCs) applications. A light-to-electricity conversion efficiency of 5.16% is achieved when the hierarchical ZnO nanostructured film is used as the photoanode under 100 mW cm −2 illumination. This efficiency is found to be much higher than that of the DSSCs with pure ordered ZnO NWs (1.45%) and disordered ZnO NRs (3.31%) photoanodes

  2. A novel hierarchical ZnO disordered/ordered bilayer nanostructured film for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yamin, E-mail: yaminfengccnuphy@outlook.com; Wu, Fei; Jiang, Jian; Zhu, Jianhui; Fodjouong, Ghislain Joel; Meng, Gaoxiang; Xing, Yanmin; Wang, Wenwu; Huang, Xintang, E-mail: xthuang@phy.ccnu.edu.cn

    2013-12-25

    Graphical abstract: A novel hierarchical disordered/ordered bilayer ZnO nanostructured film in the length of 18 μm have been successfully synthesized on the FTO substrate; the hierarchical ZnO nanostructured film electrodes applied in DSSCs exhibit photoelectric conversion efficiency as high as 5.16%. Highlights: •A novel hierarchical ZnO structure film was fabricated on a FTO substrate. •Hierarchical ZnO film is applied as the electrodes for dye sensitized solar cells. •The film possess high specific surface area and fast electron transport effect. •The light-scattering effect of the hierarchical film is pronounced. •The energy conversion efficiency of hierarchical ZnO electrode reaches to 5.16%. -- Abstract: A novel hierarchical ZnO nanostructured film is synthesized via a chemical bath deposition (CBD) method followed by a treatment of thermal decomposition onto a fluorine-doped tin oxide (FTO) substrate. This hierarchical film is composed of disordered ZnO nanorods (NRs) (top layer) and ordered ZnO nanowires (NWs) (bottom layer). The products possess the following features such as high specific surface area, fast electron transport, and pronounced light-scattering effect, which are quite suitable for dye sensitized solar cells (DSSCs) applications. A light-to-electricity conversion efficiency of 5.16% is achieved when the hierarchical ZnO nanostructured film is used as the photoanode under 100 mW cm{sup −2} illumination. This efficiency is found to be much higher than that of the DSSCs with pure ordered ZnO NWs (1.45%) and disordered ZnO NRs (3.31%) photoanodes.

  3. Piezoelectricity and charge trapping in ZnO and Co-doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Domenico D’Agostino

    2017-05-01

    Full Text Available Piezoelectricity and charge storage of undoped and Co-doped ZnO thin films were investigated by means of PiezoResponse Force Microscopy and Kelvin Probe Force Microscopy. We found that Co-doped ZnO exhibits a large piezoelectric response, with the mean value of piezoelectric matrix element d33 slightly lower than in the undoped sample. Moreover, we demonstrate that Co-doping affects the homogeneity of the piezoelectric response, probably as a consequence of the lower crystalline degree exhibited by the doped samples. We also investigate the nature of the interface between a metal electrode, made up of the PtIr AFM tip, and the films as well as the phenomenon of charge storage. We find Schottky contacts in both cases, with a barrier value higher in PtIr/ZnO than in PtIr/Co-doped ZnO, indicating an increase in the work function due to Co-doping.

  4. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Serhane, Rafik, E-mail: rserhane@cdta.dz [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Hassein-Bey, Abdelkadder [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Micro and Nano Physics Group, Faculty of Sciences, University Saad Dahlab of Blida (USDB), BP. 270, DZ-09000 Blida (Algeria); Boutkedjirt, Tarek [Equipe de Recherche Physique des Ultrasons, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, DZ-16111 Algiers (Algeria)

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO{sub 2}/Si and Al (1 1 1)/SiO{sub 2}/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as K{sub eff}{sup 2}=5.09%, with a quality factor Q{sub r} = 1001.4.

  5. Hydrophobic ZnO nanostructured thin films on glass substrate by simple successive ionic layer absorption and reaction (SILAR) method

    International Nuclear Information System (INIS)

    Kumar, P. Suresh; Raj, A. Dhayal; Mangalaraj, D.; Nataraj, D.

    2010-01-01

    In the present work, ZnO nanostructured thin films were grown on glass substrates by a simple successive ionic layer absorption and reaction method (SILAR) process at relatively low temperature for its self cleaning application. X-ray diffraction, scanning electron microscopy and Photoluminescence (PL) spectra were used to characterize the prepared ZnO nanostructured film. XRD pattern clearly reviles that the grown ZnO nanostructure film reflect (002) orientation with c-direction. SEM image clearly shows the surface morphology with cluster of spindle and flower-like nanostructured with diameter various around 350 nm. Photoluminescence (PL) spectra of ZnO nanostructures film exhibit a UV emission around 385nm and visible emission in the range around 420-500 nm. Good water repellent behavior were observed for ZnO nanostructured film without any surface modification.

  6. Effect of substrate temperature on structural and optical properties of spray deposited ZnO thin films

    Directory of Open Access Journals (Sweden)

    Larbah Y.

    2015-09-01

    Full Text Available Undoped ZnO thin films have been prepared on glass substrates at different substrate temperatures by spray pyrolysis method. The effect of temperature on the structural, morphological and optical properties of n-type ZnO films was studied. The X-ray diffraction (XRD results confirmed that the ZnO thin films were polycrystalline with wurtzite structure. Scanning electron microscopy (SEM measurements showed that the surface morphology of the films changed with temperature. The studies demonstrated that the ZnO film had a transmission of about 85 % and energy gap of 3.28 eV at 450 °C. The RBS measurements revealed that ZnO layers with a thickness up to 200 nm had a good stoichiometry.

  7. Fabrication of ZnO Thin Films by Sol-Gel Spin Coating and Their UV and White-Light Emission Properties

    Science.gov (United States)

    Kumar, Mirgender; Dubey, Sarvesh; Rajendar, Vanga; Park, Si-Hyun

    2017-10-01

    ZnO thin films have been fabricated by the sol-gel spin-coating technique and annealed under different conditions, and their ultraviolet (UV) and white-light emission properties investigated. Different ambient conditions including oxygen, nitrogen, zinc-rich nitrogen, and vacuum were used to tune the main properties of the ZnO thin films. The resistivity varied from the conductive to semi-insulating regime, and the luminescence emission from fairly intense UV to polychromatic. The emission intensity was also found to be a function of the annealing conditions. Possible routes to compensate the loss of emission characteristics are discussed. X-ray photoelectron spectroscopy (XPS) analysis was carried out to detect the chemical states of the zinc/oxygen species. The changes in the electrical and emission properties are explained based on annihilation/formation of inherent donor/acceptor-type defects. Such ZnO thin films could have potential applications in solid-state lighting.

  8. Fabrication and Characterization of High-Crystalline Nanoporous ZnO Thin Films by Modified Thermal Evaporation System

    Science.gov (United States)

    Islam, M. S.; Hossain, M. F.; Razzak, S. M. A.; Haque, M. M.; Saha, D. K.

    2016-05-01

    The aim of this work is to fabricate high-crystalline nanoporous zinc oxide (ZnO) thin films by a modified thermal evaporation system. First, zinc thin films have been deposited on bare glass substrate by the modified thermal evaporation system with pressure of 0.05mbar, source-substrate distance of 3cm and source temperature 700∘C. Then, high-crystalline ZnO thin film is obtained by annealing at 500∘C for 2h in atmosphere. The prepared ZnO films are characterized with various deposition times of 10min and 20min. The structural property was investigated by X-ray diffractometer (XRD). The optical bandgap and absorbance/transmittance of these films are examined by ultraviolet/visible spectrophotometer. The surface morphological property has been observed by scanning electron microscope (SEM). ZnO films have showed uniform nanoporous surface with high-crystalline hexagonal wurtzite structure. The ZnO films prepared with 20min has excitation absorption-edge at 369nm, which is blueshifted with respect to the bulk absorption-edge appearing at 380nm. The gap energy of ZnO film is decreased from 3.14eV to 3.09eV with increase of the deposition time, which can enhance the excitation of ZnO films by the near visible light, and is suitable for the application of photocatalyst of waste water cleaning and polluted air purification.

  9. Superhydrophobic nanostructured ZnO thin films on aluminum alloy substrates by electrophoretic deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ying; Sarkar, D.K., E-mail: dsarkar@uqac.ca; Chen, X-Grant

    2015-02-01

    Graphical abstract: - Highlights: • Fabrication of superhydrophobic ZnO thin films surfaces by electrophoretic deposition process on aluminum substrates. • Effect of bath temperature on the physical and superhydrophobic properties of thin films. • The water contact angle of 155° ± 3 with roll off property has been observed on the film that was grown at bath temperatures of 50 °C. • The activation energy for electrophoretic deposition of SA-functionalized ZnO nanoparticle is calculated to be 0.50 eV. - Abstract: Superhydrophobic thin films have been fabricated on aluminum alloy substrates by electrophoretic deposition (EPD) process using stearic acid (SA) functionalized zinc oxide (ZnO) nanoparticles suspension in alcohols at varying bath temperatures. The deposited thin films have been characterized using both X-ray diffraction (XRD) and infrared (IR) spectroscopy and it is found that the films contain low surface energy zinc stearate and ZnO nanoparticles. It is also observed that the atomic percentage of Zn and O, roughness and water contact angle of the thin films increase with the increase of the deposited bath temperature. Furthermore, the thin film deposited at 50 °C, having a roughness of 4.54 ± 0.23 μm, shows superhydrophobic properties providing a water contact angle of 155 ± 3° with rolling off properties. Also, the activation energy of electrophoretic deposition of stearic-acid-functionalized ZnO nanoparticles is calculated to be 0.5 eV.

  10. Microstructure of ZnO Thin Films Deposited by High Power Impulse Magnetron Sputtering (Postprint)

    Science.gov (United States)

    2015-03-01

    Avrutin, S. Cho , H. Morkoc, A comprehensive review of ZnO materials and devices, J. Appl. Phys. 98 (2005) 41301. [4] M. Shimizu, T. Shiosaki, A...cathodic vacuum arc, Thin Solid Films 398–399 (2001) 244. [11] C.F. Yu, C.W. Sung , S.H. Chen, S.J. Sun, Relationship between the photoluminescence...L. Sanghun, C. Dongkeun, K. Won-Jeong, H. Moon- Ho , L. Woong, Ga-doped ZnO films deposited with varying sputtering powers and substrate temperatures by

  11. Dye-Sensitized Nanocrystalline ZnO Solar Cells Based on Ruthenium(II Phendione Complexes

    Directory of Open Access Journals (Sweden)

    Hashem Shahroosvand

    2011-01-01

    Full Text Available The metal complexes (RuII (phen2(phendione(PF62(1, [RuII (phen(bpy(phendione(PF62 (2, and (RuII (bpy2(phendione(PF62 (3 (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine and phendione = 1,10-phenanthroline-5,6-dione have been synthesized as photo sensitizers for ZnO semiconductor in solar cells. FT-IR and absorption spectra showed the favorable interfacial binding between the dye-molecules and ZnO surface. The surface analysis and size of adsorbed dye on nanostructure ZnO were further examined with AFM and SEM. The AFM images clearly show both, the outgrowth of the complexes which are adsorbed on ZnO thin film and the depression of ZnO thin film. We have studied photovoltaic properties of dye-sensitized nanocrystalline semiconductor solar cells based on Ru phendione complexes, which gave power conversion efficiency of (η of 1.54% under the standard AM 1.5 irradiation (100 mW cm−2 with a short-circuit photocurrent density (sc of 3.42 mA cm−2, an open-circuit photovoltage (oc of 0.622 V, and a fill factor (ff of 0.72. Monochromatic incident photon to current conversion efficiency was 38% at 485 nm.

  12. Hydrogen-incorporated ZnO nanowire films: stable and high electrical conductivity

    Science.gov (United States)

    Kushwaha, Ajay; Aslam, M.

    2013-12-01

    Post-growth hydrogen annealing treatment of highly oriented ZnO nanowire (NW) films (ZnO : H) results in high electrical conductivity (3.7 × 103 S m-1) and fully suppressed defect emission at room temperature. The formation of hydrogen-related vacancy complexes is responsible for the suppression of vacancies ( V_{o}^{+} and V_{o}^{2+} ), leading to a reduction in defect-based emission. ZnO : H NW films show five orders larger stable electrical conductance with a four-fold increment in carrier mobility (7-28 cm2 V-1 s-1). As compared with pristine NWs, the carrier concentration in ZnO : H NW films increases from 1015 to 1019 cm-3, which is in the range of commercial transparent conducting oxides. X-ray photoelectron spectroscopy and secondary ion mass spectrometry analyses reveal stable OH bond formation, which strongly supports the prediction of H doping. These films offer a promising conducting oxide platform for photovoltaic applications.

  13. Study of structural and optical properties of ZnO films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Lemlikchi, S.; Abdelli-Messaci, S.; Lafane, S.; Kerdja, T.; Guittoum, A.; Saad, M.

    2010-01-01

    Wurtzite zinc oxides films (ZnO) were deposited on silicon (0 0 1) and corning glass substrates using the pulsed laser deposition technique. The laser fluence, target-substrate distance, substrate temperature of 300 deg. C were fixed while varying oxygen pressures from 2 to 500 Pa were used. It is observed that the structural properties of ZnO films depend strongly on the oxygen pressure and the substrate nature. The film crystallinity improves with decreasing oxygen pressure. At high oxygen pressure, the films are randomly oriented, whereas, at low oxygen pressures they are well oriented along [0 0 1] axis for Si substrates and along [1 0 3] axis for glass substrates. A honeycomb structure is obtained at low oxygen pressures, whereas microcrystalline structures were obtained at high oxygen pressures. The effect of oxygen pressure on film transparency, band gap E g and Urbach energies was investigated.

  14. Theoretical study of the multiferroic properties in M-doped (M=Co, Cr, Mg) ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bahoosh, S.G. [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Apostolov, A.T. [University of Architecture, Civil Engineering and Geodesy, Faculty of Hydrotechnics, Department of Physics, 1, Hristo Smirnenski Blvd., 1046 Sofia (Bulgaria); Apostolova, I.N. [University of Forestry, Faculty of Forest Industry, 10, Kl. Ohridsky Blvd., 1756 Sofia (Bulgaria); Trimper, S. [Institute of Physics, Martin-Luther-University, D-06099 Halle (Germany); Wesselinowa, Julia M. [University of Sofia, Department of Physics, Blvd. J. Bouchier 5, 1164 Sofia (Bulgaria)

    2015-01-01

    The origin of multiferroism is still an open problem in ZnO. We propose a microscopic model to clarify the occurrence of multiferroism in this material. Using Green's function technique we study the influence of ion doping and size effects on the magnetization and polarization of ZnO thin films. The calculations for magnetic Co- and Cr-ions are based on the s–d model, the transverse Ising model in terms of pseudo-spins and a biquadratic magnetoelectric coupling, whereas in case of nonmagnetic Mg-ions the model takes into account the Coulomb interaction and an indirect coupling between the pseudo-spins via the conduction electrons. We show that the magnetization M exhibits a maximum for a fixed concentration of the doping ions. Furthermore M increases with decreasing film thickness N. The polarization increases with increasing concentration of the dopant and decreasing N. The results are in good agreement with the experimental data. - Highlights: • The paper analyzes the multiferroic properties of doped ZnO thin films by a microscopic model. • The magnetization exhibits a maximum at a fixed doping concentration. • The polarization increases with growing dopant concentration. • The ferroelectric transition temperature is enhanced for increasing dopant concentration.

  15. Enhanced electrical properties of ZnO transparent conducting films prepared by electron beam annealing

    Science.gov (United States)

    Li, Yanli; Men, Yong; Kong, Xiangdong; Gao, Zhaoshun; Han, Li; Li, Xiaona

    2018-01-01

    Pure ZnO precursor films were prepared by a sol-gel spin coating method. The films were directly annealed by the electron beam (EB) for 5 min. The structural, optical and electrical properties were investigated by means of SEM, AFM, XRD, UV-vis spectrophotometer and Hall-effect measurement. SEM and AFM studies revealed smooth, dense film microstructure with some holes. The average grain size ranged from 10 nm to 60 nm and the surface RMS roughness of the films is less than 3 nm. X-rays diffraction patterns showed (002) preferential growth in all annealed films. From optical transmittance spectra, the absorption edge of the films was determined to be at ∼380 nm with > 85% transmittance in visible region. ZnO film annealed with beam current 0.7 mA was found to exhibit minimum resistivity value of 1.57 × 10-2 Ωcm and carrier concentration as high as 6.37 × 1019 cm-3, which is 2 ∼ 3 orders better than that of the typical pure ZnO thin films using sol-gel method.

  16. Superhydrophilic zinc oxide film prepared by controlling ZnO microrods growth and its attractive recyclable photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China); Chen, Zheng [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); Lu, Luhua, E-mail: lhlu@whut.edu.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Zhu, Guangping; Liu, Zhongliang; Liu, Qinzhuang [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China)

    2013-07-31

    Superhydrophilic functional materials have been found to be of great value for a variety of practical applications in recent years. In this paper, zinc oxide (ZnO) microrod films have been directly synthesized on a large-area zinc substrate via a simple solution method. Morphological and structural observation and crystallinity of the grown products were carried out using scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer, transmission electron microscopy, ultraviolet (UV)–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The influence of reaction time on the size and shapes of the as-prepared ZnO samples was studied. It was found that superhydrophilic ZnO films at reaction time of 20 h were made up of uniform pure ZnO microrods with 600 nm in average diameter and 6 μm in length. Room-temperature PL spectra of the ZnO products showed a UV emission and a broad green band. Photocatalytic performance and sample stability were studied. Under UV light irradiation over 95% of methylene blue was degraded by ZnO microrod films in 4 h, ZnO microrod film can be easily separated from the solution, and no observable performance degradation was observed after 5 cycles. - Highlights: • Superhydrophilic ZnO microrod films were successfully synthesized. • ZnO microrods are single crystalline with the hexagonal wurtzite structure. • ZnO microrod films can be easily separated from the solution. • Superhydrophilic ZnO microrod films can be reused.

  17. Superhydrophilic zinc oxide film prepared by controlling ZnO microrods growth and its attractive recyclable photocatalytic performance

    International Nuclear Information System (INIS)

    Dai, Kai; Chen, Zheng; Lu, Luhua; Zhu, Guangping; Liu, Zhongliang; Liu, Qinzhuang

    2013-01-01

    Superhydrophilic functional materials have been found to be of great value for a variety of practical applications in recent years. In this paper, zinc oxide (ZnO) microrod films have been directly synthesized on a large-area zinc substrate via a simple solution method. Morphological and structural observation and crystallinity of the grown products were carried out using scanning electron microscopy, X-ray diffraction, energy dispersive spectrometer, transmission electron microscopy, ultraviolet (UV)–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The influence of reaction time on the size and shapes of the as-prepared ZnO samples was studied. It was found that superhydrophilic ZnO films at reaction time of 20 h were made up of uniform pure ZnO microrods with 600 nm in average diameter and 6 μm in length. Room-temperature PL spectra of the ZnO products showed a UV emission and a broad green band. Photocatalytic performance and sample stability were studied. Under UV light irradiation over 95% of methylene blue was degraded by ZnO microrod films in 4 h, ZnO microrod film can be easily separated from the solution, and no observable performance degradation was observed after 5 cycles. - Highlights: • Superhydrophilic ZnO microrod films were successfully synthesized. • ZnO microrods are single crystalline with the hexagonal wurtzite structure. • ZnO microrod films can be easily separated from the solution. • Superhydrophilic ZnO microrod films can be reused

  18. Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach

    OpenAIRE

    Hullavarad, SS; Hullavarad, NV; Karulkar, PC; Luykx, A; Valdivia, P

    2007-01-01

    AbstractThe ZnO nanostructures consisting of micro spheres in a network of nano wires were synthesized by direct vapor phase method. X-ray Photoelectron Spectroscopy measurements were carried out to understand the chemical nature of the sample. ZnO nanostructures exhibited band edge luminescence at 383 nm. The nanostructure based ZnO thin films were used to fabricate UV sensors. The photoresponse measurements were carried out and the responsivity was measured to be 50 mA W−1. The rise a...

  19. Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach

    Directory of Open Access Journals (Sweden)

    Luykx A

    2007-01-01

    Full Text Available AbstractThe ZnO nanostructures consisting of micro spheres in a network of nano wires were synthesized by direct vapor phase method. X-ray Photoelectron Spectroscopy measurements were carried out to understand the chemical nature of the sample. ZnO nanostructures exhibited band edge luminescence at 383 nm. The nanostructure based ZnO thin films were used to fabricate UV sensors. The photoresponse measurements were carried out and the responsivity was measured to be 50 mA W−1. The rise and decay time measurements were also measured.

  20. Reversible wettability of nanostructured ZnO thin films by sol-gel method

    Science.gov (United States)

    Lü, Jianguo; Huang, Kai; Chen, Xuemei; Zhu, Jianbo; Meng, Fanming; Song, Xueping; Sun, Zhaoqi

    2010-05-01

    Nanostructured ZnO thin films were deposited on Si(1 1 1) and quartz substrate by sol-gel method. The thin films were annealed at 673 K, 873 K, and 1073 K for 60 min. Microstructure, surface topography, and water contact angle of the thin films have been measured by X-ray diffractometer, atomic force microscopy, and water contact angle apparatus. XRD results showed that the ZnO thin films are polycrystalline with hexagonal wurtzite structure. AFM studies revealed that rms roughness changes from 2.3 nm to 7.4 nm and the grain size grow up continuously with increasing annealing temperature. Wettability results indicated that hydrophobicity of the un-irradiated ZnO thin films enhances with annealing temperature increase. The hydrophobic ZnO surfaces could be reversibly switched to hydrophilic by alternation of UV illumination and dark storage (thermal treatment). By studying the magnitude and the contact angle reduction rate of the light-induced process, the contribution of surface roughness is discussed.

  1. Enhanced photovoltaic performance of dye sensitized solar cells using one dimensional ZnO nanorod decorated porous TiO{sub 2} film electrode

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Long; Ma, Qing-lan [School of Mathematic and Physics, Changzhou University, Jiangsu 213164 (China); Cai, Yungao [Department of Science and Technology, Baoshan University, Yunnan 678000 (China); Huang, Yuan Ming, E-mail: dongshanisland@126.com [School of Mathematic and Physics, Changzhou University, Jiangsu 213164 (China)

    2014-02-15

    A low cost and effective working electrode with one dimensional ZnO nanorod grown on the porous TiO{sub 2} film is used to improve the power conversion efficiency of dye sensitized solar cells. The one dimensional ZnO nanorod is introduced into the porous TiO{sub 2} film by a simple and facile hydrothermal route, and the obtained composite film is characterized using the field-emission scan electron microscopy, X-ray diffractometer and photoluminescence spectroscopy. The photocurrent–voltage curves of fabricated dye sensitized solar cells are measured by a solar cell measurement system. Compared with the bare porous TiO{sub 2} film based dye sensitized solar cell, it is found that the power conversion efficiency of dye sensitized solar cell with ZnO nanorod decorated TiO{sub 2} porous film was improved by more than triple. It is mainly believed that the improved power conversion efficiency of dye sensitized solar cell is ascribed to the increased dye adsorption amount and formation of energy barrier between ZnO nanorod and porous TiO{sub 2} film.

  2. Effect of High Temperature Annealing on Conduction-Type ZnO Films Prepared by Direct-Current Magnetron Sputtering

    International Nuclear Information System (INIS)

    Sun Li-Jie; He Dong-Kai; Xu Xiao-Qiu; Zhong Ze; Wu Xiao-Peng; Lin Bi-Xia; Fu Zhu-Xi

    2010-01-01

    We experimentally find that the ZnO thin films deposited by dc-magnetron sputtering have different conduction types after annealing at high temperature in different ambient. Hall measurements show that ZnO films annealed at 1100°C in N 2 and in O 2 ambient become n-type and p-type, respectively. This is due to the generation of different intrinsic defects by annealing in different ambient. X-ray photoelectron spectroscopy and photolumi-nescence measurements indicate that zinc interstitial becomes a main defects after annealing at 1100°C in N 2 ambient, and these defects play an important role for n-type conductivity of ZnO. While the ZnO films annealed at 1100°C in O 2 ambient, the oxygen antisite contributes ZnO films to p-type. (condensed matter: structure, mechanical and thermal properties)

  3. Influence of defects of nanostructured ZnO films on the photovoltaic characteristics of perovskite solar cells

    Science.gov (United States)

    Afanasyev, D. A.; Mirzoev, K. Yu; Ibrayev, N. Kh

    2018-01-01

    The influence of the defects in ZnO films on the electrical and photovoltaic properties of perovskite solar cells was investigated in the work. According to the results of the research it was established that the defects in ZnO films affects the concentration of defects of perovskite films synthesized on the ZnO surface. However, the difference in the defect concentration in perovskite films is about 30%, while the concentration of defects in ZnO differs by 1000 times. A less significant influence is the concentration of ZnO defects on the electrical and photovoltaic properties of perovskite solar cells. The magnitude of the short-circuit photocurrent and the open voltage of the cells are affected by the concentration of perovskite defects and the quality of the perovskite-ZnO interface.

  4. The effects of ZnO buffer layers on the properties of phosphorus doped ZnO thin films grown on sapphire by pulsed laser deposition

    International Nuclear Information System (INIS)

    Kim, K-W; Lugo, F J; Lee, J H; Norton, D P

    2012-01-01

    The properties of phosphorus doped ZnO thin films grown on sapphire by pulsed laser deposition were examined, specifically focusing on the effects of undoped ZnO buffer layers. In particular, buffer layers were grown under different conditions; the transport properties of as-deposited and rapid thermal annealed ZnO:P films were then examined. As-deposited films showed n-type conductivity. After rapid thermal annealing, the film on buffer layer grown at a low temperature showed the conversion of carrier type to p-type for specific growth conditions while the films deposited on buffer layer grown at a high temperature remained n-type regardless of growth condition. The films deposited on buffer layer grown at a low temperature showed higher resistivity and more significant change of the transport properties upon rapid thermal annealing. These results suggest that more dopants are incorporated in films with higher defect density. This is consistent with high resolution x-ray diffraction results for phosphorus doped ZnO films on different buffer layers. In addition, the microstructure of phosphorus doped ZnO films is substantially affected by the buffer layer.

  5. A comparative study of physico-chemical properties of CBD and SILAR grown ZnO thin films

    International Nuclear Information System (INIS)

    Jambure, S.B.; Patil, S.J.; Deshpande, A.R.; Lokhande, C.D.

    2014-01-01

    Graphical abstract: Schematic model indicating ZnO nanorods by CBD (Z 1 ) and nanograins by SILAR (Z 2 ). - Highlights: • Simple methods for the synthesis of ZnO thin films. • Comparative study of physico-chemical properties of ZnO thin films prepared by CBD and SILAR methods. • CBD outperforms SILAR method. - Abstract: In the present work, nanocrystalline zinc oxide (ZnO) thin films have been successfully deposited onto glass substrates by simple and economical chemical bath deposition (CBD) and successive ionic layer adsorption reaction (SILAR) methods. These films were further characterized for their structural, optical, surface morphological and wettability properties. The X-ray diffraction (XRD) patterns for both CBD and SILAR deposited ZnO thin films reveal the highly crystalline hexagonal wurtzite structure. From optical studies, band gaps obtained are 2.9 and 3.0 eV for CBD and SILAR deposited thin films, respectively. The scanning electron microscope (SEM) patterns show growth of well defined randomly oriented nanorods and nanograins on the CBD and SILAR deposited samples, respectively. The resistivity of CBD deposited films (10 2 Ω cm) is lower than that of SILAR deposited films (10 5 Ω cm). Surface wettability studies show hydrophobic nature for both films. From the above results it can be concluded that CBD grown ZnO thin films show better properties as compared to SILAR method

  6. Structural, optical and magnetic properties of pulsed laser deposited Co-doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Karzazi, O., E-mail: ouiame_karzazi@hotmail.fr [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); LPS, Physics Department, Faculty of Sciences, BP 1796, Fes (Morocco); Sekhar, K.C. [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); El Amiri, A. [LPTA, Université Hassan II-Casablanca, Faculté des Sciences, B.P. 5366, Maârif (Morocco); Hlil, E.K. [Institut Néel, CNRS, Université J. Fourier, BP 166, 38042 Grenoble (France); Conde, O. [Departamento de Física, Faculdade de Ciências, Universidade de Lisboa and CeFEMA, Campo Grande, 1749-016 Lisboa (Portugal); Levichev, S. [Research Institute for Chemistry, Nizhni Novgorod State University, 603950 Nizhni Novgorod (Russian Federation); Agostinho Moreira, J. [IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto (Portugal); Chahboun, A. [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); FST Tanger, Physics Department, BP 416, Tangier (Morocco); Almeida, A. [IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto (Portugal); Gomes, M.J.M. [Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-12-01

    Zn{sub 1−x}Co{sub x}O films with different Co concentrations (with x=0.00, 0.10, 0.15, and 0.30) were grown by pulsed laser deposition (PLD) technique. The structural and optical properties of the films were investigated by grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy and photoluminescence (PL). The magnetic properties were measured by conventional magnetometry using a SQUID and simulated by ab-initio calculations using Korring–Khon–Rostoker (KKR) method combined with coherent potential approximation (CPA). The effect of Co-doping on the GIXRD and Raman peaks positions, shape and intensity is discussed. PL studies demonstrate that Co-doping induces a decrease of the bandgap energy and quenching of the UV emission. They also suggest the presence of Zn interstitials when x≥0.15. The 10% Co-doped ZnO film shows ferromagnetism at 390 K with a spontaneous magnetic moment ≈4×10{sup −5} emu and coercive field ≈0.17 kOe. The origin of ferromagnetism is explained based on the calculations using KKR method. - Highlights: • Zn{sub 1−x}Co{sub x}O films (x=0.00, 0.10, 0.15, and 0.30) were grown by (PLD) technique. • Zn{sub 0.9}Co{sub 0.1}O film shows ferromagnetism above room temperature. • The origin of ferromagnetism behavior is attributed to the p-d hybridization. • Co-doping induces a decrease of the bandgap energy of the films.

  7. Formulation and Characterization of Cu Doped ZnO Thick Films as LPG Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. V. PATIL

    2010-12-01

    Full Text Available Thick films of pure and various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. % of Cu-doped ZnO were prepared on alumina substrates using a screen printing technique. These films were fired at a temperature of 700ºC for two hours in an air atmosphere. Morphological, compositional and structural properties of the samples were obtained using the scanning electron microscopy (SEM, Energy dispersive spectroscopy (EDAX and X-ray diffraction techniques respectively. The LPG gas sensing properties of these thick films were investigated at different operating temperatures and LPG gas concentrations. The surface resistance of thick films decreases when exposed to LPG gas. The Cu doped films show significant sensitivity to LPG gas than pure ZnO film. 5 wt. % Cu-doped ZnO film was found to be more sensitive (87.3 % to LPG gas exposed at 300 oC than other doping concentrations with fast response and recovery time.

  8. A study on the evolution of dielectric function of ZnO thin films with decreasing film thickness

    International Nuclear Information System (INIS)

    Li, X. D.; Chen, T. P.; Liu, P.; Liu, Y.; Liu, Z.; Leong, K. C.

    2014-01-01

    Dielectric function, band gap, and exciton binding energies of ultrathin ZnO films as a function of film thickness have been obtained with spectroscopic ellipsometry. As the film thickness decreases, both real (ε 1 ) and imaginary (ε 2 ) parts of the dielectric function decrease significantly, and ε 2 shows a blue shift. The film thickness dependence of the dielectric function is shown related to the changes in the interband absorption, discrete-exciton absorption, and continuum-exciton absorption, which can be attributed to the quantum confinement effect on both the band gap and exciton binding energies

  9. Development of Boron-Doped ZnO Films with Novel Thin Zn-Rich Film and Their Application to Solar Cells

    Science.gov (United States)

    Hongsingthong, Aswin; Wada, Hidetoshi; Moriya, Yuki; Sichanugrist, Porponth; Konagai, Makoto

    2012-10-01

    In this paper, we report newly developed high-haze glass/zinc oxide (ZnO) substrates with low resistivity by a combination of unique etched soda-lime glass and bilayered ZnO films with a Zn-rich (oxygen-poor) layer. The high mobility and low resistivity of bilayered ZnO films could be obtained with Zn-rich conditions. By depositing the ZnO films onto textured glass substrates, the obtained films exhibit an excellent light-scattering property, while their electrical property is still good. Furthermore, the bilayered ZnO films with a Zn-rich layer did not negatively affect the transparency of the films. Employing the bilayered ZnO films with a Zn-rich layer and an rms roughness of about 274 nm as the front transparent conductive oxide (TCO) in hydrogenated amorphous silicon (a-Si:H) solar cells, we improved the performance and quantum efficiency (QE) of the fabricated solar cells, particularly in the short-wavelength region without the deterioration of open-circuit voltage or fill factor. Thus, the developed glass/bilayered ZnO film with a Zn-rich layer is a new promising material since its resistivity is low while its light-scattering property is still high.

  10. ZnO(101) films by pulsed reactive crossed-beam laser ablation

    Indian Academy of Sciences (India)

    Administrator

    power transistors and gas sensing (Özgür et al 2005;. Jagadish and Pearton 2006; Klingshirn 2007; Rout et al. 2007). In recent years, various forms of ZnO, such as thin films, nanorods, nanowires, nanobelts, nanorings, nano- cages, etc have been prepared by physical and chemical routes aiming at various applications ...

  11. Influence of annealing temperature on ZnO thin films grown by dual ...

    Indian Academy of Sciences (India)

    In electrical characterization as well, when annealing temperature was increased from 400 to 600 °C, room temperature electron mobility enhanced from 6.534 to 13.326 cm2/V s, and then reduced with subsequent increase in temperature. Therefore, 600 °C annealing temperature produced good-quality ZnO film, suitable ...

  12. Ethanol gas sensing properties of Al2 O3 -doped ZnO thick film ...

    Indian Academy of Sciences (India)

    WINTEC

    -doped ZnO thick film resistors. D R PATIL, L A PATIL* and D P AMALNERKAR. †. Materials Research Lab, Pratap College, Amalner 425 401, India. †. Centre for Materials for Electronics Technology, Pune 411 008, India. MS received 13 July 2007. Abstract. The characterization and ethanol gas sensing properties of ...

  13. Growth and optical characteristics of high-quality ZnO thin films on graphene layers

    Directory of Open Access Journals (Sweden)

    Suk In Park

    2015-01-01

    Full Text Available We report the growth of high-quality, smooth, and flat ZnO thin films on graphene layers and their photoluminescence (PL characteristics. For the growth of high-quality ZnO thin films on graphene layers, ZnO nanowalls were grown using metal-organic vapor-phase epitaxy on oxygen-plasma treated graphene layers as an intermediate layer. PL measurements were conducted at low temperatures to examine strong near-band-edge emission peaks. The full-width-at-half-maximum value of the dominant PL emission peak was as narrow as 4 meV at T = 11 K, comparable to that of the best-quality films reported previously. Furthermore, the stimulated emission of ZnO thin films on the graphene layers was observed at the low excitation energy of 180 kW/cm2 at room temperature. Their structural and optical characteristics were investigated using X-ray diffraction, transmission electron microscopy, and PL spectroscopy.

  14. Hydrogen absorption in thin ZnO films prepared by pulsed laser deposition

    Czech Academy of Sciences Publication Activity Database

    Melikhova, O.; Čížek, J.; Lukáč, F.; Vlček, M.; Novotný, Michal; Bulíř, Jiří; Lančok, Ján; Anwand, W.; Brauer, G.; Connolly, J.; McCarthy, E.; Krishnamurthy, S.; Mosnier, J.-P.

    2013-01-01

    Roč. 580, suppl. 1 (2013), S40-S43 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GAP108/11/0958 Institutional support: RVO:68378271 Keywords : defects * hydrogen * positron annihilation * thin films * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.726, year: 2013

  15. Carrier dynamics and gain spectra at room-temperature in epitaxial ZNO thin films

    DEFF Research Database (Denmark)

    Yu, Ping; Hvam, Jørn Märcher; Wong, K. S.

    1999-01-01

    Carrier dynamics of epitaxial ZnO thin film was investigated using a frequency up-conversion tehcnique. At lower carrier densities, the decay time of free exciton recombination was measured to be 24 ps. Rapid decay times of a few picoseconds were observed at higher carrier densities, which show a...

  16. Influence of annealing temperature on ZnO thin films grown by dual ...

    Indian Academy of Sciences (India)

    Administrator

    ties were measured using four-probe Hall measurement set-up in Van der Pauw geometry with a magnetic field of. 0⋅50 Tesla. 3. Results and discussion. 3.1 Structural properties. Figure 1(a) demonstrated the variation of XRD spectra from ZnO films for different annealing temperatures. It should be mentioned at this point ...

  17. Preparation and characterization of nanostructured ZnO thin films for ...

    Indian Academy of Sciences (India)

    Administrator

    Owing to such defects ZnO shows a broad low intensity spectrum centred at green ... posed into volatile compounds under heat treatment (Ar- melao et al 2003). .... 2⋅37 ± 0⋅04. 9⋅3 ± 0⋅8. *Values represent a mean of 10–15 observations; SD: Standard deviation. Thin films of zinc oxide were subjected to phase analy-.

  18. Fabricating ZnO single microwire light-emitting diode with transparent conductive ITO film

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yingtian [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Dai, Jun [State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China); Shi, Zhifeng [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Long, Beihong [College of Materials Science and Engineering, Jinlin University, 2699 Qianjin Street, Changchun 130012 (China); Wu, Bin; Cai, Xupu; Chu, Xianwei; Du, Guotong; Zhang, Baolin [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yin, Jingzhi, E-mail: yjz886666@163.com [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2014-05-01

    In this paper, n-ZnO single microwire/p{sup +}-Si heterojunction LEDs are fabricated using the transparent conductive ITO film as an electrode. A distinct UV emission resulting from free exciton recombination in a ZnO single microwire is observed in the electroluminescence. Size difference of ZnO single microwire shows significant influence on emission efficiency. The EL spectra of n-ZnO single microwire/p-Si heterostructure exhibited relatively stronger UV emission which was compared with the EL spectra of n-ZnO single nanowire/p-Si heterostructure and n-ZnO film/p-Si heterostructure, respectively. - Highlights: • The ZnO microwires were synthesized with a vapor phase transport method. • ZnO single microwire/Si LEDs were fabricated using the ITO film as an electrode. • The EL spectra had been compared with n-ZnO film/p-Si heterostructure. • The EL spectra had been compared with n-ZnO single nanowire/p-Si heterostructure.

  19. Preparation of ZnO nanoribbon–MWCNT composite film and its ...

    Indian Academy of Sciences (India)

    2017-07-28

    Jul 28, 2017 ... A zinc oxide nanoribbon (ZnO NR)–multiwall carbon nanotube (MWCNT) composite film was prepared by filtration technique. ... carbon fibre composites imparted fire shielding property to the composite, where the ... in applications like electromagnetic induction shielding and packaging of integrated circuits ...

  20. Studies on nonvolatile resistance memory switching in ZnO thin films

    Indian Academy of Sciences (India)

    Reliable and repeated switching of the resistance of ZnO thin films was obtained between two well defined states of high and low resistance with a narrow dispersion and small switching voltages. Resistance ratios of the high resistance state to low resistance state were found to be in the range of 2–5 orders of magnitude ...

  1. Influence of pH on ZnO nanocrystalline thin films prepared by sol ...

    Indian Academy of Sciences (India)

    bDepartment of Physics, Hindusthan College of Engineering and Technology, Coimbatore 641 032, India. cDepartment of ... dDepartment of Physics, Erode Sengunthar Engineering College, Erode 638 057, India ... ZnO thin films have been coated at room temperature and at four different pH values of 4, 6, 8 and 10. The.

  2. Structural, optical and electrical properties of ZnO thin films prepared ...

    Indian Academy of Sciences (India)

    Administrator

    Indian Academy of Sciences. 433. Structural, optical and electrical properties of ZnO thin films prepared by spray pyrolysis: Effect of precursor concentration. F ZAHEDI1, R S DARIANI1,* and S M ROZATI2. 1Department of Physics, Alzahra University, Tehran 1993893973, Iran. 2Department of Physics, University of Guilan, ...

  3. Influence of Surface Modification on Physicochemical Properties of ZnO Thin Films and Nanostructures: a Review

    Science.gov (United States)

    Xian, Fenglin; Xu, Linhua

    The surface modification plays an important role on both physical and chemical properties of zinc oxide (ZnO) materials. In this review paper, efforts are made to summarize and analyze reported results regarding surface modification method, surface modification effect on the luminescence and superhydrophobic properties of ZnO thin films and nanostructures. Furthermore, the photocatalytic activity and gas sensor property of modified ZnO using both organic and inorganic species are also involved.

  4. Preparation of cadmium-doped ZnO thin films by SILAR and their ...

    Indian Academy of Sciences (India)

    firmed from elemental analysis using EDX. The optical bandgap of the films decreases with increasing Cd dopant. The value of fundamental absorption edge is 3·18 eV for pure ZnO and it decreases to 3·11 eV for 10% Cd:ZnO. Keywords. SILAR; Cd:ZnO thin film; X-ray line broadening; SEM; optical bandgap. 1. Introduction.

  5. Photoelectrocatrocatalytic hydrolysis of starch by using sprayed ZnO thin films

    Science.gov (United States)

    Sapkal, R. T.; Shinde, S. S.; Rajpure, K. Y.; Bhosale, C. H.

    2013-05-01

    Thin films of zinc oxide have been deposited onto glass/FTO substrates at optimized 400 °C by using a chemical spray pyrolysis technique. Deposited films are character photocatalytic activity by using XRD, an SEM, a UV-vis spectrophotometer, and a PEC single-cell reactor. Films are polycrystalline and have a hexagonal (wurtzite) crystal structure with c-axis (002) orientation growth perpendicular to the substrate surface. The observed direct band gap is about 3.22 eV for typical films prepared at 400 °C. The photocatalytic activity of starch with a ZnO photocatalyst has been studied by using a novel photoelectrocatalytic process.

  6. Studies of effect of deposition parameters on the ZnO films prepared by PLD

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, Shuchi [Department of Physics, University of Allahabad, Allahabad (India)], E-mail: shuchitripathi2@gmail.com; Choudhary, R.J. [UGC-DAE-Consortium for Scientific Research, Indore (India); Tripathi, A. [Inter University Accelerator Center, New Delhi (India); Baranwa, V.; Pandey, A.C. [Department of Physics, University of Allahabad, Allahabad (India); Gerlach, J.W. [Institute of Surface Modifications, Leipzig (Germany); Dar, C. [Department of Physics, University of Allahabad, Allahabad (India); Kanjilal, D. [Inter University Accelerator Center, New Delhi (India)

    2008-04-15

    Thin films of zinc oxide (ZnO), having different thicknesses were prepared by pulsed laser deposition (PLD) technique onto silicon Si(1 1 1) and quartz (SiO{sub 2}) substrates at different partial pressures of oxygen. Rutherford back scattering (RBS) analysis was carried out in order to investigate effect of deposition parameters on thickness of films. Quality of the films was investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses. The thickness of the film was found to increase with oxygen partial pressure for both Si and SiO{sub 2} substrates.

  7. Enhanced magnetic properties of chemical solution deposited BiFeO3 thin film with ZnO buffer layer

    International Nuclear Information System (INIS)

    Rajalakshmi, R.; Kambhala, Nagaiah; Angappane, S.

    2012-01-01

    Highlights: ► Enhanced magnetization of BiFeO 3 is important for strong magnetoelectric coupling. ► BiFeO 3 film with ZnO buffer layer was successfully synthesized by chemical method. ► Magnetization of BiFeO 3 has increased by more than 10 times with ZnO buffer layer. ► A mechanism for enhancement in ferromagnetism of BiFeO 3 film is proposed. - Abstract: Magnetic properties of BiFeO 3 films deposited on Si substrates with and without ZnO buffer layer have been studied in this work. We adopted the chemical solution deposition method for the deposition of BiFeO 3 as well as ZnO films. The x-ray diffraction measurements on the deposited films confirm the formation of crystalline phase of BiFeO 3 and ZnO films, while our electron microscopy measurements help to understand the morphology of few micrometers thick films. It is found that the deposited ZnO film exhibit a hexagonal particulate surface morphology, whereas BiFeO 3 film fully covers the ZnO surface. Our magnetic measurements reveal that the magnetization of BiFeO 3 has increased by more than ten times in BiFeO 3 /ZnO/Si film compared to BiFeO 3 /Si film, indicating the major role played by ZnO buffer layer in enhancing the magnetic properties of BiFeO 3 , a technologically important multiferroic material.

  8. Ferromagnetic behaviour of Fe-doped ZnO nanograined films

    Directory of Open Access Journals (Sweden)

    Boris B. Straumal

    2013-06-01

    Full Text Available The influence of the grain boundary (GB specific area sGB on the appearance of ferromagnetism in Fe-doped ZnO has been analysed. A review of numerous research contributions from the literature on the origin of the ferromagnetic behaviour of Fe-doped ZnO is given. An empirical correlation has been found that the value of the specific grain boundary area sGB is the main factor controlling such behaviour. The Fe-doped ZnO becomes ferromagnetic only if it contains enough GBs, i.e., if sGB is higher than a certain threshold value sth = 5 × 104 m2/m3. It corresponds to the effective grain size of about 40 μm assuming a full, dense material and equiaxial grains. Magnetic properties of ZnO dense nanograined thin films doped with iron (0 to 40 atom % have been investigated. The films were deposited by using the wet chemistry “liquid ceramics” method. The samples demonstrate ferromagnetic behaviour with Js up to 0.10 emu/g (0.025 μB/f.u.ZnO and coercivity Hc ≈ 0.03 T. Saturation magnetisation depends nonmonotonically on the Fe concentration. The dependence on Fe content can be explained by the changes in the structure and contiguity of a ferromagnetic “grain boundary foam” responsible for the magnetic properties of pure and doped ZnO.

  9. A comparison of ZnO films deposited on indium tin oxide and soda lime glass under identical conditions

    Directory of Open Access Journals (Sweden)

    Angshuman Deka

    2013-06-01

    Full Text Available ZnO films have been grown via a vapour phase transport (VPT on soda lime glass (SLG and indium-tin oxide (ITO coated glass. ZnO film on ITO had traces of Zn and C which gives them a dark appearance while that appears yellowish-white on SLG. X-ray photoelectron spectroscopy studies confirm the traces of C in the form of C–O. The photoluminescence studies reveal a prominent green luminescence band for ZnO film on ITO.

  10. ZnO THIN FILMS PREPARED BY SPRAY-PYROLYSIS TECHNIQUE FROM ORGANO-METALLIC PRECURSOR

    Directory of Open Access Journals (Sweden)

    Martin Mikulics

    2012-07-01

    Full Text Available Presented experiments utilize methanolic solution of zinc acetyl-acetonate as a precursor and sapphire (001 as a substrate for deposition of thin films of ZnO. The X-ray diffraction analysis revealed polycrystalline character of prepared films with preferential growth orientation along c-axis. The roughness of prepared films was assessed by AFM microscopy and represented by roughness root mean square (RMS value in range of 1.8 - 433 nm. The surface morphology was mapped by scanning electron microscopy showing periodical structure with several local defects. The optical transmittance spectrum of ZnO films was measured in wavelength range of 200-1000 nm. Prepared films are transparent in visible range with sharp ultra-violet cut-off at approximately 370 nm. Raman spectroscopy confirmed wurtzite structure and the presence of compressive stress within its structure as well as the occurrence of oxygen vacancies. The four-point Van der Pauw method was used to study the transport prosperities. The resistivity of presented ZnO films was found 8 × 10–2 Ω cm with carrier density of 1.3 × 1018 cm–3 and electron mobility of 40 cm2 V–1 s–1.

  11. Effect of Sm doping on the physical properties of ZnO thin films deposited by spray pyrolysis technique

    Science.gov (United States)

    Velusamy, P.; Babu, R. Ramesh; Aparna, K. T.

    2017-05-01

    Undoped and Sm doped ZnO thin films have been prepared by chemical spray pyrolysis method on a glass substrate at 430°C. The physical properties of undoped and Sm doped ZnO thin films are characterized by XRD, FE-SEM, UV-VIS spectroscopy, Hall measurement and PL analysis. XRD pattern reveals that all the films are polycrystalline nature. The FE-SEM study of CdO shows the smooth and uniform surface with the spherical shaped particle. The electrical study reveals the n-type semiconductor and the optical study shows that Sm doped ZnO thin films about 92% transparency and optical band gap vary between 3.266-3.276 eV. Sm doped ZnO thin films have strong green emission behavior.

  12. Regulating effect of SiO2 interlayer on optical properties of ZnO thin films

    International Nuclear Information System (INIS)

    Xu, Linhua; Zheng, Gaige; Miao, Juhong; Su, Jing; Zhang, Chengyi; Shen, Hua; Zhao, Lilong

    2013-01-01

    ZnO/SiO 2 nanocomposite films with periodic structure were prepared by electron beam evaporation technique. Regulating effect of SiO 2 interlayer with various thicknesses on the optical properties of ZnO/SiO 2 thin films was investigated deeply. The analyses of X-ray diffraction show that the ZnO layers in ZnO/SiO 2 nanocomposite films have a wurtzite structure and are preferentially oriented along the c-axis while the SiO 2 layers are amorphous. The scanning electron microscope images display that the ZnO layers are composed of columnar grains and the thicknesses of ZnO and SiO 2 layers are all very uniform. The SiO 2 interlayer presents a significant modulation effect on the optical properties of ZnO thin films, which is reflected in the following two aspects: (1) the transmittance of ZnO/SiO 2 nanocomposite films is increased; (2) the photoluminescence (PL) of ZnO/SiO 2 nanocomposite films is largely enhanced compared with that of pure ZnO thin films. The ZnO/SiO 2 nanocomposite films have potential applications in light-emitting devices and flat panel displays. -- Highlights: ► ZnO/SiO 2 nanocomposite films with periodic structure were prepared by electron beam evaporation technique. ► The SiO 2 interlayer presents a significant modulation effect on the optical properties of ZnO thin films. ► The photoluminescence of ZnO/SiO 2 nanocomposite films is largely enhanced compared with that of pure ZnO thin films. ► The ZnO/SiO 2 nanocomposite films have potential applications in light-emitting devices and flat panel displays

  13. Screen printed nanosized ZnO thick film

    Indian Academy of Sciences (India)

    Unknown

    BINDU KRISHNAN* and V P N NAMPOORI†. Centre for Materials for Electronics Technology, Athani P O, Thrissur 680 771, India. †International School of Photonics, Cochin University of Science and Technology, Cochin 682 022, India. MS received 6 November 2004; revised 5 March 2005. Abstract. Nanosized ZnO was ...

  14. Screen printed nanosized ZnO thick film

    Indian Academy of Sciences (India)

    Unknown

    attention as UV emitters and detectors. They also find applications in field emission displays ... stant stirring and heating to 120°C. After complete disso- lution of the salt, stirring was stopped and the solution ... ZnO has attracted much attention as a random lasing medium because of high optical gain and dielectric con- stant.

  15. Growth of Ag thin films on ZnO(0 0 0 -1) investigated by AES and STM

    Energy Technology Data Exchange (ETDEWEB)

    Duriau, E. [Interuniversity Microelectronic Center (IMEC), SPDT-MCA, Kapeldreef 75, B-3001 Leuven (Belgium); Agouram, S. [Dpto. Fisica Aplicada y Electromagnetismo c/Dr. Moliner no. 50, 46100 Burjassot, Valencia (Spain); Laboratoire de Physique des Materiaux Electroniques (LPME), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Morhain, C. [Centre de Recherche sur l' HeteroEpitaxie et ses Applications (CRHEA), CNRS, Rue Bernard Gregory, F-06560 Valbonne Sophia-Antipolis (France); Seldrum, T. [Laboratoire de Physique des Materiaux Electroniques (LPME), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Sporken, R. [Laboratoire de Physique des Materiaux Electroniques (LPME), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Dumont, J. [Laboratoire de Physique des Materiaux Electroniques (LPME), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium)]. E-mail: jacques.dumont@fundp.ac.be

    2006-11-15

    The growth of Ag films on ZnO(0 0 0 -1) has been investigated by Auger electron spectroscopy (AES) and scanning tunneling microscopy (STM). A high density of islands is nucleated at the earliest stages of the growth. An upstepping mechanism causes these islands to coalesce while the uncovered fraction of the ZnO surface remains constant (30%)

  16. Single fiber UV detector based on hydrothermally synthesized ZnO nanorods for wearable computing devices

    Science.gov (United States)

    Eom, Tae Hoon; Han, Jeong In

    2018-01-01

    There has been increasing interest in zinc oxide (ZnO) based ultraviolet (UV) sensing devices over the last several decades owing to their diverse range of applications. ZnO has extraordinary properties, such as a wide band gap and high exciton binding energy, which make it a beneficial material for UV sensing device. Herein, we show a ZnO UV sensing device fabricated on a cylindrical Polyethylene terephthalate (PET) monofilament. The ZnO active layer was synthesized by hydrothermal synthesis and the Cu electrodes were deposited by radio frequency (RF) magnetron sputtering. Cu thin film was deposited uniformly on a single PET fiber by rotating it inside the sputtering chamber. Various characteristics were investigated by changing the concentration of the seed solution and the growth solution. The growth of ZnO nanorods was confirmed by Field Emission Scanning Electron Microscopy (FESEM) to see the surface state and structure, followed by X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Also, current-voltage (I-V) curves were obtained to measure photocurrent and conductance. Furthermore, falling response time, rising response time, and responsivity were calculated by analyzing current-time (I-t) curves.

  17. Optical investigations of Be doped ZnO films grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingming, E-mail: andychain@live.cn [Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Zhu, Yuan, E-mail: zhuy9@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Chen, Anqi; Shen, Zhen [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Tang, Zikang, E-mail: phzktang@ust.hk [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); The Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau (China)

    2016-06-15

    Highlights: • The optical properties of Be doped ZnO films were investigated. • Low temperature photoluminescence spectrum was dominated by D°X and DAP emissions. • Shallow acceptor state with ionization energy of 116 meV was found in ZnO:Be films. • It is suggested that the incorporated Be atom might favor formation of Zn vacancies defects. • This work demonstrates that N doping BeZnO might be suitable for fabricating reliable p-type ZnO materials. - Abstract: In this article, the optical properties of ZnO:Be films grown by plasma-assisted molecular beam epitaxy were investigated by the excitation density-dependent and temperature-dependent photoluminescence measurements. The low temperature photoluminescence spectra showed a dominant excitons bound to neutral donors (D°X) emission centered at 3.3540 eV and strong donor-acceptor pair (DAP) transitions at 3.3000 eV. In addition, it showed that the intensity ratio of the DAP and D°X peaks changed with background electron concentration. Furthermore, a shallow acceptor state with ionization energy of 116 meV was found and attributed to Zn vacancy. The present study further suggests that Be and N codoping ZnO might be suitable for fabricating reliable p-type ZnO materials.

  18. Structure and composition evaluation of heavily Ge-doped ZnO nanocrystal films

    Science.gov (United States)

    Zhu, Wenliang; Kammuri, Takuya; Kitamura, Shoichiro; Sturaro, Marco; Martucci, Alessandro; Pezzotti, Giuseppe

    2018-02-01

    A series of high quality zinc oxide (ZnO) nanocrystal films doped with Ge at different Ge/Zn molar ratios were synthesized by the sol-gel method, and structural and compositional changes induced by Ge doping in the ZnO films were analyzed by x-ray diffraction, x-ray photoelectron spectroscopy and cathodoluminescence spectroscopy. Heavy Ge doping in ZnO was found to effectively reduce intrinsic defects in the films and suppress free exciton emission and defect-related emissions in the visible green-red region, by the substitution of Ge at Zn sites and the formation of non-radiative deep-level traps (GeZn)+. The generation of such non-radiative traps was found to be suppressed with respect to the dopant increase, because of a reduction in carrier concentration along with a formation of stable defect complex GeZn–VZn at high doping content. The clarification of defect alterations in Ge-doped ZnO lays the foundation of quantitative evaluation of defect effects on the electrical and optical properties for improving the quality of GeZnO devices.

  19. Improved efficiency of the chemical bath deposition method during growth of ZnO thin films

    International Nuclear Information System (INIS)

    Ortega-Lopez, Mauricio; Avila-Garcia, Alejandro; Albor-Aguilera, M.L.; Resendiz, V.M. Sanchez

    2003-01-01

    Chemical bath deposition (CBD) is an inexpensive and low temperature method (25-90 deg. C) that allows to deposit large area semiconductor thin films. However, the extent of the desired heterogeneous reaction upon the substrate surface is limited first by the competing homogeneous reaction, which is responsible for colloidal particles formation in the bulk solution, and second, by the material deposition on the CBD reactor walls. Therefore, the CBD method exhibits low efficiency in terms of profiting the whole amount of starting materials. The present work describes a procedure to deposit ZnO thin films by CBD in an efficient way, since it offers the possibility to minimize both the undesirable homogeneous reaction in the bulk solution and the material deposition on the CBD reactor walls. In a first stage, zinc peroxide (ZnO 2 ) crystallizing with cubic structure is obtained. This compound shows a good average transparency (90%) and an optical bandgap of 4.2 eV. After an annealing process, the ZnO 2 suffers a transformation toward polycrystalline ZnO with hexagonal structure and 3.25 eV of optical bandgap. The surface morphology of the films, analyzed by atomic force microscope (AFM), reveals three-dimensional growth features as well as no colloidal particles upon the surface, therefore indicating the predominance of the heterogeneous reaction during the growth

  20. The investigation of the Cr doped ZnO thin films deposited by thermionic vacuum arc technique

    Science.gov (United States)

    Mohammadigharehbagh, Reza; Pat, Suat; Musaoglu, Caner; Korkmaz, Şadan; Özen, Soner

    2018-02-01

    Cr doped ZnO thin films were prepared onto glass and polyethylene terephthalate (PET) substrates using thermionic vacuum arc. XRD patterns show the polycrystalline nature of the films. Cr, Zn, ZnO and Cr2O3 were detected in the layers. The mean crystallite sizes of the films were calculated about 20 nm for the films onto glass and PET substrates. The maximum dislocation density and internal strain values of the films are calculated. According to the optical analysis, the average transmittance and reflectance of the films were found to be approximately 53% and 16% for glass and PET substrates, respectively. The mean refractive index of the layer decreased to 2.15 from 2.38 for the PET substrate. The band gap values of the Cr-doped ZnO thin films were determined as 3.10 and 3.13 eV for glass and PET substrates.

  1. Investigation of electrical and optical properties of MEH-PPV: ZnO nanocomposite films for OLED applications

    Energy Technology Data Exchange (ETDEWEB)

    Azhar, N. E. A., E-mail: najwaezira@yahoo.com; Shafura, A. K., E-mail: shafura@ymail.com; Affendi, I. H. H., E-mail: irmahidayanti.halim@gmail.com; Shariffudin, S. S., E-mail: sobihana@gmail.com [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Saurdi, I., E-mail: saurdy788@gmail.com [Faculty of Electrical Engineering, UiTM Sarawak, Kampus Kota Meranek, Sarawak (Malaysia); Alrokayan, Salman A. H., E-mail: dr.salman@alrokayan.com; Khan, Haseeb A., E-mail: khan-haseeb@yahoo.com [Research Chair of Targeting and Treatment of Cancer Using Nanoparticles Department of Biochemistry, College of Science, King Saud University (KSU), 245 Riyadh 11454 (Saudi Arabia); Rusop, M., E-mail: rusop@salam.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA (UiTM), Shah Alam, Selangor (Malaysia)

    2016-07-06

    Recent investigations of the promising materials for optoelectronic have been demonstrated by introducing n-type inorganic material into conjugated polymer. The optical and electrical of nanocomposite films based on poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and zinc oxide (ZnO) nanostructured of various deposition layers (1 to 3 layers) have been investigated. The MEH-PPV: ZnO nanocomposite films were deposited using spin-coating technique. The surface morphology nanocomposite films were characterized using field emission scanning electron microscope. From surface profiler measurement, we found that the thickness of nanocomposite films increased as deposition time increased. The optical properties were measured using photoluminescence spectroscope. The photoluminescence (PL) spectra showed that two deposition layers is the highest intensity at visible region (green emission) due to high energy transfer from particles to the polymer. The current density for two layers sample is due to aggregation of conjugated polymer chain hence form excited interchain exciton for optical excitation. This study will provide better performance and suitable for optoelectronic device especially OLEDs application.

  2. Spectroscopic ellipsometry, optical, structural and electrical investigation of sprayed pure and Sn-doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Attaf N.

    2013-03-01

    Full Text Available In this work, we report the transparent pure and Sn-doped zinc oxide (ZnO. The films were deposited onto microscope glass substrate which was heated at 350±5C° by ultrasonic spray pyrolysis (U S P deposition technique. The concentrations of Sn were selected within the range of 0-3% by step of 0.5% and the time deposition is kept at 5 min. A (002-oriented wurtzite crystal structure was confirmed by X-rays patterns; and grain size varied within the range 7.37-14.84nm, and cristanillity is calculated goes from14.4 to 45.9%. Based on UV-VIS-IR analysis, the results revealed the high transparency of the sprayed films which exceeds 90%. The band gap energy was of 3.26-3.30 eV. The film thickness was estimated by spectroscopy ellipsometry and the found values were of 165-270nm. The refractive index is in the range of 2.75.The obtained electrical parameters were around 1018 cm−3, 3.6 cm2/Vs, 1.6Ω.cm; 5.8cm3/C. finally the Sn-doping has influenced the physical parameters of asground ZnO films

  3. Optimizing Deposition gas and Annealing Conditions for ZnO Films

    Science.gov (United States)

    Smith, Andrew; Oder, Tom

    2011-04-01

    Zinc Oxide (ZnO) is a transparent II-VI semiconductor with a direct band gap and has potential applications for making efficient optoelectronic devices such as laser diodes and light emitting diodes as well as in solar panels, taking advantage of its transparency. ZnO films have been deposited onto sapphire using radio frequency sputtering in different gases including nitrogen and different mixtures of argon and oxygen. The films were then annealed for different durations at 900 ^oC and characterized using photoluminescence spectroscopy measurements with a HeCd laser to examine the crystal quality of the samples. The conditions that give the best quality film were for films deposited in 100% argon at 500 ^oC. The optimum annealing condition was 3 min and five minutes. Photoluminescence analysis yielded peaks at 377 nm for each sample measured at room temperature 368 nm at 10 K. It was also found that pre-heating the sapphire substrate in pure oxygen prior to deposition greatly improves the quality of the ZnO film.

  4. Superior environment resistance of quartz crystal microbalance with anatase TiO{sub 2}/ZnO nanorod composite films

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Wei, E-mail: weiqiang.tju@163.com [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Tianjin (China); Wei, Li; Shaodan, Wang [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Tianjin (China); Yu, Bai [Beijing Institute of Spacecrafts Environment Engineering, Beijing 100094 (China)

    2015-08-30

    Graphical abstract: ZnO nanorod array being prepared by an in situ method on the QCM coated with Au film via hydrothermal process and surface modification with coated TiO{sub 2} by sol–gel methods to form a superhydrophobic TiO{sub 2}/ZnO composite film the anatase TiO{sub 2}/ZnO nanorod composite film with a sharp, pencil-like structure exhibiting excellent superhydrophobicity (water contact angle of 155°), non-sticking water properties, and an autonomous cleaning property under UV irradiation. The anatase TiO{sub 2}/ZnO nanorod composite film facilitates the precise measurement and extended lifetime of the QCM for the detection of organic gas molecules. - Highlights: • This work combines, for the first time, the advantage of the TiO{sub 2}/ZnO composite film on photocatalysis and reversible super-hydrophobic and super-hydrophilic transition, and puts forward a solution to satisfy weatherability of quartz crystal microbalance in long-term application. • The anatase TiO{sub 2}/ZnO nanorod composite film with pencil structure exhibit excellent super-hydrophobicity (water contact angle can reach 155°), no-sticking water properties and self-cleaning property under UV irradiation. • The photocatalysis and reversible super-hydrophobic and super-hydrophilic transition of the TiO{sub 2}/ZnO nanorod composite film is stable in long-term application. - Abstract: The precise measurement of quartz crystal microbalance (QCM) in the detection and weighing of organic gas molecules is achieved due to excellent superhydrophobicity of a deposited film composite. Photocatalysis is utilized as a method for the self-cleaning of organic molecules on the QCM for extended long-term stability in the precision of the instrument. In this paper, ZnO nanorod array is prepared via in situ methods on the QCM coated with Au film via hydrothermal process. Subsequently, a TiO{sub 2}/ZnO composite film is synthesized by surface modification with TiO{sub 2} via sol–gel methods. Results

  5. Superior environment resistance of quartz crystal microbalance with anatase TiO2/ZnO nanorod composite films

    International Nuclear Information System (INIS)

    Qiang, Wei; Wei, Li; Shaodan, Wang; Yu, Bai

    2015-01-01

    Graphical abstract: ZnO nanorod array being prepared by an in situ method on the QCM coated with Au film via hydrothermal process and surface modification with coated TiO 2 by sol–gel methods to form a superhydrophobic TiO 2 /ZnO composite film the anatase TiO 2 /ZnO nanorod composite film with a sharp, pencil-like structure exhibiting excellent superhydrophobicity (water contact angle of 155°), non-sticking water properties, and an autonomous cleaning property under UV irradiation. The anatase TiO 2 /ZnO nanorod composite film facilitates the precise measurement and extended lifetime of the QCM for the detection of organic gas molecules. - Highlights: • This work combines, for the first time, the advantage of the TiO 2 /ZnO composite film on photocatalysis and reversible super-hydrophobic and super-hydrophilic transition, and puts forward a solution to satisfy weatherability of quartz crystal microbalance in long-term application. • The anatase TiO 2 /ZnO nanorod composite film with pencil structure exhibit excellent super-hydrophobicity (water contact angle can reach 155°), no-sticking water properties and self-cleaning property under UV irradiation. • The photocatalysis and reversible super-hydrophobic and super-hydrophilic transition of the TiO 2 /ZnO nanorod composite film is stable in long-term application. - Abstract: The precise measurement of quartz crystal microbalance (QCM) in the detection and weighing of organic gas molecules is achieved due to excellent superhydrophobicity of a deposited film composite. Photocatalysis is utilized as a method for the self-cleaning of organic molecules on the QCM for extended long-term stability in the precision of the instrument. In this paper, ZnO nanorod array is prepared via in situ methods on the QCM coated with Au film via hydrothermal process. Subsequently, a TiO 2 /ZnO composite film is synthesized by surface modification with TiO 2 via sol–gel methods. Results show the anatase TiO 2 /ZnO nanorod

  6. Annealing effect on the structural, morphological and electrical properties of TiO2/ZnO bilayer thin films

    Science.gov (United States)

    Khan, M. I.; Imran, S.; Shahnawaz; Saleem, Muhammad; Ur Rehman, Saif

    2018-03-01

    The effect of annealing temperature on the structural, morphological and electrical properties of TiO2/ZnO (TZ) thin films has been observed. Bilayer thin films of TiO2/ZnO are deposited on FTO glass substrate by spray pyrolysis method. After deposition, these films are annealed at 573 K, 723 K and 873 K. XRD shows that TiO2 is present in anatase phase only and ZnO is present in hexagonal phase. No other phases of TiO2 and ZnO are present. Also, there is no evidence of other compounds like Zn-Ti etc. It also shows that the average grain size of TiO2/ZnO films is increased by increasing annealing temperature. AFM (Atomic force microscope) showed that the average roughness of TiO2/ZnO films is decreased at temperature 573-723 K and then increased at 873 K. The calculated average sheet resistivity of thin films annealed at 573 K, 723 K and 873 K is 152.28 × 102, 75.29 × 102 and 63.34 × 102 ohm-m respectively. This decrease in sheet resistivity might be due to the increment of electron concentration with increasing thickness and the temperature of thin films.

  7. Effect of thermal annealing on properties of polycrystalline ZnO thin films

    Science.gov (United States)

    Gritsenko, L. V.; Abdullin, Kh. A.; Gabdullin, M. T.; Kalkozova, Zh. K.; Kumekov, S. E.; Mukash, Zh. O.; Sazonov, A. Yu.; Terukov, E. I.

    2017-01-01

    Electrical properties (density, carriers mobility, resistivity), optical absorption and photoluminescence spectra of ZnO, grown by MOCVD and hydrothermal methods, have been investigated depending on the annealing and treatment modes in a hydrogen plasma. It has been shown that the electrical and photoluminescent (PL) properties of ZnO are strongly dependent on gas atmosphere during annealing. The annealing in oxygen atmosphere causes a sharp drop of carrier mobility and films conductivity due to the absorption of oxygen on grain boundaries. The process of ZnO electrical properties recovery by the thermal annealing in inert atmosphere (nitrogen), in oil (2×10-2 mbar) and oil-free (1×10-5 mbar) vacuum has been investigated. The hydrogen plasma treatment influence on the intensity of near-band-gap emission (NBE) has been studied. The effect of annealing and subsequent plasma treatment on PL intensity depends on the gas atmosphere of preliminary thermal annealing.

  8. Electrical characteristics of ZnO nanorods reinforced polymer nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Snigdha; Roy, Asim, E-mail: 28.asim@gmail.com [Department of Physics National Institute Technology Silchar Silchar-788010, Assam (India)

    2015-05-15

    ZnO nanorods have been prepared by simple chemical method, which is used to fabricate organic bistable devices (OBDs). OBDs are fabricated by incorporating different weight percent (wt %) of chemically synthesized Zinc Oxide (ZnO) nanorods into polymethylmethacrylate (PMMA). Current-voltage (I-V) measurements of the spin coated ZnO+PMMA nanocomopsite thin film on indium tin oxide (ITO) coated glass substrate showed current hysteresis behaviour, which is an indication of memory effect. The samples exhibit two distinct resistance states, ON and OFF states, characterised by relatively low and high resistance of the OBDs, respectively. It is also observed that with change in ZnO dopant concentration the value of ON/OFF current changes. Higher ON/OFF current ratio is desired for practical applications. Current conduction mechanism of the devices has been explained invoking various existing models, and it has been found that the trapped-charge-limited conduction mechanism was dominant in our samples.

  9. Electrospray Deposition of ZnO Thin Films and Its Application to Gas Sensors

    Directory of Open Access Journals (Sweden)

    Wenwang Li

    2018-02-01

    Full Text Available Electrospray is a simple and cost-effective method to fabricate micro-structured thin films. This work investigates the electrospray process of ZnO patterns. The effects of experimental parameters on jet characteristics and electrosprayed patterns are studied. The length of stable jets increases with increasing applied voltage and flow rate, and decreases with increasing nozzle-to-substrate distance, while electrospray angles exhibit an opposite trend with respect to the stable jet lengths. The diameter of electrosprayed particles decreases with increasing applied voltage, and increases with flow rate. Furthermore, an alcohol gas sensor is presented. The ZnAc is calcined into ZnO, which reveals good repeatability and stability of response in target gas. The sensing response, defined as the resistance ratio of R0/Rg, where R0 and Rg are resistance of ZnO in air and alcohol gas, increases with the concentration of alcohol vapors and electrospray deposition time.

  10. Enhanced ZnO Thin-Film Transistor Performance Using Bilayer Gate Dielectrics

    KAUST Repository

    Alshammari, Fwzah Hamud

    2016-08-24

    We report ZnO TFTs using Al2O3/Ta2O5 bilayer gate dielectrics grown by atomic layer deposition. The saturation mobility of single layer Ta2O5 dielectric TFT was 0.1 cm2 V-1 s-1, but increased to 13.3 cm2 V-1 s-1 using Al2O3/Ta2O5 bilayer dielectric with significantly lower leakage current and hysteresis. We show that point defects present in ZnO film, particularly VZn, are the main reason for the poor TFT performance with single layer dielectric, although interfacial roughness scattering effects cannot be ruled out. Our approach combines the high dielectric constant of Ta2O5 and the excellent Al2O3/ZnO interface quality, resulting in improved device performance. © 2016 American Chemical Society.

  11. Effect of thickness on structural and electrical properties of Al-doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Garcés, F.A., E-mail: felipe.garces@santafe-conicet.gov.ar [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Budini, N. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Arce, R.D.; Schmidt, J.A. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe S3000AOM (Argentina)

    2015-01-01

    In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknesses • Film thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness.

  12. Effect of thickness on structural and electrical properties of Al-doped ZnO films

    International Nuclear Information System (INIS)

    Garcés, F.A.; Budini, N.; Arce, R.D.; Schmidt, J.A.

    2015-01-01

    In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknesses • Film thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness

  13. Applying RF Magnetron sputtering to prepare ZnO thin films and their characterization

    International Nuclear Information System (INIS)

    Saad, M.; Kassis, A.

    2009-05-01

    ZnO thin films were prepared using Rf magnetron sputtering under several preparation conditions (different values of deposition pressure, Rf power, substrate temperature). The optical properties of these films were investigated by measuring their transmission in the spectral range (300-1000 nm), and the electrical properties were investigated by measuring their electrical resistance. Results have been discussed in terms of the modified Thornton model for sputtered thin metal oxide films. Preparation conditions for depositing the highly resistive transparent i-ZnO buffer layer and the highly conducting transparent n-ZnO window layer for solar cells were proposed. (author)

  14. Influence Applied Potential on the Formation of Self-Organized ZnO Nanorod Film and Its Photoelectrochemical Response

    Directory of Open Access Journals (Sweden)

    Nur Azimah Abd Samad

    2016-01-01

    Full Text Available The present paper reports on the facile formation of ZnO nanorod photocatalyst electrodeposited on Zn foil in the production of hydrogen gas via water photoelectrolysis. Based on the results, ZnO nanorod films were successfully grown via electrochemical deposition in an optimum electrolyte set of 0.5 mM zinc chloride and 0.1 M potassium chloride at pH level of 5-6 and electrochemical deposition temperature of around 70°C. The study was also conducted at a very low stirring rate with different applied potentials. Applied potential was one of the crucial aspects in the formation of self-organized ZnO nanorod film via control of the field-assisted dissolution and field-assisted deposition rates during the electrochemical deposition process. Interestingly, low applied potentials of 1 V during electrochemical deposition produced a high aspect ratio and density of self-organized ZnO nanorod distribution on the Zn substrate with an average diameter and length of ~37.9 nm and ~249.5 nm, respectively. Therefore, it exhibited a high photocurrent density that reached 17.8 mA/cm2 under ultraviolet illumination and 12.94 mA/cm2 under visible illumination. This behaviour was attributed to the faster transport of photogenerated electron/hole pairs in the nanorod’s one-dimensional wall surface, which prevented backward reactions and further reduced the number of recombination centres.

  15. Improvement in Performance of ZnO based DSC Prepared by Spraying Method

    Directory of Open Access Journals (Sweden)

    Rangga Winantyo

    2013-09-01

    Full Text Available This paper reports the effect of TiCl4 on the performance of ZnO based DSC. ZnO was used due to its stability against photo-corrosion  and  photochemical  properties  similar  to  TiO2.  Thin  films  of  nanocrystalline  ZnO  were  deposited  on transparent conducting oxide glass using spray  method. The ZnO  films  were treated using TiCl4. The cell’s efficiency was found to be 2.5% with TiCl4 post-treatment and 1.9% without TiCl4 post-treatment.

  16. Effect of Nano ZnO on the Optical Properties of Poly(vinyl chloride Films

    Directory of Open Access Journals (Sweden)

    Wasan Al-Taa’y

    2014-01-01

    Full Text Available Optical properties of pure and doped poly(vinyl chloride (PVC films, prepared by using casting technique, with different nanosize zinc oxide (ZnO concentrations (1–20 wt% have been studied. Parameters such as extinction coefficient, refractive index, real and imaginary parts, Urbach energy, optical conductivity, infinitely high frequency dielectric constant, and average refractive index were studied by using the absorbance and transmittance measurement from computerized UV-visible spectrophotometer (Shimadzu UV-1601 PC in the spectral range 200–800 nm. This study reveals that the optical properties of PVC are affected by the doping of ZnO where the absorption increases and transmission decreases as ZnO concentration increases. The extinction coefficient, refractive index, real and imaginary parts, infinitely high frequency dielectric constant, and average refractive index values were found to increase with increasing impurity percentage. The Urbach energy values are found to be decreasing with increasing ZnO concentration. The optical conductivity increased with photon energy after being doped and with the increase of ZnO concentration.

  17. Effect of magnesium doping on the light-induced hydrophilicity of ZnO thin films

    Science.gov (United States)

    Kai, Huang; Jianguo, Lü; Li, Zhang; Zhen, Tang; Jiangying, Yu; Ping, Li; Feng, Liu

    2012-05-01

    Undoped and Mg-doped ZnO thin films were deposited on Si (111) and quartz substrates by using the sol-gel method. Microstructure, surface topography and water contact angle of the thin films have been measured by X-ray diffraction (XRD), an atomic force microscope (AFM) and water contact angle apparatus, respectively. The XRD results show that all the thin films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. With the increase of Mg concentration, the RMS roughness increases from 2.14 to 9.56 nm and the contact angle of the un-irradiated thin films decreases from 89° to 82°. The wetting behavior of the resulting films can be reversibly switched from hydrophobic to hydrophilic, through alternation of UV illumination and dark storage. The light-induced efficiency of the thin films increases with the increase of Mg concentration.

  18. Synthesis and characterization of thermally oxidized ZnO films

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Metallic zinc thin films were deposited onto glass substrates using vacuum thermal evaporation method. By thermal oxidation of as-deposited Zn films, in ambient conditions, at different temperatures (570,. 670 and 770 K, respectively, for 1 h) zinc oxide thin films were obtained. The structural characteristics of the.

  19. Morphological, structural and optical properties of ZnO thin films deposited by dip coating method

    Energy Technology Data Exchange (ETDEWEB)

    Marouf, Sara; Beniaiche, Abdelkrim; Guessas, Hocine, E-mail: aziziamor@yahoo.fr [Laboratoire des Systemes Photoniques et Optiques Non Lineaires, Institut d' Optique et Mecanique de Precision, Universite Ferhat Abbas-Setif 1, Setif (Algeria); Azizi, Amor [Laboratoire de Chimie, Ingenierie Moleculaire et Nanostructures, Universite Ferhat Abbas-Setif 1, Setif (Algeria)

    2017-01-15

    Zinc oxide (ZnO) thin films were deposited on glass substrate by dip coating technique. The effects of sol aging time on the deposition of ZnO films was studied by using the field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and optical transmission techniques. The morphology of the films strongly depends on preparation route and deposition technique. It is noteworthy that films deposited from the freshly prepared solution feature indistinct characteristics; had relatively poor crystalline quality and low optical transmittance in the visible region. The increase in sol aging time resulted in a gradual improvement in crystallinity (in terms of peak sharpness and peak intensity) of the hexagonal phase for all diffraction peaks. Effect of sol aging on optical transparency is quite obvious through increased transmission with prolonged sol aging time. Interestingly, 72-168 h sol aging time was found to be optimal to achieve smooth surface morphology, good crystallinity and high optical transmittance which were attributed to an ideal stability of solution. These findings present a better-defined and more versatile procedure for production of clean ZnO sols of readily adjustable nanocrystalline size. (author)

  20. Effect of high-energy electron beam irradiation on the transmittance of ZnO thin films on transparent substrates

    International Nuclear Information System (INIS)

    Yun, Eui-Jung; Jung, Jin-Woo; Han, Young-Hwan; Kim, Min-Wan; Lee, Byung Cheol

    2010-01-01

    We investigated in this study the effects of high-energy electron beam irradiation (HEEBI) on the optical transmittance of undoped ZnO films grown on transparent substrates, such as corning glass and polyethersulfone (PES) plastic substrates, with a radio frequency (rf) magnetron sputtering technique. The ZnO thin films were treated with HEEBI in air at RT with an electron beam energy of 1 MeV and doses of 4.7 x 10 14 - 4.7 x 10 16 electrons/cm 2 . The optical transmittance of the ZnO films was measured using an ultraviolet visible near-infrared spectrophotometer. The detailed estimation process for separating the transmittance of HEEBI-treated ZnO films from the total transmittance of ZnO films on transparent substrates treated with HEEBI is given in this paper. We concluded that HEEBI causes a slight suppression in the optical transmittance of ZnO thin films. We also concluded that HEEBI treatment with a high dose shifted the optical band gap (E g ) toward the lower energy region from 3.29 to 3.28 eV whereas that with a low dose unchanged E g at 3.25 eV. This shift suggested that HEEBI at RT at a high dose acts like an annealing treatment at high temperature.

  1. Characteristics of surface acoustic waves in (11\\bar 2 0)ZnO film/ R-sapphire substrate structures

    Science.gov (United States)

    Wang, Yan; Zhang, ShuYi; Xu, Jing; Xie, YingCai; Lan, XiaoDong

    2018-02-01

    (11\\bar 2 0)ZnO film/ R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along [1ī00] direction, are investigated by using 3 dimensional finite element method (3D-FEM). The phase velocity ( v p), electromechanical coupling coefficient ( k 2), temperature coefficient of frequency ( TCF) and reflection coefficient ( r) of Rayleigh wave and Love wave devices are theoretically analyzed. Furthermore, the influences of ZnO films with different crystal orientation on SAW properties are also investigated. The results show that the 1st Rayleigh wave has an exceedingly large k 2 of 4.95% in (90°, 90°, 0°) (11\\bar 2 0)ZnO film/ R-sapphire substrate associated with a phase velocity of 5300 m/s; and the 0th Love wave in (0°, 90°, 0°) (11\\bar 2 0)ZnO film/ R-sapphire substrate has a maximum k 2 of 3.86% associated with a phase velocity of 3400 m/s. And (11\\bar 2 0)ZnO film/ R-sapphire substrate structures can be used to design temperature-compensated and wide-band SAW devices. All of the results indicate that the performances of SAW devices can be optimized by suitably selecting ZnO films with different thickness and crystal orientations deposited on R-sapphire substrates.

  2. Recent advances in ZnO nanostructures and thin films for biosensor applications: review.

    Science.gov (United States)

    Arya, Sunil K; Saha, Shibu; Ramirez-Vick, Jaime E; Gupta, Vinay; Bhansali, Shekhar; Singh, Surinder P

    2012-08-06

    Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review highlights recent advances in various approaches towards synthesis of ZnO nanostructures and thin films and their applications in biosensor technology. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Juan [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Onna, Diego [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Sánchez, Luis [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31, Perú (Peru); Marchi, M. Claudia [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Centro de Microscopias Avanzadas, FCEyN-Universidad ed Buenos Aires, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Candal, Roberto, E-mail: rjcandal@gmail.com [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); ECyT, 3iA, Universidad Nacional de San Martín, Martín de Irigoyen No 3100 (1650), San Martín, Pcia de Buenos Aires (Argentina); Ponce, Silvia [Universidad de Lima, Av. Javier Prado Este s/n, Monterrico, Lima 33, Perú (Peru); Bilmes, Sara A. [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina)

    2013-08-15

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  4. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    International Nuclear Information System (INIS)

    Rodríguez, Juan; Onna, Diego; Sánchez, Luis; Marchi, M. Claudia; Candal, Roberto; Ponce, Silvia; Bilmes, Sara A.

    2013-01-01

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  5. The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates

    Science.gov (United States)

    Rodríguez, Juan; Onna, Diego; Sánchez, Luis; Marchi, M. Claudia; Candal, Roberto; Ponce, Silvia; Bilmes, Sara A.

    2013-08-01

    Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 °C or 130 °C, and PET heated at 90 °C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

  6. Characterization of piesoelectric ZnO thin films and the fabrication of piezoelectric micro-cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raegan Lynn [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    In Atomic Force Microscopy (AFM), a microcantilever is raster scanned across the surface of a sample in order to obtain a topographical image of the sample's surface. In a traditional, optical AFM, the sample rests on a bulk piezoelectric tube and a control loop is used to control the tip-sample separation by actuating the piezo-tube. This method has several disadvantages--the most noticeable one being that response time of the piezo-tube is rather long which leads to slow imaging speeds. One possible solution aimed at improving the speed of imaging is to incorporate a thin piezoelectric film on top of the cantilever beam. This design not only improves the speed of imaging because the piezoelectric film replaces the piezo-tube as an actuator, but the film can also act as a sensor. In addition, the piezoelectric film can excite the cantilever beam near its resonance frequency. This project aims to fabricate piezoelectric microcantilevers for use in the AFM. Prior to fabricating the cantilevers and also part of this project, a systematic study was performed to examine the effects of deposition conditions on the quality of piezoelectric ZnO thin films deposited by RF sputtering. These results will be presented. The deposition parameters that produced the highest quality ZnO film were used in the fabrication of the piezoelectric cantilevers. Unfortunately, the fabricated cantilevers warped due to the intrinsic stress of the ZnO film and were therefore not usable in the AFM. The complete fabrication process will be detailed, the results will be discussed and reasons for the warping will be examined.

  7. Comparative study of ZnO thin films prepared by different sol-gel route

    Directory of Open Access Journals (Sweden)

    F Esmaieli Ghodsi

    2012-03-01

    Full Text Available   Retraction Notice    The paper "Comparative study of ZnO thin films prepared by different sol-gel route" by H. Absalan and F. E. Ghodsi, which appeared in Iranian Journal of Physics Research, Vol. 11, No. 4, 423-428 (in Farsi is translation of the paper "Comparative Study of ZnO Thin Films Prepared by Different Sol-Gel Route" by F. E. Ghodsi and H. Absalan, which appeared in ACTA PHYSICA POLONICA A, Vol 118 (2010 (in English and for this reason is retracted from this journal.The corresponding author  (and also the first author is the only responsible person for this action.   

  8. Growth behavior and field emission property of ZnO nanowire arrays on Au and Ag films

    Directory of Open Access Journals (Sweden)

    Sung Hyun Kim

    2013-09-01

    Full Text Available We propose a facile method to control the growth and areal density of zinc-oxide (ZnO nanowire arrays using gold or silver films deposited on aluminum-doped ZnO (AZO layers coated on glass substrates. Nanowires exceeding 5 μm in length grew on both the glass/AZO-layer and on the glass/AZO-layer/Au-film where the areal array density was controlled primarily by changing the annealing temperature. In contrast, the nanowire arrays grew only on the AZO surface but not on the Ag film owing to the formation of an Ag-oxide layer. We fabricated field emitter devices with density controlled ZnO nanowire arrays and low turn-on electric field of ∼6 V/μm and a field enhancement factor of up to 1188 were obtained with density controlled ZnO nanowire arrays.

  9. Oxidation of ZnO thin films during pulsed laser deposition process

    Indian Academy of Sciences (India)

    36, No. 3, June 2013, pp. 385–388. c Indian Academy of Sciences. Oxidation of ZnO thin films during pulsed laser deposition process. E DE POSADA1,∗. , L MOREIRA1, J PÉREZ DE LA CRUZ2, M ARRONTE1, L V PONCE1,. T FLORES1 and J G LUNNEY3. 1CICATA-Instituto Politécnico Nacional, Altamira 89600, México.

  10. Preparation of cadmium-doped ZnO thin films by SILAR and their ...

    Indian Academy of Sciences (India)

    pH measurement was carried out in a systronics pH meter. (Model 335). Cadmium doping was carried out by adding cadmium chloride (CdCl2·H2O, GR grade, Loba Chemie, mol. wt 201·32) in sodium zincate bath. Details of pure ZnO film deposition process from sodium or ammonium zincate bath has been reported earlier.

  11. Sodium and potassium doped P-type ZnO films by sol-gel spin-coating technique

    Science.gov (United States)

    Au, Benedict Wen-Cheun; Chan, Kah-Yoong

    2017-07-01

    Zinc oxide (ZnO) is a promising material in a variety of applications including sensors, transistors and solar cells. Many researchers studied N-type ZnO films and reported enhanced properties. On the other hand, P-type ZnO films were rarely attempted due to the self-compensation effect. Success in achieving P-type ZnO films is important as it will pave the way for more advanced complementary devices. In this work, P-type sodium and potassium doped ZnO films were fabricated on glass substrates with doping concentration between 0 and 25 at.%. The influences of doping concentration on surface morphology, structural, optical and electrical properties were investigated using atomic force microscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, ultraviolet-visible (UV-Vis) spectrophotometer, photoluminescence spectroscopy and Hall-effect electrical transport measurement system. The distinctive behavior of P-type ZnO films with different doping concentrations will be discussed.

  12. Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

    Science.gov (United States)

    Maldonado, Arturo; Juarez, Héctor; Pacio, Mauricio; Perez, Rene

    2015-01-01

    Summary This work presents a novel technique to deposit ZnO thin films through a metal vacuum evaporation technique using colloidal nanoparticles (average size of 30 nm), which were synthesized by our research group, as source. These thin films had a thickness between 45 and 123 nm as measured by profilometry. XRD patterns of the deposited thin films were obtained. According to the HRSEM micrographs worm-shaped nanostructures are observed in samples annealed at 600 °C and this characteristic disappears as the annealing temperature increases. The films obtained were annealed from 25 to 1000 °C, showing a gradual increase in transmittance spectra up to 85%. The optical band gaps obtained for these films are about 3.22 eV. The PL measurement shows an emission in the red and in the violet region and there is a correlation with the annealing process. PMID:25977868

  13. Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

    Directory of Open Access Journals (Sweden)

    Jose Alberto Alvarado

    2015-04-01

    Full Text Available This work presents a novel technique to deposit ZnO thin films through a metal vacuum evaporation technique using colloidal nanoparticles (average size of 30 nm, which were synthesized by our research group, as source. These thin films had a thickness between 45 and 123 nm as measured by profilometry. XRD patterns of the deposited thin films were obtained. According to the HRSEM micrographs worm-shaped nanostructures are observed in samples annealed at 600 °C and this characteristic disappears as the annealing temperature increases. The films obtained were annealed from 25 to 1000 °C, showing a gradual increase in transmittance spectra up to 85%. The optical band gaps obtained for these films are about 3.22 eV. The PL measurement shows an emission in the red and in the violet region and there is a correlation with the annealing process.

  14. Sea-Urchin-Like ZnO Nanoparticle Film for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Cheng-Wen Ma

    2015-01-01

    Full Text Available We present novel sea-urchin-like ZnO nanoparticles synthesized using a chemical solution method. Solution approaches to synthesizing ZnO nanostructures have several advantages including low growth temperatures and high potential for scaling up. We investigated the influence of reaction times on the thickness and morphology of sea-urchin-like ZnO nanoparticles, and XRD patterns show strong intensity in every direction. Dye-sensitized solar cells (DSSCs were developed using the synthesized ZnO nanostructures as photoanodes. The DSSCs comprised a fluorine-doped tin oxide (FTO glass with dense ZnO nanostructures as the working electrode, a platinized FTO glass as the counter electrode, N719-based dye, and I-/I3-liquid electrolyte. The DSSC fabricated using such nanostructures yielded a high power conversion efficiency of 1.16% with an incident photo-to-current efficiency (IPCE as high as 15.32%. Electrochemical impedance spectroscopy was applied to investigate the characteristics of DSSCs. An improvement in the electron transport in the ZnO photoanode was also observed.

  15. ZnO coated nanospring-based chemiresistors

    Science.gov (United States)

    Dobrokhotov, Vladimir; Oakes, Landon; Sowell, Dewayne; Larin, Alexander; Hall, Jessica; Kengne, Alex; Bakharev, Pavel; Corti, Giancarlo; Cantrell, Timothy; Prakash, Tej; Williams, Joseph; McIlroy, D. N.

    2012-02-01

    Chemiresistors were constructed using 3-D silica nanospring mats coated with a contiguous film of ZnO nanocrystals. Chemiresistors with an average ZnO nanocrystal radius 20 nm, were found to exhibit a relative change in conductance of a factor of 50 upon exposure to a gas flow of 20% O2 and 80% N2 with ˜500 ppm of toluene and an operational temperature of 400 °C. Samples with an average ZnO nanocrystal radius of 15 nm were found to be the most responsive with a relative conductance change of a factor of 1000. The addition of metal nanoparticles (average radius equal to 2.4 nm) onto the surface of the ZnO nanocrystals (average radius equal to 15 nm) produced a relative change in conductance of a factor of 1500. For the optimum conditions (T = 400 °C, grain size ˜15 nm) well-defined spikes in conductance to explosive vapors (TNT, TATP) were obtained for 0.1 ms exposure time at ppb levels.

  16. Effect of precursor solutions on ZnO film via solution precursor plasma spray and corresponding gas sensing performances

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z.X., E-mail: zexin.yu@utbm.fr [Univ Bourgogne Franche Comte, CNRS, Lab ICB, UMR 6303, Site UTBM, F-90010 Belfort (France); Ma, Y.Z., E-mail: yangzhou.ma@outlook.com [School of Materials Science and Engineering, Anhui University of Technology, Ma’anshan 243002 (China); Zhao, Y.L. [Univ Bourgogne Franche Comte, CNRS, Lab ICB, UMR 6303, Site UTBM, F-90010 Belfort (France); Huang, J.B.; Wang, W.Z. [Key Lab of Safety Science of Pressurized System, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237 (China); Moliere, M.; Liao, H.L. [Univ Bourgogne Franche Comte, CNRS, Lab ICB, UMR 6303, Site UTBM, F-90010 Belfort (France)

    2017-08-01

    Highlights: • C-axis preferential oriented grown ZnO films were firstly deposited via SPPS with different solutions. • ZnO films were hydrophobic due to cauliflower and honeycomb-like surface morphologies with high surface specific area. • Gas detecting performance of (002) plane oriented ZnO was predicted and compared by “first principle calculation method”. - Abstract: Solution precursor plasma spraying (SPPS) as a novel thermal spray method was employed to deposit nano-structured ZnO thin film using different formulations of the precursor solution. This article focuses on the influence of the solution composition on the preferential orientation of crystal growth, on crystal size and surface morphology of the resulting ZnO films. The trend of preferential growth along (002) lattice plane of ZnO film was studied by slow scanning X-ray diffraction using a specific coefficient P{sub (002).} It appears that the thermal spray process promotes the buildup of ZnO films preferentially oriented along the c-axis. The shape of single particle tends to change from round shaped beads to hexagonal plates by increasing the volume ratio of ethanol in the solvent. Both cauliflower and honeycomb-like surface morphologies featuring high specific surface area and roughness were obtained through the SPPS process by varying solution composition. These ZnO films are hydrophobic with contact angle as high as 136°, which is seemingly associated with micro reliefs developing high surface specific area. Then the gas sensing performances of ZnO films preferentially oriented along (002) face were tentatively predicted using the “first principle calculation method” and were compared with those of conventional films that are mainly oriented along the (101) face. The (002) face displays better hydrogen adsorption capability than the (101) face with much larger resulting changes in electrical resistance. In conclusion, the c-axis oriented ZnO films obtained through SSPS have

  17. Bias-voltage dependent ultraviolet photodetectors prepared by GaOx + ZnO mixture phase nanocrystalline thin films

    International Nuclear Information System (INIS)

    Wang, Rongxin; Yang, Lechen; Xu, Shijie; Zhang, Xiaodong; Dong, Xue; Zhao, Yingchun; Fu, Kai; Zhang, Baoshun; Yang, Hui

    2013-01-01

    Highlights: •GaO x + ZnO thin films sputtered and annealed exhibit interesting and unique optical properties, especially deep UV photo response. •GaO x + ZnO thin films can be used to fabricate efficient deep UV photodetectors. •The mixture phase nature of GaO x + ZnO thin films is revealed to be responsible for the unique characteristics of the photodetectors. •Two bands in UV range can be adjusted by a applied voltage when the PDs were fabricated using the mixture phase nature of GaO x + ZnO thin films. -- Abstract: Ultraviolet (UV) photodetectors were prepared by using the GaO x + ZnO mixture phase thin films sputtered on sapphire as the photoresponse layer. The devices show good photoresponse in UV range. More interestingly, the device responsivity in the wavelength less than 280 nm range rapidly increases with increasing the applied voltage and becomes dominant for the bias ⩾3.0 V. X-ray diffraction, absorption and cathodoluminescence measurements firmly reveal the mixture phases in the thin films. Electric field dependent detrapping of photo-excited carriers in nanocrystals in the films shall be responsible for the observed bias-voltage dependent deep UV photoresponse of the devices

  18. Structural and morphological characterizations of ZnO films grown on GaAs substrates by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Agouram, S.; Zuniga Perez, J.; Munoz-Sanjose, V. [Universitat de Valencia, Departamento de Fisica Aplicada y Electromagnetismo, Burjassot (Spain)

    2007-07-15

    ZnO films were grown on GaAs(100), GaAs(111)A and GaAs(111)B substrates by metal organic chemical vapour deposition (MOCVD). Diethylzinc (DEZn) and tertiarybutanol (t-butanol) were used as Zn and O precursors, respectively. The influence of the growth temperature and GaAs substrate orientation on the crystalline orientation and morphology of the ZnO grown films has been analysed. Crystallinity of grown films was studied by X-ray diffraction (XRD); thickness and morphology of ZnO films were investigated by scanning electron microscopy (SEM). SEM results reveal significant differences between morphologies depending on growth temperature but not significant differences were detected on the texture of grown films. (orig.)

  19. Control of hydrophobic surface and wetting states in ultra-flat ZnO films by GLAD method

    Science.gov (United States)

    Chi, Po-Wei; Su, Chih-Wei; Wei, Da-Hua

    2017-05-01

    Ultra-flat Zinc oxide (ZnO) films with natural hydrophobicity were sputtered onto glass substrates by glancing angle deposition (GLAD) method without addition of active oxygen at room temperature under different glancing angles relating to the sample holder. The sample holder was positioned at glancing angles of 0° and 30°, and the sputtering power was fixed at 75 W with low argon (Ar) pressure of 1 × 10-2 Torr during deposition process. According to analysis of surface composition and structure, the naturally hydrophobic wetting state can be attributed to the different grain structure and hydrocarbon adsorbates on the top of the film surface. On the other hand, the interfacial water molecules near the surface of ultra-flat ZnO films are confirmed belong to the hydrophobic hydrogen structure by Fourier transform infrared/attenuated total reflection. In addition, the water contact angle was significantly improved by a simple factor of glancing angle. The water contact angle value of ultra-flat ZnO films increased from 90° to 98° while the sample holder is with glancing angle of 30°. Moreover, our present ultra-flat ZnO films also exhibited excellent transparency over 80%, and the surface wetting switched from hydrophobic to hydrophilic states after exposing in ultraviolet (UV) surroundings. Then, the ZnO films could be freely and stably reversed back to hydrophobicity after stored in dark surroundings. This present study not only demonstrates that the natural wettability of ultra-flat ZnO films is strongly associated with surface composition and structure, but also provides an easy way to modulate and improve the surface wettability. This also extends the potential applications of ultra-flat ZnO thin films and aids a profound understanding for device design and material development.

  20. Sonicated sol–gel preparation of nanoparticulate ZnO thin films with various deposition speeds: The highly preferred c-axis (0 0 2) orientation enhances the final properties

    International Nuclear Information System (INIS)

    Malek, M.F.; Mamat, M.H.; Khusaimi, Z.; Sahdan, M.Z.; Musa, M.Z.; Zainun, A.R.; Suriani, A.B.; Md Sin, N.D.; Abd Hamid, S.B.; Rusop, M.

    2014-01-01

    Highlights: • Minimum stress of highly c-axis oriented ZnO was grown at suitable deposition speed. • The ZnO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZnO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on deposition speed. -- Abstract: Zinc oxide (ZnO) thin films have been deposited onto glass substrates at various deposition speeds by a sonicated sol–gel dip-coating technique. This work studies the effects of deposition speed on the crystallisation behaviour and optical and electrical properties of the resulting films. X-ray diffraction (XRD) analysis showed that thin films were preferentially oriented along the (0 0 2) c-axis direction of the crystal. The transformation sequence of strain and stress effects in ZnO thin films has also been studied. The films deposited at a low deposition speed exhibited a large compressive stress of 0.78 GPa, which decreased to 0.43 GPa as the deposition speed increased to 40 mm/min. Interestingly, the enhancement in the crystallinity of these films led to a significant reduction in compressive stress. All films exhibited an average transmittance of greater than 90% in the visible region, with absorption edges at ∼380 nm. The photoluminescence (PL) measurements indicated that the intensity of the emission peaks varied significantly with deposition speed. The optical band gap energy (E g ) was evaluated as 3.276–3.289 eV, which increased with decreasing compressive stress along the c-axis. The energy band gap of the resulting ZnO films was found to be strongly influenced by the preferred c-axis (0 0 2) orientation

  1. Sonicated sol–gel preparation of nanoparticulate ZnO thin films with various deposition speeds: The highly preferred c-axis (0 0 2) orientation enhances the final properties

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Mamat, M.H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Khusaimi, Z. [NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia); Sahdan, M.Z. [Microelectronic and Nanotechnology Centre (MiNT), Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Batu Pahat, Johor (Malaysia); Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Zainun, A.R. [Faculty of Electrical and Electronics Engineering, Universiti Malaysia Pahang (UMP), Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia); Suriani, A.B. [Department of Physics, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjung Malim, Perak (Malaysia); Md Sin, N.D. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Abd Hamid, S.B. [Nanotechnology and Catalysis Research Centre (NANOCAT), Universiti Malaya (UM), 50603 Kuala Lumpur (Malaysia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2014-01-05

    Highlights: • Minimum stress of highly c-axis oriented ZnO was grown at suitable deposition speed. • The ZnO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZnO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on deposition speed. -- Abstract: Zinc oxide (ZnO) thin films have been deposited onto glass substrates at various deposition speeds by a sonicated sol–gel dip-coating technique. This work studies the effects of deposition speed on the crystallisation behaviour and optical and electrical properties of the resulting films. X-ray diffraction (XRD) analysis showed that thin films were preferentially oriented along the (0 0 2) c-axis direction of the crystal. The transformation sequence of strain and stress effects in ZnO thin films has also been studied. The films deposited at a low deposition speed exhibited a large compressive stress of 0.78 GPa, which decreased to 0.43 GPa as the deposition speed increased to 40 mm/min. Interestingly, the enhancement in the crystallinity of these films led to a significant reduction in compressive stress. All films exhibited an average transmittance of greater than 90% in the visible region, with absorption edges at ∼380 nm. The photoluminescence (PL) measurements indicated that the intensity of the emission peaks varied significantly with deposition speed. The optical band gap energy (E{sub g}) was evaluated as 3.276–3.289 eV, which increased with decreasing compressive stress along the c-axis. The energy band gap of the resulting ZnO films was found to be strongly influenced by the preferred c-axis (0 0 2) orientation.

  2. Surface excitons on a ZnO (000-1) thin film

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S., E-mail: skuehn@mbi-berlin.de; Friede, S.; Elsaesser, T. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Str. 2A, Berlin D-12489 (Germany); Sadofev, S.; Blumstengel, S.; Henneberger, F. [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, Berlin D-12489 (Germany)

    2013-11-04

    Elementary excitations at the polar (000-1) surface of a 20 nm pseudomorphically grown ZnO thin film are examined by steady state and time-resolved photoluminescence spectroscopy at low temperature. We control the density of emission centers through the deposition of prototypical organic molecules with a carboxylic acid anchor group by the Langmuir-Blodgett technique. Knowledge of the precise film thickness, defect concentrations and number density of deposited molecules leads us to associate the surface exciton emission to defect-related localization centers that are generated through a photochemical process.

  3. Defect-band mediated ferromagnetism in Gd-doped ZnO thin films

    KAUST Repository

    Venkatesh, S.

    2015-01-07

    Gd-doped ZnO thin films prepared by pulsed laser deposition with Gd concentrations varying from 0.02–0.45 atomic percent (at. %) showed deposition oxygen pressure controlled ferromagnetism. Thin films prepared with Gd dopant levels (

  4. Detailed microstructure analysis of as-deposited and etched porous ZnO films

    International Nuclear Information System (INIS)

    Shang, Congcong; Thimont, Yohann; Barnabé, Antoine; Presmanes, Lionel; Pasquet, Isabelle; Tailhades, Philippe

    2015-01-01

    Graphical abstract: - Highlights: • Porous ZnO thin films were deposited by rf magnetron sputtering. • Surface enhancement factors were deduced from geometrical considerations. • Enlargement of the inter-grain spaces have been achieved by HCl chemical etching. • Microstructural parameters were deduced from SEM, AFM and optical measurements. - Abstract: ZnO nanostructured materials in thin film forms are of particular interest for photovoltaic or photocatalysis processes but they suffer from a lack of simple methods for optimizing their microstructure. We have demonstrated that microporous ZnO thin films with optimized inter grain accessibility can be produce by radio frequency magnetron sputtering process and chemical etching with 2.75 mM HCl solution for different duration. The as-deposited ZnO thin films were first characterized in terms of structure, grain size, inter grain space, open cavity depth and total thickness of the film by XRD, AFM, SEM, profilometry and optical measurements. A specific attention was dedicated to the determination of the surface enhancement factor (SEF) by using basic geometrical considerations and images treatments. In addition, the porous fraction and its distribution in the thickness have been estimated thanks to the optical simulation of the experimental UV–Visible–IR spectrums using the Bruggeman dielectric model and cross section SEM images analysis respectively. This study showed that the microstructure of the as-deposited films consists of a dense layer covered by a porous upper layer developing a SEF of 12–13 m 2 m −2 . This two layers architecture is not modified by the etching process. The etching process only affects the upper porous layer in which the overall porosity and the inter-grain space increase with the etching duration. Column diameter and total film thickness decrease at the same time when the films are soaked in the HCl bath. The microporous structure obtained after the etching process could

  5. Influence of Annealing on Properties of Spray Deposited ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Kalyani Nadarajah

    2013-01-01

    Full Text Available Zinc Oxide (ZnO thin films were deposited on glass substrates via the spray pyrolysis technique. The films were subsequently annealed in ambient air from 300°C to 500°C. The morphology and structural properties of the thin films were studied by field emission scanning electron microscope (FESEM, atomic force microscopy (AFM, and X-ray diffractometry (XRD techniques. Electrical resistivity of the thin films was measured using a data acquisition unit. The optical properties of the films were characterized by UV-vis spectroscopy and photoluminescence (PL technique. X-ray diffraction data showed that the films were grown in the (002 direction with a hexagonal wurtzite structure. The average grain size ranged from 15 to 27 nm. Increasing annealing temperatures resulted in larger grain sizes and higher crystallinity, with the surface roughness of annealed films being more than twice if compared to unannealed film. The electrical resistivity of the films decreased with the increasing annealing temperature. The UV and visible band emissions were observed in the photoluminescence spectra, due to exciton and defect-related emissions, respectively. The transmission values of the films were as high as 90% within the visible range (400–700 nm.

  6. Reflectometric measurement of n-hexane adsorption on ZnO2 nanohybrid film modified by hydrophobic gold nanoparticles

    Science.gov (United States)

    Sebők, Dániel; Csapó, Edit; Ábrahám, Nóra; Dékány, Imre

    2015-04-01

    Zinc-peroxide/poly(styrenesulfonate) nanohybrid thin films (containing 20 bilayers: [ZnO2/PSS]20, d ∼ 500 nm) were prepared using layer-by-layer (LbL) method. The thin film surface was functionalized by different surface modifying agents (silanes, alkylthiols and hydrophobized nanoparticles). Based on the experimental results of quartz crystal microbalance (QCM) and contact angle measurements (as prequalifications) the octanethiol covered gold nanoparticles (OT-AuNPs) were selected for further vapour adsorption studies. Reflectometric interference spectroscopy (RIfS) was used to measure n-hexane vapour adsorption on the original and modified nanohybrid films in a gas flow platform. The thin film provides only the principle of the measurement (by interference phenomenon), the selectivity and hydrophobicity is controlled and enhanced by surface functionalization (by dispersion interaction between the alkyl chains). The interference pattern shift (Δλ) caused by the increase of the optical thickness of the thin film due to vapour adsorption was investigated. It was found that due to the surface functionalization by hydrophobic nanoparticles the effect of water vapour adsorption decreased significantly, while for n-hexane opposite tendency was observed (the effective refractive index and thus the interference pattern shift increased drastically). The correlation between QCM technique and optical method (RIfS) was specified: linear specific adsorbed amount vs. wavelength shift calibration curves were determined in the pr = 0-0.4 relative vapour pressure range. The thin film is suitable for sensorial application (e.g. volatile organic compound/VOC sensor).

  7. Low-temperature deposition of ZnO thin films on PET and glass substrates by DC-sputtering technique

    International Nuclear Information System (INIS)

    Banerjee, A.N.; Ghosh, C.K.; Chattopadhyay, K.K.; Minoura, Hideki; Sarkar, Ajay K.; Akiba, Atsuya; Kamiya, Atsushi; Endo, Tamio

    2006-01-01

    The structural, optical and electrical properties of ZnO thin films (260 - 490 nm thick) deposited by direct-current sputtering technique, at a relatively low-substrate temperature (363 K), onto polyethylene terephthalate and glass substrates have been investigated. X-ray diffraction patterns confirm the proper phase formation of the material. Optical transmittance data show high transparency (80% to more than 98%) of the films in the visible portion of solar radiation. Slight variation in the transparency of the films is observed with a variation in the deposition time. Electrical characterizations show the room-temperature conductivity of the films deposited onto polyethylene terephthalate substrates for 4 and 5 h around 0.05 and 0.25 S cm -1 , respectively. On the other hand, for the films deposited on glass substrates, these values are 8.5 and 9.6 S cm -1 for similar variation in the deposition time. Room-temperature conductivity of the ZnO films deposited on glass substrates is at least two orders of magnitude higher than that of ZnO films deposited onto polyethylene terephthalate substrates under identical conditions. Hall-measurements show the maximum carrier concentration of the films on PET and glass substrate around 2.8 x 10 16 and 3.1 x 10 2 cm -3 , respectively. This report will provide newer applications of ZnO thin films in flexible display technology

  8. Structural and Magnetic Properties of Mn doped ZnO Thin Film Deposited by Pulsed Laser Deposition

    KAUST Repository

    Baras, Abdulaziz

    2011-07-01

    Diluted magnetic oxide (DMO) research is a growing field of interdisciplinary study like spintronic devices and medical imaging. A definite agreement among researchers concerning the origin of ferromagnetism in DMO has yet to be reached. This thesis presents a study on the structural and magnetic properties of DMO thin films. It attempts to contribute to the understanding of ferromagnetism (FM) origin in DMO. Pure ZnO and Mn doped ZnO thin films have been deposited by pulsed laser deposition (PLD) using different deposition conditions. This was conducted in order to correlate the change between structural and magnetic properties. Structural properties of the films were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The superconducting quantum interference device (SQUID) was used to investigate the magnetic properties of these films. The structural characterizations showed that the quality of pure ZnO and Mn doped ZnO films increased as oxygen pressure (PO) increased during deposition. All samples were insulators. In Mn doped films, Mn concentration decreased as PO increased. The Mn doped ZnO samples were deposited at 600˚C and oxygen pressure from 50-500mTorr. All Mn doped films displayed room temperature ferromagnetism (RTFM). However, at 5 K a superparamagnetic (SPM) behavior was observed in these samples. This result was accounted for by the supposition that there were secondary phase(s) causing the superparamagnetic behavior. Our findings hope to strengthen existing research on DMO origins and suggest that secondary phases are the core components that suppress the ferromagnetism. Although RTFM and SPM at low temperature has been observed in other systems (e.g., Co doped ZnO), we are the first to report this behavior in Mn doped ZnO. Future research might extend the characterization and exploration of ferromagnetism in this system.

  9. Electrodeposition and characterization of ZnO thin films using sodium thiosulfate as an additive for photovoltaic solar cells

    Science.gov (United States)

    Rahal, Hassiba; Kihal, Rafiaa; Affoune, Abed Mohamed; Ghers, Mokhtar; Djazi, Faycal

    2017-06-01

    Zinc oxide thin films have been grown by electrodeposition technique onto Cu and ITO-coated glass substrates from an aqueous zinc nitrate solution with addition of sodium thiosulfate at 90 °C. The effects of sodium thiosulfate on the electrochemical deposition of ZnO were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were obtained at -0.60 V vs. SCE and characterized by XRD, SEM, FTIR, optical, photoelectrochemical and electrical measurements. Thickness of the deposited film was measured to be 357 nm. X-ray diffraction results indicated that the synthesized ZnO has a pure hexagonal wurtzite structure with a marked preferential orientation along (002) plane. FTIR results confirmed the presence of ZnO films at peak 558 cm-1. SEM images showed uniform, compact morphology without any cracks and films composed of large flower-like ZnO agglomerates with star-shape. Optical properties of ZnO reveal a high optical transmission (> 80 % ) and high absorption coefficient (α > {10}5 {{cm}}-1) in visible region. The optical energy band gap was found to be 3.28 eV. Photoelectrochemical measurements indicated that the ZnO films had n-type semiconductor conduction. Electrical properties of ZnO films showed a low electrical resistivity of 6.54 {{Ω }}\\cdot {cm}, carrier concentration of -1.3× {10}17 {{cm}}-3 and mobility of 7.35 cm2 V-1 s-1. Project supported by the Algerian Ministry of Higher Education and Scientific Research, Algeria (No. J0101520090018).

  10. Tuning of undoped ZnO thin film via plasma enhanced atomic layer deposition and its application for an inverted polymer solar cell

    Directory of Open Access Journals (Sweden)

    Mi-jin Jin

    2013-10-01

    Full Text Available We studied the tuning of structural and optical properties of ZnO thin film and its correlation to the efficiency of inverted solar cell using plasma-enhanced atomic layer deposition (PEALD. The sequential injection of DEZn and O2 plasma was employed for the plasma-enhanced atomic layer deposition of ZnO thin film. As the growth temperature of ZnO film was increased from 100 °C to 300 °C, the crystallinity of ZnO film was improved from amorphous to highly ordered (002 direction ploy-crystal due to self crystallization. Increasing oxygen plasma time in PEALD process also introduces growing of hexagonal wurtzite phase of ZnO nanocrystal. Excess of oxygen plasma time induces enhanced deep level emission band (500 ∼ 700 nm in photoluminescence due to Zn vacancies and other defects. The evolution of structural and optical properties of PEALD ZnO films also involves in change of electrical conductivity by 3 orders of magnitude. The highly tunable PEALD ZnO thin films were employed as the electron conductive layers in inverted polymer solar cells. Our study indicates that both structural and optical properties rather than electrical conductivities of ZnO films play more important role for the effective charge collection in photovoltaic device operation. The ability to tune the materials properties of undoped ZnO films via PEALD should extend their functionality over the wide range of advanced electronic applications.

  11. Structural and optical characterization of ZnO nanostructured thin films.

    Science.gov (United States)

    Gonzalez Gonzalez, J. C.; Urbina Yarupetan, M.

    Magnetron sputtering is surely the most common technique in the industry for large-scale growth for thin films with low emissivity, where the oxide deposited is usually ZnO. One of the recognized advantages of this technique is that the effects due to ion bombardment contribute to obtain surfaces with very little roughness, in the order of nanometers, and therefore improves the quality of the silver layer deposited at the end in windows with low emissivity. Therefore, a complete characterization of the surface layers of ZnO is required. In this sense, we have analyzed three thin layers of ZnO grown on commercial glass substrates deposited by the magnetron sputtering technique with thicknesses of 20, 50 and 100 nm. We used techniques such as: XRR, XRD, SEM and Raman spectroscopy, to assess roughness, microstructure, ZnO phonons profile and other properties like as density and refraction index. The X'Pert reflectivity program was used to fit the reflectivity data; the intensity of reflections was modeled through homogeneous and uniform layers with a well-defined limit to take into account the glass substrate. Finally, the structural results were correlated with the optical results. Ciencia Activa: Grant 221-2015-FONDECYT. PERU.

  12. Growth of Ga-doped ZnO films by thermal oxidation with gallium and their optical properties

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2017-05-01

    Full Text Available Metal gallium was evaporated onto ZnS films by physical vapor deposition method and then the thermal oxidation in the air was subsequently performed for the growth of Ga-doped ZnO films. The microstructures, photoluminescence (PL and optical absorption properties of the Ga-doped ZnO films prepared under different deposition and oxidation conditions were investigated. The results showed that certain Ga doping can decrease the defects level, improve the crystallinity of ZnO films, and it became more effective with the extension of oxidation time. As the oxidation time increased, the Ga-doped ZnO films became more compact and uniform, displaying higher crystallinity. In addition, the optical band gaps of the ZnO films increased, the PL intensity of the visible emission decreased, and the luminescent center of the visible emission changed. Among them, the 505 nm emission resulted from oxygen vacancy, while the 539 nm emission was associated with oxygen interstitial.

  13. Morphology and photoluminescence of ZnO nanorods grown on sputtered GaN films with intermediate ZnO seed layer

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, R. [Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076 (India); Srinivasa, R.S. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076 (India); Major, S.S., E-mail: syed@iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076 (India)

    2016-10-01

    ZnO nanorods (NRs) were grown by chemical bath deposition on sputtered GaN over Si with and without sputtered ZnO seed layers. The effect of ZnO seed layer thickness, precursor concentration and growth temperature on the morphology and photoluminescence (PL) of ZnO-NRs has been studied. Scanning electron microscopy studies at different stages of growth have shown that the thickness of ZnO seed layer is critically important for controlling the growth behavior, morphology and density of ZnO-NRs on GaN surface. ZnO-NRs on bare GaN/Si grow with a large diameter and small aspect ratio of ∼4, displaying the tendency of lateral growth. Introduction of a thin ZnO seed layer (10 nm) under optimized precursor concentration and temperature drastically increases the aspect ratio to ∼16, due to partial coverage of ZnO on GaN surface and a moderate density of nucleation with small critical size. ZnO seed layers of higher thickness (50 nm and 100 nm) result in reduced aspect ratio due to increase in nucleation density and limited availability of reacting species. Increase in precursor concentration results in pronounced lateral growth and the decrease in growth temperature also results in compact nanorods with reduced aspect ratios. Room temperature photoluminescence (PL) studies show that ZnO-NRs on GaN, grown with or without ZnO seed layer under optimized precursor concentration and temperature, display high near-band-edge luminescence and negligible defect emission, compared to the nanorods on a ZnO seed layer over Si, as well as those grown at higher precursor concentration and lower temperatures. The enhanced PL is attributed to the absence of crystalline defects at nanorod interfaces due to lateral coalescence, arising from the moderate density and slight misalignment of the nanorods. - Highlights: • ZnO nanorods grown on sputtered GaN film display strong tendency of lateral growth. • Nanorods grown on 10 nm ZnO/GaN display moderate density and high aspect ratios.

  14. Nanocrystalline ZnO film deposited by ultrasonic spray on textured silicon substrate as an anti-reflection coating layer

    International Nuclear Information System (INIS)

    Sali, S.; Boumaour, M.; Kechouane, M.; Kermadi, S.; Aitamar, F.

    2012-01-01

    A ZnO thin film was successfully synthesized on glass, flat surface and textured silicon substrates by chemical spray deposition. The textured silicon substrate was carried out using two solutions (NaOH/IPA and Na 2 CO 3 ). Textured with Na 2 CO 3 solution, the sample surface exhibits uniform pyramids with an average height of 5 μm. The properties and morphology of ZnO films were investigated. X-ray diffraction (XRD) spectra revealed a preferred orientation of the ZnO nanocrystalline film along the c-axis where the low value of the tensile strain 0.26% was obtained. SEM images show that all films display a granular, polycrystalline morphology. The morphology of the ZnO layers depends dramatically on the substrate used and follows the contours of the pyramids on the substrate surface. The average reflectance of the textured surface was found to be around 13% and it decreases dramatically to 2.57% after deposition of a ZnO antireflection coating. FT-IR peaks arising from the bonding between Zn-O are clearly represented using a silicon textured surface. A very intense photoluminescence (PL) emission peak is observed for ZnO/textured Si, revealing the good quality of the layer. The PL peak at 380.5 nm (UV emission) and the high-intensity PL peak at 427.5 nm are observed and a high luminescence occurs when using a textured Si substrate.

  15. Influence of different carrier gases on the properties of ZnO films grown by MOCVD

    Directory of Open Access Journals (Sweden)

    Wang, Jinzhong

    2008-08-01

    Full Text Available ZnO films were grown on sapphire (001 substrate by atmospheric MOCVD using diethyl zinc and tertiary butanol precursors. The influence of different carrier gases (H2 and He on the properties was analyzed by their structural (XRD, microstructural (SEM and compositional (SIMS characterization. The intensity of the strongest diffraction peak from ZnO (002 plane was increased by about 2 orders of magnitude when He is used as carrier gas, indicating the significant enhancement in crystallinity. The surface of the samples grown using H2 and He carrier gases was composed of leaf-like and spherical grains respectively. Hydrogen [H] content in the film grown using H2 is higher than that using He, indicating that the [H] was influenced by the H2 carrier gas. Ultraviolet emission dominates the low temperature PL spectra. The emission from ZnO films grown using He show higher optical quality and more emission centers.

    Se depositaron películas de ZnO sobre sustratos de zafiro (001 utilizando dietil zinc y butanol terciario como precursores. La influencia de los diferentes gases portadores (H2 y He sobre las propiedades se estudió mediante la caracterización estructural (XRD, microestructural (SEM y composicional (SIMS. La intensidad del pico de difracción más importante del plano (002 del ZnO aumentó en dos órdenes de magnitud cuando se utiliza He como gas portador indicando un incremento significativo de la cristalinidad. La superficie de las muestras crecidas utilizando H2 y He está formada por granos en forma de hoja y de forma esférica respectivamente. El contenido en hidrógeno (H en la película es mayor cuando se utiliza H2 que cuando se utiliza He, indicando que la cantidad de hidrógeno está influenciada por el H2 del gas portador. La emisión ultravioleta domina el espectro PL de baja temperatura. La emisión de las películas de ZnO utilizando

  16. High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation.

    Science.gov (United States)

    Nomoto, Junichi; Makino, Hisao; Yamamoto, Tetsuya

    2016-12-01

    Five hundred-nanometer-thick ZnO-based textured polycrystalline films consisting of 490-nm-thick Al-doped ZnO (AZO) films deposited on 10-nm-thick Ga-doped ZnO (GZO) films exhibited a high Hall mobility (μ H) of 50.1 cm(2)/Vs with a carrier concentration (N) of 2.55 × 10(20) cm(-3). Firstly, the GZO films were prepared on glass substrates by ion plating with dc arc discharge, and the AZO films were then deposited on the GZO films by direct current magnetron sputtering (DC-MS). The GZO interface layers with a preferential c-axis orientation play a critical role in producing AZO films with texture development of a well-defined (0001) orientation, whereas 500-nm-thick AZO films deposited by only DC-MS showed a mixture of the c-plane and the other plane orientation, to exhibit a μ H of 38.7 cm(2)/Vs with an N of 2.22 × 10(20) cm(-3).

  17. Photocontrollable water permeation on the micro/nanoscale hierarchical structured ZnO mesh films.

    Science.gov (United States)

    Tian, Dongliang; Zhang, Xiaofang; Zhai, Jin; Jiang, Lei

    2011-04-05

    Most research of responsive surfaces mainly focus on the wettability transition on different solid substrate surfaces, but the dynamic properties of the micro/nanostructure-enhanced responsive wettability on microscale pore arrays are lacking and still remain a challenge. Here we report the photocontrollable water permeation on micro/nanoscale hierarchical structured ZnO-coated stainless steel mesh films. Especially, for aligned ZnO nanorod array-coated stainless steel mesh film, the film shows good water permeability under irradiation, while it is impermeable to water after dark storage. A detailed investigation indicates that the special nanostructure and the appropriate size of the microscale mesh pores play a crucial role in the excellent controllability over water permeation. The excellent controllability of water permeation on this film is promising in various important applications such as filtration, microreactor, and micro/nano fluidic devices. This work may provide interesting insight into the design of novel functional devices that are relevant to surface wettability.

  18. Photoelectrocatrocatalytic hydrolysis of starch by using sprayed ZnO thin films

    International Nuclear Information System (INIS)

    Sapkal, R. T.; Shinde, S. S.; Rajpure, K.Y.; Bhosale, C. H.

    2013-01-01

    Thin films of zinc oxide have been deposited onto glass/FTO substrates at optimized 400 °C by using a chemical spray pyrolysis technique. Deposited films are character photocatalytic activity by using XRD, an SEM, a UV-vis spectrophotometer, and a PEC single-cell reactor. Films are polycrystalline and have a hexagonal (wurtzite) crystal structure with c-axis (002) orientation growth perpendicular to the substrate surface. The observed direct band gap is about 3.22 eV for typical films prepared at 400 °C. The photocatalytic activity of starch with a ZnO photocatalyst has been studied by using a novel photoelectrocatalytic process. (semiconductor materials)

  19. Fabrication of Al doped ZnO films using atmospheric pressure cold plasma

    International Nuclear Information System (INIS)

    Suzaki, Yoshifumi; Miyagawa, Hayato; Yamaguchi, Kenzo; Kim, Yoon-Kee

    2012-01-01

    Under atmospheric pressure, homogeneous non-equilibrium cold plasma was generated stably by high voltage pulsed power (1 kV, 20 kHz, 38 W) excitation of a mixture of He and O 2 gases produced by a dielectric barrier discharge setup. By feeding Bis (2 methoxy‐6-methyl‐3, 5-heptanedione) Zn (Zn-MOPD, C 18 H 3 O 6 Zn) and Tris (2-methoxy‐6‐methy l‐3, 5-heptanedione) Al (Al-MOPD, C 27 H 45 O 9 Al) into this plasma with He carrier gas, transparent flat Al-doped ZnO (ZnO:Al) films about 120–240 nm thick were prepared on glass substrates directly under the slit made into the cathode. Deposition rates of the films were about 20–40 nm/min. The concentration of Al was measured by inductively coupled plasma atomic emission spectroscopy. The composition ratio of Al to Zn was 7.8 mol% when the carrier He gas flow rate of Al-MOPD was 30 cm 3 . The average transmittance of all films was more than 85% in the wavelength range from 400 to 800 nm. When the composition ratio of Al/Zn was between 1.1 and 7.8 mol%, the optical band gap of the film increased from 3.28 to 3.40 eV. The resistivity of ZnO:Al film was 2.96 Ω cm at 1.3 mol% of Al/Zn. In addition, the microstructure of the films was studied by X-ray diffraction measurement and field emission scanning electron microscope observation. It was revealed that doped Al is substituted onto the Zn site of the ZnO crystalline structure in ZnO:Al films. - Highlights: ► An atmospheric pressure cold plasma generator generated stable glow discharge. ► We fabricated Al doped ZnO films on glass substrates using cold plasma. ► Al concentration measured by inductively coupled plasma atomic emission spectroscopy. ► The transmission spectrum and the resistivity of the films were measured. ► The microstructure of the films was studied.

  20. Improved damp heat stability of Ga-Doped ZnO thin film by pretreatment of the polyethylene terephthalate substrate

    Science.gov (United States)

    Kim, B. B.; Seo, S. G.; Lim, Y. S.; Choi, H.-S.; Seo, W.-S.; Park, H.-H.

    2013-09-01

    A study on the damp heat stability of transparent conducting ZnO thin film grown on a polyethylene terephthalate substrate (PET) is reported. By thermal annealing of the PET substrate at 100°C with Ar flow in a vacuum chamber prior to the sputtering growth of Ga-doped ZnO (GZO) thin film, significantly enhanced damp heat stability was achieved at 60°C with a 90% relative humidity. Electrical and structural characterizations of the GZO thin films were carried out and the effects of the pretreatment on the improved damp heat stability are discussed.

  1. Synthesis and characterization of porous structured ZnO thin film for dye sensitized solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Marimuthu, T.; Anandhan, N., E-mail: anandhan-kn@rediffmail.com; Mummoorthi, M. [School of Physics, Alagappa University, Karaikudi – 630 003 (India); Dharuman, V. [Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi – 630 003 (India)

    2016-05-23

    Zinc oxide (ZnO) and zinc oxide/eosin yellow (ZnO/EY) thin films were potentiostatically deposited onto fluorine doped tin oxide (FTO) glass substrate. Effect of eosin yellow dye on structural, morphological and optical properties was studied. X-ray diffraction patterns, micro Raman spectra and photoluminescence (PL) spectra reveal hexagonal wurtzite structure with less atomic defects in 101 plane orientation of the ZnO/EY film. Scanning electron microscopy (SEM) images show flower for ZnO and porous like structure for ZnO/EY thin film, respectively. DSSC was constructed and evaluated by measuring the current density verses voltage curve.

  2. Electrical transport and Al doping efficiency in nanoscale ZnO films prepared by atomic layer deposition

    NARCIS (Netherlands)

    Wu, Y.; Hermkens, P.M.; Loo, B.W.H. van de; Knoops, H.C.M.; Potts, S.E.; Verheijen, M.A.; Roozeboom, F.; Kessels, W.M.M.

    2013-01-01

    In this work, the structural, electrical, and optical properties as well as chemical bonding state of Al-doped ZnO films deposited by atomic layer deposition have been investigated to obtain insight into the doping and electrical transport mechanisms in the films. The range in doping levels from 0%

  3. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    NARCIS (Netherlands)

    Hoye, R.L.Z.; Muñoz-Rojas, D.; Nelson, S.F.; Illiberi, A.; Poodt, P.; Roozeboom, F.; Macmanus-Driscoll, J.L.

    2015-01-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants

  4. Preferential orientation growth of ITO thin film on quartz substrate with ZnO buffer layer by magnetron sputtering technique

    Science.gov (United States)

    Du, Wenhan; Yang, Jingjing; Xiong, Chao; Zhao, Yu; Zhu, Xifang

    2017-07-01

    In order to improve the photoelectric transformation efficiency of thin-film solar cells, one plausible method was to improve the transparent conductive oxides (TCO) material property. In-doped tin oxide (ITO) was an important TCO material which was used as a front contact layer in thin-film solar cell. Using magnetron sputtering deposition technique, we prepared preferential orientation ITO thin films on quartz substrate. XRD and SEM measurements were used to characterize the crystalline structure and morphology of ITO thin films. The key step was adding a ZnO thin film buffer layer before ITO deposition. ZnO thin film buffer layer increases the nucleation center numbers and results in the (222) preferential orientation growth of ITO thin films.

  5. Magnetic Properties of Gadolinium-Doped ZnO Films and Nanostructures

    KAUST Repository

    Roqan, Iman S.

    2016-08-29

    The magnetic properties of Gd-doped ZnO films and nanostructures are important to the development of next-generation spintronic devices. Here, we elucidate the significant role played by Gd-oxygen-deficiency defects in mediating/inducing ferromagnetic coupling in in situ Gd-doped ZnO thin films deposited at low oxygen pressure by pulsed laser deposition (PLD). Samples deposited at higher oxygen pressures exhibited diamagnetic responses. Vacuum annealing was used on these diamagnetic samples (grown at a relatively high oxygen pressures) to create oxygen- deficiency defects with the aim of demonstrating reproducibility of room-temperature ferromagnetism (RTFM). Samples annealed at oxygen environment exhibited super‐ paramagnetism and blocking-temperature effects. The samples possessed secondary phases; Gd segregation led to superparamagnetism. Theoretical studies showed a shift of the 4f level of Gd to the conduction band minimum (CBM) in Gd-doped ZnO nanowires, which led to an overlap with the Fermi level, resulting in strong exchange coupling and consequently RTFM.

  6. Strain mismatch induced tilted heteroepitaxial (000l) hexagonal ZnO films on (001) cubic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bo Soo [Department of Applied Physics, Hanyang University Ansan (Korea, Republic of); Stan, Liliana; Usov, Igor O.; DePaula, Raymond F.; Arendt, Paul N.; Nastasi, Michael; Jia, Quanxi [Los Alamos National Laboratory, Los Alamos, NM (United States); Lee, Jung-Kun [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA (United States); Harriman, Tres A.; Lucca, Don A. [School of Mechanical and Aerospace Engineering, Oklahoma State University Stillwater, OK (United States); MacManus-Driscoll, Judith L. [Department of Materials Science and Metallurgy, University of Cambridge (United Kingdom); Park, Bae Ho [Division of Quantum Phases and Devices, Department of Physics, Konkuk University Seoul (Korea, Republic of)

    2011-12-15

    A novel strain mismatch induced tilted epitaxy method has been demonstrated for producing high quality (000l) hexagonal films on (001) cubic substrates. Highly oriented hexagonal (000l) ZnO films are grown on cubic (001) MgO substrates using Sm{sub 0.28}Zr{sub 0.72}O{sub 2-{delta}} (SZO) as a template. The large lattice mismatch of >13% between the obvious crystallographic matching directions of the template and substrate means that cube-on-cube epitaxy is energetically unfavorable, leading to growth instead of two high index, low energy compact planes, close to the {l_brace}111{r_brace} orientation. These planes give three different in-plane orientations resulting from coincidence site lattice matching (12 in-plane orientations in total) and provide a pseudo-hexagonal symmetry surface for the ZnO to grow on. The texture of the ensuing (000l) ZnO layer is markedly improved over the template. The work opens up both a new avenue for growing technologically important hexagonal structures on a range of readily available, (001) cubic substrates, as well as showing that there are wide possibilities for heteroepitaxial growth of a range of dissimilar materials. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Photoluminescence properties of ZnO films grown on InP by thermally oxidizing metallic Zn films

    CERN Document Server

    Chen, S J; Zhang, J Y; Lu, Y M; Shen, D Z; Fan, X W

    2003-01-01

    Photoluminescence (PL) properties of ZnO films grown on (001) InP substrates by thermal oxidization of metallic Zn films, in which oxygen vacancies and interstitial Zn ions are compensated by P ions diffusing from (001) InP substrates, are investigated. X-ray diffraction spectra indicate that P ions have diffused into the Zn films and chemically combined with Zn ions to form Zn sub 3 P sub 2. Intense free exciton emission dominates the PL spectra of ZnO films with very weak deep-level emission. Low-temperature PL spectra at 79 K are dominated by neutral-donor bound exciton emission at 3.299 eV (I sub 4) with a linewidth of 17.3 meV and neutral-acceptor bound exciton emission at 3.264 eV. The free exciton emission increases with increasing temperature and eventually dominates the emission spectrum for temperature higher than 170 K. Furthermore, the visible emission around 2.3 eV correlated with oxygen deficiencies and interstitial Zn defects was quenched to a remarkable degree by P diffusing from InP substrate...

  8. Enhancement of the Ultraviolet Photoresponsivity of Al-doped ZnO Thin Films Prepared by using the Sol-gel Spin-coating Method

    Science.gov (United States)

    Lee, Wookbin; Leem, Jae-Young

    2018-03-01

    We report the structural, morphological, optical, and ultraviolet (UV) photoresponse properties of Al-doped ZnO (AZO) thin films prepared on silicon substrates with different Al doping concentrations by using the sol-gel spin-coating method. An analysis of the X-ray diffraction patterns of the AZO thin films revealed that the average grain size decreased and the c-axis lattice constant increased with Al content. The field-emission scanning electron microscopy images showed that with Al doping, the grain size decreased, but the film density increased with increasing Al doping concentration from 0% to 3%. These results indicate that the surface area of the film increased with increasing Al doping. The absorbance spectra revealed that the UV absorbance of the AZO thin films increased with increasing Al doping concentration and that the absorption onset shifted towards lower energies. The photoluminescence spectra revealed that with increasing Al doping, the intensity of the visible emission greatly decreased and the visible emission peak shifted forward lower energy (a red shift). The UV sensor based on the AZO thin films exhibited a higher responsivity than that based on the undoped ZnO thin film. Therefore, this study provides a facile method for improving the photoresponsivity of UV sensors.

  9. Antibacterial and barrier properties of oriented polymer films with ZnO thin films applied with atomic layer deposition at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Pitkänen, Marja; Salo, Erkki; Kenttä, Eija [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Tanskanen, Anne, E-mail: Anne.Tanskanen@aalto.fi [Aalto University, School of Chemical Technology, Department of Chemistry, Laboratory of Inorganic Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Sajavaara, Timo, E-mail: timo.sajavaara@jyu.fi [University of Jyväskylä, Department of Physics, P.O. Box 35, FI-40014 Jyväskylä (Finland); Putkonen, Matti; Sievänen, Jenni; Sneck, Asko; Rättö, Marjaana [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Karppinen, Maarit, E-mail: Maarit.Karppinen@aalto.fi [Aalto University, School of Chemical Technology, Department of Chemistry, Laboratory of Inorganic Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Harlin, Ali [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland)

    2014-07-01

    Concerns on food safety, and need for high quality and extended shelf-life of packaged foods have promoted the development of antibacterial barrier packaging materials. Few articles have been available dealing with the barrier or antimicrobial properties of zinc oxide thin films deposited at low temperature with atomic layer deposition (ALD) onto commercial polymer films typically used for packaging purposes. The purpose of this paper was to study the properties of ZnO thin films compared to those of aluminum oxide. It was also possible to deposit ZnO thin films onto oriented polylactic acid and polypropylene films at relatively low temperatures using ozone instead of water as an oxidizing precursor for diethylzinc. Replacing water with ozone changed both the structure and the chemical composition of films deposited on silicon wafers. ZnO films deposited with ozone contained large grains covered and separated probably by a more amorphous and uniform layer. These thin films were also assumed to contain zinc salts of carboxylic acids. The barrier properties of a 25 nm ZnO thin film deposited with ozone at 100 °C were quite close to those obtained earlier with ALD Al{sub 2}O{sub 3} of similar apparent thickness on similar polymer films. ZnO thin films deposited at low temperature indicated migration of antibacterial agent, while direct contact between ZnO and Al{sub 2}O{sub 3} thin films and bacteria promoted antibacterial activity. - Highlights: • Thin films were grown from diethylzinc also with ozone instead of water at 70 and 100 °C. • ZnO films deposited with diethylzinc and ozone had different structures and chemistries. • Best barrier properties obtained with zinc oxide films close to those obtained with Al{sub 2}O{sub 3} • Ozone as oxygen source provided better barrier properties at 100 °C than water. • Both aluminum and zinc oxide thin films showed antimicrobial activity against E. coli.

  10. Growth and optical properties of sol-gel ZnO thin films grown on R-plane sapphire substrates

    Science.gov (United States)

    Nam, Giwoong; Kim, Min Su; Lee, Jewon; Leem, Jae-Young; Lee, Sang-heon; Jung, Jae Hak; Kim, Jin Soo; Kim, Jong Su

    2013-04-01

    Zinc-oxide (ZnO) thin films were grown on R-plane sapphire substrates by using the sol-gel spincoating method. They were annealed at temperatures ranging from 600 to 800 °C. The effects of the annealing temperature on the properties of the ZnO thin films were investigated using scanning electron microscopy, X-ray diffraction, and photoluminescence. When the annealing temperature was increased to 700 °C, the grains of the ZnO thin films coalesced, their size increased, and the residual stress in the ZnO thin films was relaxed. In addition, the intensity of the deep-level emission peak caused by defects decreased, and the full width at half maximum of the near-bandedge emission peak decreased as the annealing temperature was increased to 700 °C. However, when the annealing temperature was increased further, degradation of the structural and the optical properties was observed. The reflective index of the ZnO thin films in the UV region increased as the annealing temperature was increased to 700 °C, and n in the visible region decreased with increasing wavelength. The extinction coefficient in the UV and the visible regions decreased as the annealing temperature was increased to 700 °C. However, inflection points in the reflective index and the extinction coefficient were observed with a further increase in the annealing temperature.

  11. Effect of self-organization, defects, impurities, and autocatalytic processes on the parameters of ZnO films and nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Mezdrogina, M. M., E-mail: Margaret.M@mail.ioffe.ru; Eremenko, M. V. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Levitskii, V. S. [Saint-Petersburg State Electrotechnical University (LETI) (Russian Federation); Petrov, V. N.; Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Kaidashev, E. M.; Langusov, N. V. [Southern Federal University (Russian Federation)

    2015-11-15

    The effects of the parameters of ZnO-film deposition onto different substrates using the method of ac magnetron sputtering in a gas mixture of argon and oxygen hare studied. The phenomenon of self-organization is observed, which leads to invariability of the surface morphology of the ZnO films upon a variation in the substrate materials and deposition parameters. The parameters of the macro- and micro-photoluminescence spectra of the films differ insignificantly from the parameters of the photoluminescence spectra of bulk ZnO crystals obtained by the method of hydrothermal growth. The presence of intense emission with a narrow full-width at half-maximum (FWHM) in different regions of the spectrum allows ZnO films obtained by magnetron sputtering doped with rare-earth metal impurities (REIs) to be considered as a promising material for the creation of optoelectronic devices working in a broad spectral range. The possibility of the implementation of magnetic ordering upon legierung with REIs significantly broadens the functional possibilities of ZnO films. The parameters of the photoluminescence spectra of ZnO nanorods are determined by their geometrical parameters and by the concentration and type of the impurities introduced.

  12. Ultraviolet Stimulated Emission from Sol-Gel Spin Coated ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Ahmed S. Razeen

    2017-01-01

    Full Text Available Low cost ultraviolet stimulated emission has been generated using optical excitation of ZnO thin films deposited by sol-gel spin coating on n+ As-doped 100 Si-substrate. The number of deposited layers and the heat treatment have been investigated to obtain a film that can generate stimulated emission under optical excitation. The optimum condition for preparation of the film has been presented. X-ray diffraction and scanning electron microscope have been used for structural and morphological investigations. Input-output intensity dependence and spectral width, peak emission wavelength, and the quantum efficiency versus the pump intensity have been presented. A quantum efficiency of about 24.2% has been reported, a power exponent higher than 8 has been obtained in input-output intensity dependence, and a threshold of about 23 Mw/cm2 has been evaluated for the samples. The mechanism by which stimulated emission occurs has been discussed. The results show that sol-gel spin coating is a promising method for generating ultraviolet stimulated emission from ZnO thin films.

  13. Al-doped and in-doped ZnO thin films in heterojunctions with silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chabane, L.; Zebbar, N.; Kechouane, M. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32-16111, Algiers (Algeria); Aida, M.S. [LCMet Interface, Faculty of Sciences, University of Constantine, 25000 (Algeria); Trari, M. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32-16111 Algiers (Algeria)

    2016-04-30

    The undoped, Al-doped and In-doped ZnO thin films were deposited by ultrasonic spray pyrolysis technique, onto glass and p-Si substrates and the physical properties of the films were investigated. The X-ray diffraction, optical analysis and electrical characterisations, indicate that the films were polycrystalline with hexagonal würtzite type structure and revealed that the aluminium doping deteriorates the crystalline and optical properties and enhances the electrical conductivity whereas indium doping improves all properties. The transport mechanism controlling the conduction through the heterojunctions was studied. For the heterostructures, the temperature dependent current–voltage characteristics showed rectifying behaviour in the dark, but current transport mechanism is not the same for all heterojunctions. Therefore, the presence of the interface states and volume defects are identified as limiting factors for obtaining a high quality heterojunction interface. - Highlights: • Al-doped and In-doped ZnO thin films have been deposited onto Si. • In-doped ZnO/p-Si heterojunction showed poor rectifying behaviour. • Al-doped ZnO/p-Si heterojunction showed a good rectifying at room temperature. • The carriers transport mechanisms was controlled by interfacial and volume defects.

  14. Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Dangbegnon, J.K.; Talla, K.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth (South Africa)

    2010-06-15

    Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post-growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 C and above, low-temperature photoluminescence shows the appearance of a transition at {proportional_to}3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at {proportional_to}3.15 eV is also discussed. This work suggests annealing as a potential means for p-type doping using nitrogen (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. ZnO buffer layer for metal films on silicon substrates

    Science.gov (United States)

    Ihlefeld, Jon

    2014-09-16

    Dramatic improvements in metallization integrity and electroceramic thin film performance can be achieved by the use of the ZnO buffer layer to minimize interfacial energy between metallization and adhesion layers. In particular, the invention provides a substrate metallization method utilizing a ZnO adhesion layer that has a high work of adhesion, which in turn enables processing under thermal budgets typically reserved for more exotic ceramic, single-crystal, or metal foil substrates. Embodiments of the present invention can be used in a broad range of applications beyond ferroelectric capacitors, including microelectromechanical systems, micro-printed heaters and sensors, and electrochemical energy storage, where integrity of metallized silicon to high temperatures is necessary.

  16. The magnetic ordering in high magnetoresistance Mn-doped ZnO thin films

    KAUST Repository

    Venkatesh, S.

    2016-03-24

    We studied the nature of magnetic ordering in Mn-doped ZnO thin films that exhibited ferromagnetism at 300 K and superparamagnetism at 5 K. We directly inter-related the magnetisation and magnetoresistance by invoking the polaronpercolation theory and variable range of hopping conduction below the metal-to-insulator transition. By obtaining a qualitative agreement between these two models, we attribute the ferromagnetism to the s-d exchange-induced spin splitting that was indicated by large positive magnetoresistance (∼40 %). Low temperature superparamagnetism was attributed to the localization of carriers and non-interacting polaron clusters. This analysis can assist in understanding the presence or absence of ferromagnetism in doped/un-doped ZnO.

  17. Transparent nanocrystalline ZnO films prepared by spin coating

    International Nuclear Information System (INIS)

    Berber, M.; Bulto, V.; Kliss, R.; Hahn, H.

    2005-01-01

    Dispersions of zinc oxide nanoparticles synthesized by the electrochemical deposition under oxidizing conditions process with organic surfactants, were spin coated on glass substrates. After sintering, the microstructure, surface morphology, and electro-optical properties of the transparent nanocrystalline zinc oxide films have been investigated for different coating thicknesses and organic solvents

  18. Synthesis and characterization of thermally oxidized ZnO films

    Indian Academy of Sciences (India)

    Administrator

    was investigated for some reducing gases such as acetone, methane and liquefied petroleum gas and it was observed that the films studied were selective to acetone. Keywords. Zinc oxide; structural analysis; optical parameters; electrical conductivity; gas sensitivity. 1. Introduction. In recent years, transparent conducting ...

  19. Optoelectronic Characterization of Ta-Doped ZnO Thin Films by Pulsed Laser Deposition.

    Science.gov (United States)

    Koo, Horng-Show; Peng, Jo-Chi; Chen, Mi; Chin, Hung-I; Chen, Jaw-Yeh; Wu, Maw-Kuen

    2015-11-01

    Transparent conductive oxide of Ta-doped ZnO (TZO) film with doping amount of 3.0 wt% have been deposited on glass substrates (Corning Eagle XG) at substrate temperatures of 100 to 500 degrees C by the pulsed laser deposition (PLD) technique. The effect of substrate temperature on the structural, optical and electronic characteristics of Ta-doped ZnO (TZO) films with 3.0 wt% dopant of tantalum oxide (Ta2O5) was measured and demonstrated in terms of X-ray diffraction (XRD), ultraviolet-visible spectrometer (UV-Vis), four-probe and Hall-effect measurements. X-ray diffraction pattern shows that TZO films grow in hexagonal crystal structure of wurtzite phase with a preferred orientation of the crystallites along (002) direction and exhibits better physical characteristics of optical transmittance, electrical conductivity, carrier concentration and mobility for the application of window layer in the optoelectronic devices of solar cells, OLEDs and LEDs. The lowest electrical resistivity (ρ) and the highest carrier concentration of the as-deposited film deposited at 300 degrees C are measured as 2.6 x 10(-3) Ω-cm and 3.87 x 10(-20) cm(-3), respectively. The highest optical transmittance of the as-deposited film deposited at 500 degrees C is shown to be 93%, compared with another films deposited below 300 degrees C. It is found that electrical and optical properties of the as-deposited TZO film are greatly dependent on substrate temperature during laser ablation deposition.

  20. Fabrication of thin ZnO films with wide-range tuned optical properties by reactive magnetron sputtering

    Science.gov (United States)

    Davydova, A.; Tselikov, G.; Dilone, D.; Rao, K. V.; Kabashin, A. V.; Belova, L.

    2018-02-01

    We report the manufacturing of thin zinc oxide films by reactive magnetron sputtering at room temperature, and examine their structural and optical properties. We show that the partial oxygen pressure in DC mode can have dramatic effect on absorption and refractive index (RI) of the films in a broad spectral range. In particular, the change of the oxygen pressure from 7% to 5% can lead to either conventional crystalline ZnO films having low absorption and characteristic descending dependence of RI from 2.4–2.7 RIU in the visible to 1.8–2 RIU in the near-infrared (1600 nm) range, or to untypical films, composed of ZnO nano-crystals embedded into amorphous matrix, exhibiting unexpectedly high absorption in the visible–infrared region and ascending dependence of RI with values varying from 1.5 RIU in the visible to 4 RIU in the IR (1600 nm), respectively. Untypical optical characteristics in the second case are explained by defects in ZnO structure arising due to under-oxidation of ZnO crystals. We also show that the observed defect-related film structure remains stable even after annealing of films under relatively high temperatures (30 min under 450 °C). We assume that both types of films can be of importance for photovoltaic (as contact or active layers, respectively), as well as for chemical or biological sensing, optoelectronics etc.

  1. Superhydrophobic and anti-reflective ZnO nanorod-coated FTO transparent conductive thin films prepared by a three-step method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bao-jia, E-mail: li_bjia@126.com [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang, 212013 (China); Huang, Li-jing; Ren, Nai-fei [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang, 212013 (China); School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Kong, Xia; Cai, Yun-long; Zhang, Jie-lu [Jiangsu Tailong Reduction Box Co. Ltd., Taixing, 225400 (China)

    2016-07-25

    A ZnO nanorod-coated FTO film was prepared by sputtering an AZO layer on FTO glass, thermal annealing of the AZO/FTO film, and hydrothermal growth of ZnO nanorods at 70 °C on the annealed AZO/FTO film using zinc foils as zinc source. Two other ZnO nanorod-coated FTO films were also prepared by hydrothermal growths of ZnO nanorods on the FTO glass and the unannealed AZO/FTO film respectively for comparison purpose. The results were observed in detail using X-ray diffraction, scanning electron microscopy, water contact/sliding angle measurement, spectrophotometry and four-point probe measurement. The ZnO nanorods on the annealed AZO/FTO film were found to exhibit denser distribution and better orientation than those on the FTO glass and the unannealed AZO/FTO film. As a result, the ZnO nanorod-coated annealed AZO/FTO film demonstrated superhydrophobicity, high transparency and low reflectance in the visible range. Also this film had the lowest sheet resistance of 4.0 Ω/sq, implying its good electrical conductivity. This investigation provides a valuable reference for developing multifunctional transparent conductive films. - Highlights: • ZnO nanorod-coated annealed AZO/FTO film was obtained by a three-step method. • FTO and unannealed AZO/FTO films were also used as substrates for comparison. • ZnO nanorods on the annealed AZO/FTO film were denser and more vertically-oriented. • The ZnO nanorod-coated annealed AZO/FTO film (Z/TA-FTO) had superhydrophobicity. • The Z/TA-FTO exhibited high transparency, low reflectance and good conductivity.

  2. Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers.

    Science.gov (United States)

    Huang, Zhan-Yun; Chen, Min; Pan, Shi-Rong; Chen, Di-Hu

    2010-10-01

    In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

  3. Synthesis of ZnO Nanowires and Their Photovoltaic Application: ZnO Nanowires/AgGaSe2 Thin Film Core-Shell Solar Cell

    Directory of Open Access Journals (Sweden)

    Elif Peksu

    2015-01-01

    Full Text Available In this investigation, hydrothermal technique was employed for the synthesis of well-aligned dense arrays of ZnO nanowires (NWs on a wide range of substrates including silicon, soda-lime glass (SLG, indium tin oxide, and polyethylene terephthalate (PET. Results showed that ZnO NWs can be successfully grown on any substrate that can withstand the growth temperature (~90°C and precursor solution chemicals. Results also revealed that there was a strong impact of growth time and ZnO seed layer deposition route on the orientation, density, diameter, and uniformity of the synthesized nanowires. A core-shell n-ZnO NWs/p-AgGaSe2 (AGS thin film solar cell was fabricated as a device application of synthesized ZnO nanowires by decoration of nanowires with ~700 nm thick sputtering deposited AGS thin film layer, which demonstrated an energy conversion efficiency of 1.74% under 100 mW/cm2 of simulated solar illumination.

  4. Enhanced stimulated emission in ZnO thin films using microdisk top-down structuring

    Energy Technology Data Exchange (ETDEWEB)

    Nomenyo, K.; Kostcheev, S.; Lérondel, G. [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6281, Université de Technologie de Troyes, 12 rue Marie Curie, CS 42060, 10004 Troyes Cedex (France); Gadallah, A.-S. [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6281, Université de Technologie de Troyes, 12 rue Marie Curie, CS 42060, 10004 Troyes Cedex (France); Department of Laser Sciences and Interactions, National Institute of Laser Enhanced Sciences, Cairo University, Giza (Egypt); Rogers, D. J. [Nanovation, 8, route de Chevreuse, 78117 Châteaufort (France)

    2014-05-05

    Microdisks were fabricated in zinc oxide (ZnO) thin films using a top-down approach combining electron beam lithography and reactive ion etching. These microdisk structured thin films exhibit a stimulated surface emission between 3 and 7 times higher than that from a reference film depending on the excitation power density. Emission peak narrowing, reduction in lasing threshold and blue-shifting of the emission wavelength were observed along with enhancement in the emitted intensity. Results indicate that this enhancement is due to an increase in the internal quantum efficiency combined with an amplification of the stimulated emission. An analysis in terms of waveguiding is presented in order to explain these effects. These results demonstrate that very significant gains in emission can be obtained through conventional microstructuration without the need for more onerous top-down nanostructuration techniques.

  5. p-type ZnO films with solid-source phosphorus doping by molecular-beam epitaxy

    International Nuclear Information System (INIS)

    Xiu, F.X.; Yang, Z.; Mandalapu, L.J.; Liu, J.L.; Beyermann, W. P.

    2006-01-01

    Phosphorus-doped p-type ZnO films were grown on r-plane sapphire substrates using molecular-beam epitaxy with a solid-source GaP effusion cell. X-ray diffraction spectra and reflection high-energy electron diffraction patterns indicate that high-quality single crystalline (1120) ZnO films were obtained. Hall and resistivity measurements show that the phosphorus-doped ZnO films have high hole concentrations and low resistivities at room temperature. Photoluminescence (PL) measurements at 8 K reveal a dominant acceptor-bound exciton emission with an energy of 3.317 eV. The acceptor energy level of the phosphorus dopant is estimated to be 0.18 eV above the valence band from PL spectra, which is also consistent with the temperature dependence of PL measurements

  6. Effect of Al and N Doping on Structural and Optical Properties of Sol-Gel Derived ZnO Thin Films

    International Nuclear Information System (INIS)

    Bangbai, C.; Chongsri, K.; Pecharapa, W.; Techitdheera, W.

    2013-01-01

    In this work, the preparation of ZnO, N-doped ZnO (NZO), Al-doped ZnO (AZO) and Al, N-doped ZnO (ANZO) thin films by the sol-gel spin-coating method is reported. The structural properties and surface morphologies of films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The XRD and SEM results disclosed that the crystallization quality and grain size of as-prepared films were highly influenced by N and Al doping. UV-VIS spectrophotometer results indicated that Al and N additives could significantly enhance the optical transparency and induce the blue-shift in optical bandgap of ZnO films. (author)

  7. Investigation of the correlation between dielectric function, thickness and morphology of nano-granular ZnO very thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gilliot, Mickaël, E-mail: mickael.gilliot@univ-reims.fr [Laboratoire d' Ingénierie et Sciences des Matériaux, Université de Reims Champagne-Ardenne (France); Hadjadj, Aomar [Laboratoire d' Ingénierie et Sciences des Matériaux, Université de Reims Champagne-Ardenne (France); Martin, Jérôme [Laboratoire de Nanotechnologie et d' Instrumentation Optique, Université de Technologie de Troyes (France)

    2015-12-31

    Thin nano-granular ZnO layers were prepared using a sol–gel synthesis and spin-coating deposition process with a thickness ranging between 20 and 120 nm. The complex dielectric function (ϵ) of the ZnO film was determined from spectroscopic ellipsometry measurements. Up to a critical thickness close to 60 nm, the magnitude of both the real and the imaginary parts of ϵ rapidly increases and then slowly tends to values closer to the bulk ZnO material. This trend suggests a drastic change in the film porosity at both sides of this critical thickness, due to the pre-heating and post-crystallization processes, as confirmed by additional characterization of the structure and the morphology of the ZnO films. - Highlights: • c-Axis oriented ZnO thin films were grown with different morphological states. • The morphology and structures are controlled by controlling the thickness. • The optical properties are correlated to morphological evolution. • Two growth behaviors and property evolutions are identified around a critical thickness.

  8. P-type ZnO thin films prepared by plasma molecular beam epitaxy using radical NO

    Energy Technology Data Exchange (ETDEWEB)

    Liang, H.W.; Lu, Y.M.; Shen, D.Z.; Liu, Y.C.; Yan, J.F.; Li, B.H.; Zhang, Z.Z.; Zhang, J.Y.; Fan, X.W. [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16-Dongnanhu Road, Changchun 130033 (China); Shan, C.X. [Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong (China)

    2005-05-01

    N-doped p-type ZnO thin films were grown by plasma molecular beam epitaxy (P-MBE) on c-plane sapphire (Al{sub 2}O{sub 3}) using radical NO as oxygen source and nitrogen dopant. The reproducible ZnO thin films have maximum net hole concentration (N{sub A}-N{sub D}) of 1.2 x 10{sup 18} cm{sup -3} and minimum resistivity of 9.36 {omega} cm. The influence of N incorporation on the quality of the ZnO thin films was studied using X-ray diffraction and absorption spectra. The photoluminescence spectra at 77 K of p-type ZnO thin films are dominated by the emission from donor-acceptor pair recombination. The formation mechanism of p-type ZnO is explained by the optical emission spectra of radical N{sub 2} and radical NO. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Acceptor-modulated optical enhancements and band-gap narrowing in ZnO thin films

    Directory of Open Access Journals (Sweden)

    Ali Hassan

    2018-03-01

    Full Text Available Fermi-Dirac distribution for doped semiconductors and Burstein-Moss effect have been correlated first time to figure out the conductivity type of ZnO. Hall Effect in the Van der Pauw configuration has been applied to reconcile our theoretical estimations which evince our assumption. Band-gap narrowing has been found in all p-type samples, whereas blue Burstein-Moss shift has been recorded in the n-type films. Atomic Force Microscopic (AFM analysis shows that both p-type and n-type films have almost same granular-like structure with minor change in average grain size (∼ 6 nm to 10 nm and surface roughness rms value 3 nm for thickness ∼315 nm which points that grain size and surface roughness did not play any significant role in order to modulate the conductivity type of ZnO. X-ray diffraction (XRD, Energy Dispersive X-ray Spectroscopy (EDS and X-ray Photoelectron Spectroscopy (XPS have been employed to perform the structural, chemical and elemental analysis. Hexagonal wurtzite structure has been observed in all samples. The introduction of nitrogen reduces the crystallinity of host lattice. 97% transmittance in the visible range with 1.4 × 107 Ω-1cm-1 optical conductivity have been detected. High absorption value in the ultra-violet (UV region reveals that NZOs thin films can be used to fabricate next-generation high-performance UV detectors.

  10. Acceptor-modulated optical enhancements and band-gap narrowing in ZnO thin films

    Science.gov (United States)

    Hassan, Ali; Jin, Yuhua; Irfan, Muhammad; Jiang, Yijian

    2018-03-01

    Fermi-Dirac distribution for doped semiconductors and Burstein-Moss effect have been correlated first time to figure out the conductivity type of ZnO. Hall Effect in the Van der Pauw configuration has been applied to reconcile our theoretical estimations which evince our assumption. Band-gap narrowing has been found in all p-type samples, whereas blue Burstein-Moss shift has been recorded in the n-type films. Atomic Force Microscopic (AFM) analysis shows that both p-type and n-type films have almost same granular-like structure with minor change in average grain size (˜ 6 nm to 10 nm) and surface roughness rms value 3 nm for thickness ˜315 nm which points that grain size and surface roughness did not play any significant role in order to modulate the conductivity type of ZnO. X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) have been employed to perform the structural, chemical and elemental analysis. Hexagonal wurtzite structure has been observed in all samples. The introduction of nitrogen reduces the crystallinity of host lattice. 97% transmittance in the visible range with 1.4 × 107 Ω-1cm-1 optical conductivity have been detected. High absorption value in the ultra-violet (UV) region reveals that NZOs thin films can be used to fabricate next-generation high-performance UV detectors.

  11. Intrinsic and spatially nonuniform ferromagnetism in Co-doped ZnO films

    Science.gov (United States)

    Tseng, L. T.; Suter, A.; Wang, Y. R.; Xiang, F. X.; Bian, P.; Ding, X.; Tseng, A.; Hu, H. L.; Fan, H. M.; Zheng, R. K.; Wang, X. L.; Salman, Z.; Prokscha, T.; Suzuki, K.; Liu, R.; Li, S.; Morenzoni, E.; Yi, J. B.

    2017-09-01

    Co doped ZnO films have been deposited by a laser-molecular beam epitaxy system. X-ray diffraction and UV spectra analysis show that Co effectively substitutes the Zn site. Transmission electron microscopy (TEM) and secondary ion mass spectroscopy analysis indicate that there are no clusters. Co dopants are uniformly distributed in ZnO film. Ferromagnetic ordering is observed in all samples deposited under an oxygen partial pressure, PO2=10-3 , 10-5, and 10-7 torr, respectively. However, the magnetization of PO2=10-3 and 10-5 is very small at room temperature. At low temperature, the ferromagnetic ordering is enhanced. Muon spin relaxation (μ SR ) measurements confirm the ferromagnetism in all samples, and the results are consistent with magnetization measurements. From μ SR and TEM analysis, the film deposited under PO2=10-7 torr shows intrinsic ferromagnetism. However, the volume fraction of the ferromagnetism phase is approximately 70%, suggesting that the ferromagnetism is not carrier mediated. Resistivity versus temperature measurements indicate Efros variable range hopping dominates the conductivity. From the above results, we can confirm that a bound magnetic polaron is the origin of the ferromagnetism.

  12. Synthesis, Optical and Photoluminescence Properties of Cu-Doped Zno Nano-Fibers Thin Films: Nonlinear Optics

    Science.gov (United States)

    Ganesh, V.; Salem, G. F.; Yahia, I. S.; Yakuphanoglu, F.

    2018-03-01

    Different concentrations of copper-doped zinc oxide thin films were coated on a glass substrate by sol-gel/spin-coating technique. The structural properties of pure and Cu-doped ZnO films were characterized by different techniques, i.e., atomic force microscopy (AFM), photoluminescence and UV-Vis-NIR spectroscopy. The AFM study revealed that pure and doped ZnO films are formed as nano-fibers with a granular structure. The photoluminescence spectra of these films showed a strong ultraviolet emission peak centered at 392 nm and a strong blue emission peak cantered at 450 nm. The optical band gap of the pure and copper-doped ZnO thin films calculated from optical transmission spectra (3.29-3.23 eV) were found to be increasing with increasing copper doping concentration. The refractive index dispersion curve of pure and Cu-doped ZnO film obeyed the single-oscillator model. The optical dispersion parameters such as E o , E d , and n_{∞}2 were calculated. Further, the nonlinear refractive index and nonlinear optical susceptibility were also calculated and interpreted.

  13. Structural characterization of ZnO thin films grown on various substrates by pulsed laser deposition

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Čížek, J.; Kužel, R.; Bulíř, Jiří; Lančok, Ján; Connolly, J.; McCarthy, E.; Krishnamurthy, S.; Mosnier, J.-P.; Anwand, W.; Brauer, G.

    2012-01-01

    Roč. 45, č. 22 (2012), 1-12 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GAP108/11/0958; GA ČR GP202/09/P324 Institutional research plan: CEZ:AV0Z10100522 Keywords : ZnO thin film * pulsed laser deposition * x-ray diffraction positron implantation spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.528, year: 2012 http://dx.doi.org/10.1088/0022-3727/45/22/225101

  14. Influence of substrate temperature and Zn-precursors on atomic layer deposition of polycrystalline ZnO films on glass

    International Nuclear Information System (INIS)

    Makino, Hisao; Miyake, Aki; Yamada, Takahiro; Yamamoto, Naoki; Yamamoto, Tetsuya

    2009-01-01

    Influence of substrate temperature and Zn-precursors on growth rate, crystal structure, and electrical property of undoped ZnO thin films grown by atomic layer deposition (ALD) have been studied. Differences between dimethylzinc (DMeZn) and diethylzinc (DEtZn) used as Zn-precursors were examined. The ZnO films grown using DMeZn showed higher electrical resistivity compared to that grown using DEtZn. However, the higher resistivity in the case of DMeZn was owing to much amount of residual impurities incorporated during the ALD growth

  15. Praseodymium - A Competent Dopant for Luminescent Downshifting and Photocatalysis in ZnO Thin Films

    Science.gov (United States)

    Narayanan, Nripasree; Deepak, N. K.

    2018-05-01

    Highly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.

  16. Surface characterization and cathodoluminescence degradation of ZnO thin films

    Science.gov (United States)

    Hasabeldaim, E.; Ntwaeaborwa, O. M.; Kroon, R. E.; Craciun, V.; Coetsee, E.; Swart, H. C.

    2017-12-01

    ZnO thin films were successfully synthesized by the sol-gel method using the spin coater technique. The films were annealed at 600 °C in air for two hours and in Ar/H2(5%) flow for 30 and 60 min, respectively. Structural analysis, surface morphology and characterization, as well as optical analysis (photoluminescence and cathodeluminescence (CL)) were done on the samples and discussed in detail. CL degradation during prolonged electron irradiation on the films was also determined. A preferential orientation of the c-axis perpendicular to the surface was observed from X-ray diffraction data showing the peak from the (002) plane for the films annealed in both the air and in the H2 flow. The film annealed in air exhibited a broad visible emission as well as a strong ultraviolet emission. A single-green emission peak around 511 nm was obtained from the film that was annealed in Ar/H2 flow for 60 min. The CL study revealed that the intensity of the green emission (511 nm) was very stable during electron bombardment for electron doses of more than 160 C/cm2.

  17. Effect of praseodymium incorporation on the structural and optical properties of ZnO thin films by RF magnetron sputtering

    International Nuclear Information System (INIS)

    Vinodkumar, R.; Navas, I.; Chalana, S.R.; Mahadevan Pillai, V.P.

    2011-01-01

    In order to study the effect of praseodymium doping, thin films of ZnO and praseodymium doped ZnO (1, 3 and 5 wt %) were prepared by RF Magnetron Sputtering and the structural and optical properties are investigated by X-ray diffraction, SEM, atomic force microscopy, UV-Visible spectroscopy and photoluminescence spectroscopy. All the films posses a hexagonal Wurtzite crystal structure with preferred orientation along (002) direction. The SEM images of the doped films show a porous structure for the films. From the PL spectra all the films shows emission in the UV and visible region. The UV emission of the near band edge is due to free exciton recombination and the other is the deep-level emission in the visible region. (author)

  18. Chemical-bath ZnO buffer layer for CuInS{sub 2} thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ennaoui, A.; Weber, M.; Scheer, R.; Lewerenz, H.J. [Hahn-Meitner-Institut, Abt. Grenzflaechen, Bereich Physikalische Chemie, Glienicker Strasse 100, D-14109 Berlin (Germany)

    1998-07-13

    ZnO buffer layers were grown by a chemical-bath deposition (CBD) in order to improve the interface quality in p-CuInS{sub 2} based solar cells, to improve the light transmission in the blue wavelength region, but also as an alternative to eliminate the toxic cadmium. The process consists of immersion of different substrates (glass, CIS) in a dilute solution of tetraamminezinc II, [Zn(NH{sub 2}){sub 4}]{sup 2+}, complex at 60-95C. During the growth process, a homogeneous growth mechanism which proceeds by the sedimentation of a mixture of ZnO and Zn(OH){sub 2} clusters formed in solution, competes with the heterogeneous growth mechanism. The mechanism consists of specific adsorption of a complex Zn(II) followed by a chemical reaction. The last process of growth results in thin, hard, adherent and specularly reflecting films. The characterization of the deposited CBD-ZnO layers was performed by X-ray diffraction (XRD), optical transmittance, scanning electron microscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The as-deposited films on glass show hexagonal zincite structure with two preferred orientations (1 0 0) and (1 0 1). High optical transmittance up to 80% in the near-infrared and part of the visible region was observed. The low growth rate of the films on CIS suggests an atomic layer-by-layer growth process.The device parameters and performance are compared to heterojunction with a standard CdS buffer layer

  19. Synthesis and Characterization of ZnO Nanoflowers Grown on AlN Films by Solution Deposition

    International Nuclear Information System (INIS)

    Hai-Yong, Gao; Fa-Wang, Yan; Yang, Zhang; Jin-Min, Li; Yi-Ping, Zeng

    2008-01-01

    ZnO nanoflowers are synthesized on AlN films by solution method. The synthesized nanoflowers are composed of nanorods, which are pyramidal and grow from a central point, thus forming structures that are flower-shaped as a whole. The nanoflowers have two typical morphologies: plate-like and bush-like. The XRD spectrum corresponds to the side planes of the ZnO nanorods made up of the nanoflowers. The micro-Raman spectrum of the ZnO nanoflowers exhibits the E 2 (high) mode and the second order multiple-phonon mode. The photoluminescence spectrum of the ZnO nanoflowers exhibits ultraviolet emission centred at 375 nm and a broad green emission centred at 526 nm

  20. High energy electron irradiation effects on Ga-doped ZnO thin films for optoelectronic space applications

    Science.gov (United States)

    Serrao, Felcy Jyothi; Sandeep, K. M.; Bhat, Shreesha; Dharmaprakash, S. M.

    2018-03-01

    Gallium-doped ZnO (GZO) thin films of thickness 394 nm were prepared by a simple, cost-effective sol-gel spin coating method. The effect of 8 MeV electron beam irradiation with different irradiation doses ranging from 0 to 10 kGy on the structural, optical and electrical properties was investigated. Electron irradiation influences the changes in the structural properties and surface morphology of GZO thin films. X-ray diffraction analysis showed that the polycrystalline nature of the GZO films is unaffected by the high energy electron irradiation. The grain size and the surface roughness were found maximum for the GZO film irradiated with 10 kGy electron dosage. The average transmittance of GZO thin films decreased after electron irradiation. The optical band gap of Ga-doped ZnO films was decreased with the increase in the electron dosage. The electrical resistivity of GZO films decreased from 4.83 × 10-3 to 8.725 × 10-4 Ω cm, when the electron dosage was increased from 0 to 10 kGy. The variation in the optical and electrical properties in the Ga-doped ZnO thin films due to electron beam irradiation in the present study is useful in deciding their compatibility in optoelectronic device applications in electron radiation environment.

  1. ZnO and ZnSe thin films grown by Atomic Layer Epitaxy in a gas flow system

    Science.gov (United States)

    Godlewski, Marek; Guziewicz, Elzbieta; Kopalko, Krzysztof; Lusalowska, Elzbieta

    2003-03-01

    In the presentation we will briefly review our recent works on thin films of ZnO and ZnSe for possible applications in opto-electronics. Thin films of ZnO were grown by four different methods on either semiconductor substrates or on a glass plates. The latter system was successfully used as a substrate for deposition of amorphous GaN epilayers, using low temperature plasma-assisted MOCVD technique. Properties of ALE-grown ZnO films and of GaN epilayers grown on ZnO buffer layer will be shortly analyzed. Thin films of ZnSe were grown using synthesis from Zn and Se. These films show bright white color light emission. Temperature of the emission and brightness can be optimized by either modifications in a growth procedure or variations in excitation conditions. Nature of white emission and optimization procedures will be described. This work was partly supported by grant no. PBZ-KBN-044/P03/2001 of KBN. The ALE reactor was bought using SEZAM grant of Foundation for Polish Science.

  2. Fabrication of nanostructured ZnO film as a hole-conducting layer of organic photovoltaic cell

    Science.gov (United States)

    Kim, Hyomin; Kwon, Yiseul; Choe, Youngson

    2013-05-01

    We have investigated the effect of fibrous nanostructured ZnO film as a hole-conducting layer on the performance of polymer photovoltaic cells. By increasing the concentration of zinc acetate dihydrate, the changes of performance characteristics were evaluated. Fibrous nanostructured ZnO film was prepared by sol-gel process and annealed on a hot plate. As the concentration of zinc acetate dihydrate increased, ZnO fibrous nanostructure grew from 300 to 600 nm. The obtained ZnO nanostructured fibrous films have taken the shape of a maze-like structure and were characterized by UV-visible absorption, scanning electron microscopy, and X-ray diffraction techniques. The intensity of absorption bands in the ultraviolet region was increased with increasing precursor concentration. The X-ray diffraction studies show that the ZnO fibrous nanostructures became strongly (002)-oriented with increasing concentration of precursor. The bulk heterojunction photovoltaic cells were fabricated using poly(3-hexylthiophene-2,5-diyl) and indene-C60 bisadduct as active layer, and their electrical properties were investigated. The external quantum efficiency of the fabricated device increased with increasing precursor concentration.

  3. UV-screening, transparency and water barrier properties of semi refined iota carrageenan packaging film incorporated with ZnO nanoparticles

    Science.gov (United States)

    Khoirunnisa, Assifa Rahma; Joni, I. Made; Panatarani, Camellia; Rochima, Emma; Praseptiangga, Danar

    2018-02-01

    This study aims to develop film for food packaging application with high UV-screening, transparency and water barrier properties. Semi refined iota carrageenan (SRiC) nanocomposite films prepared by addition of zinc oxide (ZnO) nanoparticles as nanofiller using solution casting method. The effect of nanofiller with different concentration (0%, 0.5%, 1.0%, 1.5% w/w carrageenan) on UV-screening, transparency and water barrier properties of films were tested. The water barrier properties of the films were studied by measuring water vapor permeability (WVP) and the optical properties of the films were studied by using UV-Vis spectrophotometer at 280 nm for UV-screening test and at 660 nm for transparency test. WVP value of carrageenan films with addition of ZnO is low compared to a control carrageenan film and the lowest WVP value was found for the film with addition of 1.5% of ZnO. These result indicate that the addition of ZnO had a positive effect on the water barrier properties of the carrageenan matrix. Increase in the concentration of nanofiller leads to an increase in the UV-screening properties. Among all the films, carrageenan film with 1.5% ZnO has the highest UV-screening. The result showed that adding 0.5% and 1.0% of ZnO was insignificantly affect transparency of the films, however the transparency decreased sligthly when 1.5% ZnO was added. In conclusion, incorporating no more than 1.0% of ZnO to the films can obtain films with high UV-screening, transparency and water barrier properties and suitable for food packaging application.

  4. Effect of Sn-doped on microstructural and optical properties of ZnO thin films deposited by sol-gel method

    International Nuclear Information System (INIS)

    Tsay, C.-Y.; Cheng, H.-C.; Tung, Y.-T.; Tuan, W.-H.; Lin, C.-K.

    2008-01-01

    In this study, transparent thin films of Sn-doped ZnO (ZnO:Sn) were deposited onto alkali-free glass substrates by a sol-gel method; the effect of Sn doping on crystallinity, microstructural and optical properties was investigated. The atomic percentages of dopant in ZnO-based sols were Sn/Zn = 0, 1, 2, 3, and 5 at.%. The as-deposited films were pre-heated at 300 deg. C for 10 min and then annealed in air at 500 deg. C for 1 h. The results show that Sn-doped ZnO thin films demonstrate obviously improved surface roughness, enhanced transmittance in the 400-600 nm wavelength range and reduced average crystallite size. Among all of the annealed ZnO-based films in this study, films doped with 2 at.% Sn concentration exhibited the best properties, namely an average transmittance of 90%, an RMS roughness value of 1.92 nm and a resistivity of 9.3 x 10 2 Ω-cm

  5. The roles of buffer layer thickness on the properties of the ZnO epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Kun, E-mail: ktang@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Huang, Shimin [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Gu, Shulin, E-mail: slgu@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Zhu, Shunming [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Ye, Jiandong [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Nanjing University Institute of Optoelectronics at Yangzhou, Yangzhou 225009 (China); Xu, Zhonghua; Zheng, Youdou [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China)

    2016-12-01

    Highlights: • The growth mechanism has been revealed for the ZnO buffers with different thickness. • The surface morphology has been determined as the key factor to affect the epitaxial growth. • The relation between the hexagonal pits from buffers and epi-films has been established. • The hexagonal pits formed in the epi-films have been attributed to the V-shaped defects inheriting from the dislocations in the buffers. • The structural and electrical properties of the V-defects have been presented and analyzed. - Abstract: In this article, the authors have investigated the optimization of the buffer thickness for obtaining high-quality ZnO epi-films on sapphire substrates. The growth mechanism of the buffers with different thickness has been clearly revealed, including the initial nucleation and vertical growth, the subsequent lateral growth with small grain coalescence, and the final vertical growth along the existing larger grains. Overall, the quality of the buffer improves with increasing thickness except the deformed surface morphology. However, by a full-scale evaluation of the properties for the epi-layers, the quality of the epi-film is briefly determined by the surface morphology of the buffer, rather than the structural, optical, or electrical properties of it. The best quality epi-layer has been grown on the buffer with a smooth surface and well-coalescent grains. Meanwhile, due to the huge lattice mismatch between sapphire and ZnO, dislocations are inevitably formed during the growth of buffers. More importantly, as the film grows thicker, the dislocations may attracting other smaller dislocations and defects to reduce the total line energy and thus result in the formation of V-shape defects, which are connected with the bottom of the threading dislocations in the buffers. The V-defects appear as deep and large hexagonal pits from top view and they may act as electron traps which would affect the free carrier concentration of the epi-layers.

  6. The roles of buffer layer thickness on the properties of the ZnO epitaxial films

    International Nuclear Information System (INIS)

    Tang, Kun; Huang, Shimin; Gu, Shulin; Zhu, Shunming; Ye, Jiandong; Xu, Zhonghua; Zheng, Youdou

    2016-01-01

    Highlights: • The growth mechanism has been revealed for the ZnO buffers with different thickness. • The surface morphology has been determined as the key factor to affect the epitaxial growth. • The relation between the hexagonal pits from buffers and epi-films has been established. • The hexagonal pits formed in the epi-films have been attributed to the V-shaped defects inheriting from the dislocations in the buffers. • The structural and electrical properties of the V-defects have been presented and analyzed. - Abstract: In this article, the authors have investigated the optimization of the buffer thickness for obtaining high-quality ZnO epi-films on sapphire substrates. The growth mechanism of the buffers with different thickness has been clearly revealed, including the initial nucleation and vertical growth, the subsequent lateral growth with small grain coalescence, and the final vertical growth along the existing larger grains. Overall, the quality of the buffer improves with increasing thickness except the deformed surface morphology. However, by a full-scale evaluation of the properties for the epi-layers, the quality of the epi-film is briefly determined by the surface morphology of the buffer, rather than the structural, optical, or electrical properties of it. The best quality epi-layer has been grown on the buffer with a smooth surface and well-coalescent grains. Meanwhile, due to the huge lattice mismatch between sapphire and ZnO, dislocations are inevitably formed during the growth of buffers. More importantly, as the film grows thicker, the dislocations may attracting other smaller dislocations and defects to reduce the total line energy and thus result in the formation of V-shape defects, which are connected with the bottom of the threading dislocations in the buffers. The V-defects appear as deep and large hexagonal pits from top view and they may act as electron traps which would affect the free carrier concentration of the epi-layers.

  7. Using ZnO-Cr2O3-ZnO heterostructures to characterize polarization penetration depth through non-polar films.

    Science.gov (United States)

    Zhu, Xiaodong; Jhang, Jin-Hao; Zhou, Chao; Dagdeviren, Omur E; Chen, Zheng; Schwarz, Udo D; Altman, Eric I

    2017-12-13

    The ability to affect the surface properties of non-polar Cr 2 O 3 films through polar ZnO(0001) and (0001[combining macron]) supports was investigated by characterizing the polarity of ZnO films grown on top of the Cr 2 O 3 surfaces. The growth and geometric and electronic structures of the ZnO films were characterized with X-ray photoelectron spectroscopy, ultra-violet photoelectron spectroscopy, reflection high-energy electron diffraction, low-energy electron diffraction, and X-ray diffraction. The ZnO growth mode was Stranski-Krastanov, which can be attributed to the ZnO layers initially adopting a non-polar structure with a lower surface tension before transitioning to the polar bulk structure with a higher surface energy. A similar result has been reported for ZnO growth on α-Al 2 O 3 (0001), which is isostructural with Cr 2 O 3 . The polarity of the added ZnO layer was determined by examining the surface morphology following wet chemical etching with atomic force microscopy and by characterizing the surface reactivity via temperature-programmed desorption of alcohols, which strongly depends on the ZnO polarization direction. Consistent with prior work on ZnO growth on bulk Cr 2 O 3 (0001), both measurements indicate that thick Cr 2 O 3 layers support ZnO(0001[combining macron]) growth regardless of the underlying ZnO substrate polarization; however, the polarization direction of ZnO films grown on Cr 2 O 3 films less than three repeat units thick follows the direction of the underlying substrate polarization. These findings show that it is possible to manipulate the surface properties of non-polar materials with a polar substrate, but that the effect does not penetrate past just a couple of repeat units.

  8. Nanoscale determination of surface orientation and electrostatic properties of ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Perez, J.; Munoz-Sanjose, V. [Universitat de Valencia, Departament de Fisica Aplicada i Electromagnetisme, Burjassot (Spain); Palacios-Lidon, E.; Colchero, J. [Universidad de Murcia, Departamento de Fisica, Facultad de Quimica, Campus Espinardo, Murcia (Spain)

    2007-07-15

    Scanning force microscopy related techniques are applied to study surface nanoscale properties. We show that nanogoniometry can be combined with local electrostatic measurements - electrostatic force microscopy and Kelvin probe microscopy - to identify surface planes families and to study their local electrical properties. The scanning force microscopy techniques employed are analyzed and the correct way of acquiring and interpreting data is discussed in detail. The experiments performed on ZnO films grown along the nonpolar [112 anti 0] direction show that these films completely facet into {l_brace}101 anti 11{r_brace} and {l_brace}10 anti 1 anti 1{r_brace} planes, which follow a well defined pattern of surface potential along the [0001 ] direction. This pattern is explained in terms of the different ionic termination - Zn or O ions - of the exposed facets. Finally, the presence of inversion domain boundaries is discussed. (orig.)

  9. ZnO transparent conductive oxide for thin film silicon solar cells

    Science.gov (United States)

    Söderström, T.; Dominé, D.; Feltrin, A.; Despeisse, M.; Meillaud, F.; Bugnon, G.; Boccard, M.; Cuony, P.; Haug, F.-J.; Faÿ, S.; Nicolay, S.; Ballif, C.

    2010-03-01

    There is general agreement that the future production of electric energy has to be renewable and sustainable in the long term. Photovoltaic (PV) is booming with more than 7GW produced in 2008 and will therefore play an important role in the future electricity supply mix. Currently, crystalline silicon (c-Si) dominates the market with a share of about 90%. Reducing the cost per watt peak and energy pay back time of PV was the major concern of the last decade and remains the main challenge today. For that, thin film silicon solar cells has a strong potential because it allies the strength of c-Si (i.e. durability, abundancy, non toxicity) together with reduced material usage, lower temperature processes and monolithic interconnection. One of the technological key points is the transparent conductive oxide (TCO) used for front contact, barrier layer or intermediate reflector. In this paper, we report on the versatility of ZnO grown by low pressure chemical vapor deposition (ZnO LP-CVD) and its application in thin film silicon solar cells. In particular, we focus on the transparency, the morphology of the textured surface and its effects on the light in-coupling for micromorph tandem cells in both the substrate (n-i-p) and superstrate (p-i-n) configurations. The stabilized efficiencies achieved in Neuchâtel are 11.2% and 9.8% for p-i-n (without ARC) and n-i-p (plastic substrate), respectively.

  10. Sprayed Pyrolyzed ZnO Films with Nanoflake and Nanorod Morphologies and Their Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Nora S. Portillo-Vélez

    2016-01-01

    Full Text Available There is an increasing interest on the application of ZnO nanorods in photocatalysis and many growth methods have been applied, in particular the spray pyrolysis technique which is attractive for large scale production. However it is interesting to know if the nanorod morphology is the best considering its photocatalytic activity, stability, and cost effectiveness compared to a nonoriented growth. In this work we present a systematic study of the effect of the precursor solution (type of salt, solvent, and concentration on the morphology of sprayed ZnO films to obtain nanoflakes and nanorods without the use of surfactants or catalysts. The surface properties and structural characteristics of these types of films were investigated to elucidate which morphology is more favorable for photocatalytic applications. Wettability and photocatalytic experiments were carried out in the same conditions. After UV irradiation both morphologies became hydrophilic and achieved a dye discoloration efficiency higher than 90%; however, the nanoflake morphology provided the highest photocatalytic performance (99% dye discoloration and stability and the lowest energy consumption during the synthesis process. The surface-to-volume ratio revealed that the nanoflake morphology is more adequate for photocatalytic water treatment applications and that the thin nanorods should be preferred over the large ones.

  11. Comprehensive Study of Sol-Gel versus Hydrolysis-Condensation Methods To Prepare ZnO Films: Electron Transport Layers in Perovskite Solar Cells.

    Science.gov (United States)

    Zhao, Yu-Han; Zhang, Kai-Cheng; Wang, Zhao-Wei; Huang, Peng; Zhu, Kai; Li, Zhen-Dong; Li, Da-Hua; Yuan, Li-Gang; Zhou, Yi; Song, Bo

    2017-08-09

    Owing to the high charge mobility and low processing temperature, ZnO is regarded as an ideal candidate for electron transport layer (ETL) material in thin-film solar cells. For the film preparation, the presently dominated sol-gel (SG) and hydrolysis-condensation (HC) methods show great potential; however, the effect of these two methods on the performance of the resulting devices has not been investigated in the same frame. In this study, the ZnO films made through SG and HC methods were applied in perovskite solar cells (Pero-SCs), and the performances of corresponding devices were compared under parallel conditions. We found that the surface morphologies and the conductivities of the films prepared by SG and HC methods showed great differences. The HC-ZnO films with higher conductivity led to relatively higher device performance, and the best power conversion efficiencie (PCE) of 12.9% was obtained; meanwhile, for Pero-SCs based on SG-ZnO, the best PCE achieved was 10.9%. The better device performance of Pero-SCs based on HC-ZnO should be attributed to the better charge extraction and transportation ability of HC-ZnO film. Moreover, to further enhance the performance of Pero-SCs, a thin layer of pristine C 60 was introduced between HC-ZnO and perovskite layers. By doing so, the quality of perovskite films was improved, and the PCE was elevated to 14.1%. The preparation of HC-ZnO film involves relatively lower-temperature (maximum 100 °C) processing; the films showed better charge extraction and transportation properties and can be a more promising ETL material in Pero-SCs.

  12. Structural and optical properties of ZnO nanostructures electrochemically synthesized on AZO/Ag/AZO-multilayer-film-coated polyethersulfone substrates

    International Nuclear Information System (INIS)

    Oh, Dohyun; Yoo, Chanho; No, Youngsoo; Kim, Suyoun; Kim, Taewhan; Cho, Woonjo; Kim, Jinyoung

    2012-01-01

    ZnO nanostructures were formed on Al-doped ZnO (AZO)/Ag/AZO-multilayer-film-coated flexible polyethersulfone (PES) substrates at low temperature by using an electrochemical deposition method. The resistivity of the AZO/Ag/AZO multilayer films decreased with increasing thickness of the Ag film. X-ray diffraction patterns for the ZnO nanostructures showed that the crystal structure of the ZnO was hexagonal wurtzite and that the orientation was along the c-axis perpendicular to the substrate. Scanning electron microscopy images showed that the ZnO nanostructures grown at current densities of - 1.0 and - 1.5 mA/cm 2 were ZnO nanorods with diameters of 150 nm and ZnO nanoflowers with a planar dimension, respectively. Photoluminescence spectra showed that the band-edge emission peak of the ZnO nanostructures dominantly appeared in the ultraviolet region. These results showed that ZnO nanorods and nanoflowers with high quality were synthesized on AZO/Ag/AZO-multilayer-film-coated PES substrates.

  13. Functionalized carbon nanotubes in ZnO thin films for photoinactivation of bacteria

    International Nuclear Information System (INIS)

    Akhavan, O.; Azimirad, R.; Safa, S.

    2011-01-01

    Highlights: → Unfunctionalized and functionalized MWCNT/ZnO thin films were synthesized by sol-gel method. → Zn-O-C carbonaceous bonds formed in the functionalized MWCNT/ZnO thin films. → The functionalized MWCNT/ZnO had stronger photoinactivation of the bacteria than the unfunctionalize type. → 10 wt% functionalized MWCNT content had the optimum antibacterial property. - Abstract: Two types of unfunctionalized and functionalized multi-wall carbon nanotubes (MWCNTs) were prepared to be applied in fabrication of MWCNT-ZnO nanocomposite thin films with various MWCNT contents. X-ray photoelectron spectroscopy indicated formation of functional groups on surface of the functionalized MWCNTs in the MWCNT-ZnO nanocomposite. Formation of the effective carbonaceous bonds between the ZnO and the MWCNTs was also investigated through photoinactivation of Escherichia coli bacteria on surface of the both unfunctionalized and functionalized MWCNT-ZnO nanocomposites. The functionalized MWCNT-ZnO nanocomposites showed significantly stronger photoinactivation of the bacteria than the unfunctionalized ones, for all of the various MWCNT contents (from 2 to 30 wt%). While the functionalized MWCNT-ZnO nanocomposites with the optimum MWCNT content of 10 wt% inactivated whole of the bacteria after 10 min UV-visible light irradiation, the unfunctionalized ones could inactivate only 63% of the bacteria under the same conditions. The significant enhancement of the photoinactivation of the bacteria onto the surface of the functionalized MWCNT-ZnO nanocomposites was assigned to charge transfer through Zn-O-C bands formed between the Zn atoms of the ZnO film and oxygen atoms of the carboxylic functional groups of the functionalized MWCNTs.

  14. Composite structure of ZnO films coated with reduced graphene oxide: structural, electrical and electrochemical properties

    Science.gov (United States)

    Shuai, Weiqiang; Hu, Yuehui; Chen, Yichuan; Hu, Keyan; Zhang, Xiaohua; Zhu, Wenjun; Tong, Fan; Lao, Zixuan

    2018-02-01

    ZnO films coated with reduced graphene oxide (RGO-ZnO) were prepared by a simple chemical approach. The graphene oxide (GO) films transferred onto ZnO films by spin coating were reduced to RGO films by two steps (exposed to hydrazine vapor for 12 h and annealed at 600 °C). The crystal structures, electrical and photoluminescence properties of RGO-ZnO films on quartz substrates were systematically studied. The SEM images illustrated that RGO layers have successfully been coated on the ZnO films very tightly. The PL properties of RGO-ZnO were studied. PL spectra show two sharp peaks at 390 nm and a broad visible emission around 490 nm. The resistivity of RGO-ZnO films was measured by a Hall measurement system, RGO as nanofiller considerably decrease the resistivity of ZnO films. An electrode was fabricated, using RGO-ZnO films deposited on Si substrate as active materials, for super capacitor application. By comparison of different results, we conclude that the RGO-ZnO composite material couples possess the properties of super capacitor. Project supported by the National Natural Science Foundation of China (Nos. 61464005, 51562015), the Natural Science Foundation of Jiangxi Province (Nos. 20143ACB21004, 20151BAB212008, 20171BAB216015), the Jiangxi Province Foreign Cooperation Projects, China (No. 20151BDH80031), the Leader Training Object Project of Major Disciplines Academic and Technical of Jiangxi Province (No. 20123BCB22002), and the Key Technology R & D Program of the Jiangxi Provine of Science and Technology (No. 20171BBE50053).

  15. Carrier Compensation Induced by Thermal Annealing in Al-Doped ZnO Films

    Directory of Open Access Journals (Sweden)

    Takashi Koida

    2017-02-01

    Full Text Available This study investigated carrier compensation induced by thermal annealing in sputtered ZnO:Al (Al2O3: 0.25, 0.5, 1.0, and 2.0 wt % films. The films were post-annealed in a N2 atmosphere at low (1 × 10−23 atm and high (1 × 10−4 atm oxygen partial pressures (PO2. In ZnO:Al films with low Al contents (i.e., 0.25 wt %, the carrier density (n began to decrease at annealing temperatures (Ta of 600 °C at low PO2. At higher PO2 and/or Al contents, n values began to decrease significantly at lower Ta (ca. 400 °C. In addition, Zn became desorbed from the films during heating in a high vacuum (i.e., <1 × 10−7 Pa. These results suggest the following: (i Zn interstitials and Zn vacancies are created in the ZnO lattice during post-annealing treatments, thereby leading to carrier compensation by acceptor-type Zn vacancies; (ii The compensation behavior is significantly enhanced for ZnO:Al films with high Al contents.

  16. Plasmonic enhancement of UV emission from ZnO thin films induced by Al nano-concave arrays

    International Nuclear Information System (INIS)

    Norek, Małgorzata; Łuka, Grzegorz; Włodarski, Maksymilian

    2016-01-01

    Highlights: • Al nano-concave arrays with different interpore distance (D c ) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al 2 O 3 spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D c and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D c ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D c ) were used to enhance the ultraviolet light emission from ZnO thin films. Two sets of samples were prepared: in the first set the thin ZnO films were deposited directly on Al nanoconcaves (the Al/ZnO samples) and in the second set a 10 nm − Al 2 O 3 spacer was placed between the textured Al and the ZnO films (the Al/Al 2 O 3 -ALD/ZnO samples). In the Al/ZnO samples the enhancement was limited by a nonradiative energy dissipation due to the Ohmic loss in the Al metal. However, for the ZnO layer deposited directly on Al nanopits synthesized at 150 V (D c = 333 ± 18 nm), the largest 9-fold enhancement was obtained by achieving the best energy fit between the near band-edge (NBE) emission from ZnO and the λ (0,1) SPP resonance mode. In the Al/Al 2 O 3 -ALD/ZnO samples the amplification of the UV emission was smaller than in the Al/ZnO samples due to a big energy mismatch between the NBE emission and the λ (0,1) plasmonic mode. The results obtained in this work indicate that better tuning of the NBE − λ (0,1) SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al 2 O 3 -ALD/ZnO system such as Al nano-concave spacing and the thickness of the corresponding layer. This approach will reduce the negative influence of the non-radiative plasmonic modes and most likely will lead to further enhancement of the SP-modulated UV emission from ZnO thin films.

  17. Plasmonic enhancement of UV emission from ZnO thin films induced by Al nano-concave arrays

    Energy Technology Data Exchange (ETDEWEB)

    Norek, Małgorzata, E-mail: mnorek@wat.edu.pl [Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Łuka, Grzegorz [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland); Włodarski, Maksymilian [Institute of Optoelectronics, Military University of Technology, Str. Kaliskiego 2, 00-908 Warszawa (Poland)

    2016-10-30

    Highlights: • Al nano-concave arrays with different interpore distance (D{sub c}) were prepared. • PL of ZnO thin films deposited directly on the Al nano-concaves were studied. • The effect of 10 nm Al{sub 2}O{sub 3} spacer on PL emission from ZnO thin films was analyzed. • Plasmonic enhancement of the PL emission was dependent on the D{sub c} and the spacer. • The highest 9-fold enhancement was obtained for the Al/ZnO sample with D{sub c} ∼333 nm. - Abstract: Surface plasmons (SPs) supported by Al nano-concave arrays with increasing interpore distance (D{sub c}) were used to enhance the ultraviolet light emission from ZnO thin films. Two sets of samples were prepared: in the first set the thin ZnO films were deposited directly on Al nanoconcaves (the Al/ZnO samples) and in the second set a 10 nm − Al{sub 2}O{sub 3} spacer was placed between the textured Al and the ZnO films (the Al/Al{sub 2}O{sub 3}-ALD/ZnO samples). In the Al/ZnO samples the enhancement was limited by a nonradiative energy dissipation due to the Ohmic loss in the Al metal. However, for the ZnO layer deposited directly on Al nanopits synthesized at 150 V (D{sub c} = 333 ± 18 nm), the largest 9-fold enhancement was obtained by achieving the best energy fit between the near band-edge (NBE) emission from ZnO and the λ{sub (0,1)} SPP resonance mode. In the Al/Al{sub 2}O{sub 3}-ALD/ZnO samples the amplification of the UV emission was smaller than in the Al/ZnO samples due to a big energy mismatch between the NBE emission and the λ{sub (0,1)} plasmonic mode. The results obtained in this work indicate that better tuning of the NBE − λ{sub (0,1)} SPP resonance mode coupling is possible through a proper modification of geometrical parameters in the Al/Al{sub 2}O{sub 3}-ALD/ZnO system such as Al nano-concave spacing and the thickness of the corresponding layer. This approach will reduce the negative influence of the non-radiative plasmonic modes and most likely will lead to further

  18. p-Channel and n-Channel Thin-Film-Transistor Operation on Sprayed ZnO Nanoparticle Layers

    Directory of Open Access Journals (Sweden)

    Daiki Itohara

    2016-01-01

    Full Text Available Both n-channel and p-channel thin-film transistors have been realized on ZnO nanoparticle (NP layers sprayed onto quartz substrates. In this study, nitrogen-doped ZnO-NPs were synthesized using an arc-discharge-mediated gas-evaporation method that was recently developed. Sprayed NP layers were characterized by scanning electron microscopy and Hall effect measurements. It was confirmed that p-type behaving NP layers can be obtained using ZnO-NPs synthesized with lower chamber pressure, whereas n-type conductivity can be obtained with higher chamber pressure. pn-junction diodes were also tested, resulting in clear rectifying characteristics. The possibility of particle-process-based ZnO-NP electronics was confirmed.

  19. Effects of sic buffer layer on the optical properties of ZnO films grown on Si (1 1 1) substrates

    International Nuclear Information System (INIS)

    Zhang Yang; Zheng Haiwu; Su Jianfeng; Lin Bixi; Fu Zhuxi

    2007-01-01

    ZnO films have been grown by a sol-gel process on Si (1 1 1) substrates with and without SiC buffer layers. The influence of SiC buffer layer on the optical properties of ZnO films grown on Si (1 1 1) substrates was investigated. The intensity of the E 2 (high) phonon peak in the micro-Raman spectrum of ZnO film with the SiC buffer layer is stronger than that of the sample without the SiC buffer layer, and the breadth of E 2 (high) phonon peak of ZnO film with the SiC buffer layer is narrower than that of the sample without the SiC buffer layer. These results indicated that the crystalline quality of the sample with the SiC buffer layer is better than that of the sample without the SiC buffer layer. In photoluminescence spectra, the intensity of free exciton emission from ZnO films with the SiC buffer was much stronger than that from ZnO film without the SiC buffer layer, while the intensity of deep level emission from sample with the SiC buffer layer was about half of that of sample without the SiC buffer layer. The results indicate the SiC buffer layer improves optical qualities of ZnO films on Si (1 1 1) substrates

  20. Thin Film growth and characterization of Ti doped ZnO by RF/DC magnetron sputtering

    KAUST Repository

    Baseer Haider, M.

    2015-01-01

    Thin film Ti doped ZnO (Ti-ZnO) film were grown on sapphire (0001) substrate by RF and DC magnetron sputtering. Films were grown at a substrate temperature of 250 °C with different Ti/Zn concentration. Surface chemical study of the samples was performed by X-ray photoelectron spectroscopy to determine the stoichiometry and Ti/Zn ratio for all samples. Surface morphology of the samples were studied by atomic force microscopy. X-ray diffraction was carried out to determine the crystallinity of the film. No secondary phases of TixOy was observed. We observed a slight increase in the lattice constant with the increase in Ti concentration in ZnO. No ferromagnetic signal was observed for any of the samples. However, some samples showed super-paramagnetic phase. © 2015 Materials Research Society.

  1. Effects of laser wavelength and fluence on the growth of ZnO thin films by pulsed laser deposition

    NARCIS (Netherlands)

    Craciun, V.; Amirhaghi, S.; Craciun, D.; Elders, J.; Gardeniers, Johannes G.E.; Boyd, Ian W.

    Transparent, electrically conductive and c-axis oriented ZnO thin films have been grown by the pulsed laser deposition (PLD) technique on silicon and Corning glass substrates employing either a KrF excimer laser (λ = 248 nm) or a frequency-doubled Nd:YAG laser (λ = 532 nm). The crystalline

  2. Low temperature growth of highly transparent c-axis oriented ZnO thin films by pulsed laser deposition

    NARCIS (Netherlands)

    Amirhaghi, S.; Craciun, V.; Craciun, D.; Elders, J.; Boyd, I.W.

    1994-01-01

    The effects of the oxygen partial pressure, substrate temperature and laser wavelength on the structural and optical properties of thin films of ZnO grown on silicon and glass substrates by pulsed laser deposition have been studied. Regardless of thickness, all the grown layers are c-axis oriented

  3. Study of p-type ZnO and MgZnO Thin Films for Solid State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jianlin [Univ. of California, Riverside, CA (United States)

    2015-07-31

    This project on study of p-type ZnO and MgZnO thin films for solid state lighting was carried out by research group of Prof. Jianlin Liu of UCR during the four-year period between August 2011 and July 2015. Tremendous progress has been made on the proposed research. This final report summarizes the important findings.

  4. Nanostructured ZnO films with various morphologies prepared by ultrasonic spray pyrolysis and its growing process

    Czech Academy of Sciences Publication Activity Database

    Ma, H.L.; Liu, Z.W.; Zeng, D.C.; Zhong, M.L.; Yu, H.Y.; Mikmeková, Eliška

    2013-01-01

    Roč. 283, 15 October (2013), s. 1006-1011 ISSN 0169-4332 R&D Projects: GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : ZnO * Nanostructure * Film * Ultrasonic spray pyrolysis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.538, year: 2013

  5. Raman scattering investigations on Co and Mn doped ZnO epitaxial films: local vibration modes and defect associated ferromagnetism

    Science.gov (United States)

    Cao, Qiang; Liu, Guolei; Yan, Shishen; Mei, Liangmo

    2014-03-01

    The studies of local vibration modes (LVMs) of Co or Mn substitution in wurtzite ZnO lattice have been rather limited, and evolution of LVM bound defects as well as associated ferromagnetism are still poorly understood.In this paper, Raman scattering spectroscopy has been performed on high quality Co and Mn doped ZnO epitaxial films, which were grown on Al2O3 (0001) by oxygen-plasma assisted molecular beam epitaxy. Raman measurements revealed two local vibration modes (LVMs) at 723 and 699 cm?1 due to the substitution of Co2+ in wurtzite ZnO lattice. The LVM at 723 cm?1 is found to be an elemental sensitive vibration mode for Co substitution. The LVM at 699cm-1 can be attributed to enrichment of Co2+ bound with oxygen vacancy, the cobalt?oxygen vacancy?cobalt complexes, which associated with ferromagnetism. It reveals two competitive local vibration modes (LVMs) at 712 and 523 cm-1 due to the substitution of Mn ions in wurtzite ZnO lattice. The LVM at 712cm-1 is found to be an elemental vibration mode of Mn substitution in wurtzite ZnO lattice, while the LVM at 523cm-1 can be attributed to the local vibration mode of acceptor bound Mn substitution in wurtzite ZnO lattice. the NSF Grant NO. 11374189 and 51231007.

  6. CuO codoped ZnO based nanostructured materials for sensitive chemical sensor applications.

    Science.gov (United States)

    Rahman, Mohammed M; Jamal, Aslam; Khan, Sher Bahadar; Faisal, Mohd

    2011-04-01

    Due to numerous potential applications of semiconductor transition metal-doped nanomaterials and the great advantages of hydrothermal synthesis in both cost and environmental impact, a significant effort has been employed for growth of copper oxide codoped zinc oxide (CuO codoped ZnO) nanostructures via a hydrothermal route at room conditions. The structural and optical properties of the CuO codoped ZnO nanorods were characterized using various techniques such as UV-visible, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), etc. The sensing performance has been executed by a simple and reliable I-V technique, where aqueous ammonia is considered as a target analyte. CuO codoped ZnO nanorods of thin film with conducting coating agents on silver electrodes (AgE, surface area of 0.0216 cm(2)) displayed good sensitivity, stability, and reproducibility. The calibration plot is linear over the large dynamic range, where the sensitivity is approximately 1.549 ± 0.10 μA cm(-2 )mM(-1) with a detection limit of 8.9 ± 0.2 μM, based on signal/noise ratio in short response time. Hence, on the bottom of the perceptive communication between structures, morphologies, and properties, it is displayed that the morphologies and the optical characteristics can be extended to a large scale in transition-metal-doped ZnO nanomaterials and efficient chemical sensors applications. © 2011 American Chemical Society

  7. Transparent conductive ZnO layers on polymer substrates: Thin film deposition and application in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dosmailov, M. [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Leonat, L.N. [Linz Institute for Organic Solar Cells (LIOS)/Institute of Physical Chemistry, Johannes Kepler University Linz, A-4040 Linz (Austria); Patek, J. [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Roth, D.; Bauer, P. [Institute of Experimental Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Scharber, M.C.; Sariciftci, N.S. [Linz Institute for Organic Solar Cells (LIOS)/Institute of Physical Chemistry, Johannes Kepler University Linz, A-4040 Linz (Austria); Pedarnig, J.D., E-mail: johannes.pedarnig@jku.at [Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria)

    2015-09-30

    Aluminum doped ZnO (AZO) and pure ZnO thin films are grown on polymer substrates by pulsed-laser deposition and the optical, electrical, and structural film properties are investigated. Laser fluence, substrate temperature, and oxygen pressure are varied to obtain transparent, conductive, and stoichiometric AZO layers on polyethylene terephthalate (PET) that are free of cracks. At low fluence (1 J/cm{sup 2}) and low pressure (10{sup −3} mbar), AZO/PET samples of high optical transmission in the visible range, low electrical sheet resistance, and high figure of merit (FOM) are produced. AZO films on fluorinated ethylene propylene have low FOM. The AZO films on PET substrates are used as electron transport layer in inverted organic solar cell devices employing P3HT:PCBM as photovoltaic polymer-fullerene bulk heterojunction. - Highlights: • Aluminum doped and pure ZnO thin films are grown on polyethylene terephthalate. • Growth parameters laser fluence, temperature, and gas pressure are optimized. • AZO films on PET have high optical transmission and electrical conductance (FOM). • Organic solar cells on PET using AZO as electron transport layer are made. • Power conversion efficiency of these OSC devices is measured.

  8. Study of nanosized copper-doped ZnO dilute magnetic semiconductor thick films for spintronic device applications

    Science.gov (United States)

    Zargar, Rayees Ahmad; Arora, Manju; Bhat, Riyaz Ahmed

    2018-01-01

    Screen-printed pure and copper-doped ZnO dilute magnetic semiconductor thick films were casted from chemically co-precipitated zinc oxide and copper-doped zinc oxide nanoparticles followed by sintering at 550 °C to obtain desired stoichiometry in spintronic device applications. These thick films were characterized by different analytical techniques to reveal their structure, surface morphology, optical, magnetic and electrical characteristics. The diffraction peaks pertaining to wurtzite structure are observed in XRD patterns of these films, while SEM images show smooth and dense morphology. Infrared transmission and Raman spectra exhibit vibrational bands pertaining to Zn-O-stretching modes and E 2 (high) phonon mode, respectively, in 4000-400 cm-1 region. The direct bandgap energy of these films derived from diffused reflectance spectroscopy varies in 3.21-3.13 eV range and is supported by PL spectroscopy study. The semiconducting behaviour and activation energy of these thick films has been confirmed by DC conductivity measurements. Electron paramagnetic resonance spectra showed derivative signal of g value 2.0018 in pure ZnO due to oxygen vacancies produced during synthesis and 2.0704 in copper-doped ZnO dilute magnetic semiconductor films.

  9. A study on the optical and electrical properties of direct-patternable ZnO films incorporated various contents of Pt nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-June; Wang, Seok-Joo; Kim, Hyuncheol [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Koo, Kyoung-Hoe [Sam Young Fil-Tech Co., Ltd., Seoul 153-768 (Korea, Republic of); Park, Hyung-Ho, E-mail: hhpark@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2009-11-30

    Platinum nanoparticles were synthesized by the methanol reduction method, and their size was controlled to 3 nm on average using PVP [poly(N-vinyl-2-pyrrolidon)] as a protecting unit. Various contents of Pt nanoparticles were incorporated into ZnO solutions which were synthesized by a sol-gel process. ZnO films with Pt nanoparticles of various content were annealed at 500 deg. C and 600 deg. C for 1 h. The crystallinity increased with the annealing temperature and also slightly with the content of Pt nanoparticles. The sheet resistance of ZnO films decreased with the incorporation of Pt nanoparticles, however the decreasing behavior was not maintained with increasing content of Pt nanoparticles. A shift of valence band maximum energy of ZnO film with Pt nanoparticles to higher energy was also observed due to electron transfer from Pt nanoparticles to ZnO film. The optical transmittance was 88 {+-} 2% in the visible region for all the ZnO films. Well-defined 60 {mu}m wide direct-patterned ZnO films containing Pt nanoparticles of 0.5 atomic percent could be formed without using dry etching process.

  10. Growth and properties of ZnO films on polymeric substrate by spray pyrolysis method

    International Nuclear Information System (INIS)

    Kriisa, Merike; Kärber, Erki; Krunks, Malle; Mikli, Valdek; Unt, Tarmo; Kukk, Mart; Mere, Arvo

    2014-01-01

    The growth of ZnO layers deposited by spray pyrolysis on polymeric substrate was studied. Zinc acetate precursor solution was sprayed onto preheated polyimide (PI) and glass reference substrates at 380 °C. The structural, morphological, optical and electrical properties of the layers were measured by X-ray diffraction, scanning electron microscopy, optical spectroscopy and van der Pauw and Hall method. ZnO:In layers could be grown on PI when deposited onto undoped ZnO layer acting as a buffer layer on PI. Independent of the substrate type, the ZnO/ZnO:In bilayer showed a mixed morphology from smooth canvas-like surface to large scrolled belt grains dependent on buffer layer morphology. Due to the formation of scrolled belts, the ZnO:In layer shows no preferential orientation, yet the preferred orientation of the ZnO buffer crystallites is (100) plane parallel to the substrate. The bilayers deposited on PI exhibit high light scattering capability (haze factor of 85–95% in the spectral region of 350–1500 nm). The resistivity of the ZnO:In film in bilayer on PI is 4.4 × 10 −2 Ω cm mainly due to low carrier mobility of 1.5 cm 2 /Vs, the carrier concentration is 10 20 cm −3 . - Highlights: • ZnO:In layers were grown on polyimide substrate by spray pyrolysis. • The buffer layer morphology is controlled by the layer thickness and spray rate. • ZnO/ZnO:In bilayer morphology is dependent on the surface of buffer layer. • Rough buffer layer leads to rough bilayer with scrolled belts (diameter of 2–6 μm). • Due to scrolled belts layers show no preferential growth yet highly scatter light

  11. Efficient Solar-Induced Photoelectrochemical Response Using Coupling Semiconductor TiO2-ZnO Nanorod Film

    Directory of Open Access Journals (Sweden)

    Nur Azimah Abd Samad

    2016-11-01

    Full Text Available Efficient solar driven photoelectrochemical (PEC response by enhancing charge separation has attracted great interest in the hydrogen generation application. The formation of one-dimensional ZnO nanorod structure without bundling is essential for high efficiency in PEC response. In this present research work, ZnO nanorod with an average 500 nm in length and average diameter of about 75 nm was successfully formed via electrodeposition method in 0.05 mM ZnCl2 and 0.1 M KCl electrolyte at 1 V for 60 min under 70 °C condition. Continuous efforts have been exerted to further improve the solar driven PEC response by incorporating an optimum content of TiO2 into ZnO nanorod using dip-coating technique. It was found that 0.25 at % of TiO2 loaded on ZnO nanorod film demonstrated a maximum photocurrent density of 19.78 mA/cm2 (with V vs. Ag/AgCl under UV illumination and 14.75 mA/cm2 (with V vs. Ag/AgCl under solar illumination with photoconversion efficiency ~2.9% (UV illumination and ~4.3% (solar illumination. This performance was approximately 3–4 times higher than ZnO film itself. An enhancement of photocurrent density and photoconversion efficiency occurred due to the sufficient Ti element within TiO2-ZnO nanorod film, which acted as an effective mediator to trap the photo-induced electrons and minimize the recombination of charge carriers. Besides, phenomenon of charge-separation effect at type-II band alignment of Zn and Ti could further enhance the charge carrier transportation during illumination.

  12. Limits of ZnO Electrodeposition in Mesoporous Tin Doped Indium Oxide Films in View of Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Christian Dunkel

    2014-04-01

    Full Text Available Well-ordered 3D mesoporous indium tin oxide (ITO films obtained by a templated sol-gel route are discussed as conductive porous current collectors. This paper explores the use of such films modified by electrochemical deposition of zinc oxide (ZnO on the pore walls to improve the electron transport in dye-sensitized solar cells (DSSCs. Mesoporous ITO film were dip-coated with pore sizes of 20–25 nm and 40–45 nm employing novel poly(isobutylene-b-poly(ethylene oxide block copolymers as structure-directors. After electrochemical deposition of ZnO and sensitization with the indoline dye D149 the films were tested as photoanodes in DSSCs. Short ZnO deposition times led to strong back reaction of photogenerated electrons from non-covered ITO to the electrolyte. ITO films with larger pores enabled longer ZnO deposition times before pore blocking occurred, resulting in higher efficiencies, which could be further increased by using thicker ITO films consisting of five layers, but were still lower compared to nanoporous ZnO films electrodeposited on flat ITO. The major factors that currently limit the application are the still low thickness of the mesoporous ITO films, too small pore sizes and non-ideal geometries that do not allow obtaining full coverage of the ITO surface with ZnO before pore blocking occurs.

  13. Properties of low-temperature deposited ZnO thin films prepared by cathodic vacuum arc technology on different flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Cheng-Tang [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China); Yang, Ru-Yuan, E-mail: ryyang@mail.npust.edu.tw [Graduate Institute of Materials Engineering, National Pingtung University of Science and Technology, Pingtung County 912, Taiwan (China); Weng, Min-Hang [Medical Devices and Opto-Electronics Equipment Department, Metal Industries Research and Development Center, Kaohsiung City 821, Taiwan (China); Huang, Chien-Wei [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China)

    2013-07-31

    Un-doped zinc oxide (ZnO) films were deposited on three different substrates (polyethylene terephthalate (PET), polyvinyl butyral (PVB) and polyimide (PI)) at a low temperature (< 75 °C) by cathode vacuum arc deposition. The microstructure, optical and electrical properties of the deposited films were investigated and discussed. All the deposited films reveal a preferred orientation with the c-axis perpendicular to the substrate, and an average transmittance of over 85% in the visible region. The calculated optical band gaps are around 2.6, 3.14 and 3.18 eV, respectively, for the ZnO films deposited on the PI, PVB and PET substrates. The lowest resistivity and the highest Hall mobility are 5.31 × 10{sup −3} Ω-cm and 15.16 cm{sup 2}/V-s for the ZnO film deposited on the PET substrate. - Highlights: • Polyethylene terephthalate, polyvinyl butyral and polyimide were used as substrates. • ZnO films were prepared by cathodic arc plasma deposition. • ZnO films have different properties due to different substrates. • The microstructure control of ZnO film on polymer substrate is important.

  14. The frequency-dependent AC photoresistance behavior of ZnO thin films grown on different sapphire substrates.

    Science.gov (United States)

    Cholula-Díaz, Jorge L; Barzola-Quiquia, José; Videa, Marcelo; Yin, Chunhai; Esquinazi, Pablo

    2017-09-13

    Zinc oxide (ZnO) thin films were grown by pulsed layer deposition under an N 2 atmosphere at low pressures on a- and r-plane sapphire substrates. Structural studies using X-ray diffraction confirmed that all films had a wurtzite phase. ZnO thin films on a- and r-plane sapphire have grown with orientations along the [0002] and [112[combining macron]0] directions, respectively. Room temperature photoluminescence measurements indicate that the presence of native point defects (interstitial zinc, oxygen vacancies, oxygen antisites and zinc vacancies) is more preponderant for ZnO thin films grown on the r-plane sapphire substrate than the sample grown on the a-plane sapphire substrate. Room temperature impedance spectroscopy measurements were performed in an alternating current frequency range from 40 to 10 5 Hz in the dark and under normal light. An unusual positive photoresistance effect is observed at frequencies above 100 kHz, which we suggest to be due to intrinsic defects present in the ZnO thin films. Furthermore, an analysis of the optical time response revealed that the film grown on the r-plane sapphire substrate responds faster (characteristic relaxation times for τ 1 , τ 2 and τ 3 of 0.05, 0.26 and 6.00 min, respectively) than the film grown on the a-plane sapphire substrate (characteristic relaxation times for τ 1 , τ 2 and τ 3 of 0.10, 0.73 and 4.02 min, respectively).

  15. Improvement of optical transmittance and electrical properties for the Si quantum dot-embedded ZnO thin film

    OpenAIRE

    Kuo, Kuang-Yang; Liu, Chuan-Cheng; Huang, Pin-Ruei; Hsu, Shu-Wei; Chuang, Wen-Ling; Chen, You-Jheng; Lee, Po-Tsung

    2013-01-01

    A Si quantum dot (QD)-embedded ZnO thin film is successfully fabricated on a p-type Si substrate using a ZnO/Si multilayer structure. Its optical transmittance is largely improved when increasing the annealing temperature, owing to the phase transformation from amorphous to nanocrystalline Si QDs embedded in the ZnO matrix. The sample annealed at 700?C exhibits not only high optical transmittance in the long-wavelength range but also better electrical properties including low resistivity, sma...

  16. Low-Temperature Modification of ZnO Nanoparticles Film for Electron-Transport Layers in Perovskite Solar Cells.

    Science.gov (United States)

    Han, Gill Sang; Shim, Hyun-Woo; Lee, Seongha; Duff, Matthew L; Lee, Jung-Kun

    2017-06-09

    An electron-transport layer (ETL) that selectively collects photogenerated electrons is an important constituent of halide perovskite solar cells (PSCs). Although TiO 2 films are widely used as ETL of PSCs, the processing of TiO 2 films with high electron mobility requires high-temperature annealing and TiO 2 dissociates the perovskite layer through a photocatalytic reaction. Here, we report an effective surface-modification method of a room-temperature processed ZnO nanoparticles (NPs) layer as an alternative to the TiO 2 ETL. A combination of simple UV exposure and nitric acid treatment effectively removes the hydroxyl group and passivates surface defects in ZnO NPs. The surface modification of ZnO NPs increases the power conversion efficiency (PCE) of PSCs to 14 % and decreases the aging of PSCs under light soaking. These results suggest that the surface-modified ZnO film can be a good ETL of PSCs and provide a path toward low-temperature processing of efficient and stable PSCs that are compatible with flexible electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

    2016-06-07

    In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

  18. Determination of the transport mechanisms in mixed conduction of reactively sputtered ZnO thin films

    International Nuclear Information System (INIS)

    Tuezemen, S; Guer, Emre; Dogan, S

    2008-01-01

    Material grown at highly Zn-rich conditions in reactive sputtering of ZnO thin films resulted in mixed conduction, indicating that stable p-type ZnO can be produced. In n-type conductivity, neutral flaw scattering transport mechanism via V O 0 centres seems to be dominant due to the existence of oxygen vacancies in high concentrations. An exponential decrease in electron mobility is observed upon cooling from room temperature to 210 K while the concentration of the inactive V O 0 state increases. This is also a cause of p-type conduction in the low temperature range ( O 0 scattering. Quantitative evaluations of V O centres show that fractional distribution of V O 0 , V O + and V O ++ charge states are, respectively, around 4%, 95% and 1% of the total [V O ] at the room temperature conditions. The energy of phonons interacting with the centre is estimated to be 38.5 meV which is a local phonon mode relaxation, most probably resulting in negative-U behaviour of V O centres

  19. Comparison of the influence of boron and aluminium doping on the material properties of electrochemically deposited ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Calnan, Sonya [Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Riedel, Wiebke; Gledhill, Sophie [Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Fachbereich Physik, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany); Stannowski, Bernd [Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Lux-Steiner, Martha Ch. [Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Fachbereich Physik, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany); Schlatmann, Rutger [Helmholtz-Zentrum für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Fachbereich 1 Ingenieurwissenschaften I, University of Applied Science (HTW) Berlin, Wilhelminenhofstraße 75 A, 12459 Berlin (Germany)

    2015-11-02

    The effect of varying the boron and aluminium content of the starting electrolyte for extrinsically doped ZnO films grown on SnO{sub 2}:F substrates by electrochemical deposition was investigated. The ZnO:B film surface was characterized by grains with mainly hexagonal faces exposed while the exposed faces of the ZnO:Al grains were rectangular. Whereas a B{sup 3+}/Zn{sup 2+} ratio of up to 10 at.% in the electrolyte had no significant effect on the crystalline structure of the ZnO films, an Al{sup 3+}/Zn{sup 2+} ratio above 0.25 at.% increased the disorder in the crystalline structure. All the boron doped films exhibit a strong E{sub 2}-high Raman mode related to wurtzite ZnO structure but this peak was much weaker for ZnO:Al and diminished with increasing Al incorporation in the films. Exposing the films to ultra-violet light reduced their effective sheet resistance from values beyond measurement range to values between 40 and 5000 kΩ/sq for film thicknesses of 200–550 nm. Inspection of the optical spectra near the bandgap edge and the plasma edge in the mid infrared range, showed that the Al-doping resulted in a higher carrier concentration ~ 10{sup 20} cm{sup −3} than B-doping. X-ray electron spectroscopy showed that the dopant efficiency was limited by the absence of dopant atoms near the surface of all the ZnO:B films and of the lightly doped ZnO:Al and, by the formation of aluminium oxide at the surface of the more highly doped ZnO:Al films. - Highlights: • Crystalline ZnO grown by electrochemical deposition. • Comparison of influence of H{sub 3}BO{sub 3} and Al(NO{sub 3}){sub 3} as dopant sources. • Different ZnO crystalline orientation for Al and boron doping. • Film surface chemical composition suppressed electrical conductivity.

  20. Identification of Tequila with an Array of ZnO Thin Films: A Simple and Cost-Effective Method

    Directory of Open Access Journals (Sweden)

    Pedro Estanislao Acuña-Avila

    2017-12-01

    Full Text Available An array of ZnO thin film sensors was obtained by thermal oxidation of physical vapor deposited thin Zn films. Different conditions of the thermal treatment (duration and temperature were applied in view of obtaining ZnO sensors with different gas sensing properties. Films having undergone a long thermal treatment exhibited high responses to low ethanol concentrations, while short thermal treatments generally led to sensors with high ethanol sensitivity. The sensor array was used to distinguish among Tequilas and Agave liquor. Linear discriminant analysis and the multilayer perceptron neural network reached 100% and 86.3% success rates in the discrimination between real Tequila and Agave liquor and in the identification of Tequila brands, respectively. These results are promising for the development of an inexpensive tool offering low complexity and cost of analysis for detecting fraud in spirits.

  1. Optical and Electrical Characteristic of Layer-by-layer Sol-gel Spin Coated Nanoparticles ZnO Thin Films

    International Nuclear Information System (INIS)

    Shafinaz Sobihana Shariffudin; Farah Farliana Samat; Sukreen Hana; Mohamad Rusop

    2011-01-01

    Transparent ZnO thin films have been deposited on glass substrate using sol-gel spin coating technique. 0.35 M sol were prepared by dissolving zinc acetate dehydrate in 2-methoxyethanol with monoethanolamine as the stabilizer. In this paper, a novel method called layer-by-layer is introduced, where the thin film is not only dried after each layer is spin-coated, but also directly annealed at 500 degree Celsius to improve the crystallinity of the films. Samples without annealing were also prepared as the control sample. ZnO thin films were characterized using field emission scanning electron microscopy, X-ray diffraction, current-voltage measurement, UV-Vis spectroscopy and photoluminescence spectroscopy. The results revealed that layer by- layer ZnO thin films have better conductivity and higher intensity peak for PL spectra at visible spectra of 580 nm. FE-SEM images shows nanoparticles almost hexagonal shaped with high crystallinity compared to control samples. (author)

  2. Realizing luminescent downshifting in ZnO thin films by Ce doping with enhancement of photocatalytic activity

    Science.gov (United States)

    Narayanan, Nripasree; Deepak, N. K.

    2018-04-01

    ZnO thin films doped with Ce at different concentration were deposited on glass substrates by spray pyrolysis technique. XRD analysis revealed the phase purity and polycrystalline nature of the films with hexagonal wurtzite geometry and the composition analysis confirmed the incorporation of Ce in the ZnO lattice in the case of doped films. Crystalline quality and optical transmittance diminished while electrical conductivity enhanced with Ce doping. Ce doping resulted in a red-shift of optical energy gap due to the downshift of the conduction band minimum after merging with Ce related impurity bands formed below the conduction band in the forbidden gap. In the room temperature photoluminescence spectra, UV emission intensity of the doped films decreased while the intensity of the visible emission band increased drastically implying the degradation in crystallinity as well as the incorporation of defect levels capable of luminescence downshifting. Ce doping showed improvement in photocatalytic efficiency by effectively trapping the free carriers and then transferring for dye degradation. Thus Ce doped ZnO thin films are capable of acting as luminescent downshifters as well as efficient photocatalysts.

  3. Optical and electrical properties of transparent conducting B-doped ZnO thin films prepared by various deposition methods

    Energy Technology Data Exchange (ETDEWEB)

    Nomoto, Jun-ichi; Miyata, Toshihiro; Minami, Tadatsugu [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan)

    2011-07-15

    B-doped ZnO (BZO) thin films were prepared with various thicknesses up to about 500 nm on glass substrates at 200 deg. C by dc or rf magnetron sputtering deposition, pulsed laser deposition (PLD), and vacuum arc plasma evaporation (VAPE) methods. Resistivities of 4-6 x 10{sup -4}{Omega} cm were obtained in BZO thin films prepared with a B content [B/(B + Zn) atomic ratio] around 1 at. % by PLD and VAPE methods: Hall mobilities above 40 cm{sup 2}/Vs and carrier concentrations on the order of 10{sup 20} cm{sup -3}. All 500-nm-thick-BZO thin films prepared with a resistivity on the order of 10{sup -3}-10{sup -4}{Omega} cm exhibited an averaged transmittance above 80% in the wavelength range of 400-1100 nm. The resistivity in BZO thin films prepared with a thickness below about 500 nm was found to increase over time with exposure to various high humidity environments. In heat-resistance tests, the resistivity stability of BZO thin films was found to be nearly equal to that of Ga-doped ZnO thin films, so these films were judged suitable for use as a transparent electrode for thin-film solar cells.

  4. Structural and Optical Properties of Group III Doped Hydrothermal ZnO Thin Films

    KAUST Repository

    Mughal, Asad J.

    2017-01-11

    In this work, we employ a simple two-step growth technique to deposit impurity doped heteroepitaxial thin films of (0001) ZnO onto (111) MgAl2O4 spinel substrates through a combination of atomic layer deposition (ALD) and hydrothermal growth. The hydrothermal layer is doped with Al, Ga, and In through the addition of their respective nitrate salts. We evaluated the effect that varying the concentrations of these dopants has on both the structural and optical properties of these films. It was found that the epitaxial ALD layer created a ⟨111⟩MgAl2O4∥⟨0001⟩ZnO out-of-plane orientation and a ⟨1¯1¯2⟩MgAl2O4∥∥⟨011¯0⟩ZnO in-plane orientation between the film and substrate. The rocking curve line widths ranged between 0.75° and 1.80° depending on dopant concentration. The optical bandgap determined through the Tauc method was between 3.28 eV and 3.39 eV and showed a Burstein-Moss shift with increasing dopant concentration.

  5. Superhydrophobic ZnAl double hydroxide nanostructures and ZnO films on Al and glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    De, Debasis, E-mail: debasis.de@bcrec.ac.in [Electronics and Instrumentation Engineering Department, Dr. B C Roy Engineering College, Durgapur, West Bengal 713206 (India); Sarkar, D.K. [Centre Universitaire de Recherche sur l' Aluminium (CURAL), L' Université du Québec à Chicoutimi, 555 Blvd. Université, Chicoutimi, Saguenay, Québec G7H 2B1 (Canada)

    2017-01-01

    Superhydrophobic nanostructured ZnAl: layered double hydroxides (LDHs) and ZnO films have been fabricated on Al and glass substrates, respectively, by a simple and cost effective chemical bath deposition technique. Randomly oriented hexagonal patterned of ZnAl: LDHs thin nanoplates are clearly observed on Al-substrate in the scanning electron microscopic images. The average size of these hexagonal plates is ∼4 μm side and ∼30 nm of thickness. While on the glass substrate, a oriented hexagonal patterned ZnO nanorods (height ∼5 μm and 1 μm diameter) are observed and each rod is further decorated throughout the top few nanometers with several nanosteps. At the top of the nanorod, a perfectly hexagonal patterned ZnO surface with ∼250 nm sides is observed. The tendency to form hexagonal morphological features is due to the hexagonal crystal structure of ZnO confirmed from X-ray diffraction patterns and transmission electron microscopy image. The ZnAl: LDHs and/or ZnO coated substrates have been passivated by using stearic acid (SA) molecules. Infrared spectra of passivated ZnAl: LDHs coated substrates confirm the presence of SA. X-ray diffraction pattern also corroborates the results of infrared spectrum. The contact angle of the as prepared samples is zero. The superhydrophobicity is achieved by observing contact angle of ∼161° with a hysteresis of ∼4° for Al-substrate. On the glass substrate, a higher contact angle of ∼168° with a lower hysteresis of ∼3° is observed. A lower surface roughness of ∼4.93 μm is measured on ZnAl: LDHs surface layer on the Al substrate as compare to a higher surface roughness of 6.87 μm measured on ZnO layer on glass substrate. The superhydrophobicity of passivated nanostructured films on two different substrates is observed due to high surface roughness and low surface energy. - Highlights: • ZnAl: layered double hydroxides (LDHs) nanoplates are fabricated on Al substrate. • ZnO nanorods are fabricated on

  6. Growth of ZnO nanowires through thermal oxidation of metallic zinc films on CdTe substrates

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, O., E-mail: oscar@fmc.uva.es [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011, Valladolid (Spain); Hortelano, V.; Jimenez, J. [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011, Valladolid (Spain); Plaza, J.L.; Dios, S. de; Olvera, J.; Dieguez, E. [Laboratorio de Crecimiento de Cristales, Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Fath, R.; Lozano, J.G.; Ben, T.; Gonzalez, D. [Dpto. Ciencia de los Materiales e Ingenieria Metalurgica y Q.I., Facultad de Ciencias, Apdo. 40, 11510 Puerto Real, Cadiz (Spain); Mass, J. [Dpto. de Fisica, Universidad del Norte, Km.5 Via Puerto Colombia, Barranquilla (Colombia)

    2011-04-28

    Research highlights: > ZnO nanowires grown from thermal Zn oxidation. > TEM reveals high quality thin nanowires several microns long. > New phase formation at long oxidation time. > Good spectroscopic properties measured by Raman, Photo and Cathodoluminsecence spectroscopies. - Abstract: <112-bar 0> wurtzite ZnO nanowires (NWs) have been obtained by oxidizing in air at 500 deg. C thermally evaporated Zn metal films deposited onto CdTe substrates. The presence of Cd atoms from the substrate on the ZnO seeding layer and NWs seems to affect the growth of the NWs. The effects of the oxidation time on the structural and optical properties of the NWs are described in detail. It is shown that the NWs density decreases and their length increases when increasing the oxidation time. Thicker Zn layers result in thinner and longer ZnO NWs. Very long oxidation times also lead to the formation of a new CdO phase which is related to the partial destruction and quality reduction of the NWs. The possible process for ZnO NW formation on CdTe substrates is discussed.

  7. Gravimetric humidity sensor based on ZnO nanorods covered piezoresistive Si microcantilever

    Science.gov (United States)

    Xu, Jiushuai; Bertke, Maik; Li, Xiaojing; Gad, Alaaeldin; Zhou, Hao; Wasisto, Hutomo Suryo; Peiner, Erwin

    2017-06-01

    A ZnO nanorods film covered silicon resonant cantilever sensor is developed for atmosphere humidity detection by monitoring the resonant frequency shifts induced by the additional weight of adsorbed water molecules. Two different crystalline seed-layer deposition methods were applied to grow different nanorods films. The morphology of the ZnO films were characterized and the sensor sensitivities were measured under different relative humidity (RH) levels. The experiments results showed that this novel humidity sensor with ZnO nanorods has a sensitivity of 101.5 +/- 12.0 ppm/RH% (amount of adsorbed water of 36.9 +/- 4.4 ng/RH%), indicating its potential for portable sensing applications.

  8. Effect of deposition time on the properties of Al doped ZnO films prepared by DC magnetron sputtering

    Science.gov (United States)

    Bhand, Ganesh R.; Motwani, Nitu; Chaure, Nandu B.

    2017-05-01

    Aluminum-doped zinc oxide (AZO) thin films were successfully prepared on glass substrates at room temperature by DC magnetron sputtering. The sputtering time varied from 5 minute to 30 minute, while the power was kept at 230W for all depositions. The structural and optical properties of AZO films were investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman Spectroscopy, Photoluminescence, and UV-visible spectrophotometer. Polycrystalline AZO thin films with hexagonal wurtzite structure were recorded by XRD analysis. The crystallinity and surface morphologies of the films are strongly dependent on the growth time, which in turn exerts a great effect on structural and optical properties of the AZO films. The transmittance for all the AZO films was above 92% in the visible region, and the largest band gap achieved as compare to intrinsic ZnO (3.3 eV). The defect distribution was analyzed by PL analysis.

  9. Synthesis and optical properties of ZnO and carbon nanotube based coaxial heterostructures

    Science.gov (United States)

    Kim, D. S.; Lee, S.-M.; Scholz, R.; Knez, M.; Gösele, U.; Fallert, J.; Kalt, H.; Zacharias, M.

    2008-09-01

    Carbon nanotubes and ZnO based functional coaxial heterostructured nanotubes have been fabricated by using atomic layer deposition. An irregular structured shell composed of ZnO nanocrystals was deposited on pristine nanotubes, while a highly defined ZnO shell was deposited on the tubes after its functionalization with Al2O3. Photoluminescence measurements of the ZnO shell on Al2O3/nanotube show a broad green band emission, whereas the shell grown on the bare nanotube shows a band shifted to the orange spectral range.

  10. Ultrasonic spray pyrolysis growth of ZnO and ZnO:Al nanostructured films: Application to photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Kenanakis, G., E-mail: gkenanak@iesl.forth.gr [Institute of Electronic Structure and Laser, Foundation for Research and Technology – Hellas, P.O. Box 1385, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Katsarakis, N. [Institute of Electronic Structure and Laser, Foundation for Research and Technology – Hellas, P.O. Box 1385, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece)

    2014-12-15

    Highlights: • Al–ZnO thin films and nanostructures were obtained by ultrasonic spray pyrolysis. • The texture and morphology of the samples depend on the deposition parameters. • The photocatalytic degradation of stearic acid was studied upon UV-A irradiation. - Abstract: Pure and Al-doped ZnO (Al = 1, 3, 5%) nanostructured thin films were grown at 400 °C on glass substrates by ultrasonic spray pyrolysis, a simple, environmental-friendly and inexpensive method, using aqueous solutions as precursors. The structural and morphological characteristics of the samples depend drastically on deposition parameters; ZnO nanostructured films, nanopetals and nanorods were systematically obtained by simply varying the precursor solution and/or the spraying time. Transmittance measurements have shown that all samples are transparent in the visible wavelength region. Finally, the photocatalytic properties of the samples were investigated against the degradation of stearic acid under UV-A light illumination (365 nm); both pure and Al-doped ZnO nanostructured thin films show good photocatalytic activity regarding the degradation of stearic acid, due to their good crystallinity and large surface area.

  11. Matrix assisted pulsed laser evaporation of zinc benzoate for ZnO thin films and non-isothermal decomposition kinetics

    International Nuclear Information System (INIS)

    Rotaru, A.; Constantinescu, C.; Mandruleanu, Anca; Rotaru, P.; Moldovan, A.; Gyoryova, Katarina; Dinescu, Maria; Balek, V.

    2010-01-01

    Zinc(II) coordination compounds may provide a better source for ZnO thin films obtaining, since ZnO was found as the final product of their thermal decomposition. Thin films of zinc benzoate have been obtained on silicon substrates by matrix assisted pulsed laser evaporation (MAPLE) technique, using a Nd:YAG laser working at 266 nm. A comparative study of 1% zinc benzoate frozen solution in methanol at different fulences was carried out for 20,000 laser pulses; for the best deposition fluence a double deposition time was employed. Comparative thermal analysis and non-isothermal kinetic investigation of Zn(C 6 H 5 COO) 2 .2H 2 O dehydration and decomposition was performed. Thin films of ZnO have been obtained by thermal treatment of the MAPLE obtained thin films, according to the thermal analysis and decomposition kinetics of zinc benzoate. The obtained morphologies, before and after thermal treatment, have been investigated by atomic force microscopy (AFM).

  12. A Regrowth Method for the Fabrication of High-Quality ZnO Films and Their Application in Fast-Response UV Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Giwoong; Kim, Sungsu; Jo, Euije; Kim, Gyeongjae; Leem, Jae-Young [Inje University, Gimhae (Korea, Republic of); Son, Jeong-Sik [Kyungwoon University, Gumi (Korea, Republic of); Kim, Sung-O [Kansas State University, Manhattan (United States)

    2017-07-15

    In this study, we fabricated high-quality ZnO films using hydrothermally grown ZnO nanorods and a spin-coated Al-doped ZnO film by using regrowth method. The photoluminescence (PL) intensity ratios of the near-band-edge (NBE) to deep-level (DL) emission peaks (I{sub NBE}/I{sub DL}) for ZnO nanorods (samples 1) and ZnO film (sample 2) were 2.13 and 24.3, respectively. The redshift from 3.288 (sample 2) to 3.278 eV (sample 1) and low I{sub NBE}/I{sub DL} ratio in PL spectra were attributed to large mismatch between ZnO and Si substrate, resulting in a residual stress and the low optical properties. In case of sample 2, the photocurrent was sharply increased without the exponential rise because of enhanced optical properties of ZnO film by regrowth. The regrowth method is expected to represent a possible route for fast-response ultraviolet sensors.

  13. Structural and magnetic properties of cobalt-doped ZnO thin films on sapphire (0 0 0 1) substrate deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shanying, E-mail: yshy_150@163.com [Laiwu Vocational and Technical College, Laiwu, Shandong Province, 271100 (China); Lv, Rongqing [Laiwu Vocational and Technical College, Laiwu, Shandong Province, 271100 (China); Wang, Changzheng [School of Physics Science and Information Engineering, Liaocheng University, Liaocheng, Shandong Province, 252059 (China); Liu, Yunyan [School of Science, Shandong University of Technology, Zibo, Shandong Province, 255049 (China); Song, Zeqing [Laiwu Vocational and Technical College, Laiwu, Shandong Province, 271100 (China)

    2013-12-05

    Highlights: •Co-doped ZnO thin films on sapphire (0 0 0 1) substrates were deposited. •ZnLMM Auger spectrum indicated that Zn interstitials existed in thin films. •The lattice constant increasing was ascribed to the stress and interstitial atoms. •The average moment per Co atom related to the distribution of Co{sup 2+} ions and defects. -- Abstract: Co-doped ZnO thin films on sapphire (0 0 0 1) substrates were deposited by PLD at various substrate temperatures in a one Pa oxygen ambient condition. The structural and magnetic properties of as-grown thin films were characterized by using XRD, UV–Visible absorption spectrophotometer, XPS and AGM. All samples possessed wurtzite hexagonal structure of ZnO. Co atoms incorporated into ZnO matrix and substituted for Zn in ZnO lattice, and Zn interstitials existed in as-grown thin films. The c-axis lattice constants of as-deposited thin films were larger than the standard data. Crystallization of as-prepared thin films increased and then decreased with substrate temperatures enhancing. All samples exhibited room-temperature ferromagnetism. The average moment per Co atom was much smaller than that of Co{sup 2+} (3d{sup 7}), due to the different distribution of Co{sup 2+} ions and defects, as well as the different defect concentrations in thin films.

  14. Effect of atomic layer deposited Al2O3:ZnO alloys on thin-film silicon photovoltaic devices

    Science.gov (United States)

    Abdul Hadi, Sabina; Dushaq, Ghada; Nayfeh, Ammar

    2017-12-01

    In this work, we present the effects of the Al2O3:ZnO ratio on the optical and electrical properties of aluminum doped ZnO (AZO) layers deposited by atomic layer deposition, along with AZO application as the anti-reflective coating (ARC) layer and in heterojunction configurations. Here, we report complex refractive indices for AZO layers with different numbers of aluminum atomic cycles (ZnO:Al2O3 = 1:0, 39:1, 19:1, and 9:1) and we confirm their validity by fitting models to experimental data. Furthermore, the most conductive layer (ZnO:Al2O3 = 19:1, conductivity ˜4.6 mΩ cm) is used to fabricate AZO/n+/p-Si thin film solar cells and AZO/p-Si heterojunction devices. The impact of the AZO layer on the photovoltaic properties of these devices is studied by different characterization techniques, resulting in the extraction of recombination and energy band parameters related to the AZO layer. Our results confirm that AZO 19:1 can be used as a low cost and effective conductive ARC layer for solar cells. However, AZO/p-Si heterojunctions suffer from an insufficient depletion region width (˜100 nm) and recombination at the interface states, with an estimated potential barrier of ˜0.6-0.62 eV. The work function of AZO (ZnO:Al2O3 = 19:1) is estimated to be in the range between 4.36 and 4.57 eV. These material properties limit the use of AZO as an emitter in Si solar cells. However, the results imply that AZO based heterojunctions could have applications as low-cost photodetectors or photodiodes, operating under relatively low reverse bias.

  15. Electrodeposition Combination with Hydrothermal Preparation of ZnO Films and Their Application in Dye-Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Xiaoping Zou

    2014-01-01

    Full Text Available A suitable method is necessary for the high performance of dyes-sensitized solar cells (DSSCs. In this paper, photoanodes of DSSCs have been fabricated through electrodeposition and combination with hydrothermal method. The results of mix method showed better performance than the single one. After the second step electrodeposition, the ZnO films formed flack finally. With the increase of hydrothermal time, ZnO films become thicker and bigger, which can offer large surface area to absorb much more dyes. The short-circuit current (2.4 mA/cm2 and open-circuit voltage (0.67 V were greater than the single one, alternating current impedance indicating that electrodeposition and hydrothermal mix are a more suitable method for high performance DSSCs. We expected to obtain higher conversion efficiency of DSSCs by this method.

  16. Effects of deposition temperature on the crystallinity of Ga-doped ZnO thin films on glass substrates prepared by sputtering method

    International Nuclear Information System (INIS)

    Park, Yu Jin; Kim, Hyuk Nyun; Shin, Hyun Ho

    2009-01-01

    The microstructural characterization of Ga-doped (5 at.%) ZnO thin film was conducted by a transmission electron microscopy study. The atomic arrangement of Ga-doped ZnO having an wurtzite structure was identified by the experimental HRTEM and Fourier filtered images as well as the electron diffractions. As a result, we have revealed that the orientation and defect density of Ga-doped ZnO thin films were greatly influenced by the deposition temperature, resulting in the variation of electrical property. In other words, the tendency forming a c-axis oriented texture grows up and the defects such as dislocations and stacking faults decrease, as the temperature of sputtering deposition increases. Consequently, the electrical properties of Ga-doped ZnO thin films can be controlled by the deposition temperature directly related with the defect density.

  17. Determination of the transport mechanisms in mixed conduction of reactively sputtered ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tuezemen, S; Guer, Emre; Dogan, S [Department of Physics, Faculty of Arts and Sciences, Atatuerk University, 25240, Erzurum (Turkey)], E-mail: stuzemen@atauni.edu.tr

    2008-07-07

    Material grown at highly Zn-rich conditions in reactive sputtering of ZnO thin films resulted in mixed conduction, indicating that stable p-type ZnO can be produced. In n-type conductivity, neutral flaw scattering transport mechanism via V{sub O}{sup 0} centres seems to be dominant due to the existence of oxygen vacancies in high concentrations. An exponential decrease in electron mobility is observed upon cooling from room temperature to 210 K while the concentration of the inactive V{sub O}{sup 0} state increases. This is also a cause of p-type conduction in the low temperature range (<170 K). Mobility of holes has rather usual behaviour as the longitudinal acoustic phonon scattering takes place at temperatures 35-170 K. Ionized acceptor scattering is shown to be effective for holes below 35 K. P-type conduction is not affected by V{sub O}{sup 0} scattering. Quantitative evaluations of V{sub O} centres show that fractional distribution of V{sub O}{sup 0}, V{sub O}{sup +} and V{sub O}{sup ++} charge states are, respectively, around 4%, 95% and 1% of the total [V{sub O}] at the room temperature conditions. The energy of phonons interacting with the centre is estimated to be 38.5 meV which is a local phonon mode relaxation, most probably resulting in negative-U behaviour of V{sub O} centres.

  18. Correlation between structural and electrical properties of PLD prepared ZnO thin films used as a photodetector material

    Energy Technology Data Exchange (ETDEWEB)

    Triolo, C., E-mail: trioloc@unime.it [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d‘Alcontres 31, 98166, Messina (Italy); Fazio, E.; Neri, F.; Mezzasalma, A.M. [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d‘Alcontres 31, 98166, Messina (Italy); Trusso, S. [CNR-IPCF Istituto per i Processi Chimico-Fisici, Viale F. Stagno d’Alcontres 37, 98158, Messina (Italy); Patanè, S. [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d‘Alcontres 31, 98166, Messina (Italy)

    2015-12-30

    Highlights: • ZnO thin filmswere deposited by pulsed laser ablation from a metallic zinc target in a controlled oxygen atmosphere in shock wave regime. • The samples morphology is tuned, varying the growth temperature. • The transport properties were measured at RT and at 30 K under vacuumboth illuminating the sample by an UV laser and in dark conditions. • All samples are sensible to the UV radiations; the oxygen chemisorbed on the grain surface affects the speed of photoresponse. - Abstract: The electrical transport properties of a set of zinc oxide (ZnO) thin films, prepared by pulsed laser ablation, were investigated at the temperatures of 30 K and 300 K. Information about the structural and morphological properties of the samples were obtained by means of atomic force microscopy (AFM) and X-ray diffraction (XRD). A significant variation in the surface morphology and photoresponse characteristics of the ZnO thin films were observed as a function of the deposition temperature. Upon increasing the deposition temperature, the surface topography changes from a more fine-grained to a more coarse-grained structure, showing a tetragonal wurtzite crystalline structure. Time resolved photocurrent measurements showed significantly variations as function of the observed samples morphologies. A photocurrent value of about three order of magnitude larger is observed for samples showing a more coarse-grained structure with respect to the fine-grained ones. Such a result is interpreted as due to the contributions of both “bulk” and defect centers that affect the conduction mechanisms and influence both the photoconductivity values and the photoresponse speed. The observed decay times are very long with respect to films grown by other techniques, due to the reduction of the surface localized centers of defect available for recombination. In this context, the sample morphology appears to be a key parameter to control the photoconductivity in ZnO thin films.

  19. Characterization of ZnO thin films grown on different p-Si substrate elaborated by solgel spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Chebil, W., E-mail: Chbil.widad@live.fr [Laboratoire Physico-chimie des Matériaux, Unité de Service Commun de Recherche “High resolution X-ray diffractometer”, Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir (Tunisia); Fouzri, A. [Laboratoire Physico-chimie des Matériaux, Unité de Service Commun de Recherche “High resolution X-ray diffractometer”, Département de Physique, Université de Monastir, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir (Tunisia); Institut Supérieur des Sciences Appliquées et de Technologie de Sousse, Université de Sousse (Tunisia); Fargi, A. [Laboratoire de Microélectronique et Instrumentation, Faculté des Sciences de Monastir, Université de Monastir, Avenue de l’environnement, 5019 Monastir (Tunisia); Azeza, B.; Zaaboub, Z. [Laboratoire Micro-Optoélectroniques et Nanostructures, Faculté des Sciences de Monastir, Université de Monastir, Avenue de l' environnement, 5019 Monastir (Tunisia); and others

    2015-10-15

    Highlights: • High quality ZnO thin films grown on different p-Si substrates were successful obtained by sol–gel process. • PL measurement revealed that ZnO thin film grown on porous Si has the better optical quality. • I–V characteristics for all heterojunctions exhibit successful diode formation. • The diode ZnO/PSi shows a better photovoltaic effect under illumination with a maximum {sub Voc} of 0.2 V. - Abstract: In this study, ZnO thin films are deposited by sol–gel technique on p-type crystalline silicon (Si) with [100] orientation, etched silicon and porous silicon. The structural analyses showed that the obtained thin films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented along the c-axis direction. Morphological study revealed the presence of rounded and facetted grains irregularly distributed on the surface of all samples. PL spectra at room temperature revealed that ZnO thin film grown on porous Si has a strong UV emission with low defects in the visible region comparing with ZnO grown on plat Si and etched Si surface. The heterojunction parameters were evaluated from the (I–V) under dark and illumination at room temperature. The ideality factor, barrier height and series resistance of heterojunction grown on different p-Si substrates are determined by using different methods. Best electrical properties are obtained for ZnO layer deposited on porous silicon.

  20. Determination of electrical types in the P-doped ZnO thin films by the control of ambient gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Yi; Han, Won Suk [School of Advanced Materials Science and Engineering, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Cho, Hyung Koun, E-mail: chohk@skku.edu [School of Advanced Materials Science and Engineering, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2010-05-01

    Phosphorus (P)-doped ZnO thin films with amphoteric doping behavior were grown on c-sapphire substrates by radio frequency magnetron sputtering with various argon/oxygen gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio without post-annealing. The P-doped ZnO films grown at a argon/oxygen ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of 1.5 x 10{sup 17} cm{sup -3} and 2.5 cm{sup 2}/V s, respectively. X-ray diffraction showed that the ZnO (0 0 0 2) peak shifted to lower angle due to the positioning of P{sup 3-} ions with a larger ionic radius in the O{sup 2-} sites. This indicates that a p-type mechanism was due to the substitutional P{sub O}. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction light emitting diode showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

  1. Effect of surface carbon contamination on the chemical states of N-doped ZnO thin films

    Science.gov (United States)

    Zhang, Hong; Li, Wanjun; Qin, Guoping; Fang, Liang; Ruan, Haibo; Tan, Mi; Wu, Fang; Kong, Chunyang

    2018-02-01

    Nitrogen-doped ZnO thin films [ZnO:N] and intentional surface carbon-contaminated ZnO:N thin films [ZnO:N@C] were grown on quartz substrates by radio frequency magnetron sputtering deposition method. The structural, electrical and optical properties as well as chemical states of elements were investigated by means of X-ray diffraction (XRD), Hall effect measurement (Hall), UV-Vis-Near infrared spectrophotometer and X-ray photoelectron spectroscopy (XPS). The results indicate that surface carbon contamination almost does not affect the band gap of ZnO:N thin films but has a strong impact on the crystal quality of ZnO:N thin film surface and results in a significant increase in tensile stress. The XPS analysis shows that the effect of surface carbon contamination treatment on the chemical states of ZnO:N thin films is remarkable. Because the stability of Zn-N bonds in N-rich local environments is nowhere near that of those in O-rich local environments, the N atoms in N-rich local environments easily bond with surface carbon atoms to form undesirable C-N bonds, thus resulting in a decrease of NO acceptors in N-rich local environments. Obviously, it is unfavorable to subsequently prepare high stability of N-doped p-type ZnO thin films.

  2. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Hoye, Robert L. Z., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk; MacManus-Driscoll, Judith L., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Muñoz-Rojas, David [LMGP, University Grenoble-Alpes, CNRS, F-3800 Grenoble (France); Nelson, Shelby F. [Kodak Research Laboratories, Eastman Kodak Company, Rochester, New York 14650 (United States); Illiberi, Andrea; Poodt, Paul [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Roozeboom, Fred [Holst Centre/TNO Thin Film Technology, Eindhoven, 5656 AE (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB (Netherlands)

    2015-04-01

    Atmospheric pressure spatial atomic layer deposition (AP-SALD) has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics.

  3. Research Update: Atmospheric pressure spatial atomic layer deposition of ZnO thin films: Reactors, doping, and devices

    Directory of Open Access Journals (Sweden)

    Robert L. Z. Hoye

    2015-04-01

    Full Text Available Atmospheric pressure spatial atomic layer deposition (AP-SALD has recently emerged as an appealing technique for rapidly producing high quality oxides. Here, we focus on the use of AP-SALD to deposit functional ZnO thin films, particularly on the reactors used, the film properties, and the dopants that have been studied. We highlight how these films are advantageous for the performance of solar cells, organometal halide perovskite light emitting diodes, and thin-film transistors. Future AP-SALD technology will enable the commercial processing of thin films over large areas on a sheet-to-sheet and roll-to-roll basis, with new reactor designs emerging for flexible plastic and paper electronics.

  4. Bias-voltage dependent ultraviolet photodetectors prepared by GaO{sub x} + ZnO mixture phase nanocrystalline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rongxin, E-mail: rxwang2008@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Yang, Lechen [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Xu, Shijie [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Department of Physics and HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Zhang, Xiaodong; Dong, Xue; Zhao, Yingchun; Fu, Kai; Zhang, Baoshun; Yang, Hui [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2013-07-25

    Highlights: •GaO{sub x} + ZnO thin films sputtered and annealed exhibit interesting and unique optical properties, especially deep UV photo response. •GaO{sub x} + ZnO thin films can be used to fabricate efficient deep UV photodetectors. •The mixture phase nature of GaO{sub x} + ZnO thin films is revealed to be responsible for the unique characteristics of the photodetectors. •Two bands in UV range can be adjusted by a applied voltage when the PDs were fabricated using the mixture phase nature of GaO{sub x} + ZnO thin films. -- Abstract: Ultraviolet (UV) photodetectors were prepared by using the GaO{sub x} + ZnO mixture phase thin films sputtered on sapphire as the photoresponse layer. The devices show good photoresponse in UV range. More interestingly, the device responsivity in the wavelength less than 280 nm range rapidly increases with increasing the applied voltage and becomes dominant for the bias ⩾3.0 V. X-ray diffraction, absorption and cathodoluminescence measurements firmly reveal the mixture phases in the thin films. Electric field dependent detrapping of photo-excited carriers in nanocrystals in the films shall be responsible for the observed bias-voltage dependent deep UV photoresponse of the devices.

  5. Temperature-dependent electrical characterization of nitrogen-doped ZnO thin film: vacuum annealing effect

    Energy Technology Data Exchange (ETDEWEB)

    Guer, Emre; Tuezemen, S; Dogan, S [Department of Physics, Faculty of Arts and Sciences, Atatuerk University, 25240 Erzurum (Turkey)], E-mail: emregur@atauni.edu.tr

    2009-03-15

    Temperature-dependent Hall effect measurements were carried out at an N-doped ZnO thin film grown by the reactive sputtering method onto (001) Si substrate before and after being vacuum annealed at 900 deg. 403{sup 1} C. p-Type ZnO thin film was obtained with a relatively high mobility of {approx}60 cm{sup 2} V {sup -} {sup 1} s {sup -} {sup 1}, a high carrier concentration of 2.5x10{sup 17} cm {sup -} {sup 3} and a low resistivity of 0.4 ohm cm. After vacuum annealing, the temperature dependence of electrical parameters such as mobility and carrier concentration showed highly different characteristics. Time-resolved photoluminescence (TRPL), PL and x-ray diffraction measurements (XRD) were performed after the annealing process to check whether the high-temperature annealing can remove the ZnO film on Si or not. The PL measurement shows band-to-band recombination at 360 nm and TRPL shows the exciton recombination lifetime to be 571.7 ps. The XRD measurement reveals highly preferred c-axis (0002) orientation. Activation energies were calculated using the ln {sigma} versus 1000 T {sup -} {sup 1} plot to be 20 meV for the as-grown and 24 and 6.8 meV after the vacuum annealing process.

  6. Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

    Energy Technology Data Exchange (ETDEWEB)

    Loukanov, Alexandre, E-mail: loukanov@mail.saitama-u.ac.jp [Saitama University, Department of Chemistry, Faculty of Science (Japan); Filipov, Chavdar [University of Forestry, Department of Infectious pathology, hygiene, technology and control of food stuffs of animal origin, Faculty of Veterinary Medicine (Bulgaria); Valcheva, Violeta [Bulgarian Academy of Science, Department of Infectious Diseases, Institute of microbiology (Bulgaria); Lecheva, Marta [University of Mining and Geology “St. Ivan Rilski”, Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology (Bulgaria); Emin, Saim [University of Nova Gorica, Materials Research Laboratory (Slovenia)

    2015-04-15

    The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600–1000 nm). They have been prepared by using both wet sol–gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

  7. Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

    Science.gov (United States)

    Loukanov, Alexandre; Filipov, Chavdar; Valcheva, Violeta; Lecheva, Marta; Emin, Saim

    2015-04-01

    The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600-1000 nm). They have been prepared by using both wet sol-gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

  8. ZnO nanowire photodetectors based on Schottky contact with surface passivation

    Science.gov (United States)

    Zhang, Dakuan; Sheng, Yun; Wang, Jianyu; Gao, Fan; Yan, Shancheng; Wang, Junzhuan; Pan, Lijia; Wan, Qing; Shi, Yi

    2017-07-01

    Performance characteristics, such as dark current and response time, of ZnO nanowire (NW) photodetectors are usually degraded by H2O/O2 adsorption on the NW surfaces. In this work, ZnO NW photodetectors based on Au Schottky contact through passivating surface states were investigated. ZnO NW photodetectors were fabricated with a lateral electrode structure, in which Au served as Au/ZnO Schottky contact and semi-transparent top electrode. Specifically, passivation of the surface states of ZnO NWs by using highly intensive UV irradiation effectively improved the photoresponse. A physical model based on surface band theory was developed to understand the origin of the performance improvement of the photodetector. The present device architecture prevents ZnO NWs photodetector from H2O/O2 adsorption in air and efficiently extracts photogenerated carriers across a diametrical direction.

  9. Efficient detection of total cholesterol using (ChEt–ChOx/ZnO/Pt/Si) bioelectrode based on ZnO matrix

    Energy Technology Data Exchange (ETDEWEB)

    Batra, Neha; Sharma, Anjali [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Department of Physics, Miranda House, University of Delhi, Delhi 110007 (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-07-01

    Present study highlights the importance of ZnO matrix prepared by vapour phase transport technique on platinum coated Si platform (ZnO/Pt/Si) as a potential matrix for the realization of highly sensitive and selective bioelectrode for detection of total cholesterol. Bienzymes cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) have been immobilized onto the surface of ZnO thin film matrix by physical adsorption technique. The prepared bioelectrode (ChEt–ChOx/ZnO/Pt/Si) is utilized for detection of total cholesterol using the cyclic voltammetry technique. The bioelectrode (ChEt–ChOx/ZnO/Pt/Si) is found to exhibit efficient sensing response characteristics with high sensitivity of 190 μA mM{sup −1} cm{sup −2}; good linearity in the range of 0.5–12 mM total cholesterol concentration, and a very low Michaelis–Menten constant of 0.68 mM which indicates high affinity of bienzymes immobilized on ZnO towards the analyte (total cholesterol). The enhanced response is attributed to the development of ZnO thin film based matrix having good electron transport property and nanoporous morphology for effective loading of enzymes with favourable orientation. - Highlights: • Fabrication of a ZnO nanostructured thin film based efficient matrix • Utilizing prepared matrix for detection of total cholesterol (free + esterified) • Cholesterol oxidase and cholesterol esterase are the corresponding selective enzymes. • Vapour phase transport technique, for the fabrication of nanostructured ZnO matrix • The bioelectrode exhibits enhanced response characteristics towards total cholesterol detection.

  10. Irradiation effects with 100 MeV Xe ions on optical properties of Al-doped ZnO films

    International Nuclear Information System (INIS)

    Fukuoka, O.; Matsunami, N.; Tazawa, M.; Shimura, T.; Sataka, M.; Sugai, H.; Okayasu, S.

    2006-01-01

    Al-doped ZnO (AZO) films are known as n-type transparent semiconductors. We have investigated the effects of 100 MeV Xe ion irradiation on the optical and structural properties of AZO films, which were prepared on SiO 2 glass at 400 deg. C by using a RF-magnetron sputtering deposition method. We discuss relationships between these property modifications and the recent observations of the conductivity increase by ion irradiation. It is suggested that the band-gap modification has more close relation with the conductivity increase than the structural modification

  11. Negative permittivity of ZnO thin films prepared from aluminum and gallium doped ceramics via pulsed-laser deposition

    DEFF Research Database (Denmark)

    Bodea, M. A.; Sbarcea, G.; Naik, G. V.

    2013-01-01

    Aluminum and gallium doped zinc oxide thin films with negative dielectric permittivity in the near infrared spectral range are grown by pulsed laser deposition. Composite ceramics comprising ZnO and secondary phase Al2O3 or Ga2O3 are employed as targets for laser ablation. Films deposited on glass...... from dense and small-grained ceramic targets show optical transmission larger than 70 % in the visible and reveal an onset of metallic reflectivity in the near infrared at 1100 nm and a crossover to a negative real part of the permittivity at approximately 1500 nm. In comparison to noble metals, doped...

  12. Photocatalytic Activity and Stability of Porous Polycrystalline ZnO Thin-Films Grown via a Two-Step Thermal Oxidation Process

    Directory of Open Access Journals (Sweden)

    James C. Moore

    2014-08-01

    Full Text Available The photocatalytic activity and stability of thin, polycrystalline ZnO films was studied. The oxidative degradation of organic compounds at the ZnO surface results from the ultraviolet (UV photo-induced creation of highly oxidizing holes and reducing electrons, which combine with surface water to form hydroxyl radicals and reactive oxygen species. Therefore, the efficiency of the electron-hole pair formation is of critical importance for self-cleaning and antimicrobial applications with these metal-oxide catalyst systems. In this study, ZnO thin films were fabricated on sapphire substrates via direct current sputter deposition of Zn-metal films followed by thermal oxidation at several annealing temperatures (300–1200 °C. Due to the ease with which they can be recovered, stabilized films are preferable to nanoparticles or colloidal suspensions for some applications. Characterization of the resulting ZnO thin films through atomic force microscopy and photoluminescence indicated that decreasing annealing temperature leads to smaller crystal grain size and increased UV excitonic emission. The photocatalytic activities were characterized by UV-visible absorption measurements of Rhodamine B dye concentrations. The films oxidized at lower annealing temperatures exhibited higher photocatalytic activity, which is attributed to the increased optical quality. Photocatalytic activity was also found to depend on film thickness, with lower activity observed for thinner films. Decreasing activity with use was found to be the result of decreasing film thickness due to surface etching.

  13. Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

    KAUST Repository

    Phadke, Sujay

    2011-09-30

    Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ∼5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2-D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter-wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter-wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires. Solution processed Gallium doped ZnO nanowires are aligned on substrates using an innovative shear coating technique. Nanowire alignment has shown improvement in ZnO nanowire transparent electrode conductivity. 2D network simulations in conjunction with electrical measurements have revealed different regimes of operation of nanowire thin films and provided a guideline for improving electrical performance of nanowire electrodes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Photoluminescence and electrochemical properties of transparent CeO2-ZnO nanocomposite thin films prepared by Pechini method

    Science.gov (United States)

    Sani, Z. Khosousi; Ghodsi, F. E.; Mazloom, J.

    2017-02-01

    Nanocomposite thin films of CeO2-ZnO with different molar ratios of Zn/Ce (=0, 0.25, 0.5, 0.75 and 1) were prepared by the Pechini sol-gel route. Various spectroscopic and electrochemical techniques were applied to investigate the films. XRD patterns of all the samples exhibited the peaks corresponding to cubic fluorite structure of ceria and the (101) and (103) peaks of ZnO with hexagonal structure was just observed in the sample with molar ratio of 1. EDS confirmed the presence of constituent of element in the samples. FESEM images of the films showed a surface composed of nanograins. AFM analysis revealed that root mean square roughness was enhanced as molar ratio of Zn/Ce increased. Moreover, fractal dimension of surfaces were calculated by cube counting approach. Optical measurements indicated that the film with molar ratio of 1 has the highest transmission and lowest reflectivity. The optical band gap values varied between 2.95 and 3.42 eV. The compositional dependence of refractive index and extinction coefficient were reported. The UV and blue emission appeared in PL spectra. The highest photoluminescence emission intensity was observed in the 1:1 molar ratio sample. The cyclic voltammetry measurements indicated the highest charge density (9.75 mC cm-2) and diffusion coefficient (3.507 × 10-17 cm2 s-1) belonged to the Ce/Zn (1:1) thin film.

  15. Growth and Structural, Magnetic, and Magnetooptical Properties of ZnO Films Doped with a Fe57 3 d Impurity

    Science.gov (United States)

    Mezdrogina, M. M.; Aglikov, A. S.; Semenov, V. G.; Kozhanova, Yu. V.; Nefedov, S. G.; Shelukhin, L. A.; Pavlov, V. V.

    2018-03-01

    ZnO films obtained by high-frequency magnetron sputtering and doped with a Fe57 metallic 3 d impurity by the diffusion method are studied. The type of local environment of Fe57 impurity atoms on varying the deposition parameters of ZnO films is determined by Mössbauer spectroscopy. It is established that the ground state of Fe57 impurity atoms corresponds to metallic iron in the magnetically ordered state and there is a small fraction of Fe57 atoms with a local environment corresponding to the complex oxide Fe3O4, having the magnetically ordered state; there is also a fraction of iron atoms in the paramagnetic state. The magnetic and magnetooptical parameters of the films were measured using magnetooptic Kerr effect. The spectral dependences of the polar magnetooptic Kerr effect in ZnO(Fe57) films are measured in a photon energy range of 1.5-4.5 eV and simulated by the effective-medium method. It is established that ZnO(Fe57) possess an easy-plane magnetic anisotropy with a magnetization lying in the film plane.

  16. Structural, optical and electrical properties of N-doped ZnO thin films prepared by thermal oxidation of pulsed filtered cathodic vacuum arc deposited Zn{sub x}N{sub y} films

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, N.H.; Kara, K.; Ozdamar, H. [Physics Department, Cukurova University, 01330 Adana (Turkey); Kavak, H., E-mail: hkavak@cu.edu.tr [Physics Department, Cukurova University, 01330 Adana (Turkey); Esen, R. [Physics Department, Cukurova University, 01330 Adana (Turkey); Karaagac, H. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey)

    2011-09-08

    Graphical abstract: Highlights: > Thermal oxidation of Zn{sub x}N{sub y} method is used to obtain N doped ZnO. > N acceptors in ZnO is not sufficiently activated at oxidation temperature below 350 deg. C. > Oxidation treatment at 450 deg. C activates more N acceptors in ZnO. > Oxidation treatment at high temperatures above 550 deg. C reduces the N concentration in the ZnO thin film. - Abstract: In this study, N-doped ZnO thin films were fabricated by oxidation of Zn{sub x}N{sub y} films. The Zn{sub x}N{sub y} thin films were deposited on glass substrates by pulsed filtered cathodic vacuum arc deposition (PFCVAD) using metallic zinc wire (99.999%) as a cathode target in pure nitrogen plasma. The influence of oxidation temperature, on the electrical, structural and optical properties of N-doped ZnO films was investigated. P-type conduction was achieved for the N-doped ZnO obtained at 450 deg. C by oxidation of Zn{sub x}N{sub y}, with a resistivity of 16.1 {Omega} cm, hole concentration of 2.03 x 10{sup 16} cm{sup -3} and Hall mobility of 19 cm{sup 2}/V s. X-ray photoelectron spectroscopy (XPS) analysis confirmed the incorporation of N into the ZnO films. X-ray diffraction (XRD) pattern showed that the films as-deposited and oxidized at 350 deg. C were amorphous. However, the oxidized films in air atmosphere at 450-550 deg. C were polycrystalline without preferential orientation. In room temperature photoluminescence (PL) spectra, an ultraviolet (UV) peak was seen for all the samples. In addition, a broad deep level emission was observed.

  17. Incorporation of graphene in quantum dot sensitized solar cells based on ZnO nanorods.

    Science.gov (United States)

    Chen, Jing; Li, Chu; Eda, Goki; Zhang, Yan; Lei, Wei; Chhowalla, Manish; Milne, William I; Deng, Wei-Qiao

    2011-06-07

    We demonstrate a novel architecture of solar cell by incorporating graphene thin film in a quantum dot sensitized solar cell. Quantum dot sensitized nanorods with a graphene layer exhibited a 54.7% improvement comparing a quantum dot sensitized ZnO nanorods without graphene layer. A fill factor as high as ∼62% was also obtained.

  18. Morphological variations of Mn-doped ZnO dilute magnetic semiconductors thin films grown by succesive ionic layer by adsorption reaction method.

    Science.gov (United States)

    Balamurali, Subramanian; Chandramohan, Rathinam; Karunakaran, Marimuthu; Mahalingam, Thayan; Parameswaran, Padmanaban; Suryamurthy, Nagamani; Sukumar, Arcod Anandhakrishnan

    2013-07-01

    Transparent conducting Mn-doped ZnO thin films have been prepared by successive ionic layer by adsorption reaction (SILAR) method. The deposition conditions have been optimized based on their structure and on the formation of smoothness, adherence, and stoichiometry. The results of the studies by X-ray diffraction, scanning electron microscope (SEM), reveal the varieties of structural and morphological modifications feasible with SILAR method. The X-ray diffraction patterns confirm that the ZnO:Mn has wurtzite structure. The interesting morphological variations with dopant concentration are observed and discussed. The films' quality is comparable with those grown with physical methods and is suitable for spintronic applications. Copyright © 2013 Wiley Periodicals, Inc.

  19. Effect of Pre-Annealing on Thermal and Optical Properties of ZnO and Al-ZnO Thin Films

    Science.gov (United States)

    Saravanan, P.; Gnanavelbabu, A.; Pandiaraj, P.

    Zinc oxide (ZnO) nanoparticles were synthesized by a simple solution route method using zinc acetate as the precursor and ethanol as the solvent. At a temperature of 60∘C, a clear homogenous solution is heated to 100∘C for ethanol evaporation. Then the obtained precursor powder is annealed at 600∘C for the formation of ZnO nanocrystalline structure. Doped ZnO particle is also prepared by using aluminum nitrate nonahydrate to produce aluminum (Al)-doped nanoparticles using the same solution route method followed by annealing. Thin film fabrication is done by air evaporation method using the polymer polyvinyl alcohol (PVA). To analyze the optical and thermal properties for undoped and doped ZnO nanocrystalline thin film by precursor annealing, characterizations such as UV, FTIR, AFM, TGA/DTA, XRD, EDAX and Photoluminescence (PL) were also taken. It was evident that precursor annealing had great influence on thermal and optical properties of thin films while ZnO and AZO film showed low crystallinity and intensity than in the powder form. TGA/DTA suggests pre-annealing effect improves the thermal stability, which ensures that Al ZnO nanoparticle can withstand at high temperature too which is the crucial advantage in the semiconductor devices. UV spectroscopy confirmed the presence of ZnO nanoparticles in the thin film by an absorbance peak observed at 359nm with an energy bandgap of 3.4eV. A peak obtained at 301nm with an energy bandgap of 4.12eV shows a blue shift due to the presence of Al-doped ZnO nanoparticles. Both ZnO and AZO bandgap increased due to precursor annealing. In this research, PL spectrum is also studied in order to determine the optical property of the nanoparticle embedded thin film. From PL spectrum, it is observed that the intensity of the doped ZnO is much more enhanced as the dopant concentration is increased to 1wt.% and 2wt.% of Al in ZnO.

  20. Characterization of nanostructures of ZnO and ZnMnO films deposited by successive ionic layer adsorption and reaction method

    International Nuclear Information System (INIS)

    Jimenez-Garcia, F.N.; Espinosa-Arbelaez, D.G.; Vargas-Hernandez, C.; Real, A. del; Rodriguez-Garcia, M.E.

    2011-01-01

    ZnO and ZnMnO thin films were obtained by the successive ionic layer adsorption and reaction (SILAR) method. All thin films were deposited on glass microscope slide. A precursor solution of 0.1 M of ZnCl 2 complexed with ammonium hydroxide and water close to boiling point (92 deg. C) as a second solution was used for the ZnO films. An uncomplexed bath comprised of 0.1 M ZnCl 2 , 0.1 M MnCl 2, and a second solution of 0.1 ml of NH 4 OH with water close to boiling point was used for the ZnMnO films. The film samples were deposited by the SILAR method and annealed at 200 deg. C for 15 min. These samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscope. Atomic absorption was used to determine quantitatively the amount of Mn incorporated into the films. According to the XRD patterns these films were polycrystalline with wurtzite hexagonal structure. The morphology of the ZnO films constituted by rice-like and flower-like structures changed significantly to nanosheet structures with the Mn incorporation. The Mn inclusion in a ZnO structure was less than 4% according to the results from EDS, XRD, and atomic absorption.

  1. Characterization of nanostructures of ZnO and ZnMnO films deposited by successive ionic layer adsorption and reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Garcia, F.N. [Departamento de Fisica y Matematicas, Universidad Autonoma de Manizales, Antigua Estacion del Ferrocarril, Manizales, Caldas (Colombia); Departamento de Fisica y Quimica, Universidad Nacional de Colombia, Sede Manizales, Campus la Nubia, Manizales, Caldas (Colombia); Espinosa-Arbelaez, D.G. [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Blv. Juriquilla 3001, Juriquilla, Queretaro, C.P. 76230 (Mexico); Posgrado en Ciencia e Ingenieria Materiales, Instituto de Investigacion en Materiales, Universidad Nacional Autonoma de Mexico, Mexico DF (Mexico); Vargas-Hernandez, C. [Departamento de Fisica y Quimica, Universidad Nacional de Colombia, Sede Manizales, Campus la Nubia, Manizales, Caldas (Colombia); Real, A. del [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Blv. Juriquilla 3001, Juriquilla, Queretaro, C.P. 76230 (Mexico); Rodriguez-Garcia, M.E., E-mail: marioga@fata.unam.mx [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Blv. Juriquilla 3001, Juriquilla, Queretaro, C.P. 76230 (Mexico)

    2011-09-01

    ZnO and ZnMnO thin films were obtained by the successive ionic layer adsorption and reaction (SILAR) method. All thin films were deposited on glass microscope slide. A precursor solution of 0.1 M of ZnCl{sub 2} complexed with ammonium hydroxide and water close to boiling point (92 deg. C) as a second solution was used for the ZnO films. An uncomplexed bath comprised of 0.1 M ZnCl{sub 2}, 0.1 M MnCl{sub 2,} and a second solution of 0.1 ml of NH{sub 4}OH with water close to boiling point was used for the ZnMnO films. The film samples were deposited by the SILAR method and annealed at 200 deg. C for 15 min. These samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscope. Atomic absorption was used to determine quantitatively the amount of Mn incorporated into the films. According to the XRD patterns these films were polycrystalline with wurtzite hexagonal structure. The morphology of the ZnO films constituted by rice-like and flower-like structures changed significantly to nanosheet structures with the Mn incorporation. The Mn inclusion in a ZnO structure was less than 4% according to the results from EDS, XRD, and atomic absorption.

  2. Cu-Doped ZnO Thin Films Deposited by a Sol-Gel Process Using Two Copper Precursors: Gas-Sensing Performance in a Propane Atmosphere

    Directory of Open Access Journals (Sweden)

    Heberto Gómez-Pozos

    2016-01-01

    Full Text Available A study on the propane gas-sensing properties of Cu-doped ZnO thin films is presented in this work. The films were deposited on glass substrates by sol-gel and dip coating methods, using zinc acetate as a zinc precursor, copper acetate and copper chloride as precursors for doping. For higher sensitivity values, two film thickness values are controlled by the six and eight dippings, whereas for doping, three dippings were used, irrespective of the Cu precursor. The film structure was analyzed by X-ray diffractometry, and the analysis of the surface morphology and film composition was made through scanning electron microscopy (SEM and secondary ion mass spectroscopy (SIMS, respectively. The sensing properties of Cu-doped ZnO thin films were then characterized in a propane atmosphere, C3H8, at different concentration levels and different operation temperatures of 100, 200 and 300 °C. Cu-doped ZnO films doped with copper chloride presented the highest sensitivity of approximately 6 × 104, confirming a strong dependence on the dopant precursor type. The results obtained in this work show that the use of Cu as a dopant in ZnO films processed by sol-gel produces excellent catalysts for sensing C3H8 gas.

  3. Development of silane grafted ZnO core shell nanoparticles loaded diglycidyl epoxy nanocomposites film for antimicrobial applications.

    Science.gov (United States)

    Suresh, S; Saravanan, P; Jayamoorthy, K; Ananda Kumar, S; Karthikeyan, S

    2016-07-01

    In this article a series of epoxy nanocomposites film were developed using amine functionalized (ZnO-APTES) core shell nanoparticles as the dispersed phase and a commercially available epoxy resin as the matrix phase. The functional group of the samples was characterized using FT-IR spectra. The most prominent peaks of epoxy resin were found in bare epoxy and in all the functionalized ZnO dispersed epoxy nanocomposites (ZnO-APTES-DGEBA). The XRD analysis of all the samples exhibits considerable shift in 2θ, intensity and d-spacing values but the best and optimum concentration is found to be 3% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposites supported by FT-IR results. From TGA measurements, 100wt% residue is obtained in bare ZnO nanoparticles whereas in ZnO core shell nanoparticles grafted DGEBA residue percentages are 37, 41, 45, 46 and 52% for 0, 1, 3, 5 and 7% ZnO-APTES-DGEBA respectively, which is confirmed with ICP-OES analysis. From antimicrobial activity test, it was notable that antimicrobial activity of 7% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposite film has best inhibition zone effect against all pathogens under study. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. RETRACTED: Investigation of structural, optical and electronic properties in Al-Sn co-doped ZnO thin films

    Science.gov (United States)

    Pan, Zhanchang; Tian, Xinlong; Wu, Shoukun; Yu, Xia; Li, Zhuliang; Deng, Jianfeng; Xiao, Chumin; Hu, Guanghui; Wei, Zhigang

    2013-01-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Figures 3 and 4 of this paper have also been presented as belonging to other materials in other publications. This observation is evidence of fraud and therefore it is not certain that the described research and conclusions of this paper belong to the presented images. Figures 3 and 4 of this paper can also be found in: Effect of annealing on the structures and properties of Al and F co-doped ZnO nanostructures, Materials Science in Semiconductor Processing, 2014, 17, 162-167, http://dx.doi.org/10.1016/j.mssp.2013.09.023 Highly transparent and conductive Sn/F and Al co-doped ZnO thin films prepared by sol-gel method, Journal of Alloys and Compounds, 2014,583, 32-38, http://dx.doi.org/10.1016/j.jallcom.2013.06.192 Properties of fluorine and tin co-doped ZnO thin films deposited by sol-gel method, Journal of Alloys and Compounds, 2013,576, 31-37, http://dx.doi.org/10.1016/j.jallcom.2013.04.132

  5. Enhanced Broadband Photoresponse in Plasmonic Nanoparticles decorated ZnO Nanowire Film fabricated by Laser Ablation method

    Science.gov (United States)

    Nath, Rajib; Ghimire, Rishi Ram; Neogy, Rajesh Kr.; Raychaudhuri, Arup K.

    ZnO is a high band gap semiconductor which is widely used as an UV photo-detector. However, one of the draw backs of ZnO based photo-detectors is its lack of response in the visible, in particular above a wavelength (λ) of 450 nm which limits its use as broadband photodetector. Here, we report that the photoresponse of ZnO nanowire (NW) based photodetector can be significantly enhanced in wide spectral range (350 to 650nm) using ligand free attachment of plasmonic Au-nanoparticles (NP) on its surface by laser ablation process. This simple fabrication method increases responsitivity (R) (2 to 4 order) of Au-ZnO device in a window of 500financial support from Unit for Nanoscience, DST,India.

  6. ZnO piezoelectric film resonator modified with multi-walled carbon nanotubes/polyethyleneimine bilayer for the detection of trace formaldehyde

    Science.gov (United States)

    Ma, Jilong; Wang, Shaotian; Chen, Da; Wang, Wei; Zhang, Zhen; Song, Shuren; Yu, Wenhua

    2018-01-01

    We fabricated a ZnO piezoelectric film resonator modified with multi-walled carbon nanotubes/polyethyleneimine bilayer as the sensitive layer for the detection of trace gaseous formaldehyde. The resonator consists of a ZnO piezoelectric stack and an SiO2/W Bragg reflector. The multi-walled carbon nanotubes were self-assembled on the resonator surface using the n-octadecyl mercaptan monolayer and further modified with polyethyleneimine. The formaldehyde molecules are absorbed on the multi-walled carbon nanotubes/polyethyleneimine bilayer based on the reversible nucleophilic addition reaction between formaldehyde molecules and the amine functional groups on polyethyleneimine. The high working frequency ( 3.1 GHz) of the resonator provided enough mass sensitivity to probe the ultra-small mass change of the sensitive biolayer. The downshift of resonant frequency was linear with the increase of formaldehyde concentration. The experimental results show that our proposed sensor can yield rapid, sensitive, reversible and repeatable responses to formaldehyde in the concentration range of 50-400 ppb at room temperature. The piezoelectric film resonator is a promising and feasible sensor for the indoor pollution monitoring.

  7. Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Yuanyao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Wu, Fang, E-mail: fang01234@163.com [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Mao, Caiying [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Fang, Liang, E-mail: lfang@cqu.edu.cn [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China); Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Guo, Shengchun [Department of Applied Physics, College of Physics, Chongqing University, Chongqing 401331 (China); Zhou, Miao [State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044 (China)

    2015-06-05

    Highlights: • ZnO nanorods were grown on Ga-doped ZnO seed layers using hydrothermal method. • Using the ZnO nanorods as photoanodes for fabricated dye-sensitized solar cells. • The highest η of 1.23% can be achieved in a DSSC with 3 at.% Ga-doped in seeds. • The effects of ZnO seed layers on electron transport properties were investigated. • The enhancement performance of DSSCs contributed to higher dye loading and η{sub cc}. - Abstract: Zinc oxide (ZnO) nanorod arrays were grown on FTO substrates with a Ga-doped ZnO (GZO) seed layer by a hydrothermal method. GZO seed layers were obtained via sol–gel technology with Ga concentration in the range of 0–4 at.%. The dye sensitized solar cells (DSSCs) using ZnO nanorod arrays as the photoanode layers were prepared. The effect of Ga dopant concentrations in ZnO seed layer on the morphology features of ZnO nanorod arrays and the performance of DSSCs were systematically investigated. Results indicate that the average diameter and density of ZnO nanorod arrays decrease with increasing Ga concentration, but their length shows an opposite trend. The photocurrent density–voltage (J–V) characteristics reveal that the DSSCs with GZO seed layer exhibit significantly improved photovoltaic performance. In particular, the highest energy conversion efficiency (η) of 1.23% can be achieved in a DSSC with 3 at.% Ga doping, which is increased by 86.36% compared with that of the undoped DSSC. The external quantum efficiency (EQE) spectra and electrochemical impedance spectroscopy (EIS) were employed to explore the photon-to-electron conversion process in DSSCs. It is demonstrated that the performance enhancement of DSSCs based on GZO seed layer can be attributed to higher amount of dye loading, more efficient electron transportation and better electrons collection efficiency.

  8. Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

    International Nuclear Information System (INIS)

    Dou, Yuanyao; Wu, Fang; Mao, Caiying; Fang, Liang; Guo, Shengchun; Zhou, Miao

    2015-01-01

    Highlights: • ZnO nanorods were grown on Ga-doped ZnO seed layers using hydrothermal method. • Using the ZnO nanorods as photoanodes for fabricated dye-sensitized solar cells. • The highest η of 1.23% can be achieved in a DSSC with 3 at.% Ga-doped in seeds. • The effects of ZnO seed layers on electron transport properties were investigated. • The enhancement performance of DSSCs contributed to higher dye loading and η cc . - Abstract: Zinc oxide (ZnO) nanorod arrays were grown on FTO substrates with a Ga-doped ZnO (GZO) seed layer by a hydrothermal method. GZO seed layers were obtained via sol–gel technology with Ga concentration in the range of 0–4 at.%. The dye sensitized solar cells (DSSCs) using ZnO nanorod arrays as the photoanode layers were prepared. The effect of Ga dopant concentrations in ZnO seed layer on the morphology features of ZnO nanorod arrays and the performance of DSSCs were systematically investigated. Results indicate that the average diameter and density of ZnO nanorod arrays decrease with increasing Ga concentration, but their length shows an opposite trend. The photocurrent density–voltage (J–V) characteristics reveal that the DSSCs with GZO seed layer exhibit significantly improved photovoltaic performance. In particular, the highest energy conversion efficiency (η) of 1.23% can be achieved in a DSSC with 3 at.% Ga doping, which is increased by 86.36% compared with that of the undoped DSSC. The external quantum efficiency (EQE) spectra and electrochemical impedance spectroscopy (EIS) were employed to explore the photon-to-electron conversion process in DSSCs. It is demonstrated that the performance enhancement of DSSCs based on GZO seed layer can be attributed to higher amount of dye loading, more efficient electron transportation and better electrons collection efficiency

  9. Identifying the influence of the intrinsic defects in Gd-doped ZnO thin-films

    KAUST Repository

    Flemban, Tahani H.

    2016-02-08

    Gd-doped ZnO thin films were prepared using pulsed laser deposition at different oxygen pressures and varied Gd concentrations. The effects of oxygen deficiency-related defects on the Gd incorporation, optical and structural properties, were explored by studying the impact of oxygen pressure during deposition and post-growth thermal annealing in vacuum. Rutherford Backscattering Spectrometry revealed that the Gd concentration increases with increasing oxygen pressure for samples grown with the same Gd-doped ZnO target. Unexpectedly, the c-lattice parameter of the samples tends to decrease with increasing Gd concentration, suggesting that Gd-defect complexes play an important role in the structural properties. Using low-temperature photoluminescence(PL), Raman measurements and density functional theory calculations, we identified oxygen vacancies as the dominant intrinsic point defects. PL spectra show a defect band related to oxygen vacancies for samples grown at oxygen deficiency.

  10. Plasma-free nitrogen doping and homojunction light-emitting diodes based on ZnO

    International Nuclear Information System (INIS)

    Zeng, Y J; Ye, Z Z; Lu, Y F; Xu, W Z; Zhu, L P; Huang, J Y; He, H P; Zhao, B H

    2008-01-01

    The authors develop a plasma-free metalorganic chemical vapour deposition method to grow N-doped p-type ZnO films. The incorporation of the N acceptor and the corresponding change in the Fermi level are well confirmed by x-ray photoelectron spectroscopy. Temperature-dependent photoluminescence reveals the acceptor-related emissions, namely, neutral acceptor-bound exciton and probably donor-acceptor pair transition. In addition, typical rectifying I-V characteristics and room-temperature electroluminescence from ZnO homojunction light-emitting diodes are demonstrated

  11. Preparation of ZnO nanoribbon–MWCNT composite film and its ...

    Indian Academy of Sciences (India)

    2017-07-28

    Jul 28, 2017 ... activity of ciprofloxacin in the presence of ZnO nanopar- ticles. Previous studies suggest that treatment of bacteria with ZnO nanoparticles causes changes in the cell mem- brane morphology, increasing its permeability and affecting the transport through the plasma membrane. This leaves the bacterial cells ...

  12. The electrical, elemental, optical, and surface properties of Si-doped ZnO thin films prepared by thermionic vacuum arc

    Science.gov (United States)

    Mohammadigharehbagh, Reza; Özen, Soner; Yudar, Hafizittin Hakan; Pat, Suat; Korkmaz, Şadan

    2017-09-01

    The purpose of this work is to study the properties of Si-doped ZnO (SZO) thin films, which were prepared using the non-reactive thermionic vacuum arc technique. The analysis of the elemental, optical, and surface properties of ZnO:Si thin films was carried out using energy dispersive x-ray spectroscopy, UV-VIS spectrophotometry, atomic force microscopy, and scanning electron microscopy, respectively. The current-voltage measurement was employed in order to study the electrical properties of the films. The effect of Si doping on the physical properties of ZnO films was investigated. The film thicknesses were measured as 55 and 35 nm for glass and PET substrates, respectively. It was clearly observed from the x-ray diffraction results that the Si and ZnO peaks were present in the coated SZO films for all samples. The morphological studies showed that the deposited surfaces are homogenous, dense, and have a uniform surface, with the existence of some cracks only on the glass substrate. The elemental composition has confirmed the existence of Zn, Si, and O elements within the prepared films. Using a UV-VIS spectrophotometer, the optical parameters such as transmittance, absorbance, refractive index, and reflectance were calculated. It should be noted that the transparency and refractive indices obtained from the measurements decrease with increasing Si concentration. The obtained optical bandgap values using transmittance spectra were determined to be 3.74 and 3.84 eV for the glass and PET substrates, respectively. An increase in the bandgap results demonstrates that the Si doping concentration is comparable to the pure ZnO thin films. The current versus voltage curves revealed the ohmic nature of the films. Subsequently, the development and fabrication of excellent transparent conducting electrodes enabled the appropriate use of Si-doped ZnO thin films.

  13. Effects of PLA Film Incorporated with ZnO Nanoparticle on the Quality Attributes of Fresh-Cut Apple.

    Science.gov (United States)

    Li, Wenhui; Li, Lin; Cao, Yun; Lan, Tianqing; Chen, Haiyan; Qin, Yuyue

    2017-07-31

    A novel nanopackaging film was synthesized by incorporating ZnO nanoparticles into a poly-lactic acid (PLA) matrix, and its effect on the quality of fresh-cut apple during the period of preservation was investigated at 4 ± 1 °C for 14 days. Six wt % cinnamaldehyde was added into the nano-blend film. Scanning electron microscope (SEM) analysis showed a rougher cross-section of the nano-blend films and an X-ray diffraction (XRD) was carried out to determine the structure of the ZnO nanoparticles. Compared to the pure PLA film, the nano-blend film had a higher water vapor permeability (WVP) and lower oxygen permeability. With the increase of the nanoparticles (NPs) in the PLA, the elongation at break (ε) and elastic modulus (EM) increased, while tensile strength (TS) decreased. Thermogravimetric analysis (TGA) presented a relatively good thermostability. Most importantly, the physical and biochemical properties of the fresh-cut apple were also measured, such as weight loss, firmness, polyphenol oxidase (PPO), total phenolic content, browning index (BI), sensory quality, and microbiological level. The results indicated that nano-blend packaging films had the highest weight loss at the end of storage compared to the pure PLA film; however, nanopackaging provided a better retention of firmness, total phenolic countent, color, and sensory quality. It also had a remarkable inhibition on the growth of microorganisms. Therefore, Nano-ZnO active packaging could be used to improve the shelf-life of fresh-cut produce.

  14. Self-compensation in ZnO thin films: An insight from X-ray photoelectron spectroscopy, Raman spectroscopy and time-of-flight secondary ion mass spectroscopy analyses

    International Nuclear Information System (INIS)

    Saw, K.G.; Ibrahim, K.; Lim, Y.T.; Chai, M.K.

    2007-01-01

    As-grown ZnO typically exhibits n-type conductivity and the difficulty of synthesizing p-type ZnO for the realization of ZnO-based optoelectronic devices is mainly due to the compensation effect of a large background n-type carrier concentration. The cause of this self-compensation effect has not been conclusively identified although oxygen vacancies, zinc interstitials and hydrogen have been suggested. In this work, typical n-type ZnO thin films were prepared by sputtering and investigated using X-ray photoelectron spectroscopy, Raman spectroscopy and time-of-flight secondary ion mass spectroscopy to gain an insight on the possible cause of the self-compensation effect. The analyses found that the native defect that most likely behaved as the donor was zinc interstitial but some contribution of n-type conductivity could also come from the electronegative carbonates or hydrogen carbonates incorporated in the ZnO thin films

  15. Effect of disorder on carrier transport in ZnO thin films grown by atomic layer deposition at different temperatures

    Science.gov (United States)

    Saha, D.; Das, Amit. K.; Ajimsha, R. S.; Misra, P.; Kukreja, L. M.

    2013-07-01

    We have grown ˜200 nm thick ZnO films on (0001) sapphire substrates using atomic layer deposition at different substrate temperatures ranging from ˜150 to 350 °C. X-ray diffraction and photoluminescence spectra of these films showed that crystalline and compositional native defects were strongly dependent on the substrate temperature. Room temperature Hall measurement showed that all the films were degenerate with carrier concentration exceeding the Mott's critical density nc required for metallic conduction. The lowest value of room temperature resistivity ˜3.6 × 10-3 Ω cm was achieved for the film deposited at ˜200 °C, which had an estimated carrier concentration ˜5.7 × 1019 cm-3 and mobility ˜30 cm2/V s. The films deposited both below and above ˜200 °C showed increased resistivity and decreased mobility presumably due to the intensified defects and deteriorated crystalline quality of these films. To investigate the effect of disorder on the underlying charge transport mechanisms in these films, the electrical resistivity was measured in the temperature range of ˜4.2 to 300 K. The films grown at ˜150, 300, and 350 °C were found to be semiconducting in the entire range of the measurement temperature due to the intensified disorder which impeded the metallic transport in these films. However, the films grown at ˜200 and 250 °C showed a transition from metallic to semiconducting transport behaviour at lower temperatures due to the reduced defects and improved crystalline quality of these films. The observed semiconducting behaviour below the transition temperature for these films could be well explained by considering quantum corrections to the Boltzmann conductivity which includes the effect of disorder induced weak localization and coulomb electron-electron interactions.

  16. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    International Nuclear Information System (INIS)

    Zebbar, N.; Chabane, L.; Gabouze, N.; Kechouane, M.; Trari, M.; Aida, M.S.; Belhousse, S.; Hadj Larbi, F.

    2016-01-01

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10 −2 to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  17. UV and visible photoluminescence emission intensity of undoped and In-doped ZnO thin film and photoresponsivity of ZnO:In/Si hetero-junction

    Energy Technology Data Exchange (ETDEWEB)

    Zebbar, N., E-mail: nacbar2003@yahoo.fr [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Chabane, L. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Gabouze, N. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Kechouane, M. [LCMS, Faculty of Physics, University of Sciences and Technology (USTHB), BP 32, El-Alia, Algiers (Algeria); Trari, M. [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, El-Alia, Algiers (Algeria); Aida, M.S. [LCM et Interface, Faculty of Sciences, University of Constantine, 25000 (Algeria); Belhousse, S. [CRTSE, 02 Bd. Frantz Fanon, BP 140, Algiers (Algeria); Hadj Larbi, F. [MEMS & Sensors, Division Microélectronique et Nanotechnologie, Centre de Développement des Technologies Avancées (CDTA), BP 17, Baba Hassen, Algiers (Algeria)

    2016-04-30

    Undoped zinc oxide (ZnO) and indium-doped (ZnO:In) thin films were grown at different temperatures (250–400 °C) on alkali-free borosilicate glass and n-Si (100) substrates by Ultrasonic Spray Pyrolysis method. The structural, compositional, optical and electrical properties of ZnO films were investigated by X-ray diffraction, Scanning Electron Microscopy, Rutherford Back Scattering Spectroscopy, Fourier Transform Infrared spectroscopy, photoluminescence (PL) and the four-point probe technique. The predominance of ultraviolet (UV) and blue emission intensities was found to be closely dependent on the resistivity of the film. The visible emission band (peaking at 432 nm) prevails for low film resistivity, ranging from 10{sup −2} to 1 Ω·cm. By contrast, for higher resistivity (> 1 Ω·cm), there is a predominance of the UV band (382 nm). The PL and photoresponsivity results of fabricated ZnO:In/n-Si(100) heterojunctions prepared at different temperatures are discussed. The maximum spectral response of the ZnO:8%In/Si heterojunction diode fabricated at 250 °C was about 80 mA/W at zero bias. The highlighted results are attractive for the optoelectronic applications. - Highlights: • Properties of ZnO thin films grown by Ultrasonic Spray Pyrolysis at 350 °C. • Photoluminescence emission intensity in undoped ZnO film: effect of the resistivity • Photoluminescence emission intensity of In-doped ZnO film is resistivity dependent. • The spectral response of ZnO:In/Si hetero-junction deposited in the range (250–400 °C)

  18. High rate (∼7 nm/s), atmospheric pressure deposition of ZnO front electrode for Cu(In,Ga)Se2 thin-film solar cells with efficiency beyond 15%

    NARCIS (Netherlands)

    Illiberi, A.; Grob, F.; Frijters, C.; Poodt, P.; Ramachandra, R.; Winands, H.; Simor, M.; Bolt, P.J.

    2013-01-01

    Undoped zinc oxide (ZnO) films have been grown on a moving glass substrate by plasma-enhanced chemical vapor deposition at atmospheric pressure. High deposition rates of ∼7 nm/s are achieved at low temperature (200°C) for a substrate speed from 20 to 60 mm/min. ZnO films are highly transparent in

  19. Room temperature analysis of dielectric function of ZnO-based thin film on fused quartz substrate

    International Nuclear Information System (INIS)

    Kurniawan, Robi; Sutjahja, Inge M.; Winata, Toto; Rusydi, Andrivo; Darma, Yudi

    2015-01-01

    A set of sample consist of pure ZnO and Cu-doped ZnO film were grown on fused-quartz substrates using pulsed laser deposition (PLD) technique. Here, we report room temperature spectroscopic ellipsometry analysis (covering energy range of 0.5 to 6.3 eV) of pure ZnO film and Cu doped ZnO film at 8 in at. %. The thickness of pure ZnO and Cu-doped ZnO film using in this study is about 350 nm. To extract the dielectric function of ZnO thin film, multilayer modeling is performed which takes into account reflections at each interface through Fresnel coefficients. This method based on Drude-Lorentz models that connect with Kramers-Kronig relations. The best fitting of Ψ (amplitude ratio) and Δ (phase difference) taken by SE measurement are obtained reasonably well by mean the universal fitting of three different photon incident angles. The imaginary part of dielectric function (ε 2 ) show the broad peak at around 3.3 eV assigned as combination of optical band energy edge with excitonic states. The exitonic states could not be observed clearly in this stage. The evolution of extracted dielectric function is observable by introducing 8% Cu as indicated by decreasing of excitonic intensity. This result indicates the screening of excitonic state. This study will bring us to have a good undestanding for the role of Cu impurities for ZnO thin films

  20. ZnO thin film characterization by X-ray reflectivity optimization using genetic algorithm and Fourier transformation

    International Nuclear Information System (INIS)

    Solookinejad, Ghahraman; Rozatian, Amir Sayid Hassan; Habibi, Mohammad Hossein

    2011-01-01

    Zinc oxide (ZnO) thin film was fabricated by sol-gel spin coating method on glass substrate. X-ray reflectivity (XRR) and its optimization have been used for characterization and extracting physical parameters of the film. Genetic algorithm (GA) has been applied for this optimization process. The model independent information was needed to establish data analyzing process for X-ray reflectivity before optimization process. Independent information was exploited from Fourier transform of Fresnel reflectivity normalized X-ray reflectivity. This Fourier transformation (Auto Correlation Function) yields thickness of each coated layer on substrate. This information is a keynote for constructing optimization process. Specular X-ray reflectivity optimization yields structural parameters such as thickness, roughness of surface and interface and electron density profile of the film. Acceptable agreement exists between results obtained from Fourier transformation and X-ray reflectivity fitting.

  1. Young's Modulus and Coefficient of Linear Thermal Expansion of ZnO Conductive and Transparent Ultra-Thin Films

    Directory of Open Access Journals (Sweden)

    Naoki Yamamoto

    2011-01-01

    Full Text Available A new technique for measuring Young's modulus of an ultra-thin film, with a thickness in the range of about 10 nm, was developed by combining an optical lever technique for measuring the residual stress and X-ray diffraction for measuring the strain in the film. The new technique was applied to analyze the mechanical properties of Ga-doped ZnO (GZO films, that have become the focus of significant attention as a substitute material for indium-tin-oxide transparent electrodes. Young's modulus of the as-deposited GZO films decreased with thickness; the values for 30 nm and 500 nm thick films were 205 GPa and 117 GPa, respectively. The coefficient of linear thermal expansion of the GZO films was measured using the new technique in combination with in-situ residual stress measurement during heat-cycle testing. GZO films with 30–100 nm thickness had a coefficient of linear thermal expansion in the range of 4.3 × 10−6 – 5.6 × 10−6 °C−1.

  2. On single doping and co-doping of spray pyrolysed ZnO films: Structural, electrical and optical characterisation

    International Nuclear Information System (INIS)

    Vimalkumar, T.V.; Poornima, N.; Jinesh, K.B.; Kartha, C. Sudha; Vijayakumar, K.P.

    2011-01-01

    In this paper we present studies on ZnO thin films (prepared using Chemical Spray pyrolysis (CSP) technique) doped in two different ways; in one set, 'single doping' using indium was done while in the second set, 'co-doping' using indium and fluorine was adopted. In the former case, effect of in-situ as well as ex-situ doping using In was analyzed. Structural (XRD studies), electrical (I-V measurements) and optical characterizations (through absorption, transmission and photoluminescence studies) of the films were done. XRD analysis showed that, for spray-deposited ZnO films, ex-situ doping using Indium resulted in preferred (0 0 2) plane orientation, while in-situ doping caused preferred orientation along (1 0 0), (0 0 2), (1 0 1) planes; however for higher percentage of in-situ doping, orientation of grains changed from (0 0 2) plane to (1 0 1) plane. The co-doped films had (0 0 2) and (1 0 1) planes. Lowest resistivity (2 x 10 -3 Ω cm) was achieved for the films, doped with 1% Indium through in-situ method. Photoluminescence (PL) emissions of ex-situ doped and co-doped samples had two peaks; one was the 'near band edge' emission (NBE) and the other was the 'blue-green' emission. But interestingly the PL emission of in-situ doped samples exhibited only the 'near band edge' emission. Optical band gap of the films increased with doping percentage, in all cases of doping.

  3. A study of Eu incorporated ZnO thin films: An application of Al/ZnO:Eu/p-Si heterojunction diode

    Energy Technology Data Exchange (ETDEWEB)

    Turgut, G. [Department of Basic Sciences, Faculty of Science, Erzurum Technical University, Erzurum, 25240 (Turkey); Duman, S., E-mail: sduman@atauni.edu.tr [Department of Physics, Faculty of Science, Ataturk University, Erzurum, 25240 (Turkey); Sonmez, E. [Department of Physics, Faculty of K.K. Education, Ataturk University, Erzurum, 25240 (Turkey); Ozcelik, F.S. [Department of Physics, Faculty of Science, Ataturk University, Erzurum, 25240 (Turkey)

    2016-04-15

    Highlights: • Eu incorporated ZnO thin films were grown by sol–gel spin coating. • The influence of Eu contribution on features of ZnO was investigated. • Al/ZnO:Eu/p-Si heterojunction diodes were also fabricated. • The diode parameters were calculated from I–V measurements. - Abstract: In present work, the pure and europium (Eu) incorporated zinc oxide (ZnO) thin films were deposited with sol-gel spin coating by using zinc acetate dehydrate and Eu (III) chloride salts. The coated films were examined by means of XRD, AFM and UV/VIS spectrophotometer. The ZnO hexagonal wurtzite nanoparticles with (002) preferential direction were observed for all films. The values of crystallite size, micro-strain and surface roughness continuously increased from 21 nm, 1.10 × 10{sup −3} and 2.43 nm to the values of 35.56 nm, 1.98 × 10{sup −3} and 28.99 nm with Eu doping, respectively. The optical band gap value of the pure ZnO initially increased from 3.296 eV to 3.328 eV with Eu doping up to 2 at.% doping level, then it started to decrease with more Eu content. The electrical features of Al/n-ZnO:Eu/p-Si heterojunction diodes were inquired by current-voltage (I–V) measurements at the room temperature.

  4. Resistive switching: An investigation of the bipolar–unipolar transition in Co-doped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Daniel A.A., E-mail: danielandrade.ufs@gmail.com [Department of Physics, Federal University of Sergipe, São Cristóvão 49100-000 (Brazil); Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Zeng, Hao [Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Macêdo, Marcelo A. [Department of Physics, Federal University of Sergipe, São Cristóvão 49100-000 (Brazil)

    2015-06-15

    Highlights: • A purely bipolar behavior on a Co-doped ZnO thin film has been demonstrated. • We have shown what can happen if a unipolar test is performed in a purely bipolar device. • An explanation for how a sample can show a purely bipolar switching behavior was suggested. • An important open issue about resistive switching effect was put in debate. - Abstract: In order to investigate the resistive switching effect we built devices in a planar structure in which two Al contacts were deposited on the top of the film and separated by a small gap using a shadow mask. Therefore, two samples of 10% Co-doped ZnO thin films were sputtered on glass substrate. High resolution X-ray diffraction (HRXRD) revealed a highly c-axis oriented crystalline structure, without secondary phase. The high resolution scanning electron microscopy (HRSEM) showed a flat surface with good coverage and thickness about 300 nm. A Keithley 2425 semiconductor characterization system was used to perform the resistive switching tests in the bipolar and unipolar modes. Considering only the effect of compliance current (CC), the devices showed a purely bipolar behavior since an increase in CC did not induce a transition to unipolar behavior.

  5. Study on the enhanced and stable field emission behavior of a novel electrosprayed Al-doped ZnO bilayer film

    KAUST Repository

    Mahmood, Khalid

    2014-01-01

    A novel electrosprayed bilayer film composed of an over-layer (L 2) of aluminium-doped ZnO (AZO) nanoflakes (NF-AZO) and a under-layer (L1) of AZO nanocrystallites structure (NC-AZO) named BL:NF/NC-AZO is studied as an excellent field-emitter. The XRD pattern demonstrated that the doped bilayer film has preferential growth along the c-axis with hexagonal wurtzite structure and the (0 0 2) peak shifted toward the larger angle side after doping. The lowest turn-on field of ∼2.8 V μm-1, highest emission current density of 1.95 mA cm-2 is obtained for BL:NF/NC-AZO under the field of 6.8 V μm-1 and as well as the highest field enhancement factor (β) is estimated to be 4370 ± 3, compared to pure ZnO bilayer film (BL:NF/NC-ZnO) and also better than NC-AZO film and possesses the excellent long term stability of emission current. The PL intensity of doped ZnO bilayer film is very much stronger than pure ZnO bilayer structure. The superior field emission properties are attributed to the better morphologies, Al-doping and better crystallinity of bilayer AZO films. © 2014 The Royal Society of Chemistry.

  6. Influence of Mg content on tailoring optical bandgap of Mg-doped ZnO thin film prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    M.N.H. Mia

    Full Text Available Tailoring optical bandgap of ZnO nanostructured thin films doped with different elements facilitates potential material for photonic applications. Different methods of fabrication process result in different optical and structural properties for the same amount of Mg content. Therefore, details investigation of structural and optical parameters, and their correlation need to be revealed to utilize the fabricated thin films. In this work, Mg-doped ZnO thin film of 200 nm thickness was fabricated by sol-gel spin coating method on a glass substrate for four different Mg content levels. Multiple layers were deposited by a spin coater to increase the film thickness. The prepared thin films were characterized by SEM, XRD, EDS, and UV–Vis spectroscopy. The spectroscopic analysis showed a uniform crystalline nanostructured surface with less structural defects, enhanced transmittance, and higher optical bandgap than that of pure ZnO nanostructured thin film. Change of Mg content from 2% to 8% facilitated tuning of bandgap in the range of 3.30–3.39 eV. Changing trend of structural and optical parameters with Mg content showed non-linear, non-monotonic relation. In-depth analysis of structural and optical properties provides crucial information to form a better view about bandgap dependency on structural parameters. Keywords: Mg-doped ZnO, MgZnO, Bandgap tuning, Sol-gel, Spin coating

  7. Different defect levels configurations between double layers of nanorods and film in ZnO grown on c-Al2O3 by MOCVD

    International Nuclear Information System (INIS)

    Wu, Bin; Zhang, Yuantao; Shi, Zhifeng; Li, Xiang; Cui, Xijun; Zhuang, Shiwei; Zhang, Baolin; Du, Guotong

    2014-01-01

    Epitaxial ZnO structures with inherent two layers of nanorods layer on film layer were fabricated on c-Al 2 O 3 by metal-organic chemical vapor deposition (MOCVD) and studied by photoluminescence. Specially, photoluminescence spectra for the film layer were obtained by rendering the excitation from the substrate side. Different defect levels configurations between nanorods and film were revealed. Zinc vacancies tend to form in top nanorods layer, whereas abundant zinc–oxygen divacancies accumulate in bottom film layer. An acceptor state with activation energy of ∼200 meV is exclusive to the film layer. The stacking fault related acceptor and Al introduced donor are present in both layers. Besides, two other defect related donors contained in the nanorods layer perhaps also exist within the film layer. - Highlights: • Inherent double layer ZnO of nanorods on film layer were studied by PL. • V Zn tend to form in the nanorods layer, and V ZnO accumulate in the film layer. • An acceptor with activation energy of ∼200 meV is exclusive to the film layer. • Pure NBE emission without DLE in RT PL spectrum does not mean good crystallinity

  8. Structural and optical properties of DC magnetron sputtered ZnO films on glass substrate and their modification by Ag ions implantation

    Science.gov (United States)

    Ahmad, R.; Afzal, Naveed; Amjad, U.; Jabbar, S.; Hussain, T.; Hussnain, A.

    2017-07-01

    This work is focused on investigating the effects of deposition time and Ag ions implantation on structural and optical properties of ZnO film. The ZnO film was prepared on glass substrate by pulsed DC magnetron sputtering of pure Zn target in reactive oxygen environment for 2 h, 3 h, 4 h and 5 h respectively. X-ray diffraction results revealed polycrystalline ZnO film whose crystallinity was improved with increase of the deposition time. The morphological features indicated agglomeration of smaller grains into larger ones by increasing the deposition time. The UV-vis spectroscopy analysis depicted a small decrease in the band gap of ZnO from 3.36 eV to 3.27 eV with increase of deposition time. The Ag ions implantation in ZnO films deposited for 5 h on glass was carried out by using Pelletron Accelerator at different ions fluences ranging from 1  ×  1011 ions cm-2 to 2  ×  1012 ions cm-2. XRD patterns of Ag ions implanted ZnO did not show significant change in crystallite size by increasing ions fluence from 1  ×  1011 ions cm-2 to 5  ×  1011 ions cm-2. However, with further increase of the ions fluence, the crystallite size was decreased. The band gap of Ag ions implanted ZnO indicated anomalous variations with increase of the ions fluence.

  9. The Effect of Tin Addition to ZnO Nanosheet Thin Films for Ethanol and Isopropyl Alcohol Sensor Applications

    Directory of Open Access Journals (Sweden)

    Brian Yuliarto

    2015-01-01

    Full Text Available The requirements of green environmental and public health monitoring have become stricter along with greater world attention for global warming. The most common pollutants in the environment that need tightened control are volatile organic compounds (VOC. Compared to other kinds of sensors, semiconductor sensors have certain advantages, including high sensitivity, fast response, simplicity, high reliability and low cost. In this work, ZnO and Sn-doped ZnO nanostructure materials with high surface nanosheet areas were synthesized using chemical bath deposition. The X-ray diffraction patterns could be indexed according to crystallinity mainly to a hexagonal wurzite ZnO structure. The scanning electron microscopy (SEM results showed that in all samples, the thin films after the addition of Sn consisted of many kinds of microstructure patterns on a nanoscale, with various sheet shapes. The sensor performance characterizations showed that VOC levels as low as 3 vol% of isopropyl alcohol (IPA and ethanol could be detected at sensitivities of 83.86% and 85.57%, respectively. The highest sensitivity of all sensors was found at an Sn doping of 1.4 at%. This high sensor sensitivity is a result of the high surface area and Sn doping, which in turn produced a higher absorption of the targeted gas.

  10. Study on silver doped and undoped ZnO thin films working as capacitive sensor

    Science.gov (United States)

    Kiran, S.; Kumar, N. Santhosh; Kumar, S. K. Naveen

    2013-06-01

    Nanomaterials have been found to exhibit interesting properties like good conductivity, piezoelectricity, high band gap etc. among those metal oxide family, Zinc Oxide has become a material of interest among scientific community. In this paper, we present a method of fabricating capacitive sensors, in which Silver doped ZnO and pure ZnO nanoparticles act as active layer. For the synthesis of the nanoparticle, we followed biosynthesis method and wet chemical method for Ag and Ag doped ZnO nanoparticles respectively. Characterization has been done for both the particles. The XRD pattern taken for the Ag Doped ZnO nanoparticles confirmed the average size of the particles to be 15nm. AFM image of the sample is taken by doping on Silicon wafer. Also we have presented the results of CV characteristics and IV characteristics of the capacitive sensor.

  11. Modelling the growth of ZnO thin films by PVD methods and the effects of post-annealing.

    Science.gov (United States)

    Blackwell, Sabrina; Smith, Roger; Kenny, Steven D; Walls, John M; Sanz-Navarro, Carlos F

    2013-04-03

    Results are presented for modelling of the evaporation and magnetron sputter deposition of Zn(x)O(y) onto an O-terminated ZnO (0001¯) wurtzite surface. Growth was simulated through a combination of molecular dynamics (MD) and an on-the-fly kinetic Monte Carlo (otf-KMC) method, which finds diffusion pathways and barriers without prior knowledge of transitions. We examine the effects of varying experimental parameters, such as substrate bias, distribution of the deposition species and annealing temperature. It was found when comparing evaporation and sputtering growth that the latter process results in a denser and more crystalline structure, due to the higher deposition energy of the arriving species. The evaporation growth also exhibits more stacking faults than the sputtered growth. Post-annealing at 770 K did not allow complete recrystallization, resulting in films which still had stacking faults where monolayers formed in the zinc blende phase, whereas annealing at 920 K enabled the complete recrystallization of some films to the wurtzite structure. At the latter temperature atoms could also sometimes be locked in the zinc blende phase after annealing. When full recrystallization did not take place, both wurtzite and zinc blende phases were seen in the same layer, resulting in a phase boundary. Investigation of the various distributions of deposition species showed that, during evaporation, the best quality film resulted from a stoichiometric distribution where only ZnO clusters were deposited. During sputtering, however, the best quality film resulted from a slightly O rich distribution. Two stoichiometric distributions, one involving mainly ZnO clusters and the other involving mainly single species, showed that the distribution of deposition species makes a huge impact on the grown film. The deposition of predominantly single species causes many more O atoms at the surface to be sputtered or reflected, resulting in an O deficiency of up to 18% in the

  12. Flexible ZnO nanorod-based piezoelectric nanogenerators on carbon papers

    Science.gov (United States)

    Banna, G. M. Hasan Ul; Park, Il-Kyu

    2017-11-01

    We report on the fabrication of ZnO nanorod (NR)-based flexible piezoelectric nanogenerators (PENGs) on carbon paper (CP). Structural investigations indicate that the ZnO NRs grew well along the porous CP surface. Optical investigation shows that the crystal quality of the ZnO NRs on the CP was comparable to that of NRs grown on Si substrate. As the molar concentration increased from 10-70 mM, the output voltage and current increased consistently from 3.6-6.8 V and 0.79-1.45 μA, respectively. The enhancements of the voltage and current were attributed to the enhanced accumulation of the potentials generated by the increased number of ZnO NRs in the PENG devices. Therefore, the porous CP enhanced the PENG performance due to the higher surface area, and provided a super-flexible self-powering platform.

  13. Sol-gel synthesis of ZnO transparent conductive films: The role of pH

    Science.gov (United States)

    Addonizio, Maria Luisa; Aronne, Antonio; Daliento, Santolo; Tari, Orlando; Fanelli, Esther; Pernice, Pasquale

    2014-06-01

    The sol-gel synthesis of undoped and B- or Al-doped ZnO thin films were critically examined with particular reference to the influence of the pH of the reaction medium on some of their specific characteristics, such as thickness, morphology, doping level and optical properties, in view of their application in the photovoltaic field. Using triethanolamine (TEA) as chelating agent, a range of basic pH from 7.66 to 8.76 was explored starting from a very concentrated zinc acetate dehydrate (ZAD) solution in ethanol, [Zn2+] = 1.0 M, and keeping the ZAD/TEA = 1. A more basic environment gives more porous films whose thickness and crystallinity are higher than those achieved at lower pH. It was found that the morphology, as well as the sheet resistance (Rs) of films, depends on both pH and doping. Increasing the pH the Rs decreases for both undoped and doped films. At a certain pH undoped films exhibit a granular microstructure and lower Rs than B- or Al-doped films which exhibit a finer texture, characterized by a lower porosity. Optical properties strongly depend on the pH as well. Increasing the pH, a noticeable blue shift effect was observed, that was attributed mainly to structural changes and to a lesser extent to the Burnstein-Moss effect.

  14. Correlation between electrical transport, microstructure and room temperature ferromagnetism in 200 keV Ni{sup 2+} ion implanted zinc oxide (ZnO) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, B. [Gautam Buddha University, Department of Applied Sciences, Greater Noida (India); Ghosh, S.; Srivastava, P. [Indian Institute of Technology Delhi, Nanostech Laboratory, New Delhi (India); Kumar, P.; Kanjilal, D. [Aruna Asaf Ali Marg, Inter University Accelerator Centre, New Delhi (India)

    2012-05-15

    We report variable temperature resistivity measurements and mechanisms related to electrical conduction in 200 keV Ni{sup 2+} ion implanted ZnO thin films deposited by vapor phase transport. The dc electrical resistivity versus temperature curves show that all polycrystalline ZnO films are semiconducting in nature. In the room temperature range they exhibit band conduction and conduction due to thermionic emission of electrons from grain boundaries present in the polycrystalline films. In the low temperature range, nearest neighbor hopping (NNH) and variable range hopping (VRH) conduction are observed. The detailed conduction mechanism of these films and the effects of grain boundary (GB) barriers on the electrical conduction process are discussed. An attempt is made to correlate electrical conduction behavior and previously observed room temperature ferromagnetism of these films. (orig.)

  15. Influence of growth temperature on formation of continuous Ag thin film on ZnO surface by ultra-high vacuum deposition

    International Nuclear Information System (INIS)

    Zhang, T C; Mei, Z X; Guo, Y; Xue, Q K; Du, X L

    2009-01-01

    Growth of an Ag film on a ZnO (0 0 0 1) surface by ultra-high vacuum deposition has been investigated by field emission scanning electron microscopy. It is revealed that the growth temperature has a considerable effect on the formation of a continuous Ag thin film on a ZnO surface. At room temperature or above, the formation of continuous Ag films with small thickness was found to be difficult due to an upstepping mechanism, whereas a continuous Ag film as thin as 30 nm was achieved at 140 K, resulting from the reduced migration length of silver atoms and the increased saturated island density at low temperature. Coalescence between the islands occurred and predominated over upstepping during subsequent deposition, which is favourable for the formation of a continuous Ag film with a smaller thickness.

  16. Rectifying Behavior of Aligned ZnO Nano rods on Mg0.3Zn0.7O Thin Film Template

    International Nuclear Information System (INIS)

    Salina Muhamad; Suriani Abu Bakar; Mohamad Hafiz Mamat; Rafidah Ahmad; Mohamad Rusop

    2011-01-01

    Rectifying behavior more than 3 orders of aligned zinc oxide (ZnO) nano rods grown on Mg 0.3 Zn 0.7 O thin film template using chemical bath deposition method was observed, giving a barrier height of 0.75 eV, and the ideality factor achieved was almost 6, which was analyzed using thermionic emission theory. Field emission scanning electron microscope (FESEM) images revealed that the grown ZnO was in hexagonal shape, uniformly distributed and in vertically aligned form. The crystallinity of the sample being studied using X-ray diffraction (XRD), where the highest peak was found at (002) phase, confirming that high crystallinity of ZnO was attained. The effect of metal/semiconductor junction between metal and aligned ZnO nano rods was discussed in further details. (author)

  17. Solvent-assisted microstructural evolution and enhanced performance of porous ZnO films for plastic dye-sensitized solar cells

    Science.gov (United States)

    Ohashi, Hitomi; Hagiwara, Manabu; Fujihara, Shinobu

    2017-02-01

    A low-temperature process for fabricating porous ZnO films on plastic, indium tin oxide-coated polyethylene naphthalate substrates is developed for their use in dye-sensitized solar cells. A special attention is paid to modification of microscopic morphologies for enhancing interparticle connection. ZnO films having two kinds of macroscopic morphologies (flower-like particles and densely packed nanoparticles) are fabricated at temperatures below the heatproof temperature of the substrate, and subsequently immersed in mixed solvents composed of water and ethanol at 90 °C. The immersion leads to the growth of constituting ZnO particles and also the evolution of interparticle connection, depending on solvent compositions. The cell performance is largely improved especially in a short-circuit current density and a power conversion efficiency. The immersion effect is more remarkable for the cell using the densely packed ZnO film, with a 62% increase in the current density and an 84% increase in the conversion efficiency. In consequence, our plastic N719-sensitized ZnO cell shows the conversion efficiency as high as 4.1%.

  18. Photoelectrochemical properties of ZnO nanocrystals/MEH-PPV composite: The effects of nanocrystals synthetic route, film deposition and electrolyte composition

    Energy Technology Data Exchange (ETDEWEB)

    Petrella, A. [Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e Chimica, Politecnico di Bari, Via Orabona 4, 70125 Bari (Italy); Curri, M.L.; Striccoli, M. [CNR IPCF Sez. Bari c/o Dip. Chimica, Università di Bari, Via Orabona 4, 70126 Bari (Italy); Agostiano, A. [Dipartimento di Chimica, Università di Bari, via Orabona 4, 70126 Bari (Italy); CNR IPCF Sez. Bari c/o Dip. Chimica, Università di Bari, Via Orabona 4, 70126 Bari (Italy); Cosma, P., E-mail: pinalysa.cosma@uniba.it [Dipartimento di Chimica, Università di Bari, via Orabona 4, 70126 Bari (Italy); CNR IPCF Sez. Bari c/o Dip. Chimica, Università di Bari, Via Orabona 4, 70126 Bari (Italy)

    2015-11-30

    This paper reports a study on the photoelectrochemical processes occurring at the interface of ZnO nanocrystals/MEH-PPV composites. Colloidal chemical routes were used to obtain size controlled non-hydrolytic ZnO nanocrystals (NCs) dispersible in organic solvents, while a low molecular weight poly[2-methoxy-5-(2′-ethyl-hexyloxy)phenylene vinylene] (MEH-PPV), characterized by high degree of structural order, was synthesized via an organometallic method. The optical properties of the nanocomposite material were comprehensively investigated on solution and on films deposited by spin coating. Remarkably, a significant fluorescence quenching of the polymer at the MEH-PPV/ZnO junction was observed. Photoelectrochemical measurements demonstrated that the photoactivity of the composite material was significantly improved in the case of non-hydrolytic NCs with respect to hydrolytic route prepared ZnO. Moreover, the effective role of the organic/inorganic blend to improve the charge transfer with respect to the double layer hetero-junction was confirmed, thanks to the extended interfaces which enable an effective electron transfer between the hetero-junction components. The system was also studied at different film thicknesses and electrolyte compositions. The results indicated that film photoactivity increased with film thickness up to 300 nm due to the presence of a large number of interfaces, while the change of cation size influenced the ionic conductivity through the nanocomposite film. It was shown that efficient photoconductivity requires not only efficient charge separation, but also efficient transport of the carriers to the electrodes without recombination. - Highlights: • The photoelectrochemical processes at ZnO nanocrystals/MEH-PPV hetero-junction were studied. • Fluorescence quenching of the polymer at the MEH-PPV/ZnO interface was observed. • Non-hydrolytic ZnO junction showed higher photocurrents than hydrolytic equivalent. • The blends showed

  19. Controlling the surface nanostructure of ZnO and Al-doped ZnO thin films using electrostatic spraying for their application in 12% efficient perovskite solar cells

    Science.gov (United States)

    Mahmood, Khalid; Swain, Bhabani Sankar; Jung, Hyun Suk

    2014-07-01

    In this paper, ZnO and Al-doped ZnO films were deposited using the electrospraying method and studied for the first time as photoanodes for efficient perovskite solar cells. Effects of substrate temperature, deposition time, applied voltage, substrate-to-nozzle distance and flow rate (droplet size) on the morphology of ZnO were studied with the help of FE-SEM images. The major factors such as the droplet size of the spray, substrate temperature and substrate-to-nozzle distance at deposition control the film morphology. Indeed, these factors determine the density of the film, its smoothness and the flow of solution over the substrate. The droplet size was controlled by the flow rate of the spray. The substrate-to-nozzle distance and flow rate will both regulate the solution amount deposited on the surface of the substrate. The most favorable conditions for a good quality ZnO thin film were a long substrate-to-nozzle distance and lower solution flow rates. In situ droplet size measurement shows that the size and dispersion of particles were narrowed. The method was shown to have a high deposition rate and efficiency relative to well-established thin film deposition techniques such as chemical and physical vapor deposition. In addition, it also allows easy control of the microstructure and stoichiometry of the deposits. The pure ZnO film produced under optimum conditions (440 nm thick) demonstrated a high power conversion efficiency (PCE) of 10.8% when used as a photoanode for perovskite solar cells, owing to its high porosity, uniform morphology and efficient electron transport. For thicker films a drastic decrease in PCE was observed due to their low porosity. We also observed that the open-circuit voltage increases from 1010 mV to 1045 mV and also the PCE increases from 10.8% to 12.0% when pure ZnO films were doped with aluminum (Al). Under atmospheric pressure, the electrospraying system produces the reasonably uniform-sized droplets of smaller size, so the films

  20. High Temperature Thermoelectric Properties of ZnO Based Materials

    DEFF Research Database (Denmark)

    Han, Li

    on the electron and phonon transport was analyzed and discussed in detail. In order to solve the problems of high thermal conductivity without the deterioration of electrical conductivity by nanostructuring for conventional ZnO materials, the doped ZnCdO material was proposed as a new n-type oxide thermoelectric...... material. The material is sintered in air in order to maintain the oxygen stoichiometry and avoid the stability issues. The successful alloying of CdO with ZnO at a molar ratio of 1:9 resulted in a significant reduction of thermal conductivity up to 7-fold at room temperature. By careful selection......O. Following that, the nanostructuring effect for Al-doped ZnO was systematically investigated using samples with different microstructure morphologies. At last, the newly developed ZnCdO materials with superior thermoelectric properties and thermal stability were introduced as promising substitutions...

  1. Effect of boric acid composition on the properties of ZnO thin film nanotubes and the performance of dye-sensitized solar cell (DSSC)

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, M.Y.A., E-mail: mohd.yusri@ukm.edu.my; Roza, L.; Umar, A.A., E-mail: akrajas@ukm.edu.my; Salleh, M.M.

    2015-11-05

    The effect of boric acid (H{sub 3}BO{sub 3}) composition at constant concentration of hexamethylenetetramine (HMT) and zinc nitrate (Zn(NO{sub 3}){sub 2}) on the morphology, thickness, elemental composition, optical absorption, structure, photoluminescence of ZnO nanotubes has been investigated. The performance of the DSSC utilizing the ZnO samples has also been studied. It was found that the structure, thickness, elemental composition, optical absorption and morphology of ZnO nanostructure are significantly affected by the concentration of H{sub 3}BO{sub 3}. The diameter and thickness of ZnO nanotubes decreases as the composition of H{sub 3}BO{sub 3} increases. The DSSC utilizing ZnO nanotubes synthesized at 2 wt. % H{sub 3}BO{sub 3} performs the highest J{sub SC} and η of 2.67 mA cm{sup −2} and 0.29%, respectively. The highest performance of the device is due to the highest optical absorption of ZnO nanotubes sample and lowest charge interfacial resistance. - Graphical abstract: Nyquist plots of the DSSCs utilizing ZnO nanotubes prepared at various boric acid compositions. - Highlights: • Boron was doped into ZnO films by adding H{sub 3}BO{sub 3} into the growth solution. • Diameter and thickness of ZnO nanotubes decreases with the composition of H{sub 3}BO{sub 3}. • The DSSC performs the highest J{sub SC} and η of 2.67 mA cm{sup −2} and 0.29%, respectively. • This is due to high specific surface area and low charge interfacial resistance.

  2. Electronic and atomic structure of complex defects in Al- and Ga-highly doped ZnO films

    International Nuclear Information System (INIS)

    Menéndez-Proupin, Eduardo; Palacios, Pablo; Wahnón, Perla

    2015-01-01

    Point defects in Ga- and Al-doped ZnO thin films are studied by means of first principles electronic structure calculations. Candidate defects are identified to explain recently observed differences in electrical and spectroscopic behavior of both systems. Substitutional doping in Ga–ZnO explain the metallic behavior of the electrical properties. Complexes of interstitial oxygen with substitutional Ga can behave as acceptor and cause partial compensation, as well as gap states below the conduction band minimum as observed in photoemission experiments. Zn vacancies can also act as compensating acceptors. On the other hand, the semiconducting behavior of Al–ZnO and the small variation in the optical gap compared with pure ZnO, can be explained by almost complete compensation between acceptor Zn vacancies and substitutional Al donors. Interstitial Al can also be donor levels and can be the origin of the small band observed in photoemission experiments below the Fermi level. Combinations of substitutional Al with interstitial oxygen can act simultaneously as compensating acceptor and generator of the mentioned photoemission band. The theoretical calculations have been done using density functional theory (DFT) within the generalized gradient approximation with on-site Coulomb interaction. In selected cases, DFT calculations with semilocal-exact exchange hybrid functionals have been performed. Results explain photoelectron spectra of Ga–ZnO and Al–ZnO at the corresponding doping levels. - Highlights: • Defects in Ga- and Al-heavy-doped ZnO films are studied by quantum calculations. • Defects compatible with electrical, optical, and HAXPES spectra are proposed. • Doping efficiency is reduced by Zn vacancies and O interstitials. • HAXPES bands near the Fermi level are induced by Al i , and complexes Ga Zn -O i , and Al Zn -O i

  3. Electronic and atomic structure of complex defects in Al- and Ga-highly doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Menéndez-Proupin, Eduardo [Instituto de Energía Solar, Universidad Politécnica de Madrid (UPM), Ciudad Universitaria, 28040 Madrid (Spain); Departamento de Física, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, 780-0003 Ñuñoa, Santiago (Chile); Palacios, Pablo, E-mail: pablo.palacios@upm.es [Instituto de Energía Solar, Universidad Politécnica de Madrid (UPM), Ciudad Universitaria, 28040 Madrid (Spain); Dpt. FAIAN, E.T.S.I. Aeronáutica y del Espacio, UPM, Pz. Cardenal Cisneros 3, 28040 Madrid (Spain); Wahnón, Perla [Instituto de Energía Solar, Universidad Politécnica de Madrid (UPM), Ciudad Universitaria, 28040 Madrid (Spain); Dpt. TFO, E.T.S.I. Telecomunicación, UPM, Ciudad Universitaria, 28040 Madrid (Spain)

    2015-06-15

    Point defects in Ga- and Al-doped ZnO thin films are studied by means of first principles electronic structure calculations. Candidate defects are identified to explain recently observed differences in electrical and spectroscopic behavior of both systems. Substitutional doping in Ga–ZnO explain the metallic behavior of the electrical properties. Complexes of interstitial oxygen with substitutional Ga can behave as acceptor and cause partial compensation, as well as gap states below the conduction band minimum as observed in photoemission experiments. Zn vacancies can also act as compensating acceptors. On the other hand, the semiconducting behavior of Al–ZnO and the small variation in the optical gap compared with pure ZnO, can be explained by almost complete compensation between acceptor Zn vacancies and substitutional Al donors. Interstitial Al can also be donor levels and can be the origin of the small band observed in photoemission experiments below the Fermi level. Combinations of substitutional Al with interstitial oxygen can act simultaneously as compensating acceptor and generator of the mentioned photoemission band. The theoretical calculations have been done using density functional theory (DFT) within the generalized gradient approximation with on-site Coulomb interaction. In selected cases, DFT calculations with semilocal-exact exchange hybrid functionals have been performed. Results explain photoelectron spectra of Ga–ZnO and Al–ZnO at the corresponding doping levels. - Highlights: • Defects in Ga- and Al-heavy-doped ZnO films are studied by quantum calculations. • Defects compatible with electrical, optical, and HAXPES spectra are proposed. • Doping efficiency is reduced by Zn vacancies and O interstitials. • HAXPES bands near the Fermi level are induced by Al{sub i}, and complexes Ga{sub Zn}-O{sub i}, and Al{sub Zn}-O{sub i}.

  4. Electrical, optical, and photoluminescence properties of ZnO films subjected to thermal annealing and treatment in hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Abdullin, Kh. A.; Gabdullin, M. T. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Gritsenko, L. V. [Kazakh National Technical Research University (Kazakhstan); Ismailov, D. V.; Kalkozova, Zh. K. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Kumekov, S. E., E-mail: skumekov@mail.ru; Mukash, Zh. O. [Kazakh National Technical Research University (Kazakhstan); Sazonov, A. Yu. [200 University Avenue West, University of Waterloo (Canada); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-08-15

    The photoluminescence and optical absorption spectra and electrical properties of ZnO films grown by the metal–organic chemical vapor deposition and hydrothermal techniques, subjected to heat treatments and plasma treatment in a hydrogen atmosphere, are studied. It is shown that the adsorption of oxygen at grain boundaries upon annealing in an oxidizing atmosphere determines the electrical properties of the films. Vacuum annealing improves the electrical properties of the samples after degradation induced by annealing in air. Treatment in hydrogen plasma passivates surface states at the grain boundaries. The intrinsic photoluminescence intensity after plasma treatment is higher in the case of increased amounts of oxygen adsorbed at grain surfaces upon annealing in air. Surface states involving oxygen and hydrogen atoms are responsible for the high-intensity intrinsic photoluminescence band.

  5. Effect of deposition conditions on the growth rate and electrical properties of ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Roro, K.T.; Botha, J.R.; Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)

    2008-07-01

    ZnO thin films have been grown on glass substrates by MOCVD. The effect of deposition conditions such as VI/II molar ratio, DEZn flow rate and total reactor pressure on the growth rate and electrical properties of the films was studied. It is found that the growth rate decreases with an increase in the VI/II molar ratio. This behaviour is ascribed to the competitive adsorption of reactant species on the growth surface. The growth rate increases with an increase in DEZn flow rate, as expected. It is shown that the carrier concentration is independent of the DEZn flow rate. An increase in the total reactor pressure yields a decrease in growth rate. This phenomenon is attributed to the depletion of the gas phase due to parasitic prereactions between zinc and oxygen species at high pressure. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Optical and structural properties of ZnO thin films; effects of high energy electron irradiation and annealing

    International Nuclear Information System (INIS)

    Guer, Emre; Asil, Hatice; Coskun, C.; Tuezemen, S.; Meral, Kadem; Onganer, Y.; Serifoglu, Korkmaz

    2008-01-01

    High energy electron irradiation (HEEI) effects on the as-grown and annealed ZnO thin films grown by electrochemical deposition were investigated. Both samples were exposed to the sequential electron irradiations of 6, 12 and 15 MeV energies at a fluence of 1 x 10 12 e - /cm 2 . The results of X-ray diffraction suggest that a highly strong crystallographic structure can be produced by annealing process. Photoluminescence (PL) studies show that the EI produces violet emission which results from the zinc interstitial. Recombination lifetime (RL) values of the both films reveal that the high quality crystals are obtained. The decreasing trends of RL values with increasing electron energy have been explained by the formation of crystal defects due to the HEEI

  7. Optical and structural properties of ZnO thin films; effects of high energy electron irradiation and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Guer, Emre; Asil, Hatice [Atatuerk University, Art and Science Faculty, Physics Department, 25240 Erzurum (Turkey); Coskun, C. [Atatuerk University, Art and Science Faculty, Physics Department, 25240 Erzurum (Turkey)], E-mail: ccoskun@atauni.edu.tr; Tuezemen, S. [Atatuerk University, Art and Science Faculty, Physics Department, 25240 Erzurum (Turkey); Meral, Kadem; Onganer, Y. [Atatuerk University, Art and Science Faculty, Chemistry Department, 25240 Erzurum (Turkey); Serifoglu, Korkmaz [Atatuerk University, Faculty of Medicine, Radiation Oncology Department, 25240 Erzurum (Turkey)

    2008-05-15

    High energy electron irradiation (HEEI) effects on the as-grown and annealed ZnO thin films grown by electrochemical deposition were investigated. Both samples were exposed to the sequential electron irradiations of 6, 12 and 15 MeV energies at a fluence of 1 x 10{sup 12} e{sup -}/cm{sup 2}. The results of X-ray diffraction suggest that a highly strong crystallographic structure can be produced by annealing process. Photoluminescence (PL) studies show that the EI produces violet emission which results from the zinc interstitial. Recombination lifetime (RL) values of the both films reveal that the high quality crystals are obtained. The decreasing trends of RL values with increasing electron energy have been explained by the formation of crystal defects due to the HEEI.

  8. Structural and magnetic properties of Co-doped ZnO thin films grown by ultrasonic spray pyrolysis method

    Science.gov (United States)

    Baghdad, R.; Lemée, N.; Lamura, G.; Zeinert, A.; Hadj-Zoubir, N.; Bousmaha, M.; Bezzerrouk, M. A.; Bouyanfif, H.; Allouche, B.; Zellama, K.

    2017-04-01

    Cobalt-doped ZnO thin films with several different percentage of Co from 0 up to 15 at% were synthesized via a cheap, simple and versatile method i.e. ultrasonic spray pyrolysis at atmospheric pressure and a substrate temperature of 350 °C. The structure of the as-prepared samples was characterized by X-ray diffraction (XRD), Raman spectroscopy and FTIR. The Co-doping effect is revealed by the presence of three additional peaks around 235, 470 and 538 cm-1 respect to the Raman spectra of the unsubstituted film. Fourier transform infrared spectroscopy (FTIR) put in evidence the decrease of the bond force constant f with increasing Co-doping. By ultra-violet visible near infrared (UV-Vis-NIR) spectroscopy on Co-doped samples it was possible to show the presence of additional absorption bands at approximately 570, 620 and 660 nm suggesting that Co2+ ions do not change their oxidation when substituted to zinc and the ZnO lattice does not change its wurtzite structure as well. Finally, all our samples exhibit a paramagnetic behavior without any trace of intrinsic room temperature ferromagnetism.

  9. Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

    Directory of Open Access Journals (Sweden)

    Q. Humayun

    2013-01-01

    Full Text Available ZnO thin films were deposited on patterned gold electrodes using the sol-gel spin coating technique. Conventional photolithography process was used to obtain the variable microgaps of 30 and 43 μm in butterfly topology by using zero-gap chrome mask. The structural, morphological, and electrical properties of the deposited thin films were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, and Keithley SourceMeter, respectively. The current-voltage (I-V characterization was performed to investigate the effect of UV light on the fabricated devices. The ZnO fabricated sensors showed a photo to dark current (Iph/Id ratios of 6.26 for 30 μm and 5.28 for 43 μm gap electrodes spacing, respectively. Dynamic responses of both fabricated sensors were observed till 1V with good reproducibility. At the applied voltage of 1 V, the response time was observed to be 4.817 s and 3.704 s while the recovery time was observed to be 0.3738 s and 0.2891 s for 30 and 43 μm gaps, respectively. The signal detection at low operating voltages suggested that the fabricated sensors could be used for miniaturized devices with low power consumption.

  10. Quantum size effect on ZnO nanoparticle-based discs synthesized by mechanical milling

    International Nuclear Information System (INIS)

    Sendi, Rabab Khalid; Mahmud, Shahrom

    2012-01-01

    Zinc oxide (ZnO) nanoparticles ranging ∼7-15 nm in size were successfully synthesized by the ball-milling technique. Mechanical milling was found very functional in producing ZnO nanoparticles with the possibility of obtaining large quantities. The milled nanoparticles were compared with commercial ZnO nanopowder. High-resolution scanning electron microscopy and atomic force microscopy analyses revealed a reduction in the lattice space and grain size with increased milling time, as well as severe lattice deformations in some of the nanoparticles. The milling process also had a significant effect on the grain crystallinity as illustrated by decreased lattice strain based on the X-ray diffraction lattice constant and full-wave at half-maximum data. The photoluminescence (PL) spectra of the ZnO powder showed a UV emission band at 380 nm with a visible PL emission in the green band peaking at 535 nm. The relative intensities of these peaks drastically changed with increased milling time due to the size quantization effect and surface defects (oxygen vacancies and zinc/oxygen interstitials) in the ZnO nanopowder. The Raman spectra of the ZnO powder indicated eight sets of optical phonon modes at the Γ point of the Brillouin zone, which red shifted and broadened with increased milling time. As the milling proceeded, clearly reduced grain size, homogenization, and other properties were observed.

  11. Quantum size effect on ZnO nanoparticle-based discs synthesized by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Sendi, Rabab Khalid, E-mail: Last-name3@hotmail.com [Nano Optoelectronic Research (NOR) Lab, School of Physics, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang (Malaysia); Mahmud, Shahrom [Nano Optoelectronic Research (NOR) Lab, School of Physics, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang (Malaysia)

    2012-08-01

    Zinc oxide (ZnO) nanoparticles ranging {approx}7-15 nm in size were successfully synthesized by the ball-milling technique. Mechanical milling was found very functional in producing ZnO nanoparticles with the possibility of obtaining large quantities. The milled nanoparticles were compared with commercial ZnO nanopowder. High-resolution scanning electron microscopy and atomic force microscopy analyses revealed a reduction in the lattice space and grain size with increased milling time, as well as severe lattice deformations in some of the nanoparticles. The milling process also had a significant effect on the grain crystallinity as illustrated by decreased lattice strain based on the X-ray diffraction lattice constant and full-wave at half-maximum data. The photoluminescence (PL) spectra of the ZnO powder showed a UV emission band at 380 nm with a visible PL emission in the green band peaking at 535 nm. The relative intensities of these peaks drastically changed with increased milling time due to the size quantization effect and surface defects (oxygen vacancies and zinc/oxygen interstitials) in the ZnO nanopowder. The Raman spectra of the ZnO powder indicated eight sets of optical phonon modes at the {Gamma} point of the Brillouin zone, which red shifted and broadened with increased milling time. As the milling proceeded, clearly reduced grain size, homogenization, and other properties were observed.

  12. Hybrid electroluminescent device based on MEH-PPV and ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Hewidy, Dina; Gadallah, A.-S.; Fattah, G. Abdel

    2017-02-15

    Hybrid organic/inorganic electroluminescent device based on the structure of glass/ITO/PEDOT:PSS/MEH-PPV/ZnO/ZnO submicrorods/Al has been manufactured. Spin coating has been used to deposit both PEDOT:PSS and MEH-PPV. Two-step process has been used to synthesis ZnO submicrorods, namely, spin coating and chemical bath deposition. Changing the dimensions of the ZnO submicrorods in this layer structure has been investigated to improve the performance of the organic/inorganic electroluminescence device. Such layer structure provides electroluminescence with narrow emission bands due to a high gain with this structure. X-ray diffraction patterns and scanning electron microscope images show that ZnO submicrorods have hexagon structure. Current-voltage curve for the structure has been reported. Electroluminescence curves (electroluminescence intensity versus wavelength) at different bias voltages have been presented and these results show narrowing in full width at half maximum in the spectra at high current density compared to photoluminescence excitation. The narrowing in the spectrum has been explained. - Highlights: • Manufacturing of MEH-PPV and ZnO electroluminescent device has been reported. • Spin coating and chemical bath deposition have been used for preparation of ZnO. • SEM images and X-ray diffraction of ZnO have been presented. • Current-voltage curves and electroluminescent measurements have been reported.

  13. Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

    Directory of Open Access Journals (Sweden)

    Abdel-Sattar Gadallah

    2013-01-01

    Full Text Available We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

  14. Influence of Different Annealing Conditions on Optical and Electrical Properties of Sn Doped ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    LIU Tao

    2017-08-01

    Full Text Available Sn doped ZnO thin films(SZO was prepared on glasses by sol-gel method.The influence of six kinds of annealing conditions,including air annealing,low vacuum annealing,high vacuum annealing,N2 annealing,triple high vacuum annealing,cycle annealing on the crystal structure, optical and electrical properties of the SZO film was studied.The results show that all the SZO samples show preferential orientation along the c-axis.The SZO thin films has the optimum crystal structure and electrical property on the high vacuum annealing conditions.The minimum resistivity of the film is 5.4×10-2Ω·cm.The average visible transmittance of SZO thin film is above 85%.The photoluminescence peaks at 390nm and 440nm is observed in all the samples (the excitation wavelength is set at 325nm.The intensity of the peak at 440nm is enhanced significantly on air annealing,N2 annealing and low vacuum annealing.

  15. Influence of Thickness on Ethanol Sensing Characteristics of Doctor-bladed Thick Film from Flame-made ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sukon Phanichphant

    2007-02-01

    Full Text Available ZnO nanoparticles were produced by flame spray pyrolysis (FSP using zincnaphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%. The particleproperties were analyzed by XRD, BET, and HR-TEM. The sensing films were produced bymixing the particles into an organic paste composed of terpineol and ethyl cellulose as avehicle binder and were fabricated by doctor-blade technique with various thicknesses (5,10, 15 μm. The morphology of the sensing films was analyzed by SEM and EDS analyses.The gas sensing characteristics to ethanol (25-250 ppm were evaluated as a function of filmthickness at 400°C in dry air. The relationship between thickness and ethanol sensingcharacteristics of ZnO thick film on Al2O3 substrate interdigitated with Au electrodes wereinvestigated. The effects of film thickness, as well as the cracking phenomenon, though,many cracks were observed for thicker sensing films. Crack widths increased withincreasing film thickness. The film thickness, cracking and ethanol concentration havesignificant effect on the sensing characteristics. The sensing characteristics with variousthicknesses were compared, showing the tendency of the sensitivity to ethanol decreasedwith increasing film thickness and response time. The relationship between gas sensingproperties and film thickness was discussed on the basis of diffusively and reactivity of thegases inside the oxide films. The thinnest sensing film (5 μm showed the highest sensitivityand the fastest response time (within seconds.

  16. Improvement of resistive switching in ZnO film by Ti doping

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongxia; Chen, Qi; Chen, Xueping [Lab of Electronic Materials and Devices, Hangzhou Dianzi University, Hangzhou 310018 (China); Mao, Qinan [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Xi, Junhua [Lab of Electronic Materials and Devices, Hangzhou Dianzi University, Hangzhou 310018 (China); State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Ji, Zhenguo, E-mail: jizg@hdu.edu.cn [Lab of Electronic Materials and Devices, Hangzhou Dianzi University, Hangzhou 310018 (China); State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

    2013-06-30

    Pt/ZnO:Ti/n{sup +}–Si structures that showed reversible and steady resistive switching behaviors were fabricated by magnetron sputtering. The stability of the devices was improved by Ti doping and the switching mechanism of the resistive switching was theoretically studied under the guidance of the first principles. The influences of different Ti atomic doping concentrations on the crystal structure and resistive switching characteristics were also investigated. The results revealed that the oxygen vacancy appears easily around the Ti ions since the formation energies of oxygen vacancies had the minimum value when it located at the next nearest neighboring to Ti atoms. - Highlights: • ZnO:Ti based resistive random access memories were fabricated. • Effects of doping concentrations on the switching characteristics were investigated. • Formation energies of oxygen vacancy in ZnO were studied by the first-principles. • The Pt/ZnO:Ti(2%)/n{sup +}–Si cell has the optimal resistive switching characteristics.

  17. Effect of thermal annealing on the optical and electronic properties of ZnO thin films grown on p-Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Han, W.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kang, S.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, T.W. [Advanced Semiconductor Research Center, Division of Electrical and Computer Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)]. E-mail: twk@hanyang.ac.kr; Kim, D.W. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Cho, W.J. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of)

    2005-05-30

    The effects of annealing on the optical and the electronics properties of ZnO thin films grown on p-Si(1 0 0) substrates by using radio frequency magnetron sputtering were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements. The XRD patterns and pole figures showed that the crystallinity of the ZnO films grown on p-Si(1 0 0) substrates was improved by thermal treatment. XRD patterns, pole figures, and TEM images showed that the as-grown and the annealed ZnO films grown on Si(1 0 0) substrates had a c-axis preferential orientation in the [0 0 0 1] crystal direction. The PL spectra showed that luminescence peaks related to the free excitons and the deep levels appeared after annealing. The XPS spectra showed that the peak positions corresponding to the O 1s and the Zn 2p shifted slightly after thermal treatment. These results can help improve understanding of thermal effects on the optical and the electronic properties of ZnO thin films grown on p-Si(1 0 0) substrates.

  18. Optimization of the Cathode Arc Plasma Deposition Processing Parameters of ZnO Film Using the Grey-Relational Taguchi Method

    Directory of Open Access Journals (Sweden)

    Shuo-Fu Hsu

    2014-01-01

    Full Text Available We deposited undoped ZnO films on the glass substrate at a low temperature (<70°C using cathode arc plasma deposition (CAPD and the grey-relational Taguchi method was used to determine the processing parameters of ZnO thin films. The Taguchi method with an L9 orthogonal array, signal-to-noise (S/N ratio, and analysis of variance (ANOVA is employed to investigate the performances in the deposition operations. The effect and optimization of deposition parameters, comprising the Ar : O2 gas flow ratio of 1 : 6, 1 : 8, and 1 : 10, the arc current of 50 A, 60 A, and 70 A, and the deposition time of 5 min, 10 min, and 15 min, on the electrical resistivity and optical transmittance of the ZnO films are studied. The results indicate that, by using the grey-relational Taguchi method, the optical transmittance of ZnO thin films increases from 88.17% to 88.82% and the electrical resistivity decreases from 5.12×10-3Ω-cm to 4.38×10-3Ω-cm, respectively.

  19. Orientation-dependent low field magnetic anomalies and room-temperature spintronic material – Mn doped ZnO films by aerosol spray pyrolysis

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-12-01

    Full Text Available High quality un-doped and Mn-doped ZnO films deposited by a simple aerosol spray pyrolysis technique for 20 and 30 min were studied using electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques...

  20. The influence of anatase-rutile mixed phase and ZnO blocking layer on dye-sensitized solar cells based on TiO2nanofiberphotoanodes

    Science.gov (United States)

    Ding, Jianning; Li, Yan; Hu, Hongwei; Bai, Li; Zhang, Shuai; Yuan, Ningyi

    2013-01-01

    High performance is expected in dye-sensitized solar cells (DSSCs) that utilize one-dimensional (1-D) TiO2 nanostructures owing to the effective electron transport. However, due to the low dye adsorption, mainly because of their smooth surfaces, 1-D TiO2 DSSCs show relatively lower efficiencies than nanoparticle-based ones. Herein, we demonstrate a very simple approach using thick TiO2 electrospun nanofiber films as photoanodes to obtain high conversion efficiency. To improve the performance of the DSCCs, anatase-rutile mixed-phase TiO2 nanofibers are achieved by increasing sintering temperature above 500°C, and very thin ZnO films are deposited by atomic layer deposition (ALD) method as blocking layers. With approximately 40-μm-thick mixed-phase (approximately 15.6 wt.% rutile) TiO2 nanofiber as photoanode and 15-nm-thick compact ZnO film as a blocking layer in DSSC, the photoelectric conversion efficiency and short-circuit current are measured as 8.01% and 17.3 mA cm-2, respectively. Intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy measurements reveal that extremely large electron diffusion length is the key point to support the usage of thick TiO2 nanofibers as photoanodes with very thin ZnO blocking layers to obtain high photocurrents and high conversion efficiencies.

  1. Influence of Al concentration and annealing temperature on structural, optical, and electrical properties of Al co-doped ZnO thin films

    International Nuclear Information System (INIS)

    Gürbüz, Osman; Kurt, İsmail; Çalışkan, Serkan; Güner, Sadık

    2015-01-01

    Highlights: • RF magnetron sputtering technique seems to be very efficient method for fabrication of Al doped ZnO (AZO) films. • Long range single crystalline structure improves with annealing process. • Optical properties became much better after annealing process especially for the AZO films that include high Al concentration. • Much greater conductivity with increasing Al concentration and annealing process. • AZO films have potential applicability in spintronic devices. - Abstract: The pure ZnO and Al-doped ZnO (AZO) thin films (thickness: 200 nm) were prepared on both side polished silica (SiO 2 ) substrates via RF magnetron sputtering at room temperature by using 2.5 inches high-purity ZnO (99.9%) and Al (99.9%) targets. The samples were annealed at 300 °C, 400 °C and 500 °C for 45 min in N 2 ambient in quartz annealing furnace system, respectively. We investigated the effects of various Al concentrations and annealing treatment on the structural, electrical, and optical properties of films. The preferred crystallization was observed along c axis (single (0 0 2) diffraction peak) from substrate surface assigning the single crystalline Würtzite lattice for pure ZnO and AZO thin films. Although increasing Al concentration decreases the order of crystallization of as-grown films, annealing process increases the long range crystal order. The crystallite sizes vary between minimum 12.98 nm and maximum 20.79 nm for as-grown and annealed samples. The crystallite sizes decrease with increasing Al concentration but increase with increasing annealing temperature as general trend. The grain size and porosity of films change with annealing treatment. The smaller grains coalesce together to form larger grains for many films. However, a reverse behavior is seen for Al 2.23 ZnO and Al 12.30 ZnO samples. That is, Al concentration plays critical role as well as temperature on grain size. Low percent optical transmittance (T%) is observed due to higher Al

  2. Fabrication of undoped ZnO thin film via photosensitive sol–gel method and its applications for an electron transport layer of organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Luong, Chi Hieu [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Kim, Sarah [Central Research Division, LG Chem., Yuseong-gu, Daejeon 305-738 (Korea, Republic of); Surabhi, Srivathsava; Vo, Thanh Son; Lee, Kyung-Min; Yoon, Soon-Gil [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Jeong, Jun-Ho [Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Choi, Jun-Hyuk, E-mail: junhyuk@kimm.re.kr [Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Jeong, Jong-Ryul, E-mail: jrjeong@cnu.ac.kr [Department of Materials Science and Engineering and Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2015-10-01

    Highlights: • Investigated the effect of the interfacial ZnO for ETL synthesized by photochemical reaction using photosensitive 2-nitrobenzaldehyde on the inverted P3HT:PCBM OSC. • The abrupt increase of grain size and surface roughness was observed as increasing the annealing temperature above 350 °C. • The sheet resistance abruptly decreased with increasing the annealing temperature above 350 °C. • Increase of surface roughness caused by the high annealing temperature could be detrimental to the OSCs characteristics due to a high contact resistance and a large leakage current. - Abstract: We have investigated ZnO thin films prepared via photochemical reaction as the electron transport layer (ETL) of inverted organic solar cells (OSCs). Morphological and electrical properties of the ZnO thin films prepared by the photosensitive ZnO sol were studied according to the annealing temperature and their effects on the performance of the inverted poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) OSCs was characterized. It was found that the optimal annealing temperature of the ZnO thin films was 330 °C, and that devices with the ZnO ETL annealed at this temperature exhibited the largest short-circuit current density (J{sub sc}) of 9.39 mA/cm{sup 2}, as well as the highest power conversion efficiency (PCE) of 2.31%, which can be attributed to enhanced electron transport and interfacial properties. Devices containing ZnO films formed at optimal annealing condition exhibited an open circuit voltage (V{sub oc}) of 0.60 V and a fill factor (FF) of 41.0%. However, further increase of the annealing temperature led to degradation of the device performance, despite further improvements in electrical properties. We have found that marked increase in the surface roughness of the ZnO films occurred at temperatures above 350 °C which could be detrimental to the OSCs characteristics due to a high contact resistance and a large leakage current.

  3. Nanocrystalline transparent SnO{sub 2}-ZnO films fabricated at lower substrate temperature using a low-cost and simplified spray technique

    Energy Technology Data Exchange (ETDEWEB)

    Ravichandran, K.; Sakthivel, B.; Philominathan, P. [P. G. and Research Department of Physics, AVVM. Sri Pushpam College, Poondi, Thanjavur, Tamilnadu 613503 (India)

    2010-03-15

    Nanocrystalline and transparent conducting SnO{sub 2}- ZnO films were fabricated by employing an inexpensive, simplified spray technique using a perfume atomizer at relatively low substrate temperature (360{+-}5 C) compared with conventional spray method. The structural studies reveal that the SnO{sub 2}-ZnO films are polycrystalline in nature with preferential orientation along the (101) plane. The dislocation density is very low (1.48 x 10{sup 15}lines/m{sup 2}), indicating the good crystallinity of the films. The crystallite size of the films was found to be in the range of 26-34 nm. The optical transmittance in the visible range and the optical band gap are 85% and 3.6 eV respectively. The sheet resistance increases from 8.74 k{omega}/{open_square} to 32.4 k{omega}/{open_square} as the zinc concentration increases from 0 to 40 at.%. The films were found to have desirable figure of merit (1.63 x 10{sup -2} ({omega}/{open_square}){sup -1}), low temperature coefficient of resistance (-1.191/K) and good thermal stability. This simplified spray technique may be considered as a promising alternative to conventional spray for the massive production of economic SnO{sub 2} - ZnO films for solar cells, sensors and opto-electronic applications. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Enhancing Optical and Electrical Properties of La- and Al-Codoped ZnO Thin Films Prepared by Sol-Gel Method -La Codoping Effect.

    Science.gov (United States)

    He-Yan, Hai

    2017-07-10

    Backgroud: The transparent conductive ZnO film is widely used in solar cell. Enhancing the transmittance and electrical conductivity of the films is attracting many attentions to improve cell efficiency. This work focuses on the fabrication and potential application of the various cation-doped ZnO materials in recent patents and literature and then presents the La codoping effects of Al-doped ZnO films. Films were deposited by a sol-gel route and characterized by various techniques including X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis and luminescent spectroscopies, and electrical conduction analysis. The UV-vis. transmittance and band gap increased and then decreased, whereas the resistivity decreased and then slightly increased with the increase in La/Al ratio. The La/Al ratio of 0.0105 led to a maximal transmittance, a widest band gap, and a minimal resistivity. The films also illustrated a near band gap emission and some intrinsic defect-related emissions with varied intensity with La/Al ratio. This work reveal that the electrical and optical properties of the ZnO:Al films can be well enhanced by La codoping. This is significant to the applications of the ZnO:Al materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. The effect of Al-doping on the structural, optical, electrical and cathodoluminescence properties of ZnO thin films prepared by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Dghoughi, L. [Laboratoire d' Optoelectronique et de physico-chimie des Materiaux, Faculte des Sciences, Universite Ibn Tofail, Kenitra (Morocco); Ouachtari, F., E-mail: fouad489ou@gmail.co [Laboratoire de Physique Matiere et Rayonnement, Equipe de Spectroscopie Optique de la Matiere Solide, Faculte des Sciences, Universite Ibn Tofail, Kenitra (Morocco); Addou, M. [Laboratoire d' Optoelectronique et de physico-chimie des Materiaux, Faculte des Sciences, Universite Ibn Tofail, Kenitra (Morocco); Elidrissi, B.; Erguig, H.; Rmili, A.; Bouaoud, A. [Laboratoire de Physique Matiere et Rayonnement, Equipe de Spectroscopie Optique de la Matiere Solide, Faculte des Sciences, Universite Ibn Tofail, Kenitra (Morocco)

    2010-05-01

    Aluminum doped zinc oxide (Al-doped ZnO) thin films were deposited by the spray pyrolysis technique onto the glass substrates at 450 deg. C using anhydrous zinc chloride (ZnCl{sub 2}) and aluminum chloride (AlCl{sub 3}) as sources of zinc and aluminum ions, respectively. The effect of [Al]/[Zn] ratio in the solution on the structural, optical, electrical and cathodoluminescence properties of these films were investigated. XRD study revealed that both undoped and Al-doped ZnO films were polycrystalline with hexagonal structure and exhibited (0 0 2) preferential orientation. The optical and electrical studies showed that the film deposited with the [Al]/[Zn] ratio equal to 0.05 had high transmittance (of about 80% and 95% in the visible and near infra-red regions, respectively) and minimum resistivity of 1.4x10{sup -3} OMEGA cm, respectively. This resistivity value decreased with increase in temperature indicating the semiconducting nature of Al-doped ZnO films. The chemical composition analysis (EPMA) showed that this film was nearly stochiometric with a slight oxygen deficiency.

  6. Effect of sol concentration on the properties of ZnO thin films prepared by sol-gel technique

    International Nuclear Information System (INIS)

    Dutta, M.; Mridha, S.; Basak, D.

    2008-01-01

    ZnO thin films are deposited on the glass substrates by sol-gel drain coating technique by varying the concentration of the sol. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used to investigate the effect of sol concentration on the crystallinity and surface morphology of the films. The results show that with increase in sol concentration, the value of full width at half maximum (FWHM) of (0 0 2) peak decreases while the strain first increases and then decreases. The sol with higher concentration results in the increase in the grain size. The studies on the optical properties show that the band gap value increases from 3.27 to 3.3 eV when the sol concentration changes from 0.03 to 0.1 M. The photoconductivity studies reveal that the film for 0.05 M sol shows the maximum photoresponse for ultraviolet (UV) wavelength (<400 nm) which is co-related with the deep-level defects. The growth and decay of the photocurrent is found to be slowest for the same film

  7. X-ray photoelectron spectroscopy study and thermoelectric properties of Al-doped ZnO thin films

    International Nuclear Information System (INIS)

    Li Li; Fang Liang; Zhou Xianju; Liu Ziyi; Zhao Liang; Jiang Sha

    2009-01-01

    In this paper, high quality Al-doped ZnO (AZO) thin films were prepared by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5 wt.%. The films obtained were characterized by X-ray photoelectron spectroscopy (XPS) and thermoelectric measurements. The XPS results reveal that Zn and Al exist only in oxidized state, while there are dominant crystal lattice and rare adsorbed oxygen for O in the annealed AZO thin films. The studies of thermoelectric property show a striking thermoelectric effect in the AZO thin films. On the one hand, the thermoelectromotive and magnetothermoelectromotive forces increase linearly with increasing temperature difference (ΔT). On the other hand, the thermoelectric power (TEP) decreases with the electrical resistance of the sample. But the TEP increases with the increase of temperature below 300 K, and it nearly does not change around room temperature. The experimental results also demonstrate that the annealing treatment increases TEP, while the external magnetic field degrades TEP.

  8. Flexible, transparent and exceptionally high power output nanogenerators based on ultrathin ZnO nanoflakes

    Science.gov (United States)

    van Ngoc, Huynh; Kang, Dae Joon

    2016-02-01

    Novel nanogenerator structures composed of ZnO nanoflakes of less than 10 nm thickness were fabricated using a novel method involving a facile synthetic route and a rational design. The fabricated nanogenerators exhibited a short-circuit current density of 67 μA cm-2, a peak-to-peak open-circuit voltage of 110 V, and an overall output power density exceeding 1.2 mW cm-2, and to the best of our knowledge, these are the best values that have been reported so far in the literature on ZnO-based nanogenerators. We demonstrated that our nanogenerator design could instantaneously power 20 commercial green light-emitting diodes without any additional energy storage processes. Both the facile synthetic route for the ZnO nanoflakes and the straightforward device fabrication process present great scaling potential in order to power mobile and personal electronics that can be used in smart wearable systems, transparent and flexible devices, implantable telemetric energy receivers, electronic emergency equipment, and other self-powered nano/micro devices.Novel nanogenerator structures composed of ZnO nanoflakes of less than 10 nm thickness were fabricated using a novel method involving a facile synthetic