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Sample records for doped polypyrrole films

  1. Effect of the electrolyte cations and anions on the photocurrent of dodecylsulphate doped polypyrrole films

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Milena; De Paoli, Marco-A. [Laboratorio de Poliimeros Condutores, Instituto de Quimica-UNICAMP, Universidade de Campinas, Cx Postal 6154, 13081-970 , SP Campinas (Brazil)

    2002-07-01

    Photoelectrochemical and UV-Vis spectroelectrochemical measurements were performed in a three-electrode cell containing dodecylsulphate-doped polypyrrole films as active layers in contact with different aqueous electrolytes. The effect of both cations and anions of the electrolyte on the photocurrent generation and on the absorption spectra of the system was studied. Dynamic photocurrent and absorption spectra measurements performed during the redox cycles of the films show that both cation and anion insertion and deinsertion occurs during the cycles. These results are in agreement with the previously reported redox mechanism proposed for amphiphilic anion doped polypyrrole. Reduced films show cathodic photocurrent at -0.4>E>-0.8V vs. Ag|AgCl. Photocurrent voltammograms are reproducible after the conditioning of the films and the higher cathodic currents were observed in films with thickness of =0.05-0.5{mu}m.

  2. Electrochemical impedance spectroscopy of dodecylsulphate doped polypyrrole films in the dark and under illumination

    Directory of Open Access Journals (Sweden)

    Martini Milena

    2000-01-01

    Full Text Available The morphology, thickness, oxidation and illumination effects in dodecylsulphate doped polypyrrole films can be qualitatively observed by EIS and consist in variations of interfacial and bulk resistances and capacitances of a proposed equivalent circuit. The circuit well with the measured spectra of films obtained with 190 mC cm-2 of synthesis charge density. For thinner films the calculated values observed by electrochemical impedance spectroscopy (EIS deviate probably due to the absence of diffusion effects. The oxidation of the films diminishes the total impedance over the entire frequency range. The morphology effects are also observed in the entire spectra. The illumination effects are reversible and are observed as expected only in the reduced form of the polymer. The illumination reduces the internal resistance and the space-charge capacitance and increases the charge transfer resistance and the double layer capacitance.

  3. All-organic polymer-dispersed liquid crystal light-valves integrated with electroactive anthraquinone-2-sulfonate-doped polypyrrole thin films as driving electrodes

    International Nuclear Information System (INIS)

    Wang, Pen-Cheng; Yu, Jing-Yu; Li, Kuan-Hsun

    2011-01-01

    Highlights: → Fabrication of flexible semi-transparent all-polymer electrodes under ambient conditions without using a CVD system. → Characterization of the above electrodes based on anthraquinone-2-sulfonate-doped polypyrrole thin films. → Demonstration of all-organic liquid crystal light-valves with polypyrrole thin films as the driving electrodes. - Abstract: All-organic PDLC (polymer-dispersed liquid crystal) light-valves using all-polymer conductive substrates containing thin films of polypyrrole doped with anthraquinone-2-sulfonate (AQSA - ) as the driving electrodes were fabricated in this study. The all-polymer conductive substrates were prepared under ambient conditions by in situ depositing polypyrrole thin films on blank flexible poly(ethylene terephthalate), or PET, substrates from aqueous media in which oxidative polymerization of pyrrole was taking place. The obtained flexible all-polymer conductive substrates were semi-transparent with cohesive coatings of AQSA - doped polypyrrole thin films (thickness ∼55 nm). The all-polymer flexible conductive substrates had sheet resistivity ∼40 kΩ □ -1 and T% transparency against air ∼78% at 600 nm. The light-valves fabricated using the above all-polymer conductive substrates showed ∼50% transparency against air at 600 nm when 4 V μm -1 electric field was applied.

  4. A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine

    Science.gov (United States)

    Jiang, Ling; Xie, Qingji; Li, Zhili; Li, Yunlong; Yao, Shouzhuo

    2005-01-01

    Tannic acid-doped polypyrrole (PPY/TA) films have been grown on gold electrodes for selective electrochemical detection of dopamine (DA). Electrochemical quartz crystal microbalance (EQCM) studies revealed that, in vivid contrast to perchlorate-doped polypyrrole films (PPY/ClO4-), the redox switching of PPY/TA films in aqueous solutions involved only cation transport if the solution pH was greater than 3∼4. The PPY/TA Au electrodes also exhibited attractive permselectivity for electroactive cations, namely, effectively blocking the electrochemical reactions of anionic ferricyanide and ascorbic acid (AA) while well retaining the electrochemical activities of hexaammineruthenium (III) and dopamine as cationic species. A 500 Hz PPY/TA film could effectively block the redox current of up to 5.0 mM AA. The coexistence of ascorbic acid in the measurement solution notably enhanced the current signal for dopamine oxidation, due probably to the chemical regeneration of dopamine through an ascorbic acid-catalyzed reduction of the electro-oxidation product of dopamine (EC’ mechanism), and the greatest amplification was found at an ascorbic acid concentration of 1.0 mM. The differential pulse voltammetry peak current for DA oxidation was linear with DA concentration in the range of 0 to 10 μM, with sensitivity of 0.125 and 0.268 μA/μM, as well as lower detection limit of 2.0 and 0.3 μM in a PBS solution without AA and with 1.0 mM coexisting AA, respectively.

  5. Properties of electropolymerised polypyrrole thin film on silver

    Science.gov (United States)

    Jamadade, Shivaji A.; Puri, Vijaya

    2009-07-01

    This paper reports the properties of electropolymerised polypyrrole thin film on silver. The transmission, reflection, conductivity and dielectric behavior of polypyrrole coated silver has been studied in the 8-12 GHz frequency range of the electromagnetic spectrum. The polypyrrole thin film makes silver a better conductor for microwaves. The microwave conductivity is larger than the DC conductivity by many orders of magnitude. The real and imaginary part of dielectric constant increases in magnitude with increasing doping level and also it decreases in magnitude with increasing frequency.

  6. Electrochemical Synthesis of Polypyrrole Layers Doped with Glutamic Ions

    NARCIS (Netherlands)

    Meteleva-Fischer, Yulia V.; Von Hauff, Elizabeth; Parisi, Juergen

    2009-01-01

    Electrochemically synthesized polypyrrole thin films doped with glutamic ions were investigated as interesting materials for potential use as molecularly selective surfaces. Pyrrole and glutamate interact in aqueous solution, resulting in the formation of a prominent band at 240 nm in the absorption

  7. Novel polypyrrole films with excellent crystallinity and good thermal stability

    International Nuclear Information System (INIS)

    Jeeju, Pullarkat P.; Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M.; Jayalekshmi, Sankaran

    2012-01-01

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: ► Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. ► The solution casted films exhibit semi-crystallinity and good thermal stability. ► Percentage crystallinity estimated using XRD and DSC analysis is about 65%. ► Raman studies support the enhancement in crystallinity based on XRD and DSC data. ► The conductivity of the film is 30 times higher than that of HCl doped sample.

  8. Novel polypyrrole films with excellent crystallinity and good thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Jeeju, Pullarkat P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Jayalekshmi, Sankaran, E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India)

    2012-06-15

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: Black-Right-Pointing-Pointer Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. Black-Right-Pointing-Pointer The solution casted films exhibit semi-crystallinity and good thermal stability. Black-Right-Pointing-Pointer Percentage crystallinity estimated using XRD and DSC analysis is about 65%. Black-Right-Pointing-Pointer Raman studies support the enhancement in crystallinity based on XRD and DSC data. Black-Right-Pointing-Pointer The conductivity of the film is 30 times higher than that of HCl doped sample.

  9. Dye-doped nanostructure polypyrrole film for electrochemically switching solid-phase microextraction of Ni(II) and ICP-OES analysis of waste water.

    Science.gov (United States)

    Shamaeli, Ehsan; Alizadeh, Naader

    2012-01-01

    A nanostructure fiber based on conducting polypyrrole synthesized by an electrochemical method has been developed, and used for electrochemically switching solid-phase microextraction (ES-SPME). The ES-SPME was prepared by the doping of eriochrome blue in polypyrrole (PPy-ECB) and used for selectively extracting the Ni(II) cation in the presence of some transition and heavy metal ions. The cation-exchange behavior of electrochemically prepared polypyrrole on stainless-steel with and without eriochrome blue (ECB) dye was characterized using ICP-OES analysis. The effects of the scan rate for electrochemical synthesis, uptake and the release potential on the extraction behavior of the PPy-ECB conductive fiber were studied. Uptake and release time profiles show that the process of electrically switched cation exchange could be completed within 250 s. The results of the present study point concerning the possibility of developing a selective extraction process for Ni(II) from waste water was explored using such a nanostructured PPy-ECB film through an electrically switched cation exchange. 2012 © The Japan Society for Analytical Chemistry

  10. Thin composite films consisting of polypyrrole and polyparaphenylene

    International Nuclear Information System (INIS)

    Golovtsov, I.; Bereznev, S.; Traksmaa, R.; Opik, A.

    2007-01-01

    This study demonstrates that the combined method for the formation of thin composite films, consisting of polypyrrole (PPy) as a film forming agent and polyparaphenylene (PPP) with controlled electrical properties and high stability, enables one to avoid the low processability of PPP and to extend the possibilities for the development of electronic devices. The high temperature (250-600 deg. C) doping method was used for PPP preparation. The crystallinity and grindability of PPP was found to be increasing with the thermochemical modification. Thin composite films were prepared onto the light transparent substrates using the simple electropolymerization technique. The properties of films were characterized by the optical transmittance and temperature-dependent conductivity measurements. The morphology and thickness of the prepared films were determined using the scanning electron microscopy. The composite films showed a better adhesion to an inorganic substrate. It was found to be connected mostly with the improved properties of the high temperature doped PPP. The current-voltage characteristics of indium tin oxide/film/Au hybrid organic-inorganic structures showed the influence of the doping conditions of PPP inclusions in the obtained films

  11. Electrochemical fabrication of nanoporous polypyrrole thin films

    International Nuclear Information System (INIS)

    Li Mei; Yuan Jinying; Shi Gaoquan

    2008-01-01

    Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. σ rt ∼ 20.5 s/cm and can be driven to bend during redox processes in 1.0 M lithium perchlorate aqueous solution. The movement rate of an actuator based on this nanoporous film was measured to be over 90 o /s at a driving potential of 0.8 V (vs. Ag/AgCl)

  12. Electrochemical fabrication of nanoporous polypyrrole thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li Mei [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China); Yuan Jinying [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China)], E-mail: yuanjy@mail.tsinghua.edu.cn; Shi Gaoquan [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China)], E-mail: gshi@mail.tsinghua.edu.cn

    2008-04-30

    Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. {sigma}{sub rt} {approx} 20.5 s/cm and can be driven to bend during redox processes in 1.0 M lithium perchlorate aqueous solution. The movement rate of an actuator based on this nanoporous film was measured to be over 90{sup o}/s at a driving potential of 0.8 V (vs. Ag/AgCl)

  13. The Regulation of Osteogenesis Using Electroactive Polypyrrole Films

    Directory of Open Access Journals (Sweden)

    Chuan Li

    2016-07-01

    Full Text Available To evaluate the effect of electrical conductivity of biomaterials on osteogenesis, polypyrrole (PPy was fabricated by oxidative chemical polymerization as substrates for cell culture. Through adjusting the concentrations of monomer and initiator, polypyrrole films with different electrical conductivities were fabricated. These fabricated polypyrrole films are transparent enough for easy optical microscopy. Fourier transform infrared spectroscopy, X-ray spectroscopy and four-point probe were used to assess the microstructures, surface chemical compositions and electrical sheet resistance of films, respectively. Results indicate that higher monomer and initiator concentration leads to highly-branched PPy chains and thus promotes the electron mobility and electrical conductivity. Selected polypyrrole films then were applied for culturing rat bone marrow stromal cells. Cell viability and mineralization assays reveal that not only these films are biocompatible, but also capable of enhancing the calcium deposition into the extra cellular matrix by the differentiated cells.

  14. The Roll of NaPSS Surfactant on the Ceria Nanoparticles Embedding in Polypyrrole Films

    Directory of Open Access Journals (Sweden)

    Simona Popescu

    2016-01-01

    Full Text Available Cerium oxide nanoparticles (CeO2 NPs in crystalline form have been synthesized by a coprecipitation method. CeO2 nanoparticles were then embedded in polypyrrole (PPy films during the electropolymerization of pyrrole (Py on titanium substrate. The influence of poly(sodium 4-styrenesulfonate (NaPSS surfactant used during polymerization on the embedding of CeO2 NPs in polypyrrole films was investigated. The new films were characterized in terms of surface analysis, wettability, electrochemical behaviour, and antibacterial effect. The surface and electrochemical characterization revealed the role of surfactant on PPy doping process cerium oxide incorporation. In the presence of surfactant, CeO2 NPs are preferentially embedded in the polymeric film while, without surfactant, the ceria nanoparticles are quasiuniformly spread as agglomerates onto polymeric films. The antibacterial effect of studied PPy films was substantially improved in the presence of cerium oxide and depends by the polymerization conditions.

  15. Doped Overoxidized Polypyrrole Microelectrodes as Sensors for the Detection of Dopamine Released from Cell Populations

    DEFF Research Database (Denmark)

    Sasso, Luigi; Heiskanen, Arto; Diazzi, Francesco

    2013-01-01

    A surface modification of interdigitated gold microelectrodes (IDEs) with a doped polypyrrole (PPy) film for detection of dopamine released from populations of differentiated PC12 cells is presented. A thin PPy layer was potentiostatically electropolymerized from an 10 aqueous pyrrole solution onto...... electrode surfaces. The conducting polymer film was doped during electropolymerization by introducing counter ions in the monomer solution. Several counter ions were tested and the resulting electrode modifications were characterized electrochemically to find the optimal dopant that increases sensitivity...... in dopamine detection. Overoxidation of the PPy films was shown to contribute to a significant enhancement in sensitivity to dopamine. The changes caused by overoxidation in the electrochemical behavior and electrode morphology were investigated using cyclic voltammetry and SEM as well as AFM, respectively...

  16. Interference-Free Electrochemical Detection of Nanomolar Dopamine Using Doped Polypyrrole and Silver Nanoparticles

    OpenAIRE

    Saha, Suparna; Sarkar, Priyabrata; Turner, Anthony

    2014-01-01

    This paper presents a new approach to detect dopamine in nanomolar range using an electrochemical sensor utilizing a composite made of chitosan-stabilized silver nanoparticles and p-toluene sulfonic acid-doped ultrathin polypyrrole film. Studies included cyclic voltammogram, amperometry, differential pulse voltammetry and also investigation by electrochemical impedance spectroscopy. A detection limit of 0.58 nM was achieved in the linear range 1 x 10(-9) M to 1.2 x 10(-7) M. High sensitivity ...

  17. Characteristics of Electro-Optic Device Using Conducting Polymers, Polythiophene and Polypyrrole Films

    Science.gov (United States)

    Kaneto, Keiichi; Yoshino, Katsumi; Inuishi, Yoshio

    1983-07-01

    Detailed characteristics of electro-optic elements (color switching and memory) utilizing the spectral change of conducting polymers by electrochemical doping and undoping are studied. The response time of color switching, for example, red≤ftrightarrowblue in polythiophene film in the electrolyte of LiBF4/acetonitrile is 30˜100 msec under the applied voltages of -2.0{≤ftrightarrow}+4.0 V vs. Li plate. More than 103 cycles of color switch are observed quite reproducibly. Three color states of yellow green, dark brown and blue are demonstrated for polypyrrole film.

  18. Properties of polypyrrole doped with alkylbenzene sulfonates

    DEFF Research Database (Denmark)

    Bay, Lasse; Skaarup, Steen; West, Keld

    2001-01-01

    -standing 10 mu m thick film is prepared electrochemically at a constant current from an aqueous solution of pyrrole and sodium alkylbenzene sulfonate. The mechanical properties of the film (tensile strength and Young's modulus) and the reversible linear elongation between the oxidised and reduced states...

  19. Electrocatalytic properties of monometallic and bimetallic nanoparticles-incorporated polypyrrole films for electro-oxidation of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, V.; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India); Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-10-06

    Oxidative electrochemical polymerization of pyrrole at indium-doped tin oxide (ITO) is accomplished from a neat monomer solution with a supporting electrolyte (0.3M n-tetrabutyl ammonium tetrafluoroborate) by multiple-scan cyclic voltammetry. Polypyrrole (Ppy) films containing nanometer-sized platinum and Pt/Pd bimetallic particles are electro-synthesized on ITO glass plates by voltammetric cycling between -0.1 and +1V (versus Ag/AgCl/3M NaCl). The electrocatalytic oxidation of methanol on the nanoparticle-modified polypyrrole films is studied by means of electrochemical techniques. The modified electrode exhibits significant eletrocatalytic activity for methanol oxidation. The enhanced electrocatalytic activities may be due to the uniform dispersion of nanoparticles in the polypyrrole film and a synergistic effect of the highly-dispersed metal particles so that the polypyrrole film reduces electrode poisoning by adsorbed CO species. The monometallic (Pt) and bimetallic (Pt/Pd) nanoparticles are uniformly dispersed in polypyrrole matrixes, as confirmed by scanning electron microscopic and atomic force microscopic analysis. Energy dispersive X-ray analysis is used to characterize the composition of metal present in the nanoparticle-modified electrodes. (author)

  20. Properties of polypyrrole doped with alkylbenzene sulfonates

    DEFF Research Database (Denmark)

    Bay, Lasse; Skaarup, Steen; West, Keld

    2001-01-01

    -standing 10 mu m thick film is prepared electrochemically at a constant current from an aqueous solution of pyrrole and sodium alkylbenzene sulfonate. The mechanical properties of the film (tensile strength and Young's modulus) and the reversible linear elongation between the oxidised and reduced states...... are measured. Alkylbenzene sulfonates with alkyl chain lengths between 1 and 22 carbon atoms are used as dopant anion. The films made with the different anions have highly different properties and are here compared to outline the influence of the size of the anion. A maximum in linear elongation is found for p......-(n-octyl)benzene sulfonate and in conductivity for p-(n-butyl)benzene sulfonate....

  1. Polypyrrole Doped with Alkyl Benzene Sulphonates

    DEFF Research Database (Denmark)

    Bay, Lasse; Mogensen, Naja; Skaarup, Steen

    2002-01-01

    films of the materials (tensile strength and Young's modulus) together with the reversible linear elongation between the oxidized and reduced states are determined. A maximum in linear elongation of 4% is found for p-(n-octyl)benzenesulfonate, and the highest electronic conductivity is found for p-(n-butyl)benzenesulfonate....

  2. Photocurrent and photothermal current of polypyrrole (PPy) film

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Chongjun; Wang Haihong; Jiang Zhiyu

    2003-02-28

    The photoelectrochemical properties of polypyrrole (PPy) film in aqueous solutions in the potential region of -0.7 to 0.5 V (versus Ag/AgCl) were investigated by using photocurrent, photothermal and photothermal current methods under the irradiation of laser beams with wavelength of 532 and 632.8 nm, respectively. It was found that the photocurrent at more negative potential was caused by the p-type semiconductor properties, while the photocurrent at more positive potential was caused by the local temperature rather than the semiconductor properties of the films. The effect of the film thickness on the photocurrent of PPy films was studied in detail.

  3. Photocurrent and photothermal current of polypyrrole (PPy) film

    International Nuclear Information System (INIS)

    Zhao Chongjun; Wang Haihong; Jiang Zhiyu

    2003-01-01

    The photoelectrochemical properties of polypyrrole (PPy) film in aqueous solutions in the potential region of -0.7 to 0.5 V (versus Ag/AgCl) were investigated by using photocurrent, photothermal and photothermal current methods under the irradiation of laser beams with wavelength of 532 and 632.8 nm, respectively. It was found that the photocurrent at more negative potential was caused by the p-type semiconductor properties, while the photocurrent at more positive potential was caused by the local temperature rather than the semiconductor properties of the films. The effect of the film thickness on the photocurrent of PPy films was studied in detail

  4. A simple route to Develop Highly porous Nano Polypyrrole/Reduced Graphene Oxide Composite film for Selective Determination of Dopamine

    International Nuclear Information System (INIS)

    Daniel Arulraj, Abraham; Arunkumar, Arumugam; Vijayan, Muthunanthevar; Balaji Viswanath, Kamatchirajan; Vasantha, Vairathevar Sivasamy

    2016-01-01

    A highly selective sensor was developed for dopamine with electrochemically treated sodium dodecyl benzene sulfonate doped nano polypyrrole (ET-SDBS-NPPy)/reduced graphene oxide (RGO) film. First, graphene oxide (GO) was reduced on the electrode surface electrochemically and then, SDBS-NPPy film was polymerized electrochemically on the ERGO coated GCE and bare GCE also. The SDBS-NPPy/ERGO and SDBS-NPPy films were treated electrochemically in phosphate buffer solution to replace macro SDBS- anions by smaller phosphate anions. Then, the physical properties of the above composite films were characterized by scanning electron microscope (SEM) and water wettability test. The replacement of SDBS- anions by phosphate anions leaves porous structure in the polymer films and also increases the hydrophobicity in the films. Then, these composite films were applied for the determination of dopamine in the presence of ascorbic acid and uric acid. Under the optimal conditions, the linear range for dopamine detection is 0.1 μM-100.0 μM with the detection limit of 20 nM at S/N = 3. Generally, conducting polypyrrole film could sense ascorbic acid and dopamine simultaneously. However, we have proposed a simple route to synthesis a porous and hydrophobic polypyrrole composite film for selective determination of dopamine in the presence of higher concentration (five orders) of ascorbic acid and uric acid.

  5. Thermoelectric Properties of Flexible PEDOT:PSS/Polypyrrole/Paper Nanocomposite Films.

    Science.gov (United States)

    Li, Jun; Du, Yong; Jia, Runping; Xu, Jiayue; Shen, Shirley Z

    2017-07-11

    Flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/polypyrrole/paper (PEDOT:PSS/PPy/paper) thermoelectric (TE) nanocomposite films were prepared by a two-step method: first, PPy/paper nanocomposite films were prepared by an in situ chemical polymerization process, and second, PEDOT:PSS/PPy/paper TE composite films were fabricated by coating the as-prepared PPy/paper nanocomposite films using a dimethyl sulfoxide-doped PEDOT:PSS solution. Both the electrical conductivity and the Seebeck coefficient of the PEDOT:PSS/PPy/paper TE nanocomposite films were greatly enhanced from 0.06 S/cm to ~0.365 S/cm, and from 5.44 μV/K to ~16.0 μV/K at ~300 K, respectively, when compared to the PPy/paper TE nanocomposite films. The thermal conductivity of the PEDOT:PSS/PPy/paper composite film (0.1522 Wm -1 K -1 at ~300 K) was, however, only slightly higher than that of the PPy/paper composite film (0.1142 Wm -1 K -1 at ~300 K). As a result, the ZT value of the PEDOT:PSS/PPy/paper composite film (~1.85 × 10 -5 at ~300 K) was significantly enhanced when compared to that of the PPy/paper composite film (~4.73 × 10 -7 at ~300 K). The as-prepared nanocomposite films have great potential for application in flexible TE devices.

  6. Development of an Optical Urea Biosensor Using Polypyrrole-polyvinyl Sulphonate Film

    Directory of Open Access Journals (Sweden)

    H. J. KHARAT

    2009-02-01

    Full Text Available Development of an intensity modulated fiber optic PPy-PVS biosensor for the detection of urea has been presented. The sensor design is based on the modified cladding technique. Polypyrrole (PPy film doped with polyvinyl sulfonate (PVS was synthesized (by in-situ chemical polymerization at room temperature with optimized process parameters. The PPy-PVS film provides good porous matrix for the immobilization of enzyme-urease on the sensing probe by cross linking via glutaraldehyde. The characterization of the urea biosensor has been carried out with an indigenously developed sensing chamber and optical fiber test bench. This biosensor showed almost stable and linear response to urea in the range 1-100 mM up to 24 days. It shows very good selectivity and repeatability.

  7. LPG ammonia and nitrogen dioxide gas sensing properties of nanostructured polypyrrole thin film

    Energy Technology Data Exchange (ETDEWEB)

    Bagul, Sagar B., E-mail: nano.sbbagul@gmail.com; Upadhye, Deepak S.; Sharma, Ramphal, E-mail: rps.phy@gmail.com [Thin Film and Nanotechnology Laboratory, Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (India)

    2016-05-06

    Nanostructured Polypyrrole thin film was synthesized by easy and economic chemical oxidative polymerization technique on glass at room temperature. The prepared thin film of Polypyrrole was characterized by optical absorbance study by UV-visible spectroscopy and electrical study by I-V measurement system. The optical absorbance spectrum of Polypyrrole shows two fundamental peaks in region of 420 and 890 nm, which confirms the formation of Polypyrrole on glass substrate. The I-V graph of nanostructured Polypyrrole represents the Ohmic nature. Furthermore, the thin film of Polypyrrole was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents spherical nanostructured morphology of Polypyrrole on glass substrate. In order to investigate gas sensing properties, 100 ppm of LPG, Ammonia and Nitrogen Dioxide were injected in the gas chamber and magnitude of resistance has been recorded as a function of time in second. It was observed that nanostructured Polypyrrole thin film shows good sensing behavior at room temperature.

  8. Synthesis and characterization of silver-polypyrrole film composite

    Energy Technology Data Exchange (ETDEWEB)

    Ayad, Mohamad M., E-mail: mayad12000@yahoo.com [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt); Zaki, Eman [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt)

    2009-11-15

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO{sub 3}. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO{sub 3} solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  9. Synthesis and characterization of silver-polypyrrole film composite

    International Nuclear Information System (INIS)

    Ayad, Mohamad M.; Zaki, Eman

    2009-01-01

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3 . Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  10. Synthesis and characterization of silver-polypyrrole film composite

    Science.gov (United States)

    Ayad, Mohamad. M.; Zaki, Eman

    2009-11-01

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  11. High efficient removal of chromium (VI) using glycine doped polypyrrole adsorbent from aqueous solution

    CSIR Research Space (South Africa)

    Ballav, N

    2012-08-01

    Full Text Available Glycine doped polypyrrole (PPy-gly) adsorbent was prepared via in situ polymerization of pyrrole (Py) monomer in the presence of glycine (gly) for the removal of Cr(VI). Formation of PPy homopolymer and inclusion of gly in the PPy matrix were...

  12. Conducting polypyrrole films as a potential tool for electrochemical treatment of azo dyes in textile wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Md. Mominul [Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Smith, Warren T. [Samadha Pacifica Pty Ltd, Woonona, NSW 2517 (Australia); Wong, Danny K.Y., E-mail: Danny.Wong@mq.edu.au [Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2015-02-11

    Highlights: • Anion exchange property of polypyrrole films exploited in developing a treatment method for Acid Red 1. • An environmentally friendly treatment method for Acid Red 1 without generating any toxic by-products. • Acid Red 1 is anodically entrapped and cathodically liberated at polypyrrole films. • Analytical characteristics of Acid Red 1-entrapped polypyrrole films. - Abstract: In this paper, we demonstrate conducting polypyrrole films as a potential green technology for electrochemical treatment of azo dyes in wastewaters using Acid Red 1 as a model analyte. These films were synthesised by anodically polymerising pyrrole in the presence of Acid Red 1 as a supporting electrolyte. In this way, the anionic Acid Red 1 is electrostatically attracted to the cationic polypyrrole backbone formed to maintain electroneutrality, and is thus entrapped in the film. These Acid Red 1-entrapped polypyrrole films were characterised by electrochemical, microscopic and spectroscopic techniques. Based on a two-level factorial design, the solution pH, Acid Red 1 concentration and polymerisation duration were identified as significant parameters affecting the entrapment efficiency. The entrapment process will potentially aid in decolourising Acid Red 1-containing wastewaters. Similarly, in a cathodic process, electrons are supplied to neutralise the polypyrrole backbone, liberating Acid Red 1 into a solution. In this work, following an entrapment duration of 480 min in 2000 mg L{sup −1} Acid Red 1, we estimated 21% of the dye was liberated after a reduction period of 240 min. This allows the recovery of Acid Red 1 for recycling purposes. A distinctive advantage of this electrochemical Acid Red 1 treatment, compared to many other techniques, is that no known toxic by-products are generated in the treatment. Therefore, conducting polypyrrole films can potentially be applied as an environmentally friendly treatment method for textile effluents.

  13. Binding and release of glutamate from overoxidized polypyrrole via an applied potential for application as a molecular switch

    NARCIS (Netherlands)

    von Hauff, Elizabeth; Meteleva-Fischer, Yulia; Parisi, Jueirgen; Weiler, Reto

    2008-01-01

    The controlled binding and release of glutamate from overoxidized polypyrrole (PPy) films via a variable potential was investigated. Glutamate-doped PPy films were electrochemically deposited from aqueous sodium glutamate electrolytes containing the pyrrole monomer. The resulting polymer films were

  14. Controlling Physical and Chemical Bonding of Polypyrrole to Boron Doped Diamond by Surface Termination

    OpenAIRE

    Ukraintsev, Egor; Kromka, Alexander; Janssen, Wiebke; Haenen, Ken; Rezek, Bohuslav

    2013-01-01

    To elucidate and to control polypyrrole (PPy) attachment to diamond we electrochemically grow PPy layers on hydrogen- and oxygen-terminated boron doped diamonds (BDD). Atomic force microscopy (AFM) shows that the PPy layers have similar morphology (15 nm features) and thickness (> 5 nm) on H- and O-BDD. To resolve type of PPy-diamond bonding, scanning electron microscopy (SEM) is used to compare intensity of secondary electron emission from original BDD regions and regions where PPy was grown...

  15. Electropolymerization of Polypyrrole Films in Aqueous Solution with Side-Coupler Agent with Side-Coupler Agent

    Science.gov (United States)

    Alfaro-López, H. M.; Aguilar-Hernandez, J. R.; Garcia-Borquez, A.; Hernandez-Perez, M. A.; Contreras-Puente, G. S.

    A preliminary study of the electrochemical synthesis and optical characterizacion of the conducting polymer polypyrrole (PPy) was carried out, in order to understand the in-situ electropoliymerization of PPy. Electropolymerization was performed in a three electrode cell by using freshly prepared monomer solutions in presence of a side-coupler agent to hydrophobic groups: sodium dodecylsulfate (DDS), in order to improve the adherence polymer film to the surface of the working electrode. The adherence of the polymer film promotes either the ionic or electronic transport at the interface solution-working electrode. A polar chemical reactive, sodium tetrafluoroborate, TFB, was also used. In order to taylor and optimize the physical properties of the PPy films we varied some parameters during the electropolymerization: the monomer concentration, the electrolyte concentration, pH of the solution and the cell potential. This allowed us to control the oxidation level (impurification or doping) of the polymer. The obtained PPy films were characterized by using UV-Vis and IR spectroscopy. Moreover through scanning electronic microscopy we were able to observe well developed helical structures of polypyrrole.

  16. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.

    2003-01-01

    Polypyrrole (PPy) polymer films permanently doped with large, immobile anion dodecyl benzene sulfonate (DBS) have been characterized by cyclic voltammetry in order to clarify the roles of cations and anions in the aqueous electrolyte as mobile ions in the film. Aqueous solutions of 0.05-0.1 M...

  17. Doping optimization of polypyrrole with toluenesulfonic acid using Box-Behnken design

    Energy Technology Data Exchange (ETDEWEB)

    Syed Draman, Sarifah Fauziah; Daik, Rusli [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); El-Sheikh, Said M. [Nanostructured Materials and Nanotechnology Division, Central Metallurgical Research and Development Institute,11421 Cairo (Egypt); Latif, Famiza Abdul [Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia 40450 Shah Alam, Selangor (Malaysia)

    2013-11-27

    A three-level Box-Behnken design was employed in doping optimization of polypyrrole with toluenesulfonic acid (TSA-doped PPy). The material was synthesized via chemical oxidative polymerization using pyrrole, toluenesulfonic acid (TSA) and ammonium persulfate (APS) as monomer, dopant and oxidant, respectively. The critical factors selected for this study were concentration of dopant, molar ratio between dopant to monomer (pyrrole) and concentration of oxidant. Obtaining adequate doping level of TSA-doped PPy is crucial because it affects the charge carriers for doped PPy and usually be responsible for electronic mobility along polymeric chain. Furthermore, the doping level also affects other properties such as electrical and thermal conductivity. Doping level was calculated using elemental analysis. SEM images shows that the prepared TSA-doped PPy particles are spherical in shape with the diameters of about. The range of nanoparticles size is around 80-100 nm. The statistical analysis based on a Box–Behnken design showed that 0.01 mol of TSA, 1:1 mole ratio TSA to pyrrole and 0.25 M APS were the optimum conditions for sufficient doping level.

  18. Doping optimization of polypyrrole with toluenesulfonic acid using Box-Behnken design

    International Nuclear Information System (INIS)

    Syed Draman, Sarifah Fauziah; Daik, Rusli; El-Sheikh, Said M.; Latif, Famiza Abdul

    2013-01-01

    A three-level Box-Behnken design was employed in doping optimization of polypyrrole with toluenesulfonic acid (TSA-doped PPy). The material was synthesized via chemical oxidative polymerization using pyrrole, toluenesulfonic acid (TSA) and ammonium persulfate (APS) as monomer, dopant and oxidant, respectively. The critical factors selected for this study were concentration of dopant, molar ratio between dopant to monomer (pyrrole) and concentration of oxidant. Obtaining adequate doping level of TSA-doped PPy is crucial because it affects the charge carriers for doped PPy and usually be responsible for electronic mobility along polymeric chain. Furthermore, the doping level also affects other properties such as electrical and thermal conductivity. Doping level was calculated using elemental analysis. SEM images shows that the prepared TSA-doped PPy particles are spherical in shape with the diameters of about. The range of nanoparticles size is around 80-100 nm. The statistical analysis based on a Box–Behnken design showed that 0.01 mol of TSA, 1:1 mole ratio TSA to pyrrole and 0.25 M APS were the optimum conditions for sufficient doping level

  19. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    Science.gov (United States)

    Pigois-Landureau, E.; Nicolau, Y. F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3-4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces.

  20. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    International Nuclear Information System (INIS)

    Pigois-Landureau, E.; Nicolau, Y.F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3 endash 4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces. copyright 1996 American Institute of Physics

  1. Controlling physical and chemical bonding of polypyrrole to boron doped diamond by surface termination

    Czech Academy of Sciences Publication Activity Database

    Ukraintsev, Egor; Kromka, Alexander; Janssen, W.; Haenen, K.; Rezek, Bohuslav

    2013-01-01

    Roč. 8, č. 1 (2013), s. 17-26 ISSN 1452-3981 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GAP108/12/0996 Grant - others:EU FP7 Marie Curie ITN MATCON(XE) PITN-GA-2009-238201 Institutional support: RVO:68378271 Keywords : electrochemical growth * polypyrrole * boron doped diamond * scanning electron microscopy * Kelvin force microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.956, year: 2013 http://www.electrochemsci.org/papers/vol8/80100017.pdf

  2. Electrodeposition of polypyrrole films on aluminum surfaces from a p-toluene sulfonic acid medium

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2009-01-01

    Full Text Available Electrodeposition of polypyrrole films on aluminum from aqueous solutions containing p-toluene sulfonic acid and pyrrole was performed by cyclic voltammetry and galvanostatic technique. The influence of applied current density on the morphology of the films was studied by Scanning Electron Microscopy. The films displayed a cauliflower-like structure consisting of micro-spherical grains. This structure is related to dopand intercalation in the polymeric chain. Films deposited at higher current density were more susceptible to the formation of pores and defects along the polymeric chain than films deposited at lower current density. These pores allow the penetration of aggressive species, thereby favoring the corrosion process.

  3. Simple One-Step Method to Synthesize Polypyrrole-Indigo Carmine-Silver Nanocomposite

    Directory of Open Access Journals (Sweden)

    Lara Fernandes Loguercio

    2016-01-01

    Full Text Available A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films.

  4. Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2007-06-01

    Full Text Available Polypyrrole (PPy films were galvanostatically deposited on 99.9 wt. (% aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments.

  5. Synthesis, characterization and electrochemical study of Mn-doped TiO2 decorated polypyrrole nanotubes

    Science.gov (United States)

    Saidur, M. R.; Aziz, A. R. Abdul; Basirun, W. J.

    2017-06-01

    Nanostructured conductive polymers are the growing interest in the field of electrochemistry due to their superior conductivity and environmental friendliness. The existence of transition metal oxides could improve their nanostructure as well as conductive properties. In this study, polypyrrole nanotubes are synthesized in the presence of TiO2 and manganese (Mn)-doped TiO2 nanoparticles (NPs) to investigate their electrochemical properties. Details characterization of the synthesized composites were done by X-Ray diffraction (XRD) and TEM. The TEM analysis shows that doping of TiO2 with Mn decrease the grain size of the TiO2 nanoparticles and successively its effects on the synthesis of the PPy nanotubes (PPyNTs). TEM confirmed that PPyNTs synthesized in the presence of Mn-doped TiO2 are thinner in size compare to the PPyNTs synthesized in presence of pure TiO2. The electrochemical effectiveness of the synthesized PPy nanocomposite was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV and EIS both on a modified glassy carbon electrode reveal the better electron transportability for the Mn-doped TiO2 PPyNTs due to the synergistic effect of doping and decreased the size of PPyNTs as well as increased surface area.

  6. Electropolymerization of camphorsulfonic acid doped conductive polypyrrole anti-corrosive coating for 304SS bipolar plates

    Science.gov (United States)

    Jiang, Li; Syed, Junaid Ali; Gao, Yangzhi; Zhang, Qiuxiang; Zhao, Junfeng; Lu, Hongbin; Meng, Xiangkang

    2017-12-01

    Conductive polymer coating doped with large molecular organic acid is an alternative method used to protect stainless steel (SS) bipolar plates in proton exchange membrane fuel cells (PEMFCs). However, it is difficult to select the proper doping acid, which improves the corrosion resistance of the coating without affecting its conductivity. In this study, large spatial molecular group camphorsulfonic acid (CSA) doped polypyrrole (PPY) conductive coating was prepared by galvanostatic electropolymerization on 304SS. The electrochemical properties of the coating were evaluated in 0.1 M H2SO4 solution in order to simulate the PEMFC service environment. The results indicate that the coating increased the corrosion potential and shifted Ecorr towards more positive value, particularly the jcorr value of PPY-CSA coated 304SS was dropped from 97.3 to 0.00187 μA cm-2. The long-term immersion tests (660 h) show that the PPY-CSA coating exhibits better corrosion resistance in comparison with the small acid (SO42-) doped PPY-SO42- or PPY/PPY-SO42- coatings. Moreover, the PPY-CSA coating presents low contact resistance and maintains strong corrosion resistance during the prolonged exposure time due to barrier effect and anodic protection.

  7. New composite systems on the base of polyethylene porous films covered by polypyrrole and polyacrylic acid

    Czech Academy of Sciences Publication Activity Database

    Elyashevich, G. K.; Rosova, E. Yu.; Andreeva, D. V.; Polotskaya, G. A.; Trchová, Miroslava; Pientka, Zbyněk

    2005-01-01

    Roč. 97, č. 4 (2005), s. 1410-1417 ISSN 0021-8995 R&D Projects: GA ČR GA202/02/0698 Grant - others:Russian Foundation of Basic Research(RU) 01-03-32290; Russian Foundation of Basic Research(RU) 04-03-32229 Institutional research plan: CEZ:AV0Z40500505 Keywords : porous polyethylene films * polypyrrole * polyacrylic acid Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.072, year: 2005

  8. Synthesis and characterization of polypyrrole doped with anionic spherical polyelectrolyte brushes

    Directory of Open Access Journals (Sweden)

    N. Su

    2012-09-01

    Full Text Available The procedures for the synthesis of polypyrrole (PPy doped with anionic spherical polyelectrolyte brushes (ASPB (PPy/ASPB nanocomposite by means of in situ chemical oxidative polymerization were presented. Fourier transform infrared spectroscopy (FTIR and Raman spectroscopic analysis suggested the bonding structure of PPy/ASPB nanocomposite. Scanning electron microscopy (SEM was used to confirm the morphologies of samples. The crystallographic structure, chemical nature and thermal stability of conducting polymers were analyzed by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and Thermo-gravimetric analysis (TGA respectively. Investigation of the electrical conductivity at room temperature showed that the electrical conductivity of PPy/ASPB nanocomposite was 20 S/cm, which was higher than that of PPy (3.6 S/cm.

  9. Multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole DNA biosensor for label-free detection of genetically modified organisms by QCM and EIS.

    Science.gov (United States)

    Truong, Thi Ngoc Lien; Tran, Dai Lam; Vu, Thi Hong An; Tran, Vinh Hoang; Duong, Tuan Quang; Dinh, Quang Khieu; Tsukahara, Toshifumi; Lee, Young Hoon; Kim, Jong Seung

    2010-01-15

    In this paper, we describe DNA electrochemical detection for genetically modified organism (GMO) based on multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole (PPy). DNA hybridization is studied by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). An increase in DNA complementary target concentration results in a decrease in the faradic charge transfer resistance (R(ct)) and signifying "signal-on" behavior of MWCNTs-PPy-DNA system. QCM and EIS data indicated that the electroanalytical MWCNTs-PPy films were highly sensitive (as low as 4pM of target can be detected with QCM technique). In principle, this system can be suitable not only for DNA but also for protein biosensor construction.

  10. Dependence of the carrier mobility and trapped charge limited conduction on silver nanoparticles embedment in doped polypyrrole nanostructures

    Science.gov (United States)

    Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

    2013-10-01

    The present article demonstrates an intensive study upon the temperature dependent current density (J)-voltage (V) characteristics of moderately doped polypyrrole nanostructure and its silver nanoparticles incorporated nanocomposites. Analysis of the measured J-V characteristics of different synthesized nano-structured samples within a wide temperature range revealed that the electrical conduction behavior followed a trapped charge-limited conduction and a transition of charge transport mechanism from deep exponential trap limited conduction to shallow traps limited conduction had been occurred due to the incorporation of silver nanoparticles within the polypyrrole matrix. A direct evaluation of carrier mobility as a function of electric field and temperature from the measured J-V characteristics illustrates that the incorporation of silver nanoparticles within the polypyrrole matrix enhances the carrier mobility at a large extent by reducing the concentration of traps within the polypyrrole matrix. The calculated mobility is consistent with the Poole-Frenkel form for the electrical field up to a certain temperature range. The nonlinear low temperature dependency of mobility of all the nanostructured samples was explained by Mott variable range hopping conduction mechanisms. Quantitative information regarding the charge transport parameters obtained from the above study would help to extend optimization strategies for the fabrication of new organic semiconducting nano-structured devices.

  11. Dendritic Ni(Cu)-polypyrrole hybrid films for a pseudo-capacitor

    Science.gov (United States)

    Choi, Bit Na; Chun, Woo Won; Qian, Aniu; Lee, So Jeong; Chung, Chan-Hwa

    2015-11-01

    Dendritic Ni(Cu)-polypyrrole hybrid films are fabricated for a pseudo-capacitor in a unique morphology using two simple methods: electro-deposition and electrochemical de-alloying. Three-dimensional structures of porous dendrites are prepared by electro-deposition within the hydrogen evolution reaction (HER) at a high cathodic potential; the high-surface-area structure provides sufficient redox reactions between the electrodes and the electrolyte. The dependence of the active-layer thickness on the super-capacitor performance is also investigated, and the 60 μm-thick Ni(Cu)PPy hybrid electrode presents the highest performance of 659.52 F g-1 at the scan rate of 5 mV s-1. In the thicker layers, the specific capacitance became smaller due to the diffusion limitation of the ions in an electrolyte. The polypyrrole-hybridization on the porous dendritic Ni(Cu) electrode provides superior specific capacitance and excellent cycling stability due to the improvement in electric conductivity by the addition of conducting polypyrrole in the matrices of the dendritic nano-porous Ni(Cu) layer and the synergistic effect of composite materials.

  12. Dendritic Ni(Cu)-polypyrrole hybrid films for a pseudo-capacitor.

    Science.gov (United States)

    Choi, Bit Na; Chun, Woo Won; Qian, Aniu; Lee, So Jeong; Chung, Chan-Hwa

    2015-11-28

    Dendritic Ni(Cu)-polypyrrole hybrid films are fabricated for a pseudo-capacitor in a unique morphology using two simple methods: electro-deposition and electrochemical de-alloying. Three-dimensional structures of porous dendrites are prepared by electro-deposition within the hydrogen evolution reaction (HER) at a high cathodic potential; the high-surface-area structure provides sufficient redox reactions between the electrodes and the electrolyte. The dependence of the active-layer thickness on the super-capacitor performance is also investigated, and the 60 μm-thick Ni(Cu)PPy hybrid electrode presents the highest performance of 659.52 F g(-1) at the scan rate of 5 mV s(-1). In the thicker layers, the specific capacitance became smaller due to the diffusion limitation of the ions in an electrolyte. The polypyrrole-hybridization on the porous dendritic Ni(Cu) electrode provides superior specific capacitance and excellent cycling stability due to the improvement in electric conductivity by the addition of conducting polypyrrole in the matrices of the dendritic nano-porous Ni(Cu) layer and the synergistic effect of composite materials.

  13. Resonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer films

    Science.gov (United States)

    Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

    2006-02-01

    We observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The "anomalous transmission" spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the `anomalous transmission' peaks are broader in the exotic metallic PPy (PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, showing that the surface plasmon polaritons on the PPy (PF6) film surfaces have higher attenuation.

  14. Modification of glassy carbon electrode with a bilayer of multiwalled carbon nanotube/tiron-doped polypyrrole: Application to sensitive voltammetric determination of acyclovir

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokhian, Saeed, E-mail: shahrokhian@sharif.edu [Department of Chemistry, Sharif University of Technology, Tehran 11155-3516 (Iran, Islamic Republic of); Institute for Nanoscience and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Azimzadeh, Mahnaz [Department of Chemistry, Sharif University of Technology, Tehran 11155-3516 (Iran, Islamic Republic of); Amini, Mohammad K. [Department of Chemistry, Isfahan University, Isfahan (Iran, Islamic Republic of)

    2015-08-01

    A novel voltammetric sensor based on glassy carbon electrode (GCE) modified with a thin film of multi-walled carbon nanotubes (MWCNTs) coated with an electropolymerized layer of tiron-doped polypyrrole was developed and the resulting electrode was applied for the determination of acyclovir (ACV). The surface morphology and property of the modified electrode were characterized by field emission scanning electron microscopy and electrochemical impedance spectroscopy techniques. The electrochemical performance of the modified electrode was investigated by means of linear sweep voltammetry (LSV). The effect of several experimental variables, such as pH of the supporting electrolyte, drop size of the cast MWCNTssuspension, number of electropolymerization cycles and accumulation time was optimized by monitoring the LSV response of the modified electrode toward ACV. The best response was observed at pH 7.0 after accumulation at open circuit for 160 s. Under the optimized conditions, a significant electrochemical improvement was observed toward the electrooxidation of ACV on the modified electrode surface relative to the bare GCE, resulting in a wide linear dynamic range (0.03–10.0 μM) and a low detection limit (10.0 nM) for ACV. Besides high sensitivity, the sensor represented high stability and good reproducibility for ACV analysis, and provided satisfactory results for the determination of this compound in pharmaceutical and clinical preparations. - Highlights: • A simple method was employed to construct a thin film modified electrode. • Tiron-doped polypyrrole was electropolymerized on MWCNT precast glassy carbon electrode. • Electrode surface characterization was performed by microscopic and spectroscopic techniques. • The modified electrode showed nano-molar detection limit for acyclovir. • The modified electrode was applied for the detection of ACV in pharmaceutical and clinical preparations.

  15. 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 ...

  16. Fabrication of polypyrrole-grafted nitrogen-doped graphene and its application for electrochemical detection of paraquat

    International Nuclear Information System (INIS)

    Li, Ji; Lei, Wu; Xu, Yujuan; Zhang, Yuehua; Xia, Mingzhu; Wang, Fengyun

    2015-01-01

    Graphical abstract: Polypyrrole-grafted nitrogen-doped graphene (PPY-g-NGE) was successfully synthesized by simultaneous modification of graphene through nitrogen doping and polymeric grafting for an efficient detection of paraquat (PQ). - Abstract: Polypyrrole-grafted nitrogen-doped graphene (PPY-g-NGE) was successfully synthesized by simultaneous modification of graphene through nitrogen doping and polymeric grafting, and used for the detection of paraquat (PQ). The chemical structure, morphology and interaction of the obtained PPY-g-NGE were verified by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The PPY-g-NGE modified glassy carbon electrode (GCE) was fabricated to investigate its electrochemical behavior and sensitive detection of PQ by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the novel PPY-g-NGE modified GCE exhibited excellent electrochemical performance and electrocatalytic activity to the redox reaction of PQ, with comparison to NGE and non-grafted composite of PPY-NGE. The two reduction DPV peaks of PQ at −0.60 V and −1.00 V were significantly enhanced at the PPY-g-NGE modified electrode. Under the optimized condition, the reduction peak currents of PQ at the PPY-g-NGE modified electrode were linear over the concentration range from 5.00 × 10 −8 to 2.00 × 10 −6 M with detection limits of 41 nM and 58 nM for Peak 1 and Peak 2, respectively. Besides the good sensitivity, the sensor also exhibited fine stability and strong anti-interference ability due to the well-combination and synergistic effect of polypyrrole and nitrogen doped graphene

  17. Stretchable conductive polypyrrole films modified with dopaminated hyaluronic acid.

    Science.gov (United States)

    Texidó, Robert; Orgaz, Antonio; Ramos-Pérez, Victor; Borrós, Salvador

    2017-07-01

    In this paper, we report the modification of polypirrole (PPy) with dopaminated hyaluronic acid (HADA). This design improves PPy adhesion onto stretchable materials such as poly(dimethylsiloxane) (PDMS) allowing the formation of conducting films on this kind of very flexible, hydrophobic materials. The results revealed that described PPy modification allows to obtain stable PPy:HADA nano-suspension able to cast films directly on PDMS. The comparison of PPy:HADA films with conventional PPy and other modified PPy shows that the modification improved the strength of the films under tension stress and their water resistance. Moreover, the modification proposed does not affect significantly the conductivity of the PPy films. The resulting properties of the material make it especially suitable for bio-integrated device applications, where a biocompatible material with stable electrical behaviour under deformation and water media is needed. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Detection of Carbon Monoxide Using Polymer-Composite Films with a Porphyrin-Functionalized Polypyrrole

    Science.gov (United States)

    Homer, Margie L.; Ryan, Margaret A.; Yen, Shiao-Ping S.; Lara, Liana M.; Shevade, Abhijit V.; Kisor, Adam

    2012-01-01

    Post-fire air constituents that are of interest to NASA include CO and some acid gases (HCl and HCN). CO is an important analyte to be able to sense in human habitats since it is a marker for both prefire detection and post-fire cleanup. The need exists for a sensor that can be incorporated into an existing sensing array architecture. The CO sensor needs to be a low-power chemiresistor that operates at room temperature; the sensor fabrication techniques must be compatible with ceramic substrates. Early work on the JPL ElectronicNose indicated that some of the existing polymer-carbon black sensors might be suitable. In addition, the CO sensor based on polypyrrole functionalized with iron porphyrin was demonstrated to be a promising sensor that could meet the requirements. First, pyrrole was polymerized in a ferric chloride/iron porphyrin solution in methanol. The iron porphyrin is 5, 10, 15, 20-tetraphenyl-21H, 23Hporphine iron (III) chloride. This creates a polypyrrole that is functionalized with the porphyrin. After synthesis, the polymer is dried in an oven. Sensors were made from the functionalized polypyrrole by binding it with a small amount of polyethylene oxide (600 MW). This composite made films that were too resistive to be measured in the device. Subsequently, carbon black was added to the composite to bring the sensing film resistivity within a measurable range. A suspension was created in methanol using the functionalized polypyrrole (90% by weight), polyethylene oxide (600,000 MW, 5% by weight), and carbon black (5% by weight). The sensing films were then deposited, like the polymer-carbon black sensors. After deposition, the substrates were dried in a vacuum oven for four hours at 60 C. These sensors showed good response to CO at concentrations over 100 ppm. While the sensor is based on a functionalized pyrrole, the actual composite is more robust and flexible. A polymer binder was added to help keep the sensor material from delaminating from the

  19. Development of a Handmade Conductivity Measurement Device for a Thin-Film Semiconductor and Its Application to Polypyrrole

    Science.gov (United States)

    Seng, Set; Shinpei, Tomita; Yoshihiko, Inada; Masakazu, Kita

    2014-01-01

    The precise measurement of conductivity of a semiconductor film such as polypyrrole (Ppy) should be carried out by the four-point probe method; however, this is difficult for classroom application. This article describes the development of a new, convenient, handmade conductivity device from inexpensive materials that can measure the conductivity…

  20. Constitution of novel polyamic acid/polypyrrole composite films by in-situ electropolymerization

    International Nuclear Information System (INIS)

    Hess, Euodia H.; Waryo, Tesfaye; Sadik, Omowunmi A.; Iwuoha, Emmanuel I.; Baker, Priscilla G.L.

    2014-01-01

    The preparation and characterization of polyamic acid-polypyrrole (PAA/PPy) composite films are reported in this paper. The thin films were synthesized by electrochemical method from a solution containing controlled molar ratio of chemically synthesized polyamic acid (PAA) and pyrrole monomer. Homogenous films were obtained by incorporating PAA into electropolymerized polypyrrole (PPy) thin film. The concentration of PAA (1.37 × 10 −6 M) was kept fixed throughout the composite ratio analysis, whilst the concentration of PPy was varied from 1.90 × 10 −3 M to 9.90 × 10 −3 M. The PAA/PPy thin films were electrodeposited at a glassy carbon electrode (GCE) and characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and voltammetry. The composition that best represented the homogenous incorporation of PAA into PPy matrix was observed at a PAA/PPy ratio of 1: 4.13 × 10 −3 . This composite was observed to have two sets of coupled peaks with formal potential 99 mV and 567 mV respectively. The D e determined from cyclic voltammetry using the anodic peak currents were found to be twice as high (5.82 × 10 −4 cm 2 /s) compared to the D e calculated using the cathodic peak currents (2.60 × 10 −4 cm 2 /s), indicating that the composite favours anodic electron mobility. Surface morphology and spectroscopy data support the formation of a homogenous polymer blend at the synthesis ratio of 1: 4.13 × 10 −3

  1. Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

    International Nuclear Information System (INIS)

    Kumar, Vijay; Ali, Yasir; Sharma, Kashma; Kumar, Vinod; Sonkawade, R.G.; Dhaliwal, A.S.; Swart, H.C.

    2014-01-01

    Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li 3+ ion beam irradiation for various fluences (1 × 10 11 , 1 × 10 12 and 1 × 10 13 ions/cm 2 ). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence

  2. Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vijay, E-mail: vijays_phy@rediffmail.com [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Ali, Yasir [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Sharma, Kashma [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Department of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan 173212 (India); Kumar, Vinod [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Sonkawade, R.G. [Inter University Accelerator Center, Aruna Asif Ali Marg, New Delhi 110067 (India); Dhaliwal, A.S. [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa)

    2014-03-15

    Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li{sup 3+} ion beam irradiation for various fluences (1 × 10{sup 11}, 1 × 10{sup 12} and 1 × 10{sup 13} ions/cm{sup 2}). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence.

  3. Silver deposition on polypyrrole films electrosynthesised onto Nitinol alloy. Corrosion protection and antibacterial activity.

    Science.gov (United States)

    Saugo, M; Flamini, D O; Brugnoni, L I; Saidman, S B

    2015-11-01

    The electrosynthesis of polypyrrole films onto Nitinol from sodium salicylate solutions of different concentrations is reported. The morphology and corrosion protection properties of the resulting coatings were examined and they both depend on the sodium salicylate concentration. The immobilisation of silver species in PPy films constituted by hollow rectangular microtubes was studied as a function of the polymer oxidation degree. The highest amount of silver was deposited when the coated electrode was prepolarised at -1.00V (SCE) before silver deposition, suggesting an increase in the amount of non-oxidised segments in the polymer. Finally, the antibacterial activity of the coating against the Gram positive Staphylococcus aureus and Staphylococcus epidermidis bacteria was evaluated. Both strains resulted sensitive to the modified coatings, obtaining a slightly better result against S. aureus. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Electrochemical growth of two-dimensional gold nanostructures on a thin polypyrrole film modified ITO electrode.

    Science.gov (United States)

    Li, Yin; Shi, Gaoquan

    2005-12-22

    Two-dimensional gold nanostructures have been fabricated by electrochemical deposition of gold nanoparticles onto indium tin oxide (ITO) glass substrate modified with thin polypyrrole film. By controlling the electrodeposition conditions, gold nanoparticles with dendritic rod, sheet, flower-like (consisting of staggered nanosheets), and pinecone-like structures were generated. The flower-like gold nanoparticles showed high catalytic activity on electrochemical reduction of oxygen, and its activity was measured to be approximately 25 times that of gold pinecones and 10(4) times that of gold nanosheets in terms of gold weight. The pinecone-like nanoparticles can form a compact film with nano-/microscale binary structure like a lotus leaf surface. After modification with n-dodecanethiol, the surface showed superhydrophobic properties with a water contact angle of 153.4 degrees and a tilt angle of 4.4 degrees (5 microL droplet).

  5. Anomalous transmission through heavily doped conducting polymer films with periodic subwavelength hole array

    Science.gov (United States)

    Matsui, Tatsunosuke; Vardeny, Z. Valy; Agrawal, Amit; Nahata, Ajay; Menon, Reghu

    2006-08-01

    We observed resonantly enhanced (or anomalous transmission) terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF 6 molecules [PPy(PF6)]. The anomalous transmission spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the resonantly enhanced transmission peaks are broader in the exotic metallic PPy(PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, indicating that the surface plasmon polaritons on the PPy(PF6) film surfaces have higher attenuation.

  6. Simple One-Step Method to Synthesize Polypyrrole-Indigo Carmine-Silver Nanocomposite

    OpenAIRE

    Loguercio, Lara Fernandes; Demingos, Pedro; Manica, Luiza de Mattos; Griep, Jordana Borges; Santos, Marcos José Leite; Ferreira, Jacqueline

    2016-01-01

    A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, poly...

  7. In situ synthesis of cylindrical spongy polypyrrole doped protonated graphitic carbon nitride for cholesterol sensing application.

    Science.gov (United States)

    Shrestha, Bishnu Kumar; Ahmad, Rafiq; Shrestha, Sita; Park, Chan Hee; Kim, Cheol Sang

    2017-08-15

    Herein, we demonstrate the exfoliation of bulk graphitic carbon nitrides (g-C 3 N 4 ) into ultra-thin (~3.4nm) two-dimensional (2D) nanosheets and their functionalization with proton (g-C 3 N 4 H + ). The layered semiconductor g-C 3 N 4 H + nanosheets were doped with cylindrical spongy shaped polypyrrole (CSPPy-g-C 3 N 4 H + ) using chemical polymerization method. The as-prepared nanohybrid composite was utilized to fabricate cholesterol biosensors after immobilization of cholesterol oxidase (ChOx) at physiological pH. Large specific surface area and positive charge nature of CSPPy-g-C 3 N 4 H + composite has tendency to generate strong electrostatic attraction with negatively charged ChOx, and as a result they formed stable bionanohybrid composite with high enzyme loading. A detailed electrochemical characterization of as-fabricated biosensor electrode (ChOx-CSPPy-g-C 3 N 4 H + /GCE) exhibited high-sensitivity (645.7 µAmM -1 cm -2 ) in wide-linear range of 0.02-5.0mM, low detection limit (8.0μM), fast response time (~3s), long-term stability, and good selectivity during cholesterol detection. To the best of our knowledge, this novel nanocomposite was utilized for the first time for cholesterol biosensor fabrication that resulted in high sensing performance. Hence, this approach opens a new prospective to utilize CSPPy-g-C 3 N 4 H + composite as cost-effective, biocompatible, eco-friendly, and superior electrocatalytic as well as electroconductive having great application potentials that could pave the ways to explore many other new sensors fabrication and biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Functionalized polypyrrole film: synthesis, characterization, and potential applications in chemical and biological sensors.

    Science.gov (United States)

    Dong, Hua; Cao, Xiaodong; Li, Chang Ming

    2009-07-01

    In this paper, we report the synthesis of a carboxyl-functionalized polypyrrole derivative, a poly(pyrrole-N-propanoic acid) (PPPA) film, by electrochemical polymerization, and the investigation of its basic properties via traditional characterization techniques such as confocal-Raman, FTIR, SEM, AFM, UV-vis, fluorescence microscopy, and contact-angle measurements. The experimental data show that the as-prepared PPPA film exhibits a hydrophilic nanoporous structure, abundant -COOH functional groups in the polymer backbone, and high fluorescent emission under laser excitation. On the basis of these unique properties, further experiments were conducted to demonstrate three potential applications of the PPPA film in chemical and biological sensors: a permeable and permselective membrane, a membrane with specific recognition sites for biomolecule immobilization, and a fluorescent conjugated polymer for amplification of fluorescence quenching. Specifically, the permeability and permselectivity of ion species through the PPPA film are detected by means of rotating-disk-electrode voltammetry; the specific recognition sites on the film surface are confirmed with protein immobilization, and the amplification of fluorescence quenching is measured by the addition of a quenching agent with fluorescence microscopy. The results are in good agreement with our expectations.

  9. Co nanoparticles induced resistive switching and magnetism for the electrochemically deposited polypyrrole composite films.

    Science.gov (United States)

    Xu, Zedong; Gao, Min; Yu, Lina; Lu, Liying; Xu, Xiaoguang; Jiang, Yong

    2014-10-22

    The resistive switching behavior of Co-nanoparticle-dispersed polypyrrole (PPy) composite films is studied. A novel design method for resistive random access memory (ReRAM) is proposed. The conducting polymer films with metal nanocrystal (NC)-dispersed carbon chains induce the spontaneous oxidization of the conducting polymer at the surface. The resistive switching behavior is achieved by an electric field controlling the oxygen ion mobility between the metal electrode and the conducting polymer film to realize the mutual transition between intrinsic conduction (low resistive state) and oxidized layer conduction (high resistive state). Furthermore, the formation process of intrinsic conductive paths can be effectively controlled in the conducting polymer ReRAM using metal NCs in films because the inner metal NCs induce electric field lines converging around them and the intensity of the electric field at the tip of NCs can greatly exceed that of the other region. Metal NCs can also bring new characteristics for ReRAM, such as magnetism by dispersing magnetic metal NCs in polymer, to obtain multifunctional electronic devices or meet some special purpose in future applications. Our works will enrich the application fields of the electromagnetic PPy composite films and present a novel material for ReRAM devices.

  10. Investigation of polypyrrole/polyvinyl alcohol-titanium dioxide composite films for photo-catalytic applications

    Science.gov (United States)

    Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long; Dan, Yi

    2015-07-01

    Polypyrrole/polyvinyl alcohol-titanium dioxide (PPy/PVA-TiO2) composite films used as photo-catalysts were fabricated by combining TiO2 sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet-visible diffuse reflection spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO2 and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet-vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA-TiO2 composite films show better photo-catalytic properties than TiO2 film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA-TiO2 composite film was investigated and the results show that the photo-catalytic activity under both UV and visible light irradiation have no significant decrease after four times of recycle experiments, suggesting that the photo-catalyst film is stable during the photo-catalytic process, which was also confirmed by the XRD pattern and FT-IR spectra of the composite film before and after photo-catalytic.

  11. An Amperometric Biosensor for Uric Acid Determination Prepared From Uricase Immobilized in Polyaniline-Polypyrrole Film

    Directory of Open Access Journals (Sweden)

    Fatma Arslan

    2008-09-01

    Full Text Available A new amperometric uric acid biosensor was developed by immobilizing uricase by a glutaraldehyde crosslinking procedure on polyaniline-polypyrrole (pani-ppy composite film on the surface of a platinum electrode. Determination of uric acid was performed by the oxidation of enzymatically generated H2O2 at 0.4 V vs. Ag/AgCl. The linear working range of the biosensor was 2.5×10-6 – 8.5×10-5 M and the response time was about 70 s. The effects of pH, temperature were investigated and optimum parameters were found to be 9.0, 55 oC, respectively. The stability and reproducibility of the enzyme electrode have been also studied.

  12. Nitrogen and phosphorus co-doped carbon hollow spheres derived from polypyrrole for high-performance supercapacitor electrodes

    Science.gov (United States)

    Lv, Bingjie; Li, Peipei; Liu, Yan; Lin, Shanshan; Gao, Bifen; Lin, Bizhou

    2018-04-01

    Nitrogen and phosphorus co-doped carbon hollow spheres (NPCHSs) have been prepared by a carbonization and subsequent chemical activation route using dehydrated polypyrrole hollow spheres as the precursor and KOH as the activating agent. NPCHSs are interconnected into a unique 3D porous network, which endows the as-prepared carbon to exhibit a large specific surface area of 1155 m2 g-1 and a high specific capacitance of 232 F g-1 at a current density of 1 A g-1. The as-obtained NPCHSs present a high-level heteroatom doping with N, O and P contents of 11.4, 6.7 and 3.5 wt%, respectively. The capacitance of NPCHSs has been retained at 89.1% after 5000 charge-discharge cycles at a relatively high current density of 5 A g-1. Such excellent performance suggests that NPCHSs are attractive electrode candidates for electrical double layer capacitors.

  13. Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xiaojuan, E-mail: cherry-820@163.com; Shi, Yanlong; Jin, Shuping

    2015-10-30

    The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g{sup −1} at 0.3 A g{sup −1} current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g{sup −1}), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

  14. Prevention of redox shuttle using electropolymerized polypyrrole film in a lithium-oxygen battery

    Science.gov (United States)

    Togasaki, Norihiro; Shibamura, Ryuji; Naruse, Takuya; Momma, Toshiyuki; Osaka, Tetsuya

    2018-04-01

    Among the recent advancements in lithium-oxygen (Li-O2) chemistries, redox mediators (RMs) have been revealed to play a significant role in decreasing overpotential on charging and in improving cycling performance. However, an intrinsic problem is redox shuttle of RMs, which leads to degraded RM utilization and induces the accumulation of discharge products on the cathode surface; this remains a significant issue in the current battery cell configuration (Li anode/separator/cathode). To address this detrimental problem, herein we propose a novel Li-O2 cell incorporating a freestanding electropolymerized polypyrrole (PPy) film for the restriction of the redox-shuttle phenomenon of lithium iodide (Li anode/separator/PPy film/cathode). In this study, a PPy film, which is prepared through oxidative electropolymerization using an ionic liquid of 1-methyl-1-butylpyrrolidinium mixed with pyrrole and lithium bis(trifluoromethanesulfonyl)imide, is introduced between the cathode and the separator. From the charge-discharge voltage profile, it is confirmed that the PPy film suppresses the diffusion of the oxidized I3- to the Li anode, while allowing Li ion transport. Secondary scanning electron microscope measurements confirm that the chemical reactions between I3- and Li2O2 are facilitated by the presence of the PPy film because I3- remains near the cathode surface during the charging process. As a result, the cycling performance in the Li-O2 cells with PPy film exhibits a cycling life four times as long as that of the Li-O2 cells without PPy film.

  15. Investigation of polypyrrole/polyvinyl alcohol–titanium dioxide composite films for photo-catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long, E-mail: jianglong@scu.edu.cn; Dan, Yi, E-mail: danyichenweiwei@163.com

    2015-07-01

    Graphical abstract: - Highlights: • The study provides an easy and convenient method to fabricate films, which will give guidance for the preparation of three-dimensional materials. • The PPy/PVA–TiO{sub 2} films can keep better photo-catalytic activities both under UV and visible light irradiation when compared with TiO{sub 2} film. • There exist electron transfers between PPy/PVA and TiO{sub 2}. - Abstract: Polypyrrole/polyvinyl alcohol–titanium dioxide (PPy/PVA–TiO{sub 2}) composite films used as photo-catalysts were fabricated by combining TiO{sub 2} sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO{sub 2} and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet–vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA–TiO{sub 2} composite films show better photo-catalytic properties than TiO{sub 2} film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA–TiO{sub 2} composite film was investigated and the results show that

  16. Improved antibacterial behavior of titanium surface with torularhodin–polypyrrole film

    Energy Technology Data Exchange (ETDEWEB)

    Ungureanu, Camelia; Popescu, Simona; Purcel, Gabriela [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania); Tofan, Vlad [“Cantacuzino” National Institute of Research-Development for Microbiology and Immunology, 103 Splaiul Independentei, Sector 5, 050096 Bucharest (Romania); Popescu, Marian [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania); National Institute for Research and Development in Microtechnologies, 126A, Erou Iancu Nicolae Street, 077190 Bucharest (Romania); Sălăgeanu, Aurora [“Cantacuzino” National Institute of Research-Development for Microbiology and Immunology, 103 Splaiul Independentei, Sector 5, 050096 Bucharest (Romania); Pîrvu, Cristian, E-mail: c_pirvu@chim.pub.ro [University POLITEHNICA of Bucharest, 1-7 Polizu, 011061 Bucharest (Romania)

    2014-09-01

    The problem of microorganisms attaching and proliferating on implants and medical devices surfaces is still attracting interest in developing research on different coatings based on antibacterial agents. The aim of this work is centered on modifying titanium (Ti) based implants surfaces through incorporation of a natural compound with antimicrobial effect, torularhodin (T), by means of a polypyrrole (PPy) film. This study tested the potential antimicrobial activity of the new coating against a range of standard bacterial strains: Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and Pseudomonas aeruginosa. The morphology, physical and electrochemical properties of the synthesized films were assessed by SEM, AFM, UV–Vis, FTIR and cyclic voltammetry. In addition, biocompatibility of this new coating was evaluated using L929 mouse fibroblast cells. The results showed that PPy–torularhodin composite film acts as a corrosion protective coating with antibacterial activity and it has no harmful effect on cell viability. - Highlights: • Modification of titanium surfaces by incorporating a natural compound • new PPy - torularhodin corrosion protective composite coatings • antibacterial activity for the new PPy - torularhodin coating • cytocompatibility of new coating was demonstrated using mouse fibroblast cells.

  17. Development of a novel biosensor based on a polypyrrole-dodecylbenzene sulphonate (PPy-DBS) film for the determination of amperometric cholesterol.

    Science.gov (United States)

    Özer, Bayram Oğuz; Çete, Servet

    2017-06-01

    Herein a novel amperometric biosensor based on a conducting polymer with anionic dopant modified electrode was successfully developed for detection of cholesterol. Polypyrrole is deposited on a platinum surface and the sodium dodecylbenzene sulphonate (DBS) ion-doped polypyrrole film was electrochemically prepared by scanning the electrode potential between -0.8 and +0.8 V at a scan rate of 20 mV/s. The present electrochemical biosensor was optimized in terms of working potential, number of cycles, concentrations of monomer, and anionic dopant. Cholesterol oxidase (ChOx) was physically entrapped in PPy-DBS to construct an amperometric cholesterol biosensor. Amperometric determination is based on the electrochemical detection of H 2 O 2 generated in the enzymatic reaction of cholesterol. Kinetic parameters, operational and storage stabilities, pH, and temperature dependencies were determined. Km and Imax were calculated as 0.11 μM and 0.967 nM/min, respectively. The operational stability results showed that 90.0% of the response current was retained after 30 activity assays. Morphology of electrodes was characterized by SEM and AFM. Additionally, contact angle measurements were made with 1 μL water of polymer film and enzyme electrode. As a result, the cholesterol biosensor suggested in this study is easy to prepare and is highly cost-effective. This composite (PPy-DBS) can supply a biocompatible and electrochemical microenvironment for immobilization of the enzyme, making this material a good candidate for the fabrication of highly sensitive and selective cholesterol biosensors.

  18. Immobilization of Tyrosinase from Avocado Crude Extract in Polypyrrole Films for Inhibitive Detection of Benzoic Acid

    Directory of Open Access Journals (Sweden)

    André Brisolari

    2014-07-01

    Full Text Available Inhibition-based biosensors were developed by immobilizing tyrosinase (Tyr, polyphenol oxidase from the crude extract of avocado fruit on electrochemically prepared polypyrrole (PPy films. The biosensors were prepared during the electropolymerization of pyrrole in a solution containing a fixed volume of the crude extract of avocado. The dependence of the biosensor responses on the volume used from the crude extract, values of pH and temperature was studied, and a substrate, catechol, at different concentrations, was amperometrically detected by these biosensors. Benzoic acid, a competitive inhibitor of Try, was added to the catechol solutions at specific concentrations aimed at obtaining the inhibition constant, K’m, which ranged from 1.7 to 4.6 mmol∙L−1 for 0.0 and 60 µmol∙L−1 of benzoic acid, respectively. Studies on the inhibition caused by benzoic acid by using PPy/Try films, and catechol as a substrate, allowed us propose how to develop, under optimized conditions, simple and low-cost biosensors based on the use of avocado fruit.

  19. One-Step Electrosynthesis of Graphene Oxide-Doped Polypyrrole Nanocomposite as a Nanointerface for Electrochemical Impedance Detection of Cell Adhesion and Proliferation Using Two Approaches

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2016-01-01

    Full Text Available A novel nanointerface of graphene oxide-doped polypyrrole (GO/PPy is prepared on the surface of an indium tin oxide (ITO electrode for electrochemical impedance detection of cell adhesion and proliferation through a facile one-step electropolymerization. The prepared GO/PPy nanocomposite had a robust surface and provided a biocompatible substrate for A549 cells adhesion and proliferation. The adhesion and proliferation of A549 cells on the surface of the GO/PPy modified ITO electrode directly increased the electron transfer resistance of [Fe(CN6]3−/4− redox probe and influenced the impedance properties of the GO/PPy modified ITO electrode system. Based on these results, the adhesion and proliferation of A549 cells could be detected by electrochemical impedance technology using two approaches. Therefore, the present paper confirms that the GO/PPy nanocomposite film provides an excellent biological-electrical interface for cell immobilization and offers advantages of simple, low-cost fabrication and multiparameter detection and possesses potential application in cytological studies.

  20. Electrochemical characterization of methanol/O2 biofuel cell: Use of laccase biocathode immobilized with polypyrrole film and PAMAM dendrimers

    International Nuclear Information System (INIS)

    Cardoso, F.P.; Aquino Neto, S.; Fenga, P.G.; Ciancaglini, P.; De andrade, A.R.

    2013-01-01

    This paper describes the performance of a mediated electron transfer (MET) biocathode for a methanol/O 2 biofuel cell. To this end, we employed PAMAM (polyamidoamine) dendrimers for the immobilization of laccase using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) in solution or entrapped into polypyrrole films. We used the enzyme immobilized onto the carbon platform obtained either in the presence or in the absence of the electropolymerized film to determine kinetic parameters. The results point to a very similar kinetic rate conversion in both situations; however, substrate affinity seems to increase in the bioelectrode containing the entrapped substrate molecules. The electrochemical characterization tests confirmed that the electropolymerized polypyrrole film was able to retain entrapped ABTS molecules. Additionally, laccase provides enhanced catalytic oxidation current for the mediator compared with the control sample containing PAMAM dendrimer only. Compared to the control sample, which gave power density values around 0.7 μW cm −2 , tests employing ABTS as mediator furnished 6 μW cm −2 when the mediator was added in solution and around 25 μW cm −2 when it was entrapped into the biocathode layers. Overall, the developed biocathode is environmentally friendly for immobilization of the enzyme laccase, being satisfactorily stable in the kinetic tests and affording good power data in the biofuel cell tests

  1. Graphene quantum-dot-doped polypyrrole counter electrode for high-performance dye-sensitized solar cells.

    Science.gov (United States)

    Chen, Lijia; Guo, Chun Xian; Zhang, Qiaoming; Lei, Yanlian; Xie, Jiale; Ee, Shujing; Guai, Guanhong; Song, Qunliang; Li, Chang Ming

    2013-03-01

    Herein graphene quantum dot (GQD), a graphene material with lateral dimension less than 100 nm, is explored to dope PPy on F-doped tin oxide glass as an efficient counter electrode for high-performance dye-sensitized solar cells (DSSCs). The GQDs-doped PPy film has a porous structure in comparison to the densely structured plain PPy, and displays higher catalytic current density and lower charge transfer resistance than the latter toward I3(-)/I(-) redox reaction. The highest power conversion efficiency (5.27%) for DSSCs is achieved with PPy doped with10% GQDs, which is comparable to that of Pt counter electrode-based DSSCs. This work provides an inexpensive alternative to replace platinum for DSSCs.

  2. Fabrication and Protein Conjugation of Aligned Polypyrrole-Poly(L-lactic acid) Fibers Film with the Conductivity and Stability.

    Science.gov (United States)

    Qin, Jiabang; Huang, Zhongbing; Yin, Guangfu; Yang, Anneng; Han, Wei

    2016-03-01

    The conducting composite scaffold, including fiber-cores of aligned poly(L-lactic acid) (PLLA) and shell-layer of polypyrrole (PPy), was fabricated, and then bovine serum albumin (BSA) was conjugated on the PPy shell-layer. Aligned PLLA fibers (about 300 nm diameter) were obtained by electrospinning and rotating drum collection, and then coated by PPy nanoparticles (NPs, about 50 nm diameter) via chemical oxidation. The surface resistivity of PPy-PLLA fibers film were 0.971, 0.874 kΩ. cm at the fiber's vertical and parallel directions, respectively. The results of PPy-PLLA fibers film immersed in phosphate buffer saline for 8 d indicated that the fibers morphology and the film conductivity were not significantly changed, and the fluorescent images showed that FITC-labeled BSA (FITC-BSA) were successfully conjugated in the fibers film with carbodiimide chemistry, and the largest amount of FITC-BSA conjugated in the fibers film from 100 μg/mL proteins solution was 31.31 μg/cm2 due to lots of poly(glutamic acid) in surface-nanogrooves of the fibers surface. Under electrical stimulation of 100 mV, the fibers film was accompanied the release of all conjugated FITC-BSA with the detachment of some PPy NPs. These results suggested that PPy-PLLA fibers film would be potentially applied in the construction of degradable tissue engineering scaffold with protein factors, especially neurotrophic factors for nerve tissue repair.

  3. Cyclic Step-voltammetric Analysis of Cation-driven and Anion-driven Actuation in Polypyrrole Films

    Science.gov (United States)

    Takashima, Wataru; Pandey, Shyam S.; Fuchiwaki, Masaki; Kaneto, Keiichi

    2002-12-01

    Cation-driven and anion-driven electrochemomechanical deformations (ECMD) in electrodeposited polypyrrole (PPy) films have been investigated by means of cyclic voltammetry and cyclic step-voltammetry (CSV). The film deposited from hydrochloric acid (PPyCl) expanded upon anodic reaction (anodic expansion) while that deposited from dodecyl-benzene sulfonic acid (PPyDBS) exhibited cathodic expansion. In the case of the film deposited from p-phenol sulfonic acid (PPyPPS), it was found to show the anodic expansion at 600 mV (vs Ag wire as a reference electrode) along with the cathodic contraction at -800 mV in CSV. The film obtained from the same lot, however, showed cathodic contraction and anodic expansion only by changing the oxidative potential from 600 mV to -100 mV. This phase inversion indicates that not only the polymerization electrolyte but also the redox potential determines the (de)insertion of ions in the PPyPPS film. Contractive electrochemical creeping was only observed in PPyPPS film in chloride salt electrolytes, indicating that the cation insertion induces the deinsertion of initial-dopant anion from the film.

  4. Electroluminescence of doped organic thin films

    Science.gov (United States)

    Tang, C. W.; VanSlyke, S. A.; Chen, C. H.

    1989-05-01

    Electroluminescent (EL) devices are constructed using multilayer organic thin films. The basic structure consists of a hole-transport layer and a luminescent layer. The hole-transport layer is an amorphous diamine film in which the only mobile carrier is the hole. The luminescent layer consists of a host material, 8-hydroxyquinoline aluminum (Alq), which predominantly transports electrons. High radiance has been achieved at an operating voltage of less than 10 V. By doping the Alq layer with highly fluorescent molecules, the EL efficiency has been improved by about a factor of 2 in comparison with the undoped cell. Representative dopants are coumarins and DCMs. The EL quantum efficiency of the doped system is about 2.5%, photon/electron. The EL colors can be readily tuned from the blue-green to orange-red by a suitable choice of dopants as well as by changing the concentration of the dopant. In the doped system the electron-hole recombination and emission zones can be confined to about 50 Å near the hole-transport interface. In the undoped Alq, the EL emission zone is considerably larger due to exciton diffusion. The multilayer doped EL structure offers a simple means for the direct determination of exciton diffusion length.

  5. Morphology and film formation of poly(butyl methacrylate)-polypyrrole core-shell latex particles

    NARCIS (Netherlands)

    Huijs, F; Lang, J

    Core-shell latex particles made of a poly(butyl methacrylate) (PBMA) core and a thin polypyrrole (PPy) shell were synthesized by two-stage polymerization. In the first stage, PBMA latex particles were synthesized in a semicontinuous process by free-radical polymerization. PBMA latex particles were

  6. A voltammetry study on the diffusion of counter ions in polypyrrole films

    DEFF Research Database (Denmark)

    Careem, M.A.; Velmurugu, Yogambigai; Skaarup, Steen

    2006-01-01

    in 0.1 M NaCl reflecting that the amount of salt and solvent taken up by the polymer is linked to the electrolyte composition by osmotic balances. These findings have implications for the design of polypyrrole based electrodes and actuators that are required to operate at higher frequencies. (c) 2006...

  7. Composite polypyrrole-containing particles and electrical properties of thin films prepared therefrom

    Czech Academy of Sciences Publication Activity Database

    Lu, Y.; Pich, A.; Adler, H.-J.; Wang, G.; Rais, David; Nešpůrek, Stanislav

    2008-01-01

    Roč. 49, č. 23 (2008), s. 5002-5012 ISSN 0032-3861 R&D Projects: GA AV ČR KAN400720701; GA MŠk OC 138 Institutional research plan: CEZ:AV0Z40500505 Keywords : core - shell particles * polypyrrole * electrical conductivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.331, year: 2008

  8. Conductance measurement by two-line probe method of polypyrrole nano-films formed on mica by admicellar polymerization

    International Nuclear Information System (INIS)

    Mou, C.-Y.; Yuan, W.-L.; Tsai, I-S.; O'Rear, Edgar A.; Barraza, Harry

    2008-01-01

    Measuring the electrical conductance is of importance in fabricating electronic devices based on semiconducting thin films. In this report, electrically conducting polypyrrole (PPy) nano-films were deposited on insulating mica plates by admicellar polymerization. It becomes difficult to measure such film conductance in the lateral direction due the nanometric thickness which only allows for very low electrical current. In order to understand the effects of surfactant on the film conductivity, morphological studies using atomic force microscopy and conductance measurements with a sub-fA multimeter were performed. Higher conductances were found for PPy thin films made using surfactant templates, than that of a bare mica surface. Using the two-line probe method by drawing two lines of silver glue 8 mm apart on the sample surface, the current-voltage curves of bare mica surface yielded a lateral conductance of 6.0 x 10 -13 S. In comparison, PPy thin films made using sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) as surfactant templates showed conductances of 1.2 x 10 -11 S and 7.7 x 10 -12 S, respectively. The higher conductances indicate tunneling, hopping, and percolation of charge carriers throughout the films. The lower-bound conductivities were calculated as 4.0 x 10 -3 S/cm and 2.6 x 10 -3 S/cm, measured based on the average thickness 2.3 nm for the SDS-PPy films and 2.4 nm for the CTAB-PPy films. Conductivities for both SDS and CTAB template PPy films are found to be of the same order

  9. Conductance measurement by two-line probe method of polypyrrole nano-films formed on mica by admicellar polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mou, C.-Y. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Yuan, W.-L. [Department of Chemical Engineering, Feng Chia University, Taichung 40724, Taiwan (China)], E-mail: wyuan@fcu.edu.tw; Tsai, I-S. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); O' Rear, Edgar A. [School of Chemical, Biological and Material Engineering, University of Oklahoma, Norman, OK 73019 (United States); Barraza, Harry [Unilever R and D HPC, Quarry Road East, Bebington, Wirral, CH63 3JW (United Kingdom)

    2008-10-01

    Measuring the electrical conductance is of importance in fabricating electronic devices based on semiconducting thin films. In this report, electrically conducting polypyrrole (PPy) nano-films were deposited on insulating mica plates by admicellar polymerization. It becomes difficult to measure such film conductance in the lateral direction due the nanometric thickness which only allows for very low electrical current. In order to understand the effects of surfactant on the film conductivity, morphological studies using atomic force microscopy and conductance measurements with a sub-fA multimeter were performed. Higher conductances were found for PPy thin films made using surfactant templates, than that of a bare mica surface. Using the two-line probe method by drawing two lines of silver glue 8 mm apart on the sample surface, the current-voltage curves of bare mica surface yielded a lateral conductance of 6.0 x 10{sup -13} S. In comparison, PPy thin films made using sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) as surfactant templates showed conductances of 1.2 x 10{sup -11} S and 7.7 x 10{sup -12} S, respectively. The higher conductances indicate tunneling, hopping, and percolation of charge carriers throughout the films. The lower-bound conductivities were calculated as 4.0 x 10{sup -3} S/cm and 2.6 x 10{sup -3} S/cm, measured based on the average thickness 2.3 nm for the SDS-PPy films and 2.4 nm for the CTAB-PPy films. Conductivities for both SDS and CTAB template PPy films are found to be of the same order.

  10. Cu doped AlSb polycrystalline thin films

    International Nuclear Information System (INIS)

    Wu Lili; Jin Shuo; Zeng Guanggen; Zhang Jingquan; Li Wei; Feng Lianghuan; Li Bing; Wang Wenwu

    2013-01-01

    Cu-doped AlSb polycrystalline films were grown on quartz glass by magnetron co-sputtering. The structural, morphological and electrical properties of the films were studied. The incorporation of copper atoms can result in the increase of lattice constants, and annealing is helpful to eliminate this deformation. Cu-doped AlSb films exhibit weak n-type conductivity. The results show that the doping effect has a close relationship with the annealing process, meaning that the position of Cu atom in AlSb polycrystalline films might influence the doping effect. (semiconductor materials)

  11. L-lactic acid and sodium p-toluenesulfonate co-doped polypyrrole for high performance cathode in sodium ion battery

    Science.gov (United States)

    Liao, Qishu; Hou, Hongying; Liu, Xianxi; Yao, Yuan; Dai, Zhipeng; Yu, Chengyi; Li, Dongdong

    2018-04-01

    In this work, polypyrrole (PPy) was co-doped with L-lactic acid (LA) and sodium p-toluenesulfonate (TsONa) for high performance cathode in sodium ion battery (SIB) via facile one-step electropolymerization on Fe foil. The as-synthesized LA/TsONa co-doped PPy cathode was investigated in terms of scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), galvanostatic charge/discharge and cyclic voltammetry (CV). The results suggested that some oval-bud-like LA/TsONa co-doped PPy particles did form and tightly combine with the surface of Fe foil; furthermore, LA/TsONa co-doped PPy cathode also delivered higher electrochemical performances than TsONa mono-doped PPy cathode. For example, the initial specific discharge capacity was as high as about 124 mAh/g, and the reversible specific capacity still maintained at about 110 mAh/g even after 50 cycles, higher than those of TsONa mono-doped PPy cathode. The synergy effect of multi components of LA/TsONa co-doped PPy cathode should be responsible for high electrochemical performances.

  12. Ammonia detection of 1-D ZnO/polypyrrole nanocomposite: Effect of CSA doping and their structural, chemical, thermal and gas sensing behavior

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); National Centre for Nanosciences& Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India); Shimpi, Navinchandra G, E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India)

    2017-02-28

    Highlights: • Synthesis of 1-Dimensional ZnO-Polypyrrole nanocomposite using In-situ oxidative polymerization technique. • High response ammonia sensing. • Optimization of ZnO content in nanocomposites for maximum sensor response. • Effect of CSA doping on structural, thermal, optical and sensing behavior. • Optimization of CSA concentration for high sensitivity, fast response and recovery time. - Abstract: Nanocomposites of polypyrrole (PPy) with varying concentration of ZnO nanorods (ZnO NRs) were synthesized using in-situ oxidative polymerization technique. The prepared nanocomposites (PPy, PPy-ZnO and CSA doped PPy-ZnO) were studied for various oxidizing and reducing gases at room temperature and found to be more selective towards ammonia gas. Various concentrations of ZnO NRs in Ppy matrix were studied and 15% was found to be optimum in terms of sensor response (66% towards 120 ppm NH{sub 3}). Further, with 15% doping of camphor sulphonic acid (CSA) in PPy-ZnO nanocomposite for 15% ZnO NRs in Ppy matrix, sensor response increased from 66 to 79% towards 120 ppm of NH{sub 3}. Structural, Optical and thermal behavior of nanocomposites were studied using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) Spectroscopy, Thermo-gravimetric analysis (TGA) and Field Emission Scanning Electron Microscopy (FESEM). ZnO has been completely embedded inside the polymeric chains as observed from in SEM. Meanwhile, FT-IR spectra indicate better conjugation and interaction in nanocomposites. With CSA doping interaction grows stronger due to extended delocalization over π electrons leading to higher sensor response and with response time and recovery time of 24 s and 34 s respectively. CSA doped PPy-ZnO (15%) nanocomposites observed to be a potential candidate for ammonia detection at lower ppm level.

  13. Electrocatalytic properties of polypyrrole films prepared with platinate(II) counter-ions

    Czech Academy of Sciences Publication Activity Database

    Holzhauser, P.; Bouzek, K.; Bastl, Zdeněk

    2005-01-01

    Roč. 155, č. 3 (2005), s. 501-508 ISSN 0379-6779 R&D Projects: GA ČR GA104/02/0664 Grant - others:European Union, Apollon project(XE) ENK5-CT-2001-00572 Institutional research plan: CEZ:AV0Z40400503 Keywords : fuel cell * polypyrrole * platinum * electrocatalysis * hydrogen oxidation reaction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.320, year: 2005

  14. DNA damage due to perfluorooctane sulfonate based on nano-gold embedded in nano-porous poly-pyrrole film

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Liping, E-mail: lipinglu@bjut.edu.cn; Xu, Laihui; Kang, Tianfang; Cheng, Shuiyuan

    2013-11-01

    DNA damage induced from perfluorooctane sulfonate (PFOS) was further developed on a nano-porous bionic interface. The interface was formed by assembling DNA on nano-gold particles which were embedded in a nano-porous overoxidized polypyrrole film (OPPy). Atomic force microscopy, scanning electron microscope and electrochemical investigations indicate that OPPy can be treated to form nano-pore structures. DNA damage due to PFOS was proved using electrochemistry and X-ray photoelectron spectroscopy (XPS) and was investigated by detecting differential pulse voltammetry (DPV) response of methylene blue (MB) which was used as electro-active indicator in the system. The current of MB attenuates obviously after incubation of DNA in PFOS. Moreover, electrochemical impedance spectroscopy (EIS) demonstrates that PFOS weakens DNA charge transport. The tentative binding ratio of PFOS: DNA base pair was obtained by analyzing XPS data of this system.

  15. Photoluminescence of Titanium-Doped Zinc Orthosilicate Phosphor Gel Films

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Mu-Tsun; Wu, Jun-Min; Lin, Jian-You [Department of Materials Science and Engineering, National Formosa University, PO Box 385 Douliu, Yunlin 640, Taiwan (China); Lu, Fu-Hsing; Wang, Yen-Kai, E-mail: mttsai@ms23.hinet.net [Department of Materials Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China)

    2011-10-29

    Titanium-doped zinc orthosilicate ({alpha}-Zn{sub 2}SiO{sub 4}:Ti) phosphor thin films were deposited on silicon wafer substrates by the sol-gel process. The crystallization processes and photoluminescence properties of the films were investigated. X-ray diffraction revealed that the dried films were amorphous and converted into single-phase willemite structure following annealed at 600 deg. C and above. Upon thermal annealing at 800 deg. C - 1000 deg. C, Ti-doped willemite thin films had the average crystallite sizes of 17{approx}28 nm. The luminescence properties of phosphor films were characterized by excitation and emission spectra. Photoluminescence spectra of Ti-doped films exhibited prominent blue emission bands centered at 402 nm under an excitation wavelength of 225 nm. The emission intensity was dependent on the level of titanium doping, annealing temperature, and film thickness.

  16. Corrosion protection of AISI 1018 steel using Co-doped TiO{sub 2}/polypyrrole nanocomposites in 3.5% NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Ladan, Magaji, E-mail: ladanmagaji@yahoo.com [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, 50603 (Malaysia); Department of Pure and Industrial Chemistry, Bayero University Kano (Nigeria); Basirun, Wan Jeffrey, E-mail: jeff@um.edu.my [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, 50603 (Malaysia); Institute of Nanotechnology and Catalysis (NanoCat), University of Malaya, Kuala Lumpur, 50603 (Malaysia); Kazi, Salim Newaz; Rahman, Fariza Abdul [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, 50603 (Malaysia)

    2017-05-01

    A polypyrrole nanocomposites (PPy NTCs) have been effectively synthesized in the presence of TiO{sub 2} and Co-doped TiO{sub 2} nanoparticles (NPs) by an in situ chemical oxidative polymerization. Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy revealed a tube shape structure of the PPy. The TEM results confirmed that the nanocomposite size of Co-doped TiO{sub 2}/PPy NTCs was smaller than TiO{sub 2}/PPy NTCs thereby increasing the interaction between the PPy nanotube and the AISI steel surface. The corrosion performance of the coatings was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements in 3.5% NaCl solution. The EIS results show that the log |Z| of AISI 1018 coated with Co-doped TiO{sub 2}/PPy NTCs and TiO{sub 2}/PPy NTCs reached about 8.2 and 6.0 respectively after 30 days of exposure in 3.5% NaCl solution. This is likely due to the increased surface area of the PPy synthesized in the presence of Co-doped TiO{sub 2} NPs. The EIS results are confirmed by the potentiodynamic polarization and open circuit potential values of the Co-doped TiO{sub 2}/PPy which indicated little changes between 1 and 30 days of exposure which confirms the protection ability of this coating. . It is evident that the presence of Co-doped TiO{sub 2} NPs can enhance the resistance against corrosion at the steel/electrolyte interface. - Highlights: • Polymerization of pyrrole monomer in the presence of Co-doped TiO{sub 2} decreases the size of the polypyrrole nanotube (PPy NT). • The corrosion protection increases with the increase in PPy NT dispersion. • The corrosion resistance of steel coated with Co-doped TiO{sub 2}/PPy NTCs is considerably higher. • TiO{sub 2}/PPy with Co doping reduces the charge transfer across the electrolyte/AISI 1018 steel interface.

  17. Hybrid thin films based on bilayer heterojunction of titania nanocrystals/polypyrrole/natural dyes (Kappaphycus alvarezii) materials

    Science.gov (United States)

    Ghazali, Salmah Mohd; Salleh, Hasiah; Dagang, Ahmad Nazri; Ghazali, Mohd Sabri Mohd; Ali, Nik Aziz Nik; Rashid, Norlaily Abdul; Kamarulzaman, Nurul Huda; Ahmad, Wan Almaz Dhafina Che Wan

    2017-09-01

    In this research, hybrid thin films which consist of a combination of organic red seaweed (RS) (Kappaphycus alvarezii) and polypyrrole (PPy) with inorganic titania nanocrystals (TiO2 NCs) materials were fabricated. These hybrid thin films were fabricated accordingly with bilayer heterojunction of ITO/TiO2 NCs/PPy/RS via electrochemical method using Electrochemical Impedance Spectroscopy (EIS). The effect of number of scans (thickness) of titania on optical and electrical properties of hybrid thin films were studied. TiO2 NCs function as an electron acceptor and electronic conductor. Meanwhile, PPy acts as holes conductor and RS dye acts as a photosensitizer enhances the optical and electrical properties of the thin films. The UV absorption spectrum of TiO2 NCs, PPy and RS are characterized by UV-Visible spectroscopy, while the functional group of RS was characterized by Fourier transform infrared spectroscopy (FTIR). The UV-Vis spectra showed that TiO2 NCs, PPy and RS were absorbed over a wide range of light spectrum which were 200-300 nm, 300-900 nm and 250-900 nm; respectively. The FTIR spectra of the RS showed the presence of hydroxyl group which was responsible for a good sensitizer for these hybrid solar cells. The electrical conductivity of these hybrid thin films were measured by using four point probes. The electrical conductivity of ITO/ (1)TiO2 NCs/PPy/RS thin film under the radiation of 100 Wm-2 was 0.062 Scm-1, hence this hybrid thin films can be applied in solar cell application.

  18. Electrostatic spray deposition of doped ceria films

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.B.; Chang, C.L.; Hwang, B.H. [Department of Materials Science and Optoelectronics Engineering, National Sun Yat-Sen University, Kaohsiung 80424 (China); Hsu, C.S. [Kaohsiung Municipal Chung-Cheng Industrial High School, Kaohsiung 80656 (China)

    2010-12-15

    Dense and thin electrolyte films are desirable for solid oxide fuel cells (SOFCs) because of their low gas leakage and low ohmic resistances. This work aims at the preparation of thin dense Gd-doped ceria (CGO) electrolyte films using a cost-effective deposition method in ambient atmosphere-electrostatic spray deposition (ESD). The deposition parameters such as deposition temperature, concentration and flow rate of precursor solution were changed systematically to examine their effects on film morphology and hence electrochemical performance. While the film morphology was examined by a scanning electron microscope, the electrochemical performance was revealed by measuring open circuit voltages (OCVs) of NiO-CGO/CGO/Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF) cells in 500-700 C with humidified hydrogen as fuel and air as oxidant. The results show that a CGO film of 25 {mu}m thick obtained at a deposition temperature of 400 C, a precursor solution flow rate of 6 ml h{sup -1} and a precursor concentration of 0.3 M was dense with very few isolated pores and the OCV of the associated cell was 0.915 V at 500 C. This implies that the CGO film has negligible gas leakage and ESD is a promising method for preparing thin dense electrolyte films for SOFCs. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Electrodeposition of polypyrrole-multiwalled carbon nanotube-glucose oxidase nanobiocomposite film for the detection of glucose.

    Science.gov (United States)

    Tsai, Yu-Chen; Li, Shih-Ci; Liao, Shang-Wei

    2006-10-15

    A nanobiocomposite film consisted of polypyrrole (PPy), functionalized multiwalled carbon nanotubes (cMWNTs), and glucose oxidase (GOx) were electrochemically synthesized by electrooxidation of 0.1M pyrrole in aqueous solution containing appropriate amounts of cMWNTs and GOx. Potentiostatic growth profiles indicate that the anionic cMWNTs is incorporated within the growing PPy-cMWNTs nanocomposite for maintaining its electrical neutrality. The morphology of the PPy-cMWNTs nanocomposite was characterized by scanning electron microscopy (SEM). The PPy-cMWNTs nanocomposite was deposited homogeneously onto glassy carbon electrode. The amperometric responses vary proportionately to the concentration of hydrogen peroxide at the PPy-cMWNTs nanocomposite modified electrode at an operating potential of 0.7V versus Ag/AgCl (3M). The results indicate that the electroanalytical PPy-cMWNTs-GOx nanobiocomposite film was highly sensitive and suitable for glucose biosensor based on GOx function. The GOx concentration within the PPy-cMWNTs-GOx nanobiocomposite and the film thickness are crucial for the performance of the glucose biosensor. The amperometric responses of the optimized PPy-cMWNTs-GOx glucose biosensor (1.5 mgmL(-1) GOx, 141 mCcm(-2) total charge) displayed a sensitivity of 95 nAmM(-1), a linear range up to 4mM, and a response time of about 8s.

  20. Mechanical properties of phosphorus-doped polysilicon films

    CERN Document Server

    Lee, S W; Kim, J P; Park, S J; Yi, S W; Cho, D I; Kim, J J

    1998-01-01

    Polysilicon films deposited by low pressure chemical vapor deposition (LPCVD) are the most widely used structural material in microelectromechanical systems (MEMS). However, the structural properties of LPCVD polysilicon films are known to vary significantly, depending on deposition conditions as well as post-deposition processes. This paper investigates the effects of phosphorus doping and texture on Young's modulus of polysilicon films. Polysilicon films are deposited at 585 .deg. C, 605 .deg. C, and 625 .deg. C to a thickness of 2 mu m. Specimens with varying phosphorus doping levels are prepared by the diffusion process at various temperatures and times using both POCl sub 3 and phosphosilicate glass (PSG) source. Texture is measured using an X-ray diffractometer. Young's modulus is estimated from the average values of the resonant frequencies measured from four-different size lateral resonators. Our results show that Young's modulus of diffusion doped polysilicon films decreases with increasing doping co...

  1. Characterization of electrogenerated polypyrrole-benzophenone films coated on poly(pyrrole-methyl metacrylate) optic-conductive fibers.

    Science.gov (United States)

    Abu-Rabeah, Khalil; Atias, Danit; Herrmann, Sebastien; Frenkel, Julia; Tavor, Dorith; Cosnier, Serge; Marks, Robert S

    2009-09-01

    A conductive surface was created for the development of a biosensing platform via chemical polymerization of pyrrole onto the surface of poly(methyl methacrylate) (PMMA) fibers, with a subsequent electrogeneration of a photoactive linker pyrrole-benzophenone (PyBz) monomer on the fiber surface. Irradiation of the benzophenone groups embedded in the polypyrrole (Ppy) films by UV (350 nm) formed active radicals, allowing covalent attachment of the desired biomaterials. Characterization and optimization of this platform were carried out, with the platform showing conductive, stable, thin, controllable, and light-transmissible film features. Various parameters such as time deposition, process temperature, and activator plus pyrrole monomer concentrations were examined in the study. The morphology and permeability of the optic-fiber PMMA fibers were investigated to examine mass transfer ability. Cyclic voltammetry and amperometry techniques were applied to characterize the electrical features of the surface and charge transfer. The platform potential was then demonstrated by the construction of both amperometric and optical biosensors.

  2. Energy storage in hybrid organic-inorganic materials hexacyanoferrate-doped polypyrrole as cathode in reversible lithium cells

    DEFF Research Database (Denmark)

    Torres-Gomez, G,; Skaarup, Steen; West, Keld

    2000-01-01

    A study of the hybrid oganic-inorganic hexacyanoferrate-polypyrrole material as a cathode in rechargeable lithium cells is reported as part of a series of functional hybrid materials that represent a new concept in energy storage. The effect of synthesis temperatures of the hybrid in the specific...

  3. Correlation of carrier localization with relaxation time distribution and electrical conductivity relaxation in silver-nanoparticle-embedded moderately doped polypyrrole nanostructures

    Science.gov (United States)

    Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

    2014-02-01

    The electrical conductivity relaxation in moderately doped polypyrrole and its nanocomposites reinforced with different proportion of silver nanoparticles was investigated in both frequency and time domain. An analytical distribution function of relaxation times is constructed from the results obtained in the frequency domain formalism and is used to evaluate the Kohlrausch-Williams-Watts (KWW) type decay function in the time domain. The thermal evolution of different relaxation parameters was analyzed. The temperature-dependent dc electrical conductivity, estimated from the average conductivity relaxation time is observed to depend strongly on the nanoparticle loading and follows Mott three-dimensional variable range hopping (VRH) conduction mechanism. The extent of charge carrier localization calculated from the VRH mechanism is well correlated to the evidences obtained from the structural characterizations of different nanostructured samples.

  4. Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films

    National Research Council Canada - National Science Library

    Blasy, Bryan D

    2008-01-01

    ... retains monoclinic local symmetery for all levels of doping. Current as a function of voltage experiments identified the films as having poor diode characteristics with high leakage current in the forward bias region...

  5. 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...

  6. Doped nanostructured zinc oxide films grown by electrodeposition.

    Science.gov (United States)

    Donderis, V; Orozco, J; Cembrero, J; Curiel-Esparza, J; Damonte, L C; Hernández-Fenollosa, M A

    2010-02-01

    ZnO thin films doped with either In or Al are n-type oxide materials of interest for application in electronic devices and thin-film solar cells. In this work, the doped ZnO films were electrodeposited at 80 degrees C from an aqueous solution on polycrystalline conductive Indium Tin Oxide covered glass substrates. The incorporation of the dopants into the ZnO film has been verified by energy dispersive X-ray spectrum, X-Ray diffraction and optical transmission analysis. The optical and surface structure properties of the ZnO doped films are strongly affected by the In and Al concentrations in the electrodeposition solution as evidenced by optical transmission and reflection measurements, and scanning electron microscopy.

  7. Optical modelling of photoluminescence emitted by thin doped films

    International Nuclear Information System (INIS)

    Pigeat, P.; Easwarakhanthan, T.; Briancon, J.L.; Rinnert, H.

    2011-01-01

    Photoluminescence (PL) spectra emitted by doped films are deformed owing to film thickness-dependent wave interference. This hampers knowing well their PL generating mechanisms as well as designing photonic devices with suitable geometries that improve their PL efficiency. We develop in this paper an energy model for PL emitted by doped films considering the interaction between the wavelength-differing incident standing and emitted waves, their energy transfer in-between, and the interferences undergone by both. The film optical constants are estimated fitting the model to the measured PL. This simple model has thus allowed us to interpret the evolution of PL emitted by Er-doped AlN films prepared on Si substrates by reactive magnetron sputtering. The shapes, the amplitudes, and the illusive sub-spectral features of the PL spectra depend essentially on the film thickness. The model further predicts high sensitivity for PL emitted by non-homogenously doped stacked-films to incident light wavelengths and film-thickness variations. This property has potential applications in tracking wavelength variations and in measuring physical quantities producing thickness variations. This model may be used to optimise PL efficiency of photonic devices through different film geometries and optical properties.

  8. Optical Properies of Polystyrene Films Doped by Methyl Green Dye

    Directory of Open Access Journals (Sweden)

    Asrar A. Saeed

    2017-11-01

    Full Text Available Effects of methyl green (MG dye on the optical properties of polystyrene (PS have been studied. Pure polystyrene and MG doped PS films were prepared by using casting method. These films were characterized using UV/VIS spectrophotometer technique in order to estimate the type of electric transition which was found to be indirect transition. The value of the optical energy gap was decreased with increasing doping ratios of methyl green dye. Absorption coefficient, extinction coefficient, refractive index and energy gap have been also investigated; it was found that all the above parameters affects by doping dye.

  9. Polypyrrole Film as a Drug Delivery System for the Controlled Release of Risperidone

    Science.gov (United States)

    Svirskis, Darren; Travas-Sejdic, Jadranka; Rodgers, Anthony; Garg, Sanjay

    2009-07-01

    Conducting polymers are finding applications in medicine including drug delivery systems, biosensors and templates for the regeneration of nervous pathways. We aim to develop a novel system where the drug release rate can be controlled by electrical stimulation. Polypyrrole (PPY) is being used as a drug delivery system due to its inherent electrical conductivity, ease of preparation and apparent biocompatibility. Risperidone is an atypical antipsychotic drug used in the treatment of psychosis and related disorders, including schizophrenia. PPY was synthesised using p-toluene sulfonic acid as a primary dopant, in the presence of risperidone. A validated high performance liquid chromatography (HPLC) analytical method was used to quantify risperidone release. It has been demonstrated that the release rate of risperidone can be altered through the application, or absence, of electrical stimulation. Technology such as this would find use in drug-delivering implants where the dose could be adjusted through application of external stimulus, optimising benefit to side effect ratio, while simultaneously ensuring patient adherence (which is a particular challenge in mental health conditions).

  10. 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.

  11. Rhenium-doped MoS2 films

    Science.gov (United States)

    Hallam, Toby; Monaghan, Scott; Gity, Farzan; Ansari, Lida; Schmidt, Michael; Downing, Clive; Cullen, Conor P.; Nicolosi, Valeria; Hurley, Paul K.; Duesberg, Georg S.

    2017-11-01

    Tailoring the electrical properties of transition metal dichalcogenides by doping is one of the biggest challenges for the application of 2D materials in future electronic devices. Here, we report on a straightforward approach to the n-type doping of molybdenum disulfide (MoS2) films with rhenium (Re). High-Resolution Scanning Transmission Electron Microscopy and Energy-Dispersive X-ray spectroscopy are used to identify Re in interstitial and lattice sites of the MoS2 structure. Hall-effect measurements confirm the electron donating influence of Re in MoS2, while the nominally undoped films exhibit a net p-type doping. Density functional theory (DFT) modelling indicates that Re on Mo sites is the origin of the n-type doping, whereas S-vacancies have a p-type nature, providing an explanation for the p-type behaviour of nominally undoped MoS2 films.

  12. Understanding of electrochemical and structural changes of polypyrrole/polyethylene glycol composite films in aqueous solution

    International Nuclear Information System (INIS)

    Pirvu, Cristian; Manole, Claudiu Constantin; Stoian, Andrei Bogdan; Demetrescu, Ioana

    2011-01-01

    Highlights: → Electrochemical monitoring of PPy and PPy-PEG films over immersion time. → Electrochemical and surface analysis showed that PEG improves the stability of PPy films. → Mott-Schottky analysis reveals p-type conductance for both films. → In situ AFM analysis sustains electrochemical behaviour. → A model of PPy and PPy-PEG films behaviour during immersion was elaborated. - Abstract: Electrochemical monitoring of electrical and structural changes of both PPy and PPy-PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated. Electrochemical analysis suggests that PPy-PEG film inserts cations easier than PPy film for a short immersion time probably due to ability of PEG to form complexes with metal cations. The FTIR spectra showed that the PEG incorporation decreases the rate of PPy overoxidation probably by restraining the electron release and by rendering O 2 inaccessible to PPy. Mott-Schottky analysis based on capacitance measurement reveal p-type conductance for both films. The in situ AFM analysis sustains electrochemical behaviour and has permitted elaboration of a model of PPy and PPy-PEG films behaviour during immersion in testing solution.

  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. Silver incorporated polypyrrole/polyacrylic acid electrode for electrochemical supercapacitor

    Science.gov (United States)

    Patil, Dipali S.; Pawar, Sachin A.; Kamble, Archana S.; Patil, Pramod S.

    2013-06-01

    In the present work, we study Ag doping effect on the specific capacitance of Polypyrrole/Polyacrylic Acid (PPy/PAA). Ag incorporated films were prepared by simple chemical route. Fourier transform-infrared and Fourier transform-Raman techniques were used for the phase identification. Surface morphology of the films was examined by Field Emission scanning electron microscopy and revealed granular structure for PPY, attached granules for PPy/PAA and granules with bright spots of Ag particles for the PPy/PAA/Ag films. The supercapacitive behavior of the electrodes was tested in three electrode system with 0.1 M H2SO4 electrolyte by using cyclic voltammetry. The highest specific capacitance value 226 Fg-1 was observed for the PPy/PAA/Ag film.

  15. Ammonia detection of 1-D ZnO/polypyrrole nanocomposite: Effect of CSA doping and their structural, chemical, thermal and gas sensing behavior

    Science.gov (United States)

    Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D. C.; Mishra, Satyendra; Shimpi, Navinchandra G.

    2017-02-01

    Nanocomposites of polypyrrole (PPy) with varying concentration of ZnO nanorods (ZnO NRs) were synthesized using in-situ oxidative polymerization technique. The prepared nanocomposites (PPy, PPy-ZnO and CSA doped PPy-ZnO) were studied for various oxidizing and reducing gases at room temperature and found to be more selective towards ammonia gas. Various concentrations of ZnO NRs in Ppy matrix were studied and 15% was found to be optimum in terms of sensor response (66% towards 120 ppm NH3). Further, with 15% doping of camphor sulphonic acid (CSA) in PPy-ZnO nanocomposite for 15% ZnO NRs in Ppy matrix, sensor response increased from 66 to 79% towards 120 ppm of NH3. Structural, Optical and thermal behavior of nanocomposites were studied using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), UV-vis (UV-vis) absorption spectroscopy, room temperature Photoluminescence (PL) Spectroscopy, Thermo-gravimetric analysis (TGA) and Field Emission Scanning Electron Microscopy (FESEM). ZnO has been completely embedded inside the polymeric chains as observed from in SEM. Meanwhile, FT-IR spectra indicate better conjugation and interaction in nanocomposites. With CSA doping interaction grows stronger due to extended delocalization over π electrons leading to higher sensor response and with response time and recovery time of 24 s and 34 s respectively. CSA doped PPy-ZnO (15%) nanocomposites observed to be a potential candidate for ammonia detection at lower ppm level.

  16. Effect of anionic dopants on thickness, morphology and electrical properties of polypyrrole ultra-thin films prepared by in situ chemical polymerization

    International Nuclear Information System (INIS)

    Mahmoodian, Mehrnoosh; Pourabbas, Behzad; Mohajerzadeh, Shams

    2015-01-01

    The effect of different dopant anions on deposition and characteristics of polypyrrole (PPy) thin film has been studied in this work. Ultra-thin films of conducting PPy were deposited on insulating surfaces of glass and oxidized silicon wafer by in situ chemical polymerization in the presence of different anionic dopants including sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, α-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate, and camphor sulfonic acid. Hydrophilic/hydrophobic properties and morphology of the self-assembled monolayer of N-(3-trimethoxysilylpropyl)pyrrole, the surface modifying agent in this work, and PPy thin films were characterized before and after deposition by contact angle measurements, field emission scanning electron microscopy, and atomic force microscopy. Chemical structure, thickness, and conductivity of the thin films were also studied by attenuated total reflectance Fourier transform infrared spectrometer, ellipsometry, and four-point probe measurements. The results showed deposition of thin films of conducting PPy with comparable thickness in the range of 6-31 nm and different morphologies, uniformity, and smoothness with average roughness in the range of 0.3-6 nm and relatively high range of conductivity on the modified surfaces. - Highlights: • Conducting thin films of polypyrrole were deposited on glass and SiO 2 substrates. • Surface modification using pyrrole-silane was employed prior to polymerization. • Films as thin as ≈ 7 nm were deposited using different surfactant/counter ions. • Chemistry of the counter ion affects thickness, conductivity and morphology. • Lower thickness/higher conductivity were obtained by structurally flexible dopants

  17. Effect of anionic dopants on thickness, morphology and electrical properties of polypyrrole ultra-thin films prepared by in situ chemical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodian, Mehrnoosh [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Pourabbas, Behzad, E-mail: pourabas@sut.ac.ir [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Mohajerzadeh, Shams [Nano-Electronics and Thin Film Lab, School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran (Iran, Islamic Republic of)

    2015-05-29

    The effect of different dopant anions on deposition and characteristics of polypyrrole (PPy) thin film has been studied in this work. Ultra-thin films of conducting PPy were deposited on insulating surfaces of glass and oxidized silicon wafer by in situ chemical polymerization in the presence of different anionic dopants including sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, α-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate, and camphor sulfonic acid. Hydrophilic/hydrophobic properties and morphology of the self-assembled monolayer of N-(3-trimethoxysilylpropyl)pyrrole, the surface modifying agent in this work, and PPy thin films were characterized before and after deposition by contact angle measurements, field emission scanning electron microscopy, and atomic force microscopy. Chemical structure, thickness, and conductivity of the thin films were also studied by attenuated total reflectance Fourier transform infrared spectrometer, ellipsometry, and four-point probe measurements. The results showed deposition of thin films of conducting PPy with comparable thickness in the range of 6-31 nm and different morphologies, uniformity, and smoothness with average roughness in the range of 0.3-6 nm and relatively high range of conductivity on the modified surfaces. - Highlights: • Conducting thin films of polypyrrole were deposited on glass and SiO{sub 2} substrates. • Surface modification using pyrrole-silane was employed prior to polymerization. • Films as thin as ≈ 7 nm were deposited using different surfactant/counter ions. • Chemistry of the counter ion affects thickness, conductivity and morphology. • Lower thickness/higher conductivity were obtained by structurally flexible dopants.

  18. A layer-by-layer assembled graphene/zinc sulfide/polypyrrole thin-film electrode via electrophoretic deposition for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sookhakian, M., E-mail: m.sokhakian@gmail.com [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Amin, Y.M. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Baradaran, S. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Tajabadi, M.T. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Golsheikh, A. Moradi [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Nanotechnology and Catalysis Research Centre, Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-02-03

    An organic–inorganic photovoltaic electrode consisting of graphene nanosheets, zinc sulfide nanoparticles (ZnS) and polypyrrole nanotubes (PPy) was fabricated on indium tin oxide (ITO) glass using layer-by-layer electrophoretic deposition. The morphology and structure of the as-fabricated electrode were confirmed by X-ray diffraction, high resolution transmission electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. The photovoltaic properties of the ZnS, ZnS/PPy (ZP) and graphene/ZnS/PPy (GZP) ternary composite films modified on ITO electrodes were investigated for their solar cell performance. Both transient photocurrent and current–voltage curve measurements illustrated that the photocurrent and the power conversion efficiency of the GZP ternary composite film were significantly enhanced compared to the ZnS and ZP films. Based on these results, PPy nanotubes are an excellent sensitizer and hole acceptor, ZnS nanoparticles act as a bridge and graphene nanosheets are an excellent conductive collector and transporter, which means that, altogether, this combination of materials can significantly increase the photovoltaic efficiency. - Highlights: • Zinc sulfide (ZnS)/polypyrrole(PPy)/graphene by electrophoretic deposition • Support of ZnS/PPy composite shows efficient performance of organic–inorganic solar cell. • Current–voltage curve and transient current improved in the presence of graphene.

  19. Application of Thin Films of Polyaniline and Polypyrrole in Novel Light-Emitting Devices

    National Research Council Canada - National Science Library

    MacDiarmid, A

    1997-01-01

    Light-emitting electroluminescent devices are described in which the conjugated light emitting polymer is separated from one or both of the device electrodes by a film of non-conducting polyaniline...

  20. Composite films of Prussian blue and N-substituted polypyrroles: covalent immobilization of enzymes and application to near infrared optical biosensing.

    Science.gov (United States)

    Koncki, R; Wolfbeis, O S

    1999-01-01

    We demonstrate the feasibility of optical biosensing using a material which, in essence, is a modified inorganic film to which various enzymes were covalently attached. Thin and transparent blue films composed of Prussian blue and incorporated into a network of N-substituted polypyrroles are sensitive to pH in the 5-9 range at 720 nm wavelength and can be modified with enzymes to result in the respective biosensors. Several methods of enzyme immobilization, using bifunctional crosslinking reagents, and various enzymes were tested. The best results were obtained using the one-step carbodiimide method which resulted in highly active, stable and transparent biosensor films for optical determination of urea and acetylcholine. The operational stability exceeded 1 month and even after 2 months of dry storage at room temperature the activity did not drop. The biosensors allow optical determination of the respective substrates in the millimolar concentration range.

  1. Surfactant Effect in Polypyrrole and Polypyrrole with Multi Wall Carbon Nanotube Counter Electrodes: Improved Power Conversion Efficiency of Dye-Sensitized Solar Cell.

    Science.gov (United States)

    Thuy, Chau Thi Thanh; Park, Ji Young; Lee, Seung Woo; Suresh, Thogiti; Kim, Jae Hong

    2016-05-01

    In our present study, polypyrrole-1 (PPy1), polypyrrole-2 (PPy2), and polypyrrole-2/multi wall carbon nanotube composite film (PPy2/MWCNT) were proposed as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) to replace the precious Pt CE. These films were fabricated on fluorine-doped tin oxide substrates by using a facile electrochemical polymerization route, and served as CEs in DSSCs. It is shown that the introduction of anionic surfactant, sodium dodecyl sulfate (SDS), enhanced the catalytic activity, thus leading to an improvement in the performance of PPy2. Further, introduction of MWCNT resulted in increase in conversion efficiency of DSSCs with PPy2/MWCNT composite film. The Tafel and electrochemical impedance analysis revealed that the PPy2 and PPy2/MWCNT CEs prepared with anionic surfactant possessed more catalytic activity and lower charge transfer resistance in comparison with PPy1 -based CE. This resulted in a better conversion efficiency of 5.88% for PPy2/MWCNT-based DSSC under 1 sun condition, reaching 86% of the DSSC based on reference Pt counter electrode (6.86%). These results indicate that the composite film with high catalytic properties for I3- reduction can potentially be used as the CE in a high-performance DSSC.

  2. Tantalum-doped hydroxyapatite thin films: Synthesis and characterization

    International Nuclear Information System (INIS)

    Ligot, S.; Godfroid, T.; Music, D.; Bousser, E.; Schneider, J.M.; Snyders, R.

    2012-01-01

    To achieve a good bioactivity, magnetron-sputtered (MS) hydroxyapatite (HA) coatings have to be stoichiometric and crystalline. It has also been suggested that doping HA with metallic elements improves its bioactivity but frequently reduces its Young’s modulus. Therefore, efforts are still necessary to identify adequate growth conditions, good doping elements and finally to grow doped HA films. In a first attempt, HA films have been synthesized by MS. Our conditions enabled us to grow at ∼10 nm min −1 stoichiometric and crystallized HA coatings that presented a strong texture. The latter is discussed in view of the competitive growth of the material under the strong electron and ion bombardments used here. Based on ab initio calculations identifying Ta as a promising doping element, we then investigated the growth of Ta-doped hydroxyapatite (HA:Ta) by magnetron co-sputtering. The HA:Ta films were in situ crystallized. Our data reveals that for Ta contents <4.5 at.%, Ta could substitute Ca in the HA cell. For higher doping contents, a deviation from the stoichiometric compound is observed and CaO appears. By nanoindentation, we have measured an elastic modulus of 120 ± 9 GPa for a Ta content of 3 at.%. This value is very close to the value of 110 GPa calculated by ab initio calculations, supporting the substitution scenario. The elasticity drop may be understood by screening of the ionic interaction between constituents in HA upon Ta incorporation.

  3. Electrochemomechanical Behaviour of Bilayer and Trilayer Films with PEDOT and PPY Conducting Polymers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

    2008-01-01

    A detailed study on bilayer and trilayer films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers is reported. Both polymers are doped with dodecyl benzenesulfonate (DBS) anions. These multi layer films were prepared electrochemically so that the PEDOT...

  4. Ion Movement in Polypyrrole/Dodecylbenzenesulphonate Films in aqueous and non-aqueous electrolytes

    DEFF Research Database (Denmark)

    Vidanapathirana, K.; Careem, M.A.; Skaarup, Steen

    2002-01-01

    . Investigations were carried out using aqueous and non-aqueous electrolytes to study the effect of solvent on the ion movement during redox processes. When PPy films are cycled in aqueous electrolytes transport of both anion and cation occurs during oxidation and reduction. However, when cycled in the nonaqueous...... electrolyte propylene carbonate (PC) only anion movement takes place....

  5. RBS and XRD analysis of silicon doped titanium diboride films

    International Nuclear Information System (INIS)

    Mollica, S.; Sood, D.K.; Ghantasala, M.K.; Kothari, R.

    1999-01-01

    Titanium diboride is a newly developed material suitable for protective coatings. Its high temperature oxidation resistance at temperatures of 700 deg C and beyond is limited due to its poor oxidative behaviour. This paper presents a novel approach to improving the coatings' oxidative characteristics at temperatures of 700 deg C by doping with silicon. Titanium diboride films were deposited onto Si(100) wafer substrates using a DC magnetron sputtering system. Films were deposited in two different compositions, one at pure TiB 2 and the other with 20 % Si doping. These samples were vacuum annealed at 700 deg C at 1x10 -6 Torr to investigate the anaerobic behaviour of the material at elevated temperatures and to ensure that they were crystalline. Samples were then oxidised in air at 700 deg C to investigate their oxidation resistance. Annealing the films at 700 deg C in air results in the oxidation of the film as titanium and boron form TiO 2 and B 2 O 3 . Annealing is seen to produce only minor changes in the films. There is some silicon diffusion from the substrate at elevated temperatures, which is related to the porous nature of the deposited film and the high temperature heat treatments. However, silicon doped films showed relatively less oxidation characteristics after annealing in air compared with the pure TiB 2 samples

  6. Phosphorus-doped bismuth telluride films by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jian, E-mail: jzhou@xmu.edu.cn [Department of Materials Science and Engineering, College of Materials, Xiamen 361005 (China); Lin, Qinghan; Li, Hengyi [Department of Materials Science and Engineering, College of Materials, Xiamen 361005 (China); Cheng, Xuan [Department of Materials Science and Engineering, College of Materials, Xiamen 361005 (China); Fujian Key Laboratory of Advanced Materials, Xiamen University, Xiamen 361005 (China)

    2013-08-15

    Phosphorus-doped Bi{sub 2}Te{sub 3} films were synthesized on a stainless-steel electrode by electrochemical deposition. X-ray diffraction, scanning electron microscopy and transmission electron microscopy confirmed that the films are single-phased Bi{sub 2}Te{sub 3} solid solutions with a rhombohedral structure. The as-prepared films exhibit n-type characteristics with the Hall coefficient −1.76E−2 m{sup 3} C{sup −1} and the electrical conductivity 280 S cm{sup −1}. The thermal conductivity is 0.47 W m{sup −1} K{sup −1}, which is as low as one-third of the value observed in the bulk material. The doped P atoms occupy the interstitial positions between the two adjacent Te(1) layers connected by Van der Waals interaction in Bi{sub 2}Te{sub 3}. - Graphical abstract: Display Omitted - Highlights: • Phosphorus-doped Bi{sub 2}Te{sub 3} films were synthesized on a stainless-steel electrode by electrochemical deposition. • The thermal conductivity of the film is 0.47 W m{sup −1} K{sup −1}, which is one-third of the value observed in the bulk material. • The doped P atoms occupy the interstitial positions in Bi{sub 2}Te{sub 3}.

  7. Electrochemical biosensing based on polypyrrole/titania nanotube hybrid

    International Nuclear Information System (INIS)

    Xie, Yibing; Zhao, Ye

    2013-01-01

    The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. - Graphical abstract: The schematic diagram presents the fabrication of glucose oxidase modified polypyrrole/titania (GOD-PPy/TiO 2 ) nanotube enzyme electrode for biosensing application. - Highlights: • Hydrophilic polypyrrole/titania nanotube hybrid is well used as biosensing substrate. • Polypyrrole promotes GOD immobilization on titania nanotubes via glutaraldehyde. • GOD-polypyrrole/titania enzyme electrode shows good bioelectrocatalytic reactivity

  8. An investigation on the electrocatalytic properties of polypyrrole films on the kinetics of oxygen reduction reaction in PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, M.; Sharifi Asl, S.; Kazemi, Sh. [Tehran Univ., Tehran (Iran, Islamic Republic of). School of Metallurgy and Material Science Engineering

    2008-07-01

    A proton exchange membrane (PEM) fuel cell has high power density, low weight, very short start-up time and no leakage of electrolytes. However, there are some disadvantages when operating the PEM fuel cell at room temperature. Many studies involving the widespread commercial use of Pt-based electrocatalysts search for low-cost electrocatalysts for the oxygen reduction reaction. In recent years, much attention has been placed on the use of electrocatalysis for the conducting polymer electrode. Polypyrrole has attracted much attention as an advanced conducting material because of its good environmental stability, easy synthesis and high conductivity. This study examined the effect of the polypyrrole catalyst in a PEMFC cathode. The electropolymerization of pyrrole was carried out in a 3-electrode cell using pure hydrogen and oxygen as the reactants. Tests were carried out at room temperature and cell impedance was measured. The polymer was formed galvanostatically in a 0.1 M pyrrole with a 0.15 KCl aqueous solution with a 20 mA/cm{sup 2} current density. The effect of operating voltage and oxygen mass transport was examined by EIS method, which separates these two phenomena. The study showed that polypyrrole has a catalytic effect for oxygen reduction reaction in PEMFC comparable to a Pt catalyzed electrode. Although the cell potential with polypyrrole was slightly lower than a Pt coated cell, it was found to be more economical. 8 refs., 2 figs.

  9. Ammonium ions determination with polypyrrole modified electrode

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

    Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

  10. Doping graphene films via chemically mediated charge transfer

    Directory of Open Access Journals (Sweden)

    Ishikawa Ryousuke

    2011-01-01

    Full Text Available Abstract Transparent conductive films (TCFs are critical components of a myriad of technologies including flat panel displays, light-emitting diodes, and solar cells. Graphene-based TCFs have attracted a lot of attention because of their high electrical conductivity, transparency, and low cost. Carrier doping of graphene would potentially improve the properties of graphene-based TCFs for practical industrial applications. However, controlling the carrier type and concentration of dopants in graphene films is challenging, especially for the synthesis of p-type films. In this article, a new method for doping graphene using the conjugated organic molecule, tetracyanoquinodimethane (TCNQ, is described. Notably, TCNQ is well known as a powerful electron accepter and is expected to favor electron transfer from graphene into TCNQ molecules, thereby leading to p-type doping of graphene films. Small amounts of TCNQ drastically improved the resistivity without degradation of optical transparency. Our carrier doping method based on charge transfer has a huge potential for graphene-based TCFs.

  11. Characterization of molybdenum-doped indium oxide thin films by ...

    Indian Academy of Sciences (India)

    Abstract. In this research, indium oxide nanostructure undoped and doped with Mo were prepared on glass substrates using spray pyrolysis technique. Various parameters such as dopant concentration and deposition tem- peratures were studied. Structural properties of these films were investigated by X-ray diffraction and ...

  12. Characterization of molybdenum-doped indium oxide thin films by ...

    Indian Academy of Sciences (India)

    In this research, indium oxide nanostructure undoped and doped with Mo were prepared on glass substrates using spray pyrolysis technique. Various parameters such as dopant concentration and deposition temperatures were studied. Structural properties of these films were investigated by X-ray diffraction and scanning ...

  13. Characterization and electrocatalytic application of silver modified polypyrrole electrodes

    OpenAIRE

    A. DEKANSKI; S. TERZIC; V. M. JOVANOVIC

    2005-01-01

    Silver modified polypyrrole electrodeswere preparedwith the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS). The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electroch...

  14. Boron-doped nanocrystalline silicon thin films for solar cells

    International Nuclear Information System (INIS)

    Fathi, E.; Vygranenko, Y.; Vieira, M.; Sazonov, A.

    2011-01-01

    This article reports on the structural, electronic, and optical properties of boron-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films. The films were deposited by plasma-enhanced chemical vapour deposition (PECVD) at a substrate temperature of 150 deg. C. Crystalline volume fraction and dark conductivity of the films were determined as a function of trimethylboron-to-silane flow ratio. Optical constants of doped and undoped nc-Si:H were obtained from transmission and reflection spectra. By employing p + nc-Si:H as a window layer combined with a p' a-SiC buffer layer, a-Si:H-based p-p'-i-n solar cells on ZnO:Al-coated glass substrates were fabricated. Device characteristics were obtained from current-voltage and spectral-response measurements.

  15. Fabrication and Characterization of Nickel Chloride Doped PMMA Films

    Directory of Open Access Journals (Sweden)

    Wasan A. Al-Taa’y

    2015-01-01

    Full Text Available Films of PMMA and PMMA doped with NiCl2 with different contents were prepared using the casting technique. The optical properties of all films were investigated using spectrophotometric measurements of absorbance and transmittance in the wavelength range 200–800 nm. The change of the calculated values of the optical energy gaps with increasing NiCl2 content has been interpreted in terms of the structural modifications of the PMMA matrix. The optical energy gap decreased from 3.6 to 3.05 eV with increasing the NiCl2 concentration to 0.4%. The effect of doping on the optical constants of films such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant, optical conductivity, and skin depth has been reported. All these constants were increased with increasing NiCl2 concentration with the exception of skin depth which is different result.

  16. Electrocatalytic reduction of oxygen at glassy carbon electrode modified by polypyrrole/anthraquinones composite film in various pH media

    International Nuclear Information System (INIS)

    Valarselvan, S.; Manisankar, P.

    2011-01-01

    Graphical abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . Highlights: → Hydroxyl derivatives of anthraquinones as electrocatalysts for dioxygen reduction. → AQ/PPy composite film on GC electrode exhibits potent electrocatalytic activity. → Substituent groups influence electrocatalytic dioxygen reduction. → Surface coverage varies the rate of electrocatalytic dioxygen reduction. - Abstract: The electrocatalytic reduction of dioxygen by one mono and four dihydroxy derivatives of 9,10-anthraquinone (AQ) incorporated in polypyrrole (PPy) matrix on glassy carbon electrode has been investigated. The electrochemical behaviour of the modified electrodes was examined in various pH media and both the formal potential of anthraquinones and reduction potential of dioxygen exhibited pH dependence. AQ and PPy composite film showed excellent electrocatalytic performance for the reduction of O 2 to H 2 O 2 . pH 6.0 was chosen as the most suitable medium to study the electrocatalysis by comparing the peak potential of oxygen reduction and enhancement in peak current for oxygen reduction. The diffusion coefficient values of AQ at the modified electrodes and the number of electrons involved in AQ reduction were evaluated by chronoamperometric and chronocoulometric techniques, respectively. In addition, hydrodynamic voltammetric studies showed the involvement of two electrons in O 2 reduction. The mass specific activity of AQ used, the diffusion coefficient of oxygen and the heterogeneous rate constants for the oxygen reduction at the surface of modified electrodes were also determined by rotating disk voltammetry.

  17. Effects of Ni doping on photocatalytic activity of TiO2 thin films ...

    Indian Academy of Sciences (India)

    Ni-doped TiO2 thin films can be used as photocatalyst for the photodegradation of methyl orange dye. It was found that, organic dye undergoes degradation efficiently in presence of non-uniformly Ni-doped TiO2 thin films when compared to uniformly doped films and pure TiO2 films under visible light. The photocatalytic ...

  18. 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.

  19. Elevated transition temperature in Ge doped VO2 thin films

    Science.gov (United States)

    Krammer, Anna; Magrez, Arnaud; Vitale, Wolfgang A.; Mocny, Piotr; Jeanneret, Patrick; Guibert, Edouard; Whitlow, Harry J.; Ionescu, Adrian M.; Schüler, Andreas

    2017-07-01

    Thermochromic GexV1-xO2+y thin films have been deposited on Si (100) substrates by means of reactive magnetron sputtering. The films were then characterized by Rutherford backscattering spectrometry (RBS), four-point probe electrical resistivity measurements, X-ray diffraction, and atomic force microscopy. From the temperature dependent resistivity measurements, the effect of Ge doping on the semiconductor-to-metal phase transition in vanadium oxide thin films was investigated. The transition temperature was shown to increase significantly upon Ge doping (˜95 °C), while the hysteresis width and resistivity contrast gradually decreased. The precise Ge concentration and the film thickness have been determined by RBS. The crystallinity of phase-pure VO2 monoclinic films was confirmed by XRD. These findings make the use of vanadium dioxide thin films in solar and electronic device applications—where higher critical temperatures than 68 °C of pristine VO2 are needed—a viable and promising solution.

  20. Electrochromism and Swelling of Polypyrrole Membranes: An Electrochemical and Ellipsometric Study

    Directory of Open Access Journals (Sweden)

    J. O. Zerbino

    2011-01-01

    Full Text Available The growth of polypyrrole (Ppy layers on gold electrodes in nearly neutral pH solutions is analysed using “in situ” voltametric and ellipsometric techniques. Different film structures are obtained depending on the potentiodynamic programme and the composition of the electrolyte. More compact dodecylsulphate-(DS doped Ppy layers were grown at 1.2 V versus RHE than those obtained by applying a higher potential. The more compact layers correspond to the growth of an oxidised Ppy/DS layer that shows low pseudo capacity behaviour. After dipping, the doped Ppy/DS film in KCl solution-significant variations in optical indices and thickness are detected as a function of the applied potential. Higher electrochromism as well as decrease in film thickness after cathodisation is achieved. The optical indices and the thickness of the Ppy layer formed under different applied potential/time programmes are estimated.

  1. Synthesis and Characterization of La-Doped Luminescent Multilayer Films

    Directory of Open Access Journals (Sweden)

    Tianlei Wang

    2017-01-01

    Full Text Available In this work, we have successfully designed ordered luminescent multilayer films based on La-doped nonmagnetic or magnetic inorganic nanostructure with electronic microenvironment (EM. The inorganic nanosheets with opposite charge can assemble EM between the interlayers. At the same time, their elements on nanosheets of layer double hydroxides (LDHs are facile to be replaced so that we can introduce transition metal or lanthanide elements. Besides, ferromagnetic effect (FE can be formed in this microenvironment due to introducing transition metal on LDHs nanosheets. As a result, we confirm that EM, FE, and doping La element in the LDHs can affect the vibration of backbone of chromophores and then prolong the luminescent lifetime, which suggests a new pathway for developing the novel light-emitting thin films.

  2. 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 ...

  3. Structural and optical studies of Au doped titanium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Alves, E., E-mail: ealves@itn.pt [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Gama Pinto, 21649-003 Lisboa (Portugal); Franco, N.; Barradas, N.P. [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Gama Pinto, 21649-003 Lisboa (Portugal); Nunes, B. [Instituto Tecnologico e Nuclear (ITN), 2686-953 Sacavem (Portugal); Lopes, J. [Instituto Superior de Engenharia de Lisboa (Portugal); Cavaleiro, A. [SEC-CEMUC - Universidade de Coimbra, Dept. Eng. Mecanica, Polo II, 3030-788 Coimbra (Portugal); Torrell, M.; Cunha, L.; Vaz, F. [Centro de Fisica, Universidade do Minho, 4800-058 Guimaraes (Portugal)

    2012-02-01

    Thin films of TiO{sub 2} were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 Degree-Sign C. The undoped films were implanted with Au fluences in the range of 5 Multiplication-Sign 10{sup 15} Au/cm{sup 2}-1 Multiplication-Sign 10{sup 17} Au/cm{sup 2} with a energy of 150 keV. At a fluence of 5 Multiplication-Sign 10{sup 16} Au/cm{sup 2} the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3-5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 Degree-Sign C, reaching the precipitates dimensions larger than 40 nm at 600 Degree-Sign C. Annealing above 700 Degree-Sign C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  4. Structural and optical studies of Au doped titanium oxide films

    International Nuclear Information System (INIS)

    Alves, E.; Franco, N.; Barradas, N.P.; Nunes, B.; Lopes, J.; Cavaleiro, A.; Torrell, M.; Cunha, L.; Vaz, F.

    2012-01-01

    Thin films of TiO 2 were doped with Au by ion implantation and in situ during the deposition. The films were grown by reactive magnetron sputtering and deposited in silicon and glass substrates at a temperature around 150 °C. The undoped films were implanted with Au fluences in the range of 5 × 10 15 Au/cm 2 –1 × 10 17 Au/cm 2 with a energy of 150 keV. At a fluence of 5 × 10 16 Au/cm 2 the formation of Au nanoclusters in the films is observed during the implantation at room temperature. The clustering process starts to occur during the implantation where XRD estimates the presence of 3–5 nm precipitates. After annealing in a reducing atmosphere, the small precipitates coalesce into larger ones following an Ostwald ripening mechanism. In situ XRD studies reveal that Au atoms start to coalesce at 350 °C, reaching the precipitates dimensions larger than 40 nm at 600 °C. Annealing above 700 °C promotes drastic changes in the Au profile of in situ doped films with the formation of two Au rich regions at the interface and surface respectively. The optical properties reveal the presence of a broad band centered at 550 nm related to the plasmon resonance of gold particles visible in AFM maps.

  5. Doped organic films for OLEDs probed with neutron reflectometry

    International Nuclear Information System (INIS)

    Smith, Arthur R. G.; Lo, Shih-Chun; Gentle, Ian R.

    2009-01-01

    Full text: Conjugated organic semiconductors form an exciting class of materials that can be used in a variety of cutting edge technologies including organic light-emitting diodes, solar cells and transistors. In all these technologies the thin film morphology and interfacial interactions are key areas for their operation. In order to optimise the materials and devices it is critical to understand the structural property relationships for the organic semiconductors by relating the 'molecular' structure to the film morphology and correlating these to the photophysical and device characteristics. Organic light emitting diodes (OLEO) have gained interest for their superior performance compared to current display technologies. Optimising the active emissive layer remains a challenge which can significantly affect the final performance of the device [1]. We have investigated the layering behaviour of small molecule co-evaporated films of deuterated 4,4'-bis(9-carbazolyl)-1, 1 '-biphenyl doped with tris-phenylpyridine iridium(llI) using neutron reflectometry The behaviour of doped emissive layers is dependent on the ratio between dopant and host material. The morphology and internal structure of such films have not yet been investigated, leading to questions about the phase separation and ordering of layers within the film.

  6. Nanostructure conducting molecularly imprinted polypyrrole film as a selective sorbent for benzoate ion and its application in spectrophotometric analysis of beverage samples.

    Science.gov (United States)

    Manbohi, Ahmad; Shamaeli, Ehsan; Alizadeh, Naader

    2014-07-15

    The benzoate anion was selectively extracted by electrochemically controlled solid-phase microextraction (EC-SPME) using a electro-synthesised nanostructure conducting molecularly imprinted polypyrrole (CMIP) film that imprinted for benzoate ions (template ion). The sorbent behaviors of CMIP were characterised using spectrophotometry analysis. The effect of pH, uptake and released times and potentials, template ion concentration, and interference were investigated, and experimental conditions optimised. The film exhibited excellent selectivity in the presence of potential interference from anions including salicylate, sorbate, citrate, phosphate, acetate and chloride ions. The calibration graph was linear (R(2)⩾ 0.993) in the range 1.1 × 10(-5)-5.5 × 10(-4) mol L(-1) and detection limit was 5.2 × 10(-6) mol L(-1). The relative standard deviation was less than 4.5% (n=3). The CMIP film, as a solid-phase micro-extraction absorbent, was applied for the selective clean up and quantification of benzoate in beverage samples using the EC-SPME-spectrophotometric method. The results were in agreement with those obtained using HPLC analysis. This method has a good selectivity and mechanical stability and is disposable simple to construct. However, HPLC method is more selective for determination of benzoate in some food products which have interference compounds such as vanilla and flavoring agents. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Rare earth-doped alumina thin films deposited by liquid source CVD processes

    Energy Technology Data Exchange (ETDEWEB)

    Deschanvres, J.L.; Meffre, W.; Joubert, J.C.; Senateur, J.P. [Ecole Nat. Superieure de Phys. de Grenoble, St. Martin d`Heres (France). Lab. des Materiaux et du Genie Phys.; Robaut, F. [Consortium des Moyens Technologiques Communs, Institut National Polytechnique de Grenoble, BP 75, 38402 St Martin d`Heres (France); Broquin, J.E.; Rimet, R. [Laboratoire d`Electromagnetisme, Microondes et Optoelectronique, CNRS-Ecole Nationale Superieure d`Electronique et Radioelectricite de Grenoble, BP 257, 38016 Grenoble, Cedex (France)

    1998-07-24

    Two types of liquid-source CVD processes are proposed for the growth of rare earth-doped alumina thin films suitable as amplifying media for integrated optic applications. Amorphous, transparent, pure and erbium- or neodymium-doped alumina films were deposited between 573 and 833 K by atmospheric pressure aerosol CVD. The rare earth doping concentration increases by decreasing the deposition temperature. The refractive index of the alumina films increases as a function of the deposition temperature from 1.53 at 573 K to 1.61 at 813 K. Neodymium-doped films were also obtained at low pressure by liquid source injection CVD. (orig.) 7 refs.

  8. Strontium doped hydroxyapatite film formed by micro-arc oxidation

    International Nuclear Information System (INIS)

    Nan Kaihui; Wu Tao; Chen Jionghao; Jiang Shan; Huang Yong; Pei Guoxian

    2009-01-01

    A porous strontium-doped hydroxyapatite (Sr-HA) film was prepared on titanium substrates by an electrochemical oxidation method, i.e. micro-arc oxidation (MAO). The reaction was processed using a pulse power supply with titanium substrate acted as the anode in electrolytic solution containing calcium acetate, strontium acetate and β-glycerol phosphate disodium salt pentahydrate (β-GP). The thickness, phase, composition and morphology of the coatings were investigated with X-ray diffraction (XRD), electron probe microanalysis (EPMA) and scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS). The thickness of the film was about 20 μm with the porous and uneven surfaces. XRD showed that the film was mainly made up of hydroxyapatite doped with strontium and the (Sr/(Sr + Ca) ratios ranged from 0-100%, which could be expressed as the general formula of Ca 10-X Sr X (PO 4 ) 6 (OH) 2 , 0 ≤ X ≤ 10). Such films are expected to have significant medical applications as dental implants and artificial bone joints.

  9. Nanostructure of aluminium (Al) - Doped zinc oxide (AZO) thin films

    Science.gov (United States)

    Hussin, Rosniza; Husin, M. Asri

    2017-12-01

    Aluminium (Al)-doped Zinc Oxide (ZnO) was deposited on glass substrates by using the sol-gel dip coating technique. Next, AZO sol-gel solution was produced via sol-gel method. Al was used as doped element with molar ratios of 1%, 2%, and 3%, while the calcination temperatures were set at 400°C, 500°C, and 600°C for 2 hours. In fact, characterization was carried out in order to determine the effect of calcination temperature and molar ratio of doping by using several techniques, such as X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), and Ultraviolet-Visible spectroscopy (UV-Vis). XRD was performed to investigate the crystal structure in which the ZnO was in wurtzite hexagonal form. Next, Energy Dispersive Spectroscopy (EDS) was used to determine the composition of thin films where the result revealed the existence of zinc, oxygen, and aluminium. The roughness of the deposited film was later measured by using the AFM approach where the findings indicated increment in RMS from 8.496 nm to 35.883 nm as the temperature was increased. Additionally, FESEM was carried out to look into the microstructure surfaces of the deposited AZO thin film for increased temperature caused the particle to grow bigger for all molar ratio of dopant. Lastly, UV-Vis was conducted to study the optical properties of AZO, in which the result demonstrated that AZO thin film possessed the highest transmittance percentage among all samples above 90% with band gap value that ranged from 3.25 eV to 3.32 eV.

  10. The structure of fullerene films and their metallocene doping

    Energy Technology Data Exchange (ETDEWEB)

    Domrachev, G.A.; Kaverin, B.S.; Domracheva, E.G. [Institute of Organometallic Chemistry, Nizhnii Novgorod (Russian Federation)] [and others

    1995-02-01

    Hexagonal close-packed (HCP) C{sub 60} and C{sub 70} films have been prepared by the Langmuir method and examined by electron microscopy and electron-diffraction analysis. It has been shown that the vacuum deposition of a C{sub 60} + C{sub 70} mixture results in the formation of a film with small sized grains and a distorted C{sub 60}-HCP structure. The simultaneous deposition of C{sub 60} and ferrocene results in the formation of a film with a changed morphology and an electron-diffraction pattern that contains a variable amount of ferrocene depending on the experimental conditions. The electron-diffraction pattern corresponds to the presence of the known molecular complex C{sub 60}[(C{sub 5}H{sub 5}){sub 2}Fe]{sub 2}. The analogous simultaneous deposition of fullerene C{sub 60} and cobaltocene results in the formation of a C{sub 60} film stable in air and water, which contains carbon and cobalt (from the data of X-ray fluorescence, electron microscopy and microdiffraction). It has a different morphology and different diffraction patterns than pure C{sub 60} films and, depending on the cobaltocene content (relative to that of fullerene), appears to be a fullerite film doped with various amounts of cobaltocenium fulleride, which is an ionic compound.

  11. Potentiometric sulfite biosensor based on entrapment of sulfite oxidase in a polypyrrole film on a platinum electrode modified with platinum nanoparticles

    International Nuclear Information System (INIS)

    Adeloju, Samuel B.; Hussain, Shahid

    2016-01-01

    The surface of a platinum electrode has been modified with platinum nanoparticles (PtNPs) and the enzyme sulfite oxidase (SOx), was entrapped on its surface in an ultrathin polypyrrole (PPy) film. The PtNPs, with a diameter of 30-40 nm, were deposited on the Pt electrode by cycling the electrode potential 20 times from -200 to 200 mV at a sweep rate of 50 mV.s -1 . Morphological evidence of the successful incorporation of SOx and the presence of PtNPs were obtained by scanning electron microscopy. Also, the electrochemical behavior of the PtNPs/PPy-SOx film was examined by cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy and potentiometry. Under optimized conditions, the biosensor achieved a sensitivity of 57.5 mV.decade -1 , a linear response that extends from 0.75 to 65 μM of sulfite, a detection limit of 12.4 nM, and a response time of 3-5 s. The biosensor was successfully applied to the determination of sulfite in wine and beer samples. (author)

  12. High-performance glucose biosensor based on chitosan-glucose oxidase immobilized polypyrrole/Nafion/functionalized multi-walled carbon nanotubes bio-nanohybrid film.

    Science.gov (United States)

    Shrestha, Bishnu Kumar; Ahmad, Rafiq; Mousa, Hamouda M; Kim, In-Gi; Kim, Jeong In; Neupane, Madhav Prasad; Park, Chan Hee; Kim, Cheol Sang

    2016-11-15

    A highly electroactive bio-nanohybrid film of polypyrrole (PPy)-Nafion (Nf)-functionalized multi-walled carbon nanotubes (fMWCNTs) nanocomposite was prepared on the glassy carbon electrode (GCE) by a facile one-step electrochemical polymerization technique followed by chitosan-glucose oxidase (CH-GOx) immobilization on its surface to achieve a high-performance glucose biosensor. The as-fabricated nanohybrid composite provides high surface area for GOx immobilization and thus enhances the enzyme-loading efficiency. The structural characterization revealed that the PPy-Nf-fMWCNTs nanocomposite films were uniformly formed on GCE and after GOx immobilization, the surface porosities of the film were decreased due to enzyme encapsulation inside the bio-nanohybrid composite materials. The electrochemical behavior of the fabricated biosensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry measurements. The results indicated an excellent catalytic property of bio-nanohybrid film for glucose detection with improved sensitivity of 2860.3μAmM(-1)cm(-2), the linear range up to 4.7mM (R(2)=0.9992), and a low detection limit of 5μM under a signal/noise (S/N) ratio of 3. Furthermore, the resulting biosensor presented reliable selectivity, better long-term stability, good repeatability, reproducibility, and acceptable measurement of glucose concentration in real serum samples. Thus, this fabricated biosensor provides an efficient and highly sensitive platform for glucose sensing and can open up new avenues for clinical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Optical study on doped polyaniline composite films

    International Nuclear Information System (INIS)

    Li, G; Zheng, P; Wang, N L; Long, Y Z; Chen, Z J; Li, J C; Wan, M X

    2004-01-01

    Localization driven by disorder has a strong influence on the conducting properties of conducting polymers. Some authors hold the opinion that disorder in the material is homogeneous and that the conducting polymer is a disordered metal close to the Anderson-Mott metal-insulator (MI) transition, while others treat the disorder as inhomogeneous and have the opinion that conducting polymers are a composite of ordered metallic regions and disordered insulating regions. The morphology of conducting polymers is an important factor that has an influence on the type and extent of disorder. Different protonic acids used as dopants and moisture have influence on the polymer chain arrangement and interchain interactions. We performed optical reflectance measurements on several PANI-CSA/PANI-DBSA composite films with different dopant ratios and moisture contents. Optical conductivity and the real part of the dielectric function are calculated by Kramers-Kronig (KK) relations. σ 1 (ο) and ε 1 (ο) deviate from the simple Drude model in the low frequency range and the tendencies of the three sample are different and non-monotonic. The localization modified Drude model (LMD) in the framework of the Anderson-Mott theory cannot give a good fit to the experimental data. By introducing the distribution of relaxation time into the LMD, reasonable fits for all three samples are obtained. This result supports the inhomogeneous picture

  14. Magnetic and microwave absorption properties of rare earth ions (Sm{sup 3+}, Er{sup 3+}) doped strontium ferrite and its nanocomposites with polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Juhua, E-mail: luojuhua@163.com [School of Materials Engineering, Yancheng Institute of Technology, Yancheng 224051 (China); Xu, Yang; Mao, Hongkai [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2015-05-01

    M-type strontium ferrite substituted by RE (RE=Sm{sup 3+}, Er{sup 3+}) were prepared via a sol–gel method. Polypyrrole (PPy)/ferrite nanocomposites (with 20 wt% ferrite) were prepared by in situ polymerization method in the presence of ammonium persulfate. Effect of the substituted RE ions on structure, magnetic properties and microwave absorption properties were investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and vector network analyzer. All XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. The crystallite size of synthesized particle is within the range of 22.2–38.1 nm. The structural in character of the composites were investigated with FT-IR analysis. It shows that the ferrite successfully packed by PPy. TEM photographs show that the particle size had grown up to 50–100 nm after coating with PPy. In the magnetization for the PPy/SrSm{sub 0.3}Fe{sub 11.7}O{sub 19} (SrEr{sub 0.3}Fe{sub 11.7}O{sub 19}) composites, the coercivity (H{sub c}) of the composites both increased compared with the undoped composite while the saturation magnetization (M{sub s}) appeared opposite change with different RE ions. Considering the electromagnetic loss and impedance matching comprehensively, the Er-doped ferrite/PPy composite got the better microwave absorption performance with the maximum RL value of −24.01 dB in 13.8 GHz at 3.0 mm. And its width (<−10 dB) has reached 7.2 GHz which has covered the whole Ku band. - Highlights: • The influence of RE ions on the structure of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on the magnetic properties of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on electromagnetic losses of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • PPy/SrEr{sub 0.3}Fe{sub 11.7}O{sub 19} possessed the excellent absorption property.

  15. Synthesis of H2SO4 doped polyaniline film by potentiometric method

    Indian Academy of Sciences (India)

    Unknown

    Synthesis of H2SO4 doped polyaniline film by potentiometric method. P D GAIKWAD, D J SHIRALE, V K GADE, ... transition from insulator to semiconductor when doped with oxidizing or reducing agent (Kobayashi et ... protonation (doping) and many other physical–chemical properties are connected to the presence of ...

  16. Electron field emission from undoped and doped DLC films

    International Nuclear Information System (INIS)

    Chakhovskoi, A G; Evtukh, A A; Felter, T E; Klyui, N I; Kudzinovsky, S Y; Litovchenko, V G; Litvin, Y M

    1999-01-01

    Electron field emission and electrical conductivity of undoped and nitrogen doped DLC films have been investigated. The films were grown by the PE CVD method from CH(sub 4):H(sub 2) and CH(sub 4):H(sub 2):N(sub 2) gas mixtures, respectively. By varying nitrogen content in the gas mixture over the range 0 to 45%, corresponding concentrations of 0 to 8% (atomic) could be achieved in the films. Three different gas pressures were used in the deposition chamber: 0.2, 0.6 and 0.8 Torr. Emission current measurements were performed at approximately 10(sup -6) Torr using the diode method with emitter-anode spacing set at 20(micro)m. The current - voltage characteristics of the Si field electron emission arrays covered with DLC films show that threshold voltage (V(sub th)) varies in a complex manner with nitrogen content. As a function of nitrogen content, V(sub th) initially increases rapidly, then decreases and finally increases again for the highest concentration. Corresponding Fowler-Nordheim (F-N) plots follow F-N tunneling over a wide range. The F-N plots were used for determination of the work function, threshold voltage, field enhancement factor and effective emission area. For a qualitative explanation of experimental results, we treat the DLC film as a diamond-like (sp(sup 3) bonded) matrix with graphite-like inclusions

  17. Characteristic Study of Boron Doped Carbon Nanowalls Films Deposited by Microwave Plasma Enhanced Chemical Vapor Deposition.

    Science.gov (United States)

    Lu, Chunyuan; Dong, Qi; Tulugan, Kelimu; Park, Yeong Min; More, Mahendra A; Kim, Jaeho; Kim, Tae Gyu

    2016-02-01

    In this research, catalyst-free vertically aligned boron doped carbon nanowalls films were fabricated on silicon (100) substrates by MPECVD using feeding gases CH4, H2 and B2H6 (diluted with H2 to 5% vol) as precursors. The substrates were pre-seeded with nanodiamond colloid. The fabricated CNWs films were characterized by Scanning Electron Microscopy (SEM) and Raman Spectroscopy. The data obtained from SEM confirms that the CNWs films have different density and wall thickness. From Raman spectrum, a G peak around 1588 cm(-1) and a D band peak at 1362 cm(-1) were observed, which indicates a successful fabrication of CNWs films. The EDX spectrum of boron doped CNWs film shows the existence of boron and carbon. Furthermore, field emission properties of boron doped carbon nanowalls films were measured and field enhancement factor was calculated using Fowler-Nordheim plot. The result indicates that boron doped CNWs films could be potential electron emitting materials.

  18. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    Lower values of the bandgap energy were observed for the doped CdS films as compared to those of the undoped. CdS films. ... promotes the formation of acceptor levels above the CdS valence band, resulting in lower bandgap energy values for the doped ... solar cell efficiencies have been recently reported using CdS.

  19. Synthesis of H2SO4 doped polyaniline film by potentiometric method

    Indian Academy of Sciences (India)

    H2SO4 doped polyaniline films were synthesized in aqueous acidic media. The polyaniline film deposited on platinum electrode exhibits highest conductivity. The conductivity of each H2SO4 doped polyaniline sample was determined by the four-probe technique. The current–voltage curve exhibits that polyaniline sample ...

  20. Low doping concentration studies of doped PVA-Coumarin nanocomposite films

    International Nuclear Information System (INIS)

    Tripathi, J.; Bisen, R.; Choudhary, A.; Tripathi, S.; Sharma, A.; Shripathi, T.

    2016-01-01

    The observations of combination of Poly (vinyl) alcohol and Coumarin properties in nanocmposite films are reported. The X-ray diffraction measurements reveal nanocrystalline nature of PVA film, which remains nanocrystalline after doping Coumarin but along with PVA peaks, additional peak due to dopant crystallinity is seen. The absorption edge shows a double edge feature, where distinct bandgaps for PVA host and dopant Coumarin are obtained. However at a higher doping wt % of 1 and 2, the absorption is mainly dominated by Coumarin and single absorption edge is observed giving a bandgap equal to that of bulk Coumarin (3.3 eV). The composite formation affects the bonding of host drastically and is seen through the bond modification in FTIR spectra. The results suggest that doping below 2 wt% is advantageous as combination of PVA and Coumarin properties are obtained but at 2 wt %, the properties are dominated by mainly Coumarin and the signature of PVA from optical properties is completely lost.

  1. Low doping concentration studies of doped PVA-Coumarin nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, J., E-mail: jtripathi00@rediffmail.com; Bisen, R.; Choudhary, A. [Dept. of Physics, ISLE, IPS Academy, Indore (India); Tripathi, S. [Dept. of Physics, Manipal University Jaipur, Jaipur (India); Presently at: Optics and Thin Film Laboratory, Bhabha Atomic Research Centre-Vizag, Visakhapatnam (India); Sharma, A. [Dept. of Physics, Manipal University Jaipur, Jaipur (India); Shripathi, T. [UGC-DAE Consortium for Scientific Research, Indore (India)

    2016-05-23

    The observations of combination of Poly (vinyl) alcohol and Coumarin properties in nanocmposite films are reported. The X-ray diffraction measurements reveal nanocrystalline nature of PVA film, which remains nanocrystalline after doping Coumarin but along with PVA peaks, additional peak due to dopant crystallinity is seen. The absorption edge shows a double edge feature, where distinct bandgaps for PVA host and dopant Coumarin are obtained. However at a higher doping wt % of 1 and 2, the absorption is mainly dominated by Coumarin and single absorption edge is observed giving a bandgap equal to that of bulk Coumarin (3.3 eV). The composite formation affects the bonding of host drastically and is seen through the bond modification in FTIR spectra. The results suggest that doping below 2 wt% is advantageous as combination of PVA and Coumarin properties are obtained but at 2 wt %, the properties are dominated by mainly Coumarin and the signature of PVA from optical properties is completely lost.

  2. Hierarchical N-Doped Carbon as CO2 Adsorbent with High CO2 Selectivity from Rationally Designed Polypyrrole Precursor.

    Science.gov (United States)

    To, John W F; He, Jiajun; Mei, Jianguo; Haghpanah, Reza; Chen, Zheng; Kurosawa, Tadanori; Chen, Shucheng; Bae, Won-Gyu; Pan, Lijia; Tok, Jeffrey B-H; Wilcox, Jennifer; Bao, Zhenan

    2016-01-27

    Carbon capture and sequestration from point sources is an important component in the CO2 emission mitigation portfolio. In particular, sorbents with both high capacity and selectivity are required for reducing the cost of carbon capture. Although physisorbents have the advantage of low energy consumption for regeneration, it remains a challenge to obtain both high capacity and sufficient CO2/N2 selectivity at the same time. Here, we report the controlled synthesis of a novel N-doped hierarchical carbon that exhibits record-high Henry's law CO2/N2 selectivity among physisorptive carbons while having a high CO2 adsorption capacity. Specifically, our synthesis involves the rational design of a modified pyrrole molecule that can co-assemble with the soft Pluronic template via hydrogen bonding and electrostatic interactions to give rise to mesopores followed by carbonization. The low-temperature carbonization and activation processes allow for the development of ultrasmall pores (d CO2 affinity. Furthermore, our described work provides a strategy to initiate developments of rationally designed porous conjugated polymer structures and carbon-based materials for various potential applications.

  3. Doping site dependent thermoelectric properties of epitaxial strontium titanate thin films

    KAUST Repository

    Abutaha, Anas I.

    2014-01-01

    We demonstrate that the thermoelectric properties of epitaxial strontium titanate (STO) thin films can be improved by additional B-site doping of A-site doped ABO3 type perovskite STO. The additional B-site doping of A-site doped STO results in increased electrical conductivity, but at the expense of Seebeck coefficient. However, doping on both sites of the STO lattice significantly reduces the lattice thermal conductivity of STO by adding more densely and strategically distributed phononic scattering centers that attack wider phonon spectra. The additional B-site doping limits the trade-off relationship between the electrical conductivity and total thermal conductivity of A-site doped STO, leading to an improvement in the room-temperature thermoelectric figure of merit, ZT. The 5% Pr3+ and 20% Nb5+ double-doped STO film exhibits the best ZT of 0.016 at room temperature. This journal is

  4. Structural, morphological, optical and electrical properties of spray deposited lithium doped CdO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Velusamy, P.; Babu, R. Ramesh, E-mail: rampap2k@yahoo.co.in [Crystal Growth and Thin Films Laboratory, Department of Physics, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu (India); Ramamurthi, K. [Crystal Growth and Thin Films Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur – 603 203, Tamil Nadu (India)

    2016-05-23

    In the present work, CdO and Li doped CdO thin films were deposited on microscopic glass substrates at 300°C by a spray pyrolysis experimental setup. The deposited CdO and Li doped CdO thin films were subjected to XRD, SEM, UV-VIS spectroscopy and Hall measurement analyses. XRD studies revealed the polycrystalline nature of the deposited films and confirmed that the deposited CdO and Li doped CdO thin films belong to cubic crystal system. The Scanning electron microscopy analysis revealed the information on shape of CdO and Li doped CdO films. Electrical study reveals the n-type semiconducting nature of CdO and the optical band gap is varied between 2.38 and 2.44 eV, depending on the Li doping concentrations.

  5. Local Electrical Response in Alkaline-Doped Electrodeposited CuInSe2/Cu Films

    Directory of Open Access Journals (Sweden)

    Javier A. Barón-Miranda

    2016-12-01

    Full Text Available The local electrical response in alkaline-doped CuInSe2 films prepared by single-step electrodeposition onto Cu substrates was studied by current-sensing atomic force microscopy. The CuInSe2 (CIS films were prepared from single baths containing the dopant ions (Li, Na, K or Cs and were studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and photocurrent response. Increased crystallinity and surface texturing as the ion size increased were observed, as well as an enhanced photocurrent response in Cs-doped CIS. Li- and Na-doped films had larger conductivity than the undoped film while the K- and Cs-doped samples displayed shorter currents and the current images indicated strong charge accumulation in the K- and Cs-doped films, forming surface capacitors. Corrected current-sensing AFM IV curves were adjusted with the Shockley equation.

  6. Enhanced flux-pinning in fluorine-free MOD YBCO films by chemical doping

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T.; Pu, M.H.; Yang, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.c [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2010-11-01

    YBCO films without and with dilute cobalt and zinc doping were prepared on (0 0 l) LaAlO{sub 3} substrate by non-fluorine metal organic deposition method. Effects of dilute cobalt and zinc doping on biaxial texture, microstructure and flux-pinning properties of YBCO films were investigated. The surface density and smoothness of the doped YBCO films have been distinctly improved compared with that of the pure film. Dilute cobalt- and zinc-doped YBCO films exhibit significantly enhanced J{sub c} values in the magnetic field. The best result is achieved in the cobalt-doped YBCO film. At 77 K, J{sub c} values of cobalt-doped film are 1.7 and 5.4 times higher than that of pure film in 0.5 T and 1.5 T, respectively. These results strongly suggest that dilute cobalt and zinc doping is a promising way to increase the current carrying capability of YBCO films.

  7. Investigation on the pure and fluorine doped vanadium oxide thin films deposited by spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Margoni, Mudaliar Mahesh; Mathuri, S. [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur, – 603203 Kancheepuram Dt., Tamil Nadu (India); Ramamurthi, K., E-mail: krmurthin@yahoo.co.in [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur, – 603203 Kancheepuram Dt., Tamil Nadu (India); Babu, R. Ramesh [Crystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli – 620024, Tamil Nadu (India); Sethuraman, K. [School of Physics, Madurai Kamaraj University, Madurai – 625021, Tamil Nadu (India)

    2016-05-01

    Vanadium oxide and fluorine doped vanadium oxide thin films were deposited on the micro-slide glass substrates at 400 °C by spray pyrolysis technique. Vanadium oxide films were deposited using 0.1 M ammonium meta vanadate aqua solution. Precursor solution used to deposit fluorine doped vanadium oxide films was prepared adding separately 5 wt.%, 10 wt.%, 15 wt.% and 20 wt.% of ammonium fluoride with the 0.1 M ammonium meta vanadate aqua solution. X-ray diffraction results showed that the films are in mixed phases of β-V{sub 2}O{sub 5}, V{sub 2}O{sub 5} and V{sub 3}O{sub 7}. Surface morphology and band gap of these films were modified due to different levels of fluorine doping. The average visible transmittance (500–800 nm) of vanadium oxide films is decreased due to low level concentration of fluorine doping. - Highlights: • Addition of a few ml HCl yielded clear precursor aqua solution. • F doped vanadium oxide films were deposited for less concentration of fluorine. • Low level fluorine doping modified the surface morphology of the thin films. • Direct band gap of vanadium oxide film is slightly increased by fluorine doping.

  8. Antimicrobial properties of silver-doped hydroxyapatite nano-powders and thin films

    Science.gov (United States)

    Sygnatowicz, Michael; Keyshar, Kunttal; Tiwari, Ashutosh

    2010-07-01

    Silver-doped hydroxyapatite nanopowders were prepared using a solution based sol-gel method and thoroughly characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Antibacterial tests showed silver-doped HAP powders prevented the growth and reproduction of bacteria. Silver-doped HAP powders were pressed into pellets and on these pellets a pulsed laser deposition (PLD) technique was employed to grow amorphous and crystalline thin films on sapphire substrates. Crystalline films had silver nano-particles present within the HAP matrix. Film stability tests showed crystalline films to be far more stable in prolonged solution submersion than their amorphous counterparts.

  9. Methods for enhancing P-type doping in III-V semiconductor films

    Science.gov (United States)

    Liu, Feng; Stringfellow, Gerald; Zhu, Junyi

    2017-08-01

    Methods of doping a semiconductor film are provided. The methods comprise epitaxially growing the III-V semiconductor film in the presence of a dopant, a surfactant capable of acting as an electron reservoir, and hydrogen, under conditions that promote the formation of a III-V semiconductor film doped with the p-type dopant. In some embodiments of the methods, the epitaxial growth of the doped III-V semiconductor film is initiated at a first hydrogen partial pressure which is increased to a second hydrogen partial pressure during the epitaxial growth process.

  10. 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.

  11. Electrosynthesis and characterization of conducting polypyrrole ...

    African Journals Online (AJOL)

    The preparation of polypyrrole conducting polymer in aqueous medium by electrochemical method containing several alkylsulfonate dopants such as methylsulfonate (C1), butylsulfonate (C4), octylsulfonate (C8) and dodecylsulfonate (C12) are reported. The prepared polymer films were characterized by cyclic voltammetry, ...

  12. Polypyrrole for Artificial Muscles: Ionic Mechanisms

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2006-01-01

    is centered on polypyrrole (PPy), which is the material most used and studied. The tetraethyl ammonium cation (TEA) is shown to be able to move in and out of PPy(DBS) polymer films, in contrast to expectations. There is a switching between ionic mechanisms during cycling in TEACl electrolyte....

  13. Polypyrrole and graphene quantum dots @ Prussian Blue hybrid film on graphite felt electrodes: Application for amperometric determination of l-cysteine.

    Science.gov (United States)

    Wang, Lei; Tricard, Simon; Yue, Pengwei; Zhao, Jihua; Fang, Jian; Shen, Weiguo

    2016-03-15

    A novel polypyrrole (PPy) and graphene quantum dots (GQDs) @ Prussian Blue (PB) nanocomposite has been grafted on a graphite felt (GF) substrate (PPy/GQDs@PB/GF), and has been proven to be an efficient electrochemical sensor for the determination of l-cysteine (l-cys). GQDs, which were fabricated by carbonization of citric acid and adsorbed on GF surface ultrasonically, played an important role for promoting the synthesis process of PB via a spontaneous redox reaction between Fe(3+) and [Fe(CN)6](3-). The PPy film has been electro-polymerized to improve the electrochemical stability of the PPy/GQDs@PB/GF electrode. The as-prepared electrode was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), X-ray diffraction (XRD) and electrochemical methods. It exhibited an excellent activity for the electrocatalytic oxidation of l-cys, with a detection sensitivity equal to 0.41 Amol(-1) L for a concentration range of 0.2-50 μmolL(-1), and equal to 0.15 Amol(-1) L for a concentration range of 50-1000 μmolL(-1). A low detection limit of 0.15 μmolL(-1), as well as a remarkable long-time stability and a negligible sensitivity to interfering analytes, were also ascertained. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

    KAUST Repository

    Zhang, Bo

    2017-05-22

    Thin-film Mg2Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed that the deposited films are polycrystalline Mg2Si. The Sn and Al doping concentrations were measured using Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray spectroscopy (EDS). The charge carrier concentration and the charge carrier type of the Mg2Si films were measured using a Hall bar structure. Hall measurements show that as the doping concentration increases, the carrier concentration of the Al-doped films increases, whereas the carrier concentration of the Sn-doped films decreases. Combined with the resistivity measurements, the mobility of the Al-doped Mg2Si films is found to decrease with increasing doping concentration, whereas the mobility of the Sn-doped Mg2Si films is found to increase.

  15. Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

    International Nuclear Information System (INIS)

    Turgut, Güven; Koçyiğit, Adem; Sönmez, Erdal

    2015-01-01

    The Pr and Ta separately doped FTO (10 at.% F incorporated SnO 2 ) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications. (paper)

  16. Role of La doping for topological Hall effect in epitaxial EuO films

    Science.gov (United States)

    Yun, Yu; Ma, Yang; Su, Tang; Xing, Wenyu; Chen, Yangyang; Yao, Yunyan; Cai, Ranran; Yuan, Wei; Han, Wei

    2018-03-01

    We report the critical role of La doping in the topological Hall effect observed in L axE u1 -xO thin films (˜50 nm ) grown by molecular beam epitaxy. When the La doping exceeds 0.036, topological Hall effect emerges, which we attribute to the formation of magnetic skyrmions. Besides, the La doping is found to play a critical role in determining the phases, densities, and sizes of the skyrmions in the L axE u1 -xO thin films. The maximum region of the skyrmion phase diagram is observed on the L a0.1E u0.9O thin film. As the La doping increases, the skyrmion density increases while the skyrmion size decreases. Our findings demonstrate the important role of La doping for the skyrmions in EuO films, which could be important for future studies of magnetic skyrmions in Heisenberg ferromagnets.

  17. Electrical, optical, and electronic properties of Al:ZnO films in a wide doping range

    Energy Technology Data Exchange (ETDEWEB)

    Valenti, Ilaria; Valeri, Sergio [CNR, Istituto Nanoscienze, S3, Via G. Campi 213/a, 41125 Modena (Italy); Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena (Italy); Benedetti, Stefania, E-mail: stefania.benedetti@unimore.it; Bona, Alessandro di [CNR, Istituto Nanoscienze, S3, Via G. Campi 213/a, 41125 Modena (Italy); Lollobrigida, Valerio [Dipartimento di Scienze, Università Roma Tre, I-00146 Rome, Italy and Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome (Italy); Perucchi, Andrea; Di Pietro, Paola [INSTM Udr Trieste-ST and Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Trieste (Italy); Lupi, Stefano [CNR-IOM and Dipartimento di Fisica, Università di Roma Sapienza, P.le Aldo Moro 2, I-00185 Roma (Italy); Torelli, Piero [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy)

    2015-10-28

    The combination of photoemission spectroscopies, infrared and UV-VIS absorption, and electric measurements has allowed to clarify the mechanisms governing the conductivity and the electronic properties of Al-doped ZnO (AZO) films in a wide doping range. The contribution of defect-related in-gap states to conduction has been excluded in optimally doped films (around 4 at. %). The appearance of gap states at high doping, the disappearance of occupied DOS at Fermi level, and the bands evolution complete the picture of electronic structure in AZO when doped above 4 at. %. In this situation, compensating defects deplete the conduction band and increase the electronic bandgap of the material. Electrical measurements and figure of merit determination confirm the high quality of the films obtained by magnetron sputtering, and thus allow to extend their properties to AZO films in general.

  18. Electrochemical properties and electrochemical impedance spectroscopy of polypyrrole-coated platinum electrodes

    Directory of Open Access Journals (Sweden)

    M. Fall

    2006-12-01

    Full Text Available Polypyrrole (PPy films of different thickness were characterized by electrochemical impedance spectroscopy (EIS measurements in acetonitrile and aqueous solutions, containing 0.1 M NaClO4 or sodium dodecylsulfate as the dopant. The PPy films were electrochemically deposited on Pt, and their electrochemical properties studied by cyclic voltammetry. Impedance spectra were obtained at potentials ranging from 0 to 0.8 V/SCE. The EIS data were fitted using two different equivalent electrical circuits (depending on the nature of the dopant. They involve a diffusive capacitance, which increased with the passing charge during electrosynthesis (i.e. film thickness for ClO4--doped PPy, but was practically unaffected by the film thickness in the case of SDS-doped PPy. Also, a double-layer capacitance was found only in the circuit of ClO4--doped PPy. It increased with the film thickness, and showed a minimum near the open-circuit potential. Finally the charge-transfer resistance (Rct obtained with SDS is nearly 200-fold higher than that obtained with ClO4- in the same solvent (H2O. With the same dopant (ClO4-, Rct is about five times higher in acetonitrile relative to water. All these EIS results of the different types of PPy suggest a relation with the wettability of the polymer.

  19. Effect of low level doping of boron and phosphorus on the properties of amorphous silicon films

    International Nuclear Information System (INIS)

    Tran, N.T.; Epstein, K.A.; Grimmer, D.P.; Vernstrom, G.D.

    1987-01-01

    Effect of the low level doping of boron and phosphorus on the properties of amorphous silicon films (a-Si:H) were studied. Doping level of both boron and phosphorus was in the range of 10/sup 17/ atoms/cm/sup 3/. Apparent improvement in the stability of dark and photoconductivity of a-Si: films upon low level doping does not result from the elimination of light-induced defects. The stability of the dark and photoconductivity upon doping is an indication of pinning of the Fermi level

  20. Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

    Energy Technology Data Exchange (ETDEWEB)

    Mengui, U.A., E-mail: ursulamengui@gmail.com [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Campos, R.A.; Alves, K.A.; Antunes, E.F. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Hamanaka, M.H.M.O. [Centro de Tecnologia da Informação Renato Archer, Divisão de Superfícies de Interação e Displays, Rodovia D. Pedro I (SP 65) km 143.6, CP 6162, CEP 13089-500, Campinas, SP (Brazil); Corat, E.J.; Baldan, M.R. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil)

    2015-04-15

    Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films.

  1. Effect of La doping on crystalline orientation, microstructure and dielectric properties of PZT thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wencai; Li, Qi; Wang, Xing [Dalian Univ. of Technology, Dalian (China). School of Mechanical Engineering; Yin, Zhifu [Jilin Univ., Changchun (China). Faculty of the School of Mechanical Science and Engineering; Zou, Helin [Dalian Univ. of Technology, Dalian (China). Key Lab. for Micro/Nano Systems and Technology

    2017-11-01

    Lanthanum (La)-modified lead zirconate titanate (PLZT) thin films with doping concentration from 0 to 5 at.-% have been fabricated by sol-gel methods to investigate the effects of La doping on crystalline orientation, microstructure and dielectric properties of the modified films. The characterization of PLZT thin films were performed by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and precision impedance analysis. XRD analysis showed that PLZT films with La doping concentration below 4 at.-% exhibited (100) preferred orientation. SEM results indicated that PLZT films presented dense and columnar microstructures when La doping concentration was less than 3 at.-%, while the others showed columnar microstructures only at the bottom of the cross section. The maximum dielectric constant (1502.59 at 100 Hz) was obtained in a 2 at.-% La-doped film, which increased by 53.9 % compared with undoped film. Without introducing a seed layer, (100) oriented PLZT thin films were prepared by using conventional heat treatment process and adjusting La doping concentration.

  2. Sb (P, As OR F) - DOPED SnO2 FILMS PREPARED BY MOCVD

    OpenAIRE

    Luo, W.; Tan, C.; Ren, P.; Tan, Z.

    1991-01-01

    Metallorganic chemical vapour deposition (MOCVD) is employed for the growth of Sb(P, As or F) doped thin films of SnO2. Using (CH3)4Sn (TMT) as a tin source, oxygen-argon mixture as the carrier gas and Sb (P, As or F) as dopants, we have obtained four kinds of doped SnO2 films on different substrates. These films (thickness 102-103Å) possess sheet resistances of 30-40 [MATH] and transmissivities up to 85-95% in the visible spectral region. The experiments show that the doping causes a change ...

  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. The microstructures and electrical properties of Y-doped amorphous vanadium oxide thin films

    Science.gov (United States)

    Gu, Deen; Zhou, Xin; Guo, Rui; Wang, Zhihui; Jiang, Yadong

    2017-03-01

    One of promising approaches for further improving the sensitivity of microbolometer arrays with greatly-reduced pixel size is using the thermal-sensitive materials with higher performance. In this paper, Y-doped vanadium oxide (VOx) thin films prepared by a reactively sputtering process exhibit enhanced performance for the microbolometer application compared with frequently-applied VOx thin films. Both undoped and Y-doped VOx thin films are amorphous due to the relatively low deposition temperature. Y-doped VOx thin films exhibit smoother surface morphology than VOx due to the restrained expansion of particles during depositions. Y-doping increases the temperature coefficient of resistivity by over 20% for the doping level of 1.30 at%. The change rate of resistivity, after aging for 72 h, of thin films was reduced from about 15% for undoped VOx to 2% due to the introduction of Y. Moreover, Y-doped VOx thin films have a low 1/f noise level as VOx ones. Y-doping provides an attractive approach for preparing VOx thermal-sensitive materials with enhanced performance for microbolometers.

  5. Relation between film thickness and surface doping of MoS2 based field effect transistors

    Science.gov (United States)

    Lockhart de la Rosa, César J.; Arutchelvan, Goutham; Leonhardt, Alessandra; Huyghebaert, Cedric; Radu, Iuliana; Heyns, Marc; De Gendt, Stefan

    2018-05-01

    Ultra-thin MoS2 film doping through surface functionalization with physically adsorbed species is of great interest due to its ability to dope the film without reduction in the carrier mobility. However, there is a need for understanding how the thickness of the MoS2 film is related to the induced surface doping for improved electrical performance. In this work, we report on the relation of MoS2 film thickness with the doping effect induced by the n-dopant adsorbate poly(vinyl-alcohol). Field effect transistors built using MoS2 films of different thicknesses were electrically characterized, and it was observed that the ION/OFF ratio after doping in thin films is more than four orders of magnitudes greater when compared with thick films. Additionally, a semi-classical model tuned with the experimental devices was used to understand the spatial distribution of charge in the channel and explain the observed behavior. From the simulation results, it was revealed that the two-dimensional carrier density induced by the adsorbate is distributed rather uniformly along the complete channel for thin films (<5.2 nm) contrary to what happens for thicker films.

  6. Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

    International Nuclear Information System (INIS)

    Rahman, Airul Azha Abd; Umar, Akrajas Ali; Salleh, Muhamad Mat; Chen, Xiaomei; Oyama, Munetaka

    2016-01-01

    The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m -1 K -2 ) and 10 μV/K (and 19.5 μW m -1 K -2 ), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output load as high as 50

  7. Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Airul Azha Abd [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Technology Park Malaysia, Malaysia Institute of Microelectronics and System, Kuala Lumpur (Malaysia); Umar, Akrajas Ali; Salleh, Muhamad Mat [Universiti Kebangsaan Malaysia UKM, Institute of Microengineering and Nanoelectronics, Bangi, Selangor (Malaysia); Chen, Xiaomei [Jimei University, College of Food and Biological Engineering, Jimei, Xiamen (China); Oyama, Munetaka [Kyoto University, Graduate School of Engineering, Nishikyoku, Kyoto (Japan)

    2016-02-15

    The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m{sup -1} K{sup -2}) and 10 μV/K (and 19.5 μW m{sup -1} K{sup -2}), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output

  8. Biocompatible Eu-doped TiO{sub 2} nanodot film with in situ protein adsorption characterization property

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kui; Zhu, Yifei [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Weng, Wenjian, E-mail: wengwj@zju.edu.cn [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); The Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai, 200050 (China); Lin, Jun; Wang, Huiming [The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, 310003 (China)

    2015-06-01

    Europium (Eu) doped TiO{sub 2} nanodot films were prepared through a phase-separation-induced self-assembly method. Eu was doped to impart the nanodots with luminescence property so that the protein adsorption could be in situ characterized quantitatively. Bovine serum albumin (BSA) was adsorbed on the surface of Eu-doped titanium nanodot films. It was found that the photo luminescence intensity at 616 nm decreased with the increase of BSA adsorption time. Also, Eu-doped TiO{sub 2} nanodot films showed good biocompatibility. These results suggested that Eu-doped TiO{sub 2} nanodot films could provide a feasible in situ way to evaluate protein adsorption if prepared on the surface of bioimplants. - Highlights: • Simple preparation of Eu doped TiO{sub 2} nanodot films • Eu doped nanodot films show good biocompatibility. • Easy in situ evaluation of protein adsorption via photo luminescence of Eu.

  9. Characterization of Pb-Doped GaN Thin Films Grown by Thermionic Vacuum Arc

    Science.gov (United States)

    Özen, Soner; Pat, Suat; Korkmaz, Şadan

    2018-03-01

    Undoped and lead (Pb)-doped gallium nitride (GaN) thin films have been deposited by a thermionic vacuum arc (TVA) method. Glass and polyethylene terephthalate were selected as optically transparent substrates. The structural, optical, morphological, and electrical properties of the deposited thin films were investigated. These physical properties were interpreted by comparison with related analysis methods. The crystalline structure of the deposited GaN thin films was hexagonal wurtzite. The optical bandgap energy of the GaN and Pb-doped GaN thin films was found to be 3.45 eV and 3.47 eV, respectively. The surface properties of the deposited thin films were imaged using atomic force microscopy and field-emission scanning electron microscopy, revealing a nanostructured, homogeneous, and granular surface structure. These results confirm that the TVA method is an alternative layer deposition system for Pb-doped GaN thin films.

  10. 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%

  11. 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.

  12. Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications

    Science.gov (United States)

    Gómez-Pozos, Heberto; González-Vidal, José Luis; Torres, Gonzalo Alberto; Rodríguez-Baez, Jorge; Maldonado, Arturo; de la Luz Olvera, María; Acosta, Dwight Roberto; Avendaño-Alejo, Maximino; Castañeda, Luis

    2013-01-01

    Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well. PMID:23482091

  13. Photoelectric characteristics of rare earth element Eu-doped MoS2 thin films

    Science.gov (United States)

    Shi, Weilin; Li, Zhichao; Wang, Lin; Wu, Shuyan; Zhang, Gaoning; Meng, Miaofei; Ma, Xiying

    2018-01-01

    We present the influences of rare earth element Eu3+ doping on the photoelectric characteristics of molybdenum disulfide (MoS2) films deposited on p-Si substrates using vapor deposition method. The surface topography, crystalline structure, light absorption, and luminescence properties of Eu3+ doped and undoped MoS2 thin films were investigated in detail. We found that the Eu3+ doped MoS2 films have better crystallinity, and their electron mobility and conductivity are approximately one order of magnitude higher than those of the undoped films. In addition, we observed that the light absorption and photoluminescence intensities of the doped films in the visible light range, they were enhanced by approximately two orders of magnitude than those of the undoped MoS2 films at room temperature. Moreover, we found that the photoelectric response characteristics of the doped MoS2 / Si heterojunction improved significantly. The results show that the Eu3+ doped MoS2 films can be used to fabricate high efficiency luminescent and optoelectronic devices.

  14. Electrochemically controlled release of anticancer drug methotrexate using nanostructured polypyrrole modified with cetylpyridinium: Release kinetics investigation

    International Nuclear Information System (INIS)

    Alizadeh, Naader; Shamaeli, Ehsan

    2014-01-01

    A new simple strategy for direct electrochemical incorporation of chemotherapeutic methotrexate (MTX) into conductive polypyrrole (PPy) has been suggested for an electrochemically controlled loading and release system. Electropolymerization of MTX doped polypyrrole yielded poor quality with low efficiency of doping, but a well-doped, nanostructure and increased capacity of drug loading (24.5 mg g −1 ) has been obtained in the presence of cetylpyridinium (CP) as a modifier. When CP was preloaded onto PPy, the hydrophobic surface of the PPy serves as a backbone to which the hydrophobic chain of the CP can be attached. Electrostatic interaction between cationic CP with anionic MTX and aromatic interaction between pyridinium head of CP with pyrimidine and pyrazine rings of MTX increases drug doping. Then release kinetics were investigated at various applied potentials and temperatures. Kinetics analysis based on Avrami's equation showed that the drug release was controlled and accelerated by increasing temperature and negative potential and sustained by increasing positive potential. At open circuit condition, the release parameter (n) represented a diffusive mechanism and at applying electrochemical potentials, a first-order mode. Activation energy parameters (E a , ΔG ≠ , ΔH ≠ and ΔS ≠ ) and half-life time (t 1/2 ) of drug release are also analyzed as a function of applied potential. The nanostructured polymer films (PPy/CP/MTX) were characterized by several techniques: scanning electron microscopy, Furrier transforms Infrared, UV-vis spectroscopy. Overall, our results demonstrate that the PPy/CP/MTX films, combined with electrical stimulation, permit a programmable release of MTX by altering the interaction strength between the PPy/CP and MTX

  15. Polypyrrole-poly(3,4-ethylenedioxythiophene)-Ag (PPy-PEDOT-Ag) nanocomposite films for label-free electrochemical DNA sensing.

    Science.gov (United States)

    Radhakrishnan, S; Sumathi, C; Umar, Ahmad; Jae Kim, Sang; Wilson, J; Dharuman, V

    2013-09-15

    The electrochemical DNA hybridization sensing of bipolymer polypyrrole and poly(3,4-ethylenedioxythiophene) (PPy-PEDOT) nanotubes functionalized with Ag nanoparticles has been investigated. The bipolymer nanotubes are prepared by simple chemical route and silver nanoparticles (Ag) further deposited over the PPy-PEDOT nanotubes to form PPy-PEDOT-Ag nanocomposite films. DNA labeled at 5'end using 6-mercapto-1-hexhane (HS-ssDNA) is immobilized on the PPy-PEDOT-Ag surface to form PPy-PEDOT-Ag-S-ssDNA and hybridization sensing is done in phosphate buffer. The presence of Ag nanoparticles (~28±5nm) well dispersed in the polymer composite with high surface area, high electrical conductivity and catalytic activity provides desirable microenvironment for the immobilization of probe DNA with controlled orientation leading to increased hybridization efficiency with target DNA. The morphological and structural characterizations by a scanning electron microscope (SEM) and X-ray diffraction (XRD) confirm the nanotube structure of composite polymer while Raman measurements indicate the efficient interactions between the PPy, PEDOT, Ag and HS-ssDNA. The sensor effectively discriminates different target DNA sequences with PPy-PEDOT-Ag-S-ssDNA substrate. The observed dynamic detection range is found between 1×10(-11)M and 1×10(-14)M with the lowest detection limit (3 σ/b) of 5.4×10(-15)M. This observed value is of higher sensitivity than that for MWCNT-Ag, PANi-Au, MWCNT-PPy-Au and PPy-PANi-Au composites reported previously. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Investigation of the Optoelectronic Properties of Ti-doped Indium Tin Oxide Thin Film.

    Science.gov (United States)

    Pu, Nen-Wen; Liu, Wei-Sheng; Cheng, Huai-Ming; Hu, Hung-Chun; Hsieh, Wei-Ting; Yu, Hau-Wei; Liang, Shih-Chang

    2015-09-21

    : In this study, direct-current magnetron sputtering was used to fabricate Ti-doped indium tin oxide (ITO) thin films. The sputtering power during the 350-nm-thick thin-film production process was fixed at 100 W with substrate temperatures increasing from room temperature to 500 °C. The Ti-doped ITO thin films exhibited superior thin-film resistivity (1.5 × 10 - ⁴ Ω/cm), carrier concentration (4.1 × 10 21 cm - ³), carrier mobility (10 cm²/Vs), and mean visible-light transmittance (90%) at wavelengths of 400-800 nm at a deposition temperature of 400 °C. The superior carrier concentration of the Ti-doped ITO alloys (>10 21 cm - ³) with a high figure of merit (81.1 × 10 - ³ Ω - ¹) demonstrate the pronounced contribution of Ti doping, indicating their high suitability for application in optoelectronic devices.

  17. Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

    International Nuclear Information System (INIS)

    Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie; Gu, Changzhi

    2014-01-01

    B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3 K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63 nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity

  18. Use of co-spray pyrolysis for synthesizing nitrogen-doped TiO2 films

    Indian Academy of Sciences (India)

    Nitrogen-doped nanocrystalline TiO2 is well known as the most promising photocatalyst. Despite many years after discovery, seeking of efficient method to prepare TiO2 doped with nitrogen still attracts a lot of attention. In this paper, we present the result of using co-spray pyrolysis to synthesize nitrogen-doped TiO2 films ...

  19. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    Abstract. Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ZnCl2 and CuCl2 were incorporated as dopant agents into the conventional CdS chemical bath in order to promote the CdS doping process. The effect of the deposition time and the doping concentration on the ...

  20. Chemical bath deposition of CdS thin films doped with Zn and Cu

    Indian Academy of Sciences (India)

    Zn- and Cu-doped CdS thin films were deposited onto glass substrates by the chemical bath technique. ZnCl2 and CuCl2 were incorporated as dopant agents into the conventional CdS chemical bath in order to promote the CdS doping process. The effect of the deposition time and the doping concentration on the physical ...

  1. Development of Doped Microcrystalline Silicon Oxide and its Application to Thin‑Film Silicon Solar Cells

    NARCIS (Netherlands)

    Lambertz, A.

    2015-01-01

    The aim of the present study is the development of doped microcrystalline silicon oxide (µc‑SiOx:H) alloys and its application in thin‑film silicon solar cells. The doped µc‑SiOx:H material was prepared from carbon dioxide (CO2), silane (SiH4), hydrogen (H2) gas mixtures using plasma enhanced

  2. Study of high mobility carriers in Ni-doped CdO films

    Indian Academy of Sciences (India)

    Their d.c. conductivity, carrier concentration and mobility increased compared to undoped CdO film. The largest mobility of 112·6 cm2/V·s was measured for 1–2% Ni-doped CdO film. From optoelectronics point of view, Ni-doped CdO can be used in infrared-transparent-conducting-oxide (NIR–TCO) applications. Keywords.

  3. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    Energy Technology Data Exchange (ETDEWEB)

    Puthirath, Anand B.; Varma, Sreekanth J.; Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India); Methattel Raman, Shijeesh [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India)

    2016-04-18

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  4. Low-Concentration Indium Doping in Solution-Processed Zinc Oxide Films for Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Xue Zhang

    2017-07-01

    Full Text Available We investigated the influence of low-concentration indium (In doping on the chemical and structural properties of solution-processed zinc oxide (ZnO films and the electrical characteristics of bottom-gate/top-contact In-doped ZnO thin-film transistors (TFTs. The thermogravimetry and differential scanning calorimetry analysis results showed that thermal annealing at 400 °C for 40 min produces In-doped ZnO films. As the In content of ZnO films was increased from 1% to 9%, the metal-oxygen bonding increased from 5.56% to 71.33%, while the metal-hydroxyl bonding decreased from 72.03% to 9.63%. The X-ray diffraction peaks and field-emission scanning microscope images of the ZnO films with different In concentrations revealed a better crystalline quality and reduced grain size of the solution-processed ZnO thin films. The thickness of the In-doped ZnO films also increased when the In content was increased up to 5%; however, the thickness decreased on further increasing the In content. The field-effect mobility and on/off current ratio of In-doped ZnO TFTs were notably affected by any change in the In concentration. Considering the overall TFT performance, the optimal In doping concentration in the solution-processed ZnO semiconductor was determined to be 5% in this study. These results suggest that low-concentration In incorporation is crucial for modulating the morphological characteristics of solution-processed ZnO thin films and the TFT performance.

  5. Electrochemical biosensing based on polypyrrole/titania nanotube hybrid.

    Science.gov (United States)

    Xie, Yibing; Zhao, Ye

    2013-12-01

    The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. © 2013 Elsevier B.V. All rights reserved.

  6. Investigation of Physical Properties and Electrochemical Behavior of Nitrogen-Doped Diamond-Like Carbon Thin Films

    Directory of Open Access Journals (Sweden)

    Rattanakorn Saensak

    2014-03-01

    Full Text Available This work reports characterizations of diamond-like carbon (DLC films used as electrodes for electrochemical applications. DLC thin films are prepared on glass slides and silicon substrates by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD using a gas mixture of methane and hydrogen. In addition, the DLC films are doped with nitrogen in order to reduce electrical resistivity. Compared to the undoped DLC films, the electrical resistivity of nitrogen-doped (N-doped DLC films is decreased by three orders of magnitude. Raman spectroscopy and UV/Vis spectroscopy analyses show the structural transformation in N-doped DLC films that causes the reduction of band gap energy. Contact angle measurement at N-doped DLC films indicates increased hydrophobicity. The results obtained from the cyclic voltammetry measurements with Fe(CN63-/Fe(CN64- redox species exhibit the correlation between the physical properties and electrochemical behavior of DLC films.

  7. The electrical and optical properties of Cu-doped In{sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Fan [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technology, Shenzhen University, Shenzhen, 518060 (China); Cai, Xing-Min, E-mail: caixm@graduate.hku.hk [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technology, Shenzhen University, Shenzhen, 518060 (China); Zhong, Xue; Tian, Xiao-Qing [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technology, Shenzhen University, Shenzhen, 518060 (China); Jing, Shou-Yong [The Institute of Optoelectronics, Shenzhen University, Shenzhen, 518060 (China); Huang, Long-Biao; Roy, V.A.L. [Center of Super-Diamond and Advanced Films (COSDAF)and Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong (China); Zhang, Dong-Ping; Fan, Ping; Luo, Jing-Tin; Zheng, Zhuang-Hao; Liang, Guang-Xing [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technology, Shenzhen University, Shenzhen, 518060 (China)

    2014-04-01

    To study the effect of Cu doping, In{sub 2}O{sub 3} and Cu-doped In{sub 2}O{sub 3} films were deposited on K9 glass and Si substrates with the same experimental parameters. All the films were found to be body centered cubic and have the same preferred orientation. No secondary phases were detected in Cu-doped In{sub 2}O{sub 3}. The atomic ratio of Cu to Cu plus In was approximately 18% in Cu-doped In{sub 2}O{sub 3} films which were found to be n-type. After Cu doping, the resistivity of the films increased by 3 to 4 orders of magnitude and the film with higher Cu content had larger resistivity, due to compensation. Cu doping is found to widen the optical band gap of In{sub 2}O{sub 3} films, possibly due to a metal–insulator transition. - Highlights: • Cu doping changes neither the structure nor the preferred orientation of the films. • Cu doped In{sub 2}O{sub 3} are n-type. • Cu doped In{sub 2}O{sub 3} films have much larger resistivity than undoped In{sub 2}O{sub 3}. • Cu doped In{sub 2}O{sub 3} films have larger optical band gaps than undoped In{sub 2}O{sub 3}.

  8. Temperature dependence of gas sensing behaviour of TiO2 doped PANI composite thin films

    International Nuclear Information System (INIS)

    Srivastava, Subodh; Sharma, Preetam; Singh, M.; Vijay, Y. K.; Sharma, S. S.; Sharma, Vinay; Rajura, Rajveer Singh

    2014-01-01

    In the present work we have reported the effect of temperature on the gas sensing properties of TiO 2 doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO 2 doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline at low temperature. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature TiO 2 doped PANI composite sensor shows higher response value and showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement

  9. 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

  10. Effect of Sr doping on LaTiO3 thin films

    International Nuclear Information System (INIS)

    Vilquin, B.; Kanki, T.; Yanagida, T.; Tanaka, H.; Kawai, T.

    2005-01-01

    We report on the electric properties of La 1-x Sr x TiO 3 (0 ≤ x ≤ 0.5) thin films fabricated by pulsed laser deposition method. Crystallographic measurement of the thin films showed the epitaxial c-axis perovskite structure. The electric property of LaTiO 3 thin film, which is a typical Mott insulative material in bulk, showed insulative behaviour, while the Sr-doped films showed metallic conduction suffering electron-electron scattering. Below x = 0.1, the major carrier type was identified to be hole, and switched to electron with further increasing Sr-doping above x = 0.15. In fact, the switching from p-type to n-type for La 1-x Sr x TiO 3 thin films is first demonstrated in this study. The transition suggests that effective Coulomb gap vanishes due to over-additional Sr doping

  11. Preparation of thin {alpha}-particle sources using poly-pyrrole films functionalized by a chelating agent; Preparation de sources minces d'emetteurs alpha a l'aide de films de polypyrrole fonctionnalises par un ligand chelatant

    Energy Technology Data Exchange (ETDEWEB)

    Mariet, C. [CEA Saclay, INSTN, Institut National des Sciences et Techniques Nucleaires, 91 - Gif-sur-Yvette (France); Universite Pierre et Marie Curie, 75 - Paris (France)

    2000-07-01

    This work takes place in the scope of analysis of the {alpha}-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the {alpha}-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D{sub U} and D{sub Am} could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  12. Nitrogen doping in atomic layer deposition grown titanium dioxide films by using ammonium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, M.-L., E-mail: marja-leena.kaariainen@lut.fi; Cameron, D.C.

    2012-12-30

    Titanium dioxide films have been created by atomic layer deposition using titanium chloride as the metal source and a solution of ammonium hydroxide in water as oxidant. Ammonium hydroxide has been used as a source of nitrogen for doping and three thickness series have been deposited at 350 Degree-Sign C. A 15 nm anatase dominated film was found to possess the highest photocatalytic activity in all film series. Furthermore almost three times better photocatalytic activity was discovered in the doped series compared to undoped films. The doped films also had lower resistivity. The results from X-ray photoemission spectroscopy showed evidence for interstitial nitrogen in the titanium dioxide structure. Besides, there was a minor red shift observable in the thickest samples. In addition the film conductivity was discovered to increase with the feeding pressure of ammonium hydroxide in the oxidant precursor. This may indicate that nitrogen doping has caused the decrease in the resistivity and therefore has an impact as an enhanced photocatalytic activity. The hot probe test showed that all the anatase or anatase dominant films were p-type and all the rutile dominant films were n-type. The best photocatalytic activity was shown by anatase-dominant films containing a small amount of rutile. It may be that p-n-junctions are formed between p-type anatase and n-type rutile which cause carrier separation and slow down the recombination rate. The combination of nitrogen doping and p-n junction formation results in superior photocatalytic performance. - Highlights: Black-Right-Pointing-Pointer We found all N-doped and undoped anatase dominating films p-type. Black-Right-Pointing-Pointer We found all N-doped and undoped rutile dominating films n-type. Black-Right-Pointing-Pointer We propose that p-n junctions are formed in anatase-rutile mixture films. Black-Right-Pointing-Pointer We found that low level N-doping has increased TiO{sub 2} conductivity. Black

  13. In situ ellipsometry — A powerful tool for monitoring alkali doping of organic thin films

    International Nuclear Information System (INIS)

    Haidu, F.; Ludemann, M.; Schäfer, P.; Gordan, O.D.; Zahn, D.R.T.

    2014-01-01

    The changes of the optical properties of several organic thin films induced by potassium doping were monitored using in situ spectroscopic ellipsometry. The samples were prepared in a high vacuum chamber by organic molecular deposition. Then, potassium (K) was evaporated by passing current through K getters. The three different organic molecules used, show very distinct and different spectral behaviour upon doping. While for Tris-(8-hydroxyquinoline)-aluminium(III) and N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-(1,1′-biphenyl)-4,4′-diamine only small shifts of the spectral features were noticed, Manganese Phthalocyanine revealed significant changes of the optical properties induced by the K doping. This work indicates that the K doping process can have a dramatic effect on the electronic and the optical properties of the organic molecules, but the effect on the optical spectra remains specific for each organic molecule used, and cannot be easily predicted. - Highlights: • Monitoring organic film growth and doping with in situ spectroscopic ellipsometry • K doped organic thin films • Optical properties of organic thin films change by K doping. • The changes in the optical spectra remain specific for each organic molecule used

  14. Structural, optical and electrochemical properties of F-doped vanadium oxide transparent semiconducting thin films

    Science.gov (United States)

    Mousavi, M.; Khorrami, Gh. H.; Kompany, A.; Yazdi, Sh. Tabatabai

    2017-12-01

    In this study, F-doped vanadium oxide thin films with doping levels up to 60 at % were prepared by spray pyrolysis method on glass substrates. To measure the electrochemical properties, some films were deposited on fluorine-tin oxide coated glass substrates. The effect of F-doping on the structural, electrical, optical and electrochemical properties of vanadium oxide samples was investigated. The X-ray diffractographs analysis has shown that all the samples grow in tetragonal β-V2O5 phase structure with the preferred orientation of [200]. The intensity of (200) peak belonging to β-V2O5 phase was strongest in the undoped vanadium oxide film. The scanning electron microscopy images show that the samples have nanorod- and nanobelt-shaped structure. The size of the nanobelts in the F-doped vanadium oxide films is smaller than that in the pure sample and the width of the nanobelts increases from 30 to 70 nm with F concentration. With increasing F-doping level from 10 to 60 at %, the resistivity, the transparency and the optical band gap decrease from 111 to 20 Ω cm, 70 to 50% and 2.4 to 2.36 eV, respectively. The cyclic voltammogram (CV) results show that the undoped sample has the most extensive CV and by increasing F-doping level from 20 to 60 at %, the area of the CV is expanded. The anodic and cathodic peaks in F-doped samples are stronger.

  15. 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.

  16. Magnetic and electromagnetic properties of Pr doped strontium ferrite/polyaniline composite film

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ying; Li, Yuqing; Wang, Yan, E-mail: wangyan287580632@126.com

    2014-11-15

    This paper reported three acid (including hydrochloric acid HCl, p-toluenesulfonic acid PTS and D-camphor-10-acid CSA) doped SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}/PANI composite film and the HCl–PANI film prepared by a sol–gel method and in-situ oxidative polymerization. The characteristics of the film phase structure, surface morphology, conductivity and magnetic and electromagnetic properties were studied by using XRD, XPS, FESEM, four-probe tester, VSM and Vector Network Analyzer. The resistivity of organic acid doped composite films is higher than that of the HCl doped one. The saturation and remanent magnetization of PTS and HCl doped composite films are greater than the CSA-doped one; however, the coercivity of the three acid doped composite films is basically 5546 Oe. The saturation magnetization, remanent magnetization and coercivity of SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film are greater than those of the SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}–PANI composite film. In the frequency range of 8–12 GHz, the dielectric loss of HCl–PANI film is the maximum, and the dielectric loss of SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film is the minimum; the magnetic loss of the four films is in descending order as SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film, PrSrM/(HCl–PANI) composite film, PrSrM/(CSA–PANI) and HCl–PANI film. - Highlights: • Synthesizing three acid doped SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}/PANI composite films. • By sol–gel method and in-situ oxidative polymerization. • With excellent magnetic and electromagnetic properties. • The particular coating structure of PANI and Sr-ferrite. • Great interest for magnetic material and microwave absorbers.

  17. The Effects of Boron Doping on Residual Stress of Hfcvd Diamond Film for Mems Applications

    Science.gov (United States)

    Zhao, Tianqi; Wang, Xinchang; Sun, Fanghong

    In this study, the residual stress of boron-doped diamond (BDD) films is investigated as a function of boron doping level using X-ray diffraction (XRD) analysis. Boron doping level is controlled from 1000ppm to 9000ppm by dissolving trimethyl borate into acetone. BDD films are deposited on silicon wafers using a bias-enhanced hot filament chemical vapor deposition (BE-HFCVD) system. Residual stress calculated by sin2 ψ method varies linearly from ‑2.4GPa to ‑1.1GPa with increasing boron doping level. On the BDD film of ‑1.75GPa, free standing BDD cantilevers are fabricated by photolithography and ICP-RIE processes, then tested by laser Doppler vibrometer (LDV). A cantilever with resonant frequency of 183KHz and Q factor of 261 in the air is fabricated.

  18. Impacts of doping on epitaxial germanium thin film quality and Si-Ge interdiffusion

    KAUST Repository

    Zhou, Guangnan

    2018-04-03

    Ge-on-Si structures with three different dopants (P, As and B) and those without intentional doping were grown, annealed and characterized by several different material characterization methods. All samples have a smooth surface (roughness < 1.5 nm), and the Ge films are almost entirely relaxed. B doped Ge films have threading dislocations above 1 × 10 cm, while P and As doping can reduce the threading dislocation density to be less than 10 cm without annealing. The interdiffusion of Si and Ge of different films have been investigated experimentally and theoretically. A quantitative model of Si-Ge interdiffusion under extrinsic conditions across the full x range was established including the dislocationmediated diffusion. The Kirkendall effect has been observed. The results are of technical significance for the structure, doping, and process design of Ge-on-Si based devices, especially for photonic applications.

  19. Preparation of thin α-particle sources using poly-pyrrole films functionalized by a chelating agent

    International Nuclear Information System (INIS)

    Mariet, C.

    2000-01-01

    This work takes place in the scope of analysis of the α-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the α-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D U and D Am could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  20. Electrical properties of vacuum-annealed titanium-doped indium oxide films

    NARCIS (Netherlands)

    Yan, L.T.; Rath, J.K.; Schropp, R.E.I.

    2011-01-01

    Titanium-doped indium oxide (ITiO) films were deposited on Corning glass 2000 substrates at room temperature by radio frequency magnetron sputtering followed by vacuum post-annealing. With increasing deposition power, the as-deposited films showed an increasingly crystalline nature. As-deposited

  1. Preparation of manganese-doped ZnO thin films and their ...

    Indian Academy of Sciences (India)

    Abstract. In this study, pure and manganese-doped zinc oxide (Mn:ZnO) thin films were deposited on quartz substrate following successive ion layer adsorption and reaction (SILAR) technique. The film growth rate was found to increase linearly with number of dipping cycle. Characterization techniques of XRD, SEM with ...

  2. Nanocrystalline Pt-doped TiO2 thin films prepared by spray pyrolysis ...

    Indian Academy of Sciences (India)

    Administrator

    Nanocrystalline Pt-doped TiO2 thin films prepared by spray pyrolysis for hydrogen gas detection. LALCHAND A PATIL* .... tions of nanocrystalline TiO2 thin films using spray pyro- lysis. 2.4 Thickness and roughness determination of ... Electrical and gas sensing properties were measured using a static gas sensing system.

  3. Preparation of manganese-doped ZnO thin films and their ...

    Indian Academy of Sciences (India)

    In this study, pure and manganese-doped zinc oxide (Mn:ZnO) thin films were deposited on quartz substrate following successive ion layer adsorption and reaction (SILAR) technique. The film growth rate was found to increase linearly with number of dipping cycle. Characterization techniques of XRD, SEM with EDX and ...

  4. 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...

  5. Magnetism of carbon doped Mn 5 Si 3 and Mn 5 Ge 3 films

    Indian Academy of Sciences (India)

    The magnetic properties of Mn5Si3C and Mn5Ge3C films prepared by magnetron cosputtering or C+-ion implantation are studied. The carbon-doped films exhibit ferromagnetic properties with Curie temperatures C well above room temperature and metallic conductivity, making them possible candidates for future ...

  6. Stress-Induced Crystallization of Ge-Doped Sb Phase-Change Thin Films

    NARCIS (Netherlands)

    Eising, Gert; Pauza, Andrew; Kooi, Bart J.

    The large effects of moderate stresses on the crystal growth rate in Ge-doped Sb phase-change thin films are demonstrated using direct optical imaging. For Ge6Sb94 and Ge7Sb93 phase-change films, a large increase in crystallization temperature is found when using a polycarbonate substrate instead of

  7. Effect of indium doping on zinc oxide films prepared by chemical ...

    Indian Academy of Sciences (India)

    We report the conducting and transparent In doped ZnO films fabricated by a homemade chemical spray pyrolysis system (CSPT). The effect of In concentration on the structural, morphological, electrical and optical properties have been studied. These films are found to show (0 0 2) preferential growth at low indium ...

  8. Resistance switching of thin AlOx and Cu-doped-AlOx films

    International Nuclear Information System (INIS)

    Wu, Ya-Ting; Jou, Shyankay; Yang, Ping-Jung

    2013-01-01

    Thin copper-doped aluminum oxide (Cu-doped-AlO x ) and AlO x films of about 5 nm thick were generated by oxidizing the surfaces of Al and Al-5 wt.% Cu (Al-Cu) films in an oxygen plasma. According to X-ray photoelectron spectroscopy analyses, these two oxide films were found to be deficient in oxygen and had gradient concentrations of Al and O. The oxide films were employed as resistor layers sandwiched between an Al top electrode and an Al or Al-Cu bottom electrode to form resistive memory devices. The devices demonstrated unipolar resistance switching between high resistance state and low resistance state (LRS), and their resistance ratios measured at + 0.2 V were around 10 5 . Furthermore, their current–voltage characteristics showed ohmic conduction with the resistance increasing with temperature, in LRS. Conductive filaments were thought to form inside the AlO x film and the Cu-doped AlO x film, causing resistive switching. The resistive memory device using the AlO x film had unstable switching behaviors during cyclic testing, whereas the device using the Cu-doped AlO x film demonstrated stable resistance switching during 100 cycles of testing. The presence of the Cu ingredient in the AlO x film is likely to facilitate the formation and rupture of conductive filaments and induced stable resistance switching. - Highlights: • AlO x layers are formed by plasma oxidation for resistance memory device (RRAM). • Al/AlO x /Al and Al/AlO x -CuO x /Al-Cu exhibit unipolar resistance switching. • Cu doping assists formation of the filaments of mixed Al and Cu in AlO x . • Cu doping improves endurance and retention of the AlO x -based RRAM

  9. Rare Earth-Doped BiFeO3 Thin Films: Relationship between Structural and Magnetic Properties

    Directory of Open Access Journals (Sweden)

    Ngo Thu Huong

    2015-01-01

    Full Text Available Rare Earth- (RE- doped BiFeO3 (BFO thin films were grown on LaAlO3 substrates by using pulsed laser deposition technique. All of BFO films doped with 10% of RE show a single phase of rhombohedral structure. The saturated magnetization in the Ho- and Sm-doped films is much larger than those reported in literature and was observed at a quite low field as of 0.2 T. As for Pr- and Nd-doped BFO films, Fe2+ amount is not dominant; thus, ferromagnetism is not favored. As the RE concentration goes up to 20%, all compounds have drastically gone through a structural transition. The RE-doped BFO films have changed from rhombohedral to either pure orthorhombic phase (for Ho, Sm, or a mixed phase of orthorhombic and tetragonal (for Pr, Nd, or pure tetragonal (for Eu. We observed magnetic properties of RE-doped BFO films have significantly changed. While 20% Ho/Sm-doped BFO films have ferromagnetism degraded in comparison with the 10% doping case, the 20% Pr/Nd-doped BFO thin films, whose structure is a mixed phase, have magnetic ordering improved due to the fact that the Fe2+ amount has become greater. It seems that one can control the magnetic properties of BFO films by using appropriate RE dopants and concentrations.

  10. Aluminum-doped hydrogenated microcrystalline cubic silicon carbide films deposited by hot wire CVD

    International Nuclear Information System (INIS)

    Miyajima, Shinsuke; Yamada, Akira; Konagai, Makoto

    2006-01-01

    Aluminum-doped hydrogenated microcrystalline cubic silicon carbide (Al-doped μc-3C-SiC:H) films were successfully deposited by hot wire chemical vapor deposition using a gas mixture of monomethylsilane, hydrogen and trimethylaluminum (TMA). Deposition rate and infrared absorption measurements indicate that radicals generated from TMA extract hydrogen atoms from the growing surface of the films. Infrared absorption and secondary ion mass spectroscopy measurements suggest the existence of Al-H complexes in the deposited film. The dark conductivity was found to be below 10 - 7 S/cm for as-deposited films and 10 - 6 -10 - 4 S/cm for annealed films. Our studies indicate the possibility of forming p-type μc-3C-SiC:H films on glass substrates at process temperature below 400 deg. C

  11. 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.

  12. Preparation and characterization of poly-pyrrole thin films functionalized by ion exchanger groups. Application to preparation of alpha sources

    International Nuclear Information System (INIS)

    Stephan, Olivier

    1995-01-01

    After having outlined that dosing methods still present problems related to chemical separations techniques used before radioactivity measurements, and to spectrometric methods, this research thesis proposes the study of a new method of fabrication of a radioactive source. This method comprises the fabrication of a chemically reactive thin film by electro-polymerization, and the incorporation of actinides in the deposit by ion exchange. In this case, the deposit thickness could be controlled and the material transfer chemical mechanisms could be predicted and controlled [fr

  13. Deposition of Cu-doped PbS thin films with low resistivity using DC sputtering

    Science.gov (United States)

    Soetedjo, Hariyadi; Siswanto, Bambang; Aziz, Ihwanul; Sudjatmoko

    2018-03-01

    Investigation of the electrical resistivity of Cu-doped PbS thin films has been carried out. The films were prepared using a DC sputtering technique. The doping was achieved by introducing the Cu dopant plate material directly on the surface of the PbS sputtering target plate. SEM-EDX data shows the Cu concentration in the PbS film to be proportional to the Cu plate diameter. The XRD pattern indicates the film is in crystalline cubic form. The Hall effect measurement shows that Cu doping yields an increase in the carrier concentration to 3.55 × 1019 cm-3 and a significant decrease in electrical resistivity. The lowest resistivity obtained was 0.13 Ωcm for a Cu concentration of 18.5%. Preferential orientation of (1 1 1) and (2 0 0) occurs during deposition.

  14. Highly conducting and crystalline doubly doped tin oxide films fabricated using a low-cost and simplified spray technique

    Energy Technology Data Exchange (ETDEWEB)

    Ravichandran, K., E-mail: kkr1365@yahoo.co [P.G. and Research Department of Physics, AVVM. Sri Pushpum College, Poondi, Thanjavur District, Tamil Nadu 613503 (India); Muruganantham, G.; Sakthivel, B. [P.G. and Research Department of Physics, AVVM. Sri Pushpum College, Poondi, Thanjavur District, Tamil Nadu 613503 (India)

    2009-11-15

    Doubly doped (simultaneous doping of antimony and fluorine) tin oxide films (SnO{sub 2}:Sb:F) have been fabricated by employing an inexpensive and simplified spray technique using perfume atomizer from aqueous solution of SnCl{sub 2} precursor. The structural studies revealed that the films are highly crystalline in nature with preferential orientation along the (2 0 0) plane. It is found that the size of the crystallites of the doubly doped tin oxide films is larger (69 nm) than that (27 nm) of their undoped counterparts. The dislocation density of the doubly doped film is lesser (2.08x10{sup 14} lines/m{sup 2}) when compared with that of the undoped film (13.2x10{sup 14} lines/m{sup 2}), indicating the higher degree of crystallinity of the doubly doped films. The SEM images depict that the films are homogeneous and uniform. The optical transmittance in the visible range and the optical band gap of the doubly doped films are 71% and 3.56 eV respectively. The sheet resistance (4.13 OMEGA/square) attained for the doubly doped film in this study is lower than the values reported for spray deposited fluorine or antimony doped tin oxide films prepared from aqueous solution of SnCl{sub 2} precursor (without using methanol or ethanol).

  15. Preparation and characterisation of Al-doped Zn O thin films

    International Nuclear Information System (INIS)

    Saad, M.; Kassis, A.; Nounou, F.

    2010-12-01

    Al-doped Zn O thin films were prepared using RF magnetron sputtering under several preparation conditions (deposition pressure, RF power, substrate temperature). The films were optically and electrically characterized by measuring their transmission and resistance. Furthermore, x-ray diffraction spectroscopy was used in order to study the structural properties of these films. As a result of this study, the preparation conditions suitable for the highly conductive part of the window layer in solar cells were determined. (author)

  16. 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.

  17. Antimicrobial Activity of Thin Solid Films of Silver Doped Hydroxyapatite Prepared by Sol-Gel Method

    Science.gov (United States)

    Iconaru, Simona Liliana; Chapon, Patrick; Le Coustumer, Philippe; Predoi, Daniela

    2014-01-01

    In this work, the preparation and characterization of silver doped hydroxyapatite thin films were reported and their antimicrobial activity was characterized. Silver doped hydroxyapatite (Ag:HAp) thin films coatings substrate was prepared on commercially pure Si disks by sol-gel method. The silver doped hydroxyapatite thin films were characterized by various techniques such as Scanning electron microscopy (SEM) with energy Dispersive X-ray attachment (X-EDS), Fourier transform infrared spectroscopy (FT-IR), and glow discharge optical emission spectroscopy (GDOES). These techniques have permitted the structural and chemical characterisation of the silver doped hydroxyapatite thin films. The antimicrobial effect of the Ag:HAp thin films on Escherichia coli and Staphylococcus aureus bacteria was then investigated. This is the first study on the antimicrobial effect of Ag:HAp thin films obtained by sol-gel method. The results of this study have shown that the Ag:HAp thin films with x Ag = 0.5 are effective against E. coli and S. aureus after 24 h. PMID:24523630

  18. Iron, nitrogen and silicon doped diamond like carbon (DLC) thin films: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Sekhar C., E-mail: Raysc@unisa.ac.za [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Private Bag X6, Florida, 1710, Science Campus, Christiaan de Wet and Pioneer Avenue, Florida Park, Johannesburg (South Africa); Pong, W.F. [Department of Physics, Tamkang University, Tamsui 251, New Taipei City, Taiwan (China); Papakonstantinou, P. [Nanotechnology and Integrated Bio-Engineering Centre, University of Ulster, Shore Road, Newtownabbey BT37 0QB (United Kingdom)

    2016-07-01

    The X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), valence band photoemission (VB-PES) and Raman spectroscopy results show that the incorporation of nitrogen in pulsed laser deposited diamond like carbon (DLC) thin films, reverts the sp{sup 3} network to sp{sup 2} as evidenced by an increase of the sp{sup 2} cluster and I{sub D}/I{sub G} ratio in C K-edge XANES and Raman spectra respectively which reduces the hardness/Young's modulus into the film network. Si-doped DLC film deposited in a plasma enhanced chemical vapour deposition process reduces the sp{sup 2} cluster and I{sub D}/I{sub G} ratio that causes the decrease of hardness/Young's modulus of the film structure. The Fe-doped DLC films deposited by dip coating technique increase the hardness/Young's modulus with an increase of sp{sup 3}-content in DLC film structure. - Highlights: • Fe, N and Si doped DLC films deposited by dip, PLD and PECVD methods respectively • DLC:Fe thin films have higher hardness/Young's modulus than DLC:N(:Si) thin films. • sp{sup 3} and sp{sup 2} contents are estimated from C K-edge XANES and VB-PES measurements.

  19. In situ diazonium-modified flexible ITO-coated PEN substrates for the deposition of adherent silver-polypyrrole nanocomposite films.

    Science.gov (United States)

    Samanta, Soumen; Bakas, Idriss; Singh, Ajay; Aswal, Dinesh K; Chehimi, Mohamed M

    2014-08-12

    In this paper, we report a simple and versatile process of electrografting the aryl multilayers onto indium tin oxide (ITO)-coated flexible poly(ethylene naphthalate) (PEN) substrates using a diazonium salt (4-pyrrolylphenyldiazonium) solution, which was generated in situ from a reaction between the 4-(1H-pyrrol-1-yl)aniline precursor and sodium nitrite in an acidic medium. The first aryl layer bonds with the ITO surface through In-O-C and Sn-O-C bonds which facilitate the formation of a uniform aryl multilayer that is ∼8 nm thick. The presence of the aryl multilayer has been confirmed by impedance spectroscopy as well as by electron-transfer blocking measurements. These in situ diazonium-modified ITO-coated PEN substrates may find applications in flexible organic electronics and sensor industries. Here we demonstrate the application of diazonium-modified flexible substrates for the growth of adherent silver/polpyrrole nanocomposite films using surface-confined UV photopolymerization. These nanocomposite films have platelet morphology owing to the template effect of the pyrrole-terminated aryl multilayers. In addition, the films are highly doped (32%). This work opens new areas in the design of flexible ITO-conductive polymer hybrids.

  20. Atmospheric Pressure Plasma Polymerization Synthesis and Characterization of Polyaniline Films Doped with and without Iodine.

    Science.gov (United States)

    Park, Choon-Sang; Jung, Eun Young; Kim, Dong Ha; Kim, Do Yeob; Lee, Hyung-Kun; Shin, Bhum Jae; Lee, Dong Ho; Tae, Heung-Sik

    2017-11-06

    Although polymerized aniline (polyaniline, PANI) with and without iodine (I₂) doping has already been extensively studied, little work has been done on the synthesis of PANI films using atmospheric pressure plasma (APP) deposition. Therefore, this study characterized pure and I₂-doped PANI films synthesized using an advanced APP polymerization system. The I₂ doping was conducted ex-situ and using an I₂ chamber method following the APP deposition. The pure and I₂-doped PANI films were structurally analyzed using field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and time of flight secondary ion mass spectrometry (ToF-SIMS) studies. When increasing the I₂ doping time, the plane and cross-sectional SEM images showed a decrease in the width and thickness of the PANI nanofibers, while the AFM results showed an increase in the roughness and grain size of the PANI films. Moreover, the FT-IR, XPS, and ToF-SIMS results showed an increase in the content of oxygen-containing functional groups and C=C double bonds, yet decrease in the C-N and C-H bonds when increasing the I₂ doping time due to the reduction of hydrogen in the PANI films via the I₂. To check the suitability of the conductive layer for polymer display applications, the resistance variations of the PANI films grown on the interdigitated electrode substrates were also examined according to the I₂ doping time.

  1. Atmospheric Pressure Plasma Polymerization Synthesis and Characterization of Polyaniline Films Doped with and without Iodine

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2017-11-01

    Full Text Available Although polymerized aniline (polyaniline, PANI with and without iodine (I2 doping has already been extensively studied, little work has been done on the synthesis of PANI films using atmospheric pressure plasma (APP deposition. Therefore, this study characterized pure and I2-doped PANI films synthesized using an advanced APP polymerization system. The I2 doping was conducted ex-situ and using an I2 chamber method following the APP deposition. The pure and I2-doped PANI films were structurally analyzed using field emission scanning electron microscope (FE-SEM, atomic force microscope (AFM, X-ray Diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectroscopy (XPS, and time of flight secondary ion mass spectrometry (ToF-SIMS studies. When increasing the I2 doping time, the plane and cross-sectional SEM images showed a decrease in the width and thickness of the PANI nanofibers, while the AFM results showed an increase in the roughness and grain size of the PANI films. Moreover, the FT-IR, XPS, and ToF-SIMS results showed an increase in the content of oxygen-containing functional groups and C=C double bonds, yet decrease in the C–N and C–H bonds when increasing the I2 doping time due to the reduction of hydrogen in the PANI films via the I2. To check the suitability of the conductive layer for polymer display applications, the resistance variations of the PANI films grown on the interdigitated electrode substrates were also examined according to the I2 doping time.

  2. Effect of HCl doping on optoelectrical and LPG sensing properties of nanostructured polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Upadhye, Deepak S., E-mail: deepaksu22@gmail.com; Huse, Nanasaheb P.; Sharma, Ramphal, E-mail: rps.phy@gmail.com [Thin Film and Nanotechnology Laboratory, Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (India)

    2016-05-06

    Nanostructure Polyaniline thin films doped with 0.5 M, 0.7 M, and 1 M of HCL were synthesized by simple and inexpensive chemical oxidative polymerization technique at room temperature. All prepared thin films of Polyaniline were characterized by optical absorbance study by UV-visible spectroscopy. The absorbance spectrum of Polyaniline shows three fundamental peaks at 356, 419 and 820 nm with increase in absorption intensity. The electrical study shows magnitude of resistance of HCL doped Polyaniline is dependent on doping level. Furthermore, the thin film of Polyaniline was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents irregular granular morphology. In order to investigate LPG sensing properties, I-V characteristics of the Polyaniline films doped with 0.5 M, 0.7 M, and 1 M of HCL were recorded at room temperature in presence of air and 100 ppm of LPG. The observed values of sensitivity found to be 7.21%, 9.85% and 17.46 % for 0.5 M, 0.75 M, and 1.0 M of HCL doped Polyaniline thin films respectively.

  3. 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.

  4. PENINGKATAN KUALITAS FILM TIPIS CdTe SEBAGAI ABSORBER SEL SURYA DENGAN MENGGUNAKAN DOPING TEMBAGA (Cu

    Directory of Open Access Journals (Sweden)

    P. Marwoto

    2012-07-01

    Full Text Available Film tipis CdTe dengan doping tembaga (Cu berkonsenterasi 2% telah berhasil ditumbuhkan di atas substrat Indium Tin Oxide (ITO dengan metode dc magnetron sputtering. Penelitian ini dilakukan untuk mengetahui pengaruh doping Cu(2% terhadap struktur morfologi, struktur kristal, fotoluminisensi dan resistivitas listrik film CdTe. Citra morfologi Scanning Electron Microscopy (SEM dan hasil analisis struktur dengan X-Ray Diffraction (XRD menunjukkan bahwa film CdTe:Cu(2% mempunyai citra permukaan dan struktur kristal yang lebih sempurna dibandingkan film CdTe tanpa doping. Hasil analisis spektrometer fotoluminisensi menunjukkan bahwa film CdTe dan CdTe(2% mempunyai puncak fotoluminisensi pada tiga panjang gelombang yang identik yaitu 685 nm (1,81 eV, 725 nm (1,71 eV dan 740 nm (1,67 eV. Film CdTe dengan doping Cu(2% memiliki intensitas puncak fotoluminisensi yang lebih tajam pada pita energi 1,81 eV dibandingkan dengan film CdTe tanpa doping. Pengukuran arus dan tegangan (I-V menunjukkan bahwa pemberian doping Cu(2% dapat menurunkan resistivitas film dari 8,40x109 Ωcm menjadi 6,92x105 Ωcm. Sebagai absorber sel surya, kualitas film tipis CdTe telah berhasil ditingkatkan dengan pemberian doping Cu(2%.CdTe:Cu(2% thin film has been successfully grown on Indium Tin Oxide (ITO substrates by using dc magnetron sputtering. This study was carried out in order to investigate the effect of Cu(2% doping on the morphologycal structure, crystal structure, photoluminesence, and resistivity of CdTe thin film. Scanning Electron Microscopy (SEM  images and X-Ray Diffraction (XRD results showed that CdTe:Cu(2% thin film has morphologycal and crystal structures more perfect than undoped CdTe film. Photoluminesence spectroscopy results showed that CdTe and CdTe:Cu(2% thin films have luminesence peak at three identical wevelength regions i.e. 685 nm (1.81 eV, 725 nm (1.71 eV and 740 nm (1.67 eV however CdTe:Cu(2% film shows sharper photoluminescence peak at band

  5. Alumina particles doped in a polymer film act as scatterers for random laser generation

    Science.gov (United States)

    Cao, Dan; Huang, Dengfeng; Zhang, Xiaoqiang; Zeng, Shumao; Parbey, Joseph; Liu, Shenye; Wang, Chuanke; Yi, Tao; Li, Tingshuai

    2018-02-01

    Lasing can be achieved with a system that has randomly distributed particles that act as scatterers in polymer films doped with laser dyes; a strict resonant cavity is not required. In this study, alumina particles and Rhodamine 6G dye were dispersed in polyvinyl pyrrolidone solutions as slurry to prepare thin films by a spin-coating method. These films were then pumped as a laser generator using a pulsed Nd:YLF laser. The results indicate that film thickness had an obvious affect on laser emission, and the lasing intensity increased with the pump energy, which tended to increase and then decrease with film thickness. An optical model based on the fabricated films was established to analyze light coupling with the films and possible distribution of light in films.

  6. Structural and magnetic studies of Cr doped nickel ferrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, Kalpana, E-mail: kalpanapanwar99@gmail.com [Department of Pure & Applied Physics, University of Kota, Kota-324010 (India); Department of Physics, Govt. Women Engg. College, Ajmer-305002 (India); Heda, N. L. [Department of Pure & Applied Physics, University of Kota, Kota-324010 (India); Tiwari, Shailja [Department of Physics, Govt. Women Engg. College, Ajmer-305002 (India); Bapna, Komal; Ahuja, B. L. [Department of Physics, M. L. Sukhadia University, Udaipur-313001 (India); Choudhary, R. J.; Phase, D. M. [UGC-DAE Consortium for Scientific Research, University Campus, Indore-452017 (India)

    2016-05-23

    We have studied the structural and magnetic properties of Cr doped nickel ferrite thin films deposited on Si (100) and Si (111) using pulsed laser deposition technique. The films were deposited under vacuum and substrate temperature was kept at 700°C. X-ray diffraction analysis revealed that films on both substrates have single phase cubic spinel structure. However, the film grown on Si (111) shows better crystalline behavior. Fourier transform infrared spectroscopy suggests that films on both substrates have mixed spinel structure. These films show magnetic hysteresis behavior and magnetization value of film on Si (100) is larger than that on Si (111). It turns out that structural and magnetic properties of these two films are correlated.

  7. Tailoring of magnetic properties of ultrathin epitaxial Fe films by Dy doping

    Directory of Open Access Journals (Sweden)

    A. A. Baker

    2015-07-01

    Full Text Available We report on the controlled modification of relaxation parameters and magnetic moments of epitaxial Fe thin films through Dy doping. Ferromagnetic resonance measurements show that an increase of Dy doping from 0.1% to 5% gives a tripling in Gilbert damping, and more importantly a strongly enhanced anisotropic damping that can be qualitatively understood through the slow-relaxing impurity model. X-ray magnetic circular dichroism measurements show a pronounced suppression of the orbital moment of the Fe with Dy doping, leading to an almost threefold drop in the orbital to spin moment ratio, ml/ms. Doping with Dy can therefore be used to control both dynamic and static properties of thin ferromagnetic films for improved performance in spintronics device applications, mediated through the antiferromagnetic interaction of the 4f and 3d states.

  8. Tailoring of magnetic properties of ultrathin epitaxial Fe films by Dy doping

    Energy Technology Data Exchange (ETDEWEB)

    Baker, A. A. [Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU (United Kingdom); Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE (United Kingdom); Figueroa, A. I.; Laan, G. van der [Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE (United Kingdom); Hesjedal, T. [Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU (United Kingdom)

    2015-07-15

    We report on the controlled modification of relaxation parameters and magnetic moments of epitaxial Fe thin films through Dy doping. Ferromagnetic resonance measurements show that an increase of Dy doping from 0.1% to 5% gives a tripling in Gilbert damping, and more importantly a strongly enhanced anisotropic damping that can be qualitatively understood through the slow-relaxing impurity model. X-ray magnetic circular dichroism measurements show a pronounced suppression of the orbital moment of the Fe with Dy doping, leading to an almost threefold drop in the orbital to spin moment ratio, m{sub l}/m{sub s}. Doping with Dy can therefore be used to control both dynamic and static properties of thin ferromagnetic films for improved performance in spintronics device applications, mediated through the antiferromagnetic interaction of the 4f and 3d states.

  9. Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jiezhu; Wang Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Haque, M A [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-05-26

    We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

  10. Nitrogen and europium doped TiO2 anodized films with applications in photocatalysis

    International Nuclear Information System (INIS)

    Chi, Choong-Soo; Choi, Jinwook; Jeong, Yongsoo; Lee, Oh Yeon; Oh, Han-Jun

    2011-01-01

    Micro-arc oxidation method is a useful process for mesoporous titanium dioxide films. In order to improve the photocatalytic activity of the TiO 2 film, N-Eu co-doped titania catalyst was synthesized by micro-arc oxidation in the H 2 SO 4 /Eu(NO 3 ) 3 mixture solution. The specific surface area and the roughness of the anodic titania film fabricated in the H 2 SO 4 /Eu(NO 3 ) 3 electrolyte, were increased compared to that of the anodic TiO 2 film prepared in H 2 SO 4 solution. The absorbance response of N-Eu titania film shows a higher adsorption onset toward visible light region, and the incorporated N and Eu ions during anodization as a dopant in the anodic TiO 2 film significantly enhanced the photocatalytic activity for dye degradation. After dye decomposition test for 3 h, dye removal rates for the anodic TiO 2 film were 60.7% and 90.1% for the N-Eu doped titania film. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the surface enlargement and the new electronic state of the TiO 2 band gap by N and Eu co-doping.

  11. Optical Analysis of Iron-Doped Lead Sulfide Thin Films for Opto-Electronic Applications

    Science.gov (United States)

    Chidambara Kumar, K. N.; Khadeer Pasha, S. K.; Deshmukh, Kalim; Chidambaram, K.; Shakil Muhammad, G.

    Iron-doped lead sulfide thin films were deposited on glass substrates using successive ionic layer adsorption and reaction method (SILAR) at room temperature. The X-ray diffraction pattern of the film shows a well formed crystalline thin film with face-centered cubic structure along the preferential orientation (1 1 1). The lattice constant is determined using Nelson Riley plots. Using X-ray broadening, the crystallite size is determined by Scherrer formula. Morphology of the thin film was studied using a scanning electron microscope. The optical properties of the film were investigated using a UV-vis spectrophotometer. We observed an increase in the optical band gap from 2.45 to 3.03eV after doping iron in the lead sulfide thin film. The cutoff wavelength lies in the visible region, and hence the grown thin films can be used for optoelectronic and sensor applications. The results from the photoluminescence study show the emission at 500-720nm. The vibrating sample magnetometer measurements confirmed that the lead sulfide thin film becomes weakly ferromagnetic material after doping with iron.

  12. Micro-orientation control of silicon polymer thin films on graphite surfaces modified by heteroatom doping

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Iwao, E-mail: shimoyama.iwao@jaea.go.jp [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Baba, Yuji [Fukushima Administrative Department, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Hirao, Norie [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan)

    2017-05-31

    Highlights: • Micro-orientation control method for organic polysilane thin films is proposed. • This method utilizes surface modification of graphite using heteroatom doping. • Lying, standing, and random orientations can be freely controlled by this method. • Micro-pattering of a polysilane film with controlled orientations is achieved. - Abstract: Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is applied to study orientation structures of polydimethylsilane (PDMS) films deposited on heteroatom-doped graphite substrates prepared by ion beam doping. The Si K-edge NEXAFS spectra of PDMS show opposite trends of polarization dependence for non irradiated and N{sub 2}{sup +}-irradiated substrates, and show no polarization dependence for an Ar{sup +}-irradiated substrate. Based on a theoretical interpretation of the NEXAFS spectra via first-principles calculations, we clarify that PDMS films have lying, standing, and random orientations on the non irradiated, N{sub 2}{sup +}-irradiated, and Ar{sup +}-irradiated substrates, respectively. Furthermore, photoemission electron microscopy indicates that the orientation of a PDMS film can be controlled with microstructures on the order of μm by separating irradiated and non irradiated areas on the graphite surface. These results suggest that surface modification of graphite using ion beam doping is useful for micro-orientation control of organic thin films.

  13. Effects of starting material of aluminum doped zinc oxide underlayer on the electric properties of palladium doped silver film

    Science.gov (United States)

    Oyama, T.; Maekawa, M.; Yanagisawa, T.

    2003-07-01

    Crystallographic and electric properties of a palladium doped silver (Ag-Pd) layer formed on an aluminum doped zinc oxide (AZO) film in the multilayer system of Ag-Pd(10.5 nm)/AZO(42 nm)/glass were investigated. All of the films in this study were deposited by dc magnetron sputtering. Two kinds of sputtering targets, aluminum doped zinc metal (AZ) and AZO, were used for the deposition of AZO films. The AZ target was sputtered in an oxygen or carbon dioxide atmosphere whereas the AZO target was sputtered in an argon or argon/oxygen atmosphere. The Ag-Pd layers were deposited under the fixed sputtering condition. From x-ray diffraction patterns it was found that the most developed Ag(111) peak appeared in the case of the Ag-Pd film on the AZO layer deposited from the AZ metal target with oxygen. Atomic force microscope observation revealed that the smallest surface roughness was obtained in this case. Electrical resistivity of the Ag-Pd layer changed by up to 17% depending on deposition conditions and the target materials of the underlayer. The Ag-Pd film deposited on the AZO layer from the AZ target in an oxygen atmosphere also showed the lowest resistivity of 7.1×10-6 Ω cm. The smallest refractive index of Ag-Pd film was shown by the same sample from an analysis using spectroscopic ellipsometry (SE). Deposition of a thin metal (Zn-Al) overlayer on Ag-Pd/AZO/glass increased the overall resistivity of the multilayer. This may imply the diffusion of zinc atoms into the Ag-Pd layer, however, the resistivity recovery was observed after some storage time, which suggests the effect of an electron scattering at the surface.

  14. Structural, electronic transport and optical properties of Cr doped PbS thin film by chemical bath deposition

    Science.gov (United States)

    Preetha, K. C.

    2017-06-01

    Incorporation of Chromium ions into Lead Sulphide thin films have been achieved by CBD technique. Effects of doping were investigated as a function of Pb/Cr ratio from o to 2 at %. X-ray diffraction patterns showed that films were polycrystalline in nature with increase in crystallite size up to an optimum doping concentration. Scanning electron microscopic study revealed excellent morphology with doping concentration. The low transmittance in the UV-VIS region offered the suitability of the samples as solar control coatings. The thin films were found to be P type and electrical conductivity enhanced on doping.

  15. The origin of magnetism in transition metal-doped ZrO2 thin films: Experiment and theory

    KAUST Repository

    Hong, Nguyenhoa

    2013-10-04

    We have investigated the magnetic properties of Fe/Co/Ni-doped ZrO 2 laser ablated thin films in comparison with the known results of Mn-doped ZrO2, which is thought to be a promising material for spintronics applications. It is found that doping with a transition metal can induce room temperature ferromagnetism in \\'fake\\' diamond. Theoretical analysis based on density functional theory confirms the experimental measurements, by revealing that the magnetic moments of Mn- and Ni-doped ZrO2 thin films are much larger than that of Fe- or Co-doped ZrO2 thin films. Most importantly, our calculations confirm that Mn- and Ni-doped ZrO2 show a ferromagnetic ground state in comparison to Co- and Fe-doped ZrO 2, which favor an antiferromagnetic ground state. © 2013 IOP Publishing Ltd.

  16. A versatile new method for synthesis and deposition of doped, visible light-activated TiO2 thin films

    DEFF Research Database (Denmark)

    In, Su-il; Kean, A.H.; Orlov, A.

    2009-01-01

    A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates.......A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates....

  17. Effect of doping on TSD relaxation in cellulose acetate films

    Indian Academy of Sciences (India)

    Unknown

    The peak currents, released charge and activation energies associated with the peaks are affected by AA doping. The effect of doping with acrylic acid on the discharge current indicates the formation of molecular aggregates. Keywords. TSD relaxation; cellulose acetate; acrylic acid; molecular aggregates. 1. Introduction.

  18. In-situ boron doping of chemical-bath deposited CdS thin films

    International Nuclear Information System (INIS)

    Khallaf, Hani; Park, S.; Schulte, Alfons; Chai, Guangyu; Lupan, Oleg; Chow, Lee; Heinrich, Helge

    2009-01-01

    In-situ boron doping of CdS using chemical-bath deposition (CBD) is reported. The effect of B doping on optical properties, as well as electrical properties, crystal structure, chemistry, and morphology of CdS films is studied. We present a successful approach towards B doping of CdS using CBD, where a resistivity as low as 1.7 x 10 -2 Ωcm and a carrier density as high as 1.91 x 10 19 cm -3 were achieved. The bandgap of B-doped films was found to slightly decrease as the[B]/[Cd] ratio in the solution increases. X-ray diffraction studies showed B 3+ ions likely enter the lattice substitutionally. A phase transition, due to annealing, as well as induced lattice defects, due to B doping, were detected by micro-Raman spectroscopy and transmission electron microscopy. The chemistry and morphology of films were unaffected by B doping. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Influence of iron doping on tetravalent nickel content in catalytic oxygen evolving films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nancy; Bediako, D. Kwabena; Hadt, Ryan G.; Hayes, Dugan; Kempa, Thomas J.; von Cube, Felix; Bell, David C.; Chen, Lin X.; Nocera, Daniel G.

    2017-01-30

    Iron doping of nickel oxide films results in enhanced activity for promoting the oxygen evolution reaction (OER). Whereas this enhanced activity has been ascribed to a unique iron site within the nickel oxide matrix, we show here that Fe doping influences the Ni valency. The percent of Fe3+ doping promotes the formation of formal Ni4+, which in turn directly correlates with an enhanced activity of the catalyst in promoting OER. The role of Fe3+ is consistent with its behavior as a superior Lewis acid.

  20. Mn doping effect on structure and magnetism of epitaxial (FePt)1-xMnx films

    International Nuclear Information System (INIS)

    Huang, J.C.A.; Chang, Y.C.; Yu, C.C.; Yao, Y.D.; Hu, Y.M.; Fu, C.M.

    2003-01-01

    We study the structure and perpendicular magnetism of molecular beam epitaxy grown (FePt) 1-x Mn x films with doping concentration x=0, 1%, 2%, 3%, 4%, and 5%. The (FePt) 1-x Mn x films were made by multilayers growth of [Fe/Pt/Mn]xN at 100 deg. C and annealed at 600 deg. C. X-ray diffraction scans indicate that relatively better L1 0 ordered structure for low Mn doping (x 3%. The perpendicular magnetic anisotropy effect of the (FePt) 1-x Mn x films tends to decrease with the increase of Mn doping for x>1%. However, the x=1% doped films possess slightly better perpendicular magnetic anisotropy effect than the zero doped film. The perpendicular magnetic anisotropy constant are of about 1.3x10 7 and 1.6x10 7 erg/cm 3 for x=0% and x=1%, respectively

  1. Effects of Ge- and Sb-doping and annealing on the tunable bandgaps of SnS films

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsuan-Tai; Chiang, Ming-Hung; Huang, Chen-Hao [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Wen-Tai, E-mail: wtlin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Fu, Yaw-Shyan [Department of Greenergy, National University of Tainan, Tainan 700, Taiwan (China); Guo, Tzung-Fang [Department of Photonics, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)

    2015-06-01

    SnS, Ge- and Sb-doped SnS films with single orthorhombic SnS phase were fabricated via solvothermal routes and subsequent spin-coating, respectively. The substitution solubilities of Ge and Sb in SnS are about 6 and 5 at.%, respectively. The bandgaps of Ge- and Sb-doped SnS films can be tuned in the ranges of 1.25–1.35 and 1.30–1.39 eV, respectively. The possible mechanisms for the tunable bandgaps of Ge- and Sb-doped SnS films are discussed. For the Ge- and Sb-doped SnS films subjected to annealing at 200–350 °C in N{sub 2}, the bandgaps of 200 °C-annealed films remain unchanged, while those of 300 °C- and 350 °C-annealed films decrease with the annealing temperature because of the evaporation of Ge and Sb respectively. - Highlights: • Ge- and Sb-doped SnS films were fabricated via spin-coating. • The solubilities of Ge and Sb in SnS are about 6 and 5 at.%, respectively. • The bandgaps of SnS films can be tuned by Ge and Sb doping respectively. • Annealing above 300 °C reduces the bandgaps of Ge- and Sb-doped SnS films.

  2. The influence of polymerization rate on conductivity and crystallinity of electropolymerized polypyrrole

    DEFF Research Database (Denmark)

    Dyreklev, P.; Granström, M.; Inganäs, O.

    1996-01-01

    We report studies on electronic conductivity and crystallinity in electropolymerized polypyrrole. Different growth rates during electropolymerization strongly influence and determine structural and electronic properties. Polymer films grown using low current density show higher electronic...

  3. Study on Resistive Switching Property of Ti Doped Novel NiO Thin Films

    Science.gov (United States)

    Li, Y.; Zhao, G. Y.; Kou, Z. B.; Liu, J. C.; Zhu, R.

    2018-01-01

    Ti doped nickel oxide thin films have been fabricated by sol-gel dip-coating process using nickel acetate and tetrabutyl titanate as source materials. The effect of the amount of Ti dopant on the surface roughness, optical, chemical state and electrical properties of NiO: Ti thin films was observed by atomic force microscopy (AFM), Uv-vis spectroscopy, X-ray photoelectron spectroscopy(XPS) and I-V measurement, respectively. Results show that the Ti doping is an effective ways to improve the resistive switching behaviors and it is a convenient way to understand the mechanism of the resistive switching behaviors.

  4. Ferromagnetism carried by highly delocalized hybrid states in Sc-doped ZnO thin films

    KAUST Repository

    Benali Kanoun, Mohammed

    2012-05-29

    We present first-principles results for Sc-doped ZnOthin films. Neighboring Sc atoms in the surface and/or subsurface layers are found to be coupled ferromagnetically, where only two of the possible configurations induce spin polarization. In the first configuration, the polarization is carried by the Sc d states as expected for transition metaldoping. However, there is a second configuration which is energetically favorable. It is governed by polarized hybrid states of the Zns, O p, and Sc d orbitals. Such highly delocalized states can be an important ingredient for understanding the magnetism of dopedZnOthin films.

  5. Ag- and Cu-doped multifunctional bioactive nanostructured TiCaPCON films

    Energy Technology Data Exchange (ETDEWEB)

    Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky prospekt 4, Moscow 119049 (Russian Federation); Batenina, I.V.; Kiryukhantsev-Korneev, Ph.V.; Sheveyko, A.N.; Kuptsov, K.A. [National University of Science and Technology “MISIS”, Leninsky prospekt 4, Moscow 119049 (Russian Federation); Zhitnyak, I.Y.; Anisimova, N.Yu.; Gloushankova, N.A. [N.N. Blokhin Russian Cancer Research Center of RAMS, Kashirskoe shosse 24, Moscow 115478 (Russian Federation)

    2013-11-15

    A key property of multicomponent bioactive nanostructured Ti(C,N)-based films doped with Ca, P, and O (TiCaPCON) that can be improved further is their antibacterial effect that should be achieved without compromising the implant bioactivity and biocompatibility. The present work is focused on the study of structure, chemical, mechanical, tribological, and biological properties of Ag- and Cu-doped TiCaPCON films. The films with Ag (0.4–4 at.%) and Cu (13 at.%) contents were obtained by simultaneous sputtering of a TiC{sub 0.5}–Ca{sub 3}(PO{sub 4}){sub 2} target and either an Ag or a Cu target. The film structure was studied using X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray spectroscopy, glow discharge optical emission spectroscopy, and Raman-shift and IR spectroscopy. The films were characterized in terms of their hardness, elastic modulus, dynamic impact resistance, friction coefficient and wear rate (both in air and normal saline), surface wettability, electrochemical behavior and Ag or Cu ion release in normal saline. Particular attention was paid to the influence of inorganic bactericides (Ag and Cu ions) on the bactericidal activity against unicellular yeast fungus Saccharomyces cerevisiae and gram-positive bacteria Lactobacillus acidophilus, as well as on the attachment, spreading, actin cytoskeleton organization, focal adhesions, and early stages of osteoblastic cell differentiation. The obtained results show that the Ag-doped films are more suitable for the protection of metallic surfaces against bacterial infection compared with their Cu-doped counterpart. In particular, an excellent combination of mechanical, tribological, and biological properties makes Ag-doped TiCaPCON film with 1.2 at.% of Ag very attractive material for bioengineering and modification of load-bearing metal implant surfaces.

  6. Ag- and Cu-doped multifunctional bioactive nanostructured TiCaPCON films

    Science.gov (United States)

    Shtansky, D. V.; Batenina, I. V.; Kiryukhantsev-Korneev, Ph. V.; Sheveyko, A. N.; Kuptsov, K. A.; Zhitnyak, I. Y.; Anisimova, N. Yu.; Gloushankova, N. A.

    2013-11-01

    A key property of multicomponent bioactive nanostructured Ti(C,N)-based films doped with Ca, P, and O (TiCaPCON) that can be improved further is their antibacterial effect that should be achieved without compromising the implant bioactivity and biocompatibility. The present work is focused on the study of structure, chemical, mechanical, tribological, and biological properties of Ag- and Cu-doped TiCaPCON films. The films with Ag (0.4-4 at.%) and Cu (13 at.%) contents were obtained by simultaneous sputtering of a TiC0.5-Ca3(PO4)2 target and either an Ag or a Cu target. The film structure was studied using X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray spectroscopy, glow discharge optical emission spectroscopy, and Raman-shift and IR spectroscopy. The films were characterized in terms of their hardness, elastic modulus, dynamic impact resistance, friction coefficient and wear rate (both in air and normal saline), surface wettability, electrochemical behavior and Ag or Cu ion release in normal saline. Particular attention was paid to the influence of inorganic bactericides (Ag and Cu ions) on the bactericidal activity against unicellular yeast fungus Saccharomyces cerevisiae and gram-positive bacteria Lactobacillus acidophilus, as well as on the attachment, spreading, actin cytoskeleton organization, focal adhesions, and early stages of osteoblastic cell differentiation. The obtained results show that the Ag-doped films are more suitable for the protection of metallic surfaces against bacterial infection compared with their Cu-doped counterpart. In particular, an excellent combination of mechanical, tribological, and biological properties makes Ag-doped TiCaPCON film with 1.2 at.% of Ag very attractive material for bioengineering and modification of load-bearing metal implant surfaces.

  7. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lyutakov, O., E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Goncharova, I. [Department of Analytical Chemistry, Institute of Chemical Technology, Prague (Czech Republic); Rimpelova, S. [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague (Czech Republic); Kolarova, K.; Svanda, J.; Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic)

    2015-04-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag{sup +} had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag{sup +} doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching.

  8. Silver release and antimicrobial properties of PMMA films doped with silver ions, nano-particles and complexes

    International Nuclear Information System (INIS)

    Lyutakov, O.; Goncharova, I.; Rimpelova, S.; Kolarova, K.; Svanda, J.; Svorcik, V.

    2015-01-01

    Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with L-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag + had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag + doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. - Highlights: • PMMA thin films doped with silver ions, nanoparticles (AgNPs) and silver–imidazole helical complexes (AgIm) were studied. • Silver release from doped polymer films and its biological activity were estimated. • Antimicrobial properties of doped polymer films were also studied. • Ag ions doped films showed the strongest antimicrobial activity, which quickly disappeared. • AgIm and AgNPs doped films showed more stable antimicrobial properties. • AgIm complexes conserve their structure after addition into polymer and after leaching

  9. Improvement of electrical and optical properties of molybdenum doped zinc oxide films by introducing hydrogen

    Science.gov (United States)

    Wang, Yanfeng; Huang, Qian; Wei, Changchun; Zhang, Dekun; Zhao, Ying; Zhang, Xiaodan

    2012-09-01

    Doped ZnO films are promising candidates as a front electrode in silicon film solar cells. In present work, we report on efforts to obtain highly conductive and transparent hydrogen and molybdenum co-doped ZnO (HMZO) films prepared by pulsed direct current (DC) magnetron sputtering. Investigations were made to see the effect of hydrogen (H2) flow rate on structural, electrical and optical properties. The results indicate that H2 flow rate has a considerable influence on the transparent conductive properties of molybdenum doped ZnO (MZO) films. A reduced resistivity of 69.2% and a broadening optical band gap of 5.7% were obtained with the optimal H2 flow rate of 5 sccm. The average transmittance of more than 86% in the range of 400-1100 nm was obtained with the optimal H2 flow rate. Crater-like surface morphology with root-mean-square (RMS) roughness of 46.5 nm was also obtained after etching by diluted hydrochloric acid (HCl). Such a co-doping growing method present here may be useful for wide spectra absorption thin film solar cells.

  10. Influence of metallic and semiconducting nanostructures on the optical properties of dye-doped polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Enculescu, M., E-mail: mdatcu@infim.ro; Matei, E.

    2016-09-01

    Dye-doped polymer thin films were obtained by spin-coating of 8% polyvinylpyrrolidone (PVP) solutions (in ethanol). Ni or ZnO nanowires were incorporated in Rhodamine 6G doped polymer films (10{sup −4} M dye concentration). Optical and morphological properties of simple dye-doped polymer films and films containing metallic or semiconducting nanostructures were investigated. Optical microscopy and scanning electron microscopy were used to image the nanowires. The presence of Ni nanowires induces a small shift (2–3 nm) to longer wavelengths on the emission band of Rh 6G doped PVP film. The ZnO nanowires' presence was confirmed by X-ray diffraction measurements. An enhancement of the emission of the dye doped polymer is induced by the semiconducting structures. - Highlights: • Rhodamine 6G doped polyvinylpyrrolidone thin films were obtained by spin-coating. • Ni or ZnO nanowires were incorporated in Rhodamine 6G doped polymer films. • Ni nanowires' presence induces a shift to shorter wavelengths on the emission band. • Enhancement of dye-doped polymer emission induced by the semiconducting structures.

  11. Effects of aluminium doping on zinc oxide transparent thin films grown by filtered vacuum arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gontijo, L.C., E-mail: pleooog@gmail.com [Instituto Federal do Espirito Santo, Programa de Pos-Graduacao em Engenharia Metalurgica e de Materiais, Av. Vitoria, 1729, Jucutuquara, 29040-780, Vitoria, ES (Brazil); Machado, R., E-mail: rogerio.machado.2l@gmail.com [Universidade Federal de Sergipe, Departamento de Fisica, Rod. Mal Rondon S/N, Jd Rosa Elze, CEP 49.100-000, Sao Cristovao, SE (Brazil); Nascimento, V.P., E-mail: valberpn@yahoo.com.br [Universidade Federal do Espirito Santo, Departamento de Fisica, Av. Fernando Ferrari, 514 Goiabeiras, CEP 29075-910, Vitoria, ES (Brazil)

    2012-06-25

    Highlights: Black-Right-Pointing-Pointer AZO films prepared by filtered vacuum arc deposition. Black-Right-Pointing-Pointer Systematic variation of Al concentration. Black-Right-Pointing-Pointer Structural, electrical and optical properties analyzed. Black-Right-Pointing-Pointer Optimized system for Al concentration between 4% and 6%. - Abstract: Thin n-type ZnO films doped with different atomic concentrations of aluminium were grown by filtered vacuum arc deposition (FVAD) on glass substrates. The films were deposited using an oxygen working pressure of 2.0 mTorr with an arc current running at two 100 ms pulses s{sup -1}. Structural, optical and electrical properties were investigated to understand the effect of Al doping on ZnO films. The best values were found for an ideal aluminium percentage between 4 and 6 at.%.

  12. Physical properties and characterization of Ag doped CdS thin films

    International Nuclear Information System (INIS)

    Shah, N.A.; Nazir, A.; Mahmood, W.; Syed, W.A.A.; Butt, S.; Ali, Z.; Maqsood, A.

    2012-01-01

    Highlights: ► CdS thin films were grown. ► By ion exchange, Ag was doped. ► Physical properties were investigated. - Abstract: Thin films of cadmium sulfide with very well defined preferential orientation and relatively high absorption coefficient were fabricated by thermal evaporation technique. The research is focused to the fabrication and characterization of the compositional data of CdS thin films obtained by using X-ray diffraction, scanning electron microscope along with energy dispersive X-ray spectroscopy. The optical properties were studied by using a UV-VIS-NIR spectrophotometer. The effects of silver-doping by ion exchange process on the properties of as-deposited CdS thin films have been investigated.

  13. 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)

  14. Zirconium doped TiO{sub 2} thin films deposited by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Juma, A. [Laboratory of Thin Film Chemical Technologies, Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Department of Physics and Astronomy, Botswana International University of Science and Technology, Private bag 16, Palapye (Botswana); Oja Acik, I., E-mail: ilona.oja@ttu.ee [Laboratory of Thin Film Chemical Technologies, Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Oluwabi, A.T.; Mere, A. [Laboratory of Thin Film Chemical Technologies, Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Mikli, V.; Danilson, M. [Chair of Semiconductor Materials Technology, Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Krunks, M. [Laboratory of Thin Film Chemical Technologies, Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia)

    2016-11-30

    Highlights: • Mean crystallite size of TiO{sub 2}:Zr film decreases with increasing [Zr] in the solution. • Zr doping supresses the anatase to rutile transformation process in TiO{sub 2} films. • Band gap of TiO{sub 2}:Zr film is 3.4 eV irrespective of the annealing temperature. - Abstract: Chemical spray pyrolysis (CSP) is a flexible deposition technique that allows for mixing of the precursor solutions in different proportions suitable for doping thin films. The CSP method was used to dope TiO{sub 2} thin films with Zr by adding zirconium(IV) acetylacetonate into a solution of titanium(IV) isopropoxide in ethanol stabilized by acetylacetone at [Zr]/[Ti] of 0, 5, 10 and 20 at%. The Zr-doped TiO{sub 2} thin films were uniform and homogeneous showing much smaller grains than the undoped TiO{sub 2} films. Zr stabilized the anatase phase to temperatures above 800 °C depending on Zr concentration in the spray solution. The concentration of Zr determined by XPS was 6.4 at% for the thin film deposited from the 20 at% solution. According to AFM studies, Zr doping decreased the root mean square roughness of TiO{sub 2} film from 5.9 to 1.1 nm. An XRD study of samples with the highest Zr amount showed the ZrTiO{sub 4} phase started forming after annealing at 800 °C. The optical band gap for TiO{sub 2} decreased from 3.3 eV to 3.0 eV after annealing at 800 °C but for the TiO{sub 2}:Zr(20) film it remained at 3.4 eV. The dielectric constant increased by more than four times with Zr-doping and this was associated with the change in the bond formations caused by substitution of Ti by Zr in the lattice.

  15. Synthesis and electrochemical properties of Ti-doped DLC films by a hybrid PVD/PECVD process

    Science.gov (United States)

    Jo, Yeong Ju; Zhang, Teng Fei; Son, Myoung Jun; Kim, Kwang Ho

    2018-03-01

    Low electrical conductivity and poor adhesion to metallic substrates are the main drawbacks of diamond-like carbon (DLC) films when used in electrode applications. In this study, Ti-doped DLC films with various Ti contents were synthesized on metal Ti substrates by a hybrid PVD/PECVD process, where PECVD was used for deposition of DLC films and PVD was used for Ti doping. The effects of the Ti doping ratio on the microstructure, adhesion strength, and electrical and electrochemical properties of the DLC films were systematically investigated. An increase in the Ti content led to increased surface roughness and a higher sp2/sp3 ratio of the Ti-DLC films. Ti atoms existed as amorphous-phase Ti carbide when the Ti doping ratio was less than 2.8 at.%, while the nanocrystalline TiC phase was formed in DLC films when the Ti doping ratio was exceeded 4.0 at.%. The adhesion strength, electrical resistivity, electrochemical activity and reversibility of the DLC films were greatly improved by Ti doping. The influence of Ti doping ratio on the electrical and electrochemical properties of the DLC films were also investigated and the best performance was obtained at a Ti content of 2.8 at.%.

  16. Fluorine compounds for doping conductive oxide thin films

    Science.gov (United States)

    Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

    2013-04-23

    Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

  17. Characterization of Sn Doped ZnS Thin Films Synthesized by CBD

    OpenAIRE

    Mukherjee, Ayan; Mitra, Partha

    2017-01-01

    Zinc sulphide (ZnS) thin film were prepared using chemical bath deposition (CBD) process and tin (Sn) doping was successfully carried out in ZnS. Structural, morphological and microstructural characterization was carried out using XRD, TEM, FESEM and EDX. XRD and SAED pattern confirms presence of hexagonal phase. Reitveld analysis using MAUD software was used for particle size estimation. A constantly decreasing trend in particle size was observed with increasing tin incorporation in ZnS film...

  18. Study of high mobility carriers in Ni-doped CdO films

    Indian Academy of Sciences (India)

    Their d.c. conductivity, carrier concentration and mobility increased compared to undoped CdO film. The largest mobility of 112.6 cm2/V.s was measured for 1–2% Ni-doped CdO film. ... A A Dakhel1. Department of Physics, College of Science, University of Bahrain, P.O. Box 32038, Bahrain, Kingdom of Bahrain ...

  19. Nanocrystalline Pt-doped TiO2 thin films prepared by spray pyrolysis ...

    Indian Academy of Sciences (India)

    These thin films were fired for one hour at 550 °C. The sensing performance of these films was tested for various gases such as LPG, H2, CO2, ethanol, NH3 and Cl2 (1000 ppm). The Pt-doped TiO2 (1 : 99) was observed to be most sensitive (572) to H2 at 400 °C with high selectivity against other gases. Its response time ...

  20. Indirect excitation of Er3+ in sol-gel hybrid films doped with an erbium complex

    Science.gov (United States)

    Park, Oun-Ho; Seo, Se-Young; Bae, Byeong-Soo; Shin, Jung H.

    2003-04-01

    Transparent sol-gel hybrid films doped with erbium tris 8-hydroxyquinoline were prepared using methyltriethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane as precursors. We obtain a strong 1.53-μm Er3+ luminescence with a wide full width at half-maximum and no thermal quenching. Comparison of absorption of the film with the pump wavelength dependence of Er3+ luminescence intensity indicates the presence of an efficient indirect excitation path for Er3+ via organic ligands.

  1. Structural and optical properties of Zn doped CuInS2 thin films

    Indian Academy of Sciences (India)

    tivity and we predict that Zn species can be considered as suitable candidates for use as doped acceptors to fabricate ... rature of the substrate and concentration of Zn (1–5)% from 0·16 M ZnCl2) on the quality of CuInS2 thin films achieved by spray .... the conditions that make possible the synthesis of crystalline. CIS films.

  2. Influence of MWCNTs Doping on the Structure and Properties of PEDOT:PSS Films

    OpenAIRE

    Li, Jiao; Liu, Juncheng; Gao, Congjie; Zhang, Jinling; Sun, Hanbin

    2009-01-01

    Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) doped with multi-walled carbon nanotubes (MWCNTs) films is fabricated on quartz substrates by spin coating method. The effects of MWCNTs on the structure and properties of PEDOT:PSS film have been investigated. X-ray diffractometer (XRD) and Fourier transform Raman spectroscopy (FTRM) show that the crystallization behavior and the main chain of PEDOT:PSS are not changed. Atomic force microscopy (AFM) shows that individual n...

  3. Effect of Gallium Doping on the Characteristic Properties of Polycrystalline Cadmium Telluride Thin Film

    Science.gov (United States)

    Ojo, A. A.; Dharmadasa, I. M.

    2017-08-01

    Ga-doped CdTe polycrystalline thin films were successfully electrodeposited on glass/fluorine doped tin oxide substrates from aqueous electrolytes containing cadmium nitrate (Cd(NO3)2·4H2O) and tellurium oxide (TeO2). The effects of different Ga-doping concentrations on the CdTe:Ga coupled with different post-growth treatments were studied by analysing the structural, optical, morphological and electronic properties of the deposited layers using x-ray diffraction (XRD), ultraviolet-visible spectrophotometry, scanning electron microscopy, photoelectrochemical cell measurement and direct-current conductivity test respectively. XRD results show diminishing (111)C CdTe peak above 20 ppm Ga-doping and the appearance of (301)M GaTe diffraction above 50 ppm Ga-doping indicating the formation of two phases; CdTe and GaTe. Although, reductions in the absorption edge slopes were observed above 20 ppm Ga-doping for the as-deposited CdTe:Ga layer, no obvious influence on the energy gap of CdTe films with Ga-doping were detected. Morphologically, reductions in grain size were observed at 50 ppm Ga-doping and above with high pinhole density within the layer. For the as-deposited CdTe:Ga layers, conduction type change from n- to p- were observed at 50 ppm, while the n-type conductivity were retained after post-growth treatment. Highest conductivity was observed at 20 ppm Ga-doping of CdTe. These results are systematically reported in this paper.

  4. Quartz crystal microbalance and spectroscopy measurements for acid doping in polyaniline films

    Directory of Open Access Journals (Sweden)

    Mohamad M Ayad and Eman A Zaki

    2008-01-01

    Full Text Available We investigated the doping of thin polyaniline (PANI films, prepared by the chemical oxidation of aniline, with different acids. The initial step in the investigation is the preparation of PANI films from aqueous hydrochloric acid solution. This is followed by dedoping with ammonia to obtain a PANI base, which is subsequently doped with strong acids (e.g. hydrochloric, sulfuric, phosphoric and trichloroacetic acids and with a weak acid (acetic acid. The dopant weight fraction (w, which is connected with the gain of mass during the doping of PANI, was determined in situ using a quartz crystal microbalance (QCM. The behavior of PANI upon doping with different anions derived from strong acids indicates that both proton and the anion uptake into the polymer chains occur sharply, rapidly, completely, and reversibly. However the uptake in the case in acetic acid is characterized by slow diffusion. The doping was studied at different concentrations of acetic acid. A second cycle of dedoping–redoping was also performed. The kinetics of the doping reaction is dominated by Fickian diffusion kinetics. The diffusion coefficients (D of the dopant ions into the PANI chains were determined using the QCM and by UV–Vis absorption spectroscopy in the range of (0.076–1.64× 10−15 cm2 s−1. It was found that D in the second cycle of doping is larger than that evaluated from the first cycle of doping for high concentrations of acetic acid. D for the diffusion and for the dopant ion expulsion from the PANI chains was also determined during the redoping process. It was found that D for acetic acid ions in the doping process is larger than that calculated for the dedoping process.

  5. Crystallization behavior of Ge-doped eutectic Sb70Te30 films in optical disks

    Science.gov (United States)

    Khulbe, Pramod K.; Hurst, Terril; Horie, Michikazu; Mansuripur, Masud

    2002-10-01

    We report laser-induced crystallization behavior of binary Sb-Te and ternary Ge-doped eutectic Sb70Te30 thin film samples in a typical quadrilayer stack as used in phase-change optical disk data storage. Several experiments have been conducted on a two-laser static tester in which one laser operating in pulse mode writes crystalline marks on amorphous film or amorphous marks on crystalline film, while the second laser operating at low-power cw mode simultaneously monitors the progress of the crystalline or amorphous mark formation in real time in terms of the reflectivity variation. The results of this study show that the crystallization kinetics of this class of film is strongly growth dominant, which is significantly different from the crystallization kinetics of stochiometric Ge-Sb-Te compositions. In Sb-Te and Ge-doped eutectic Sb70Te30 thin-film samples, the crystallization behavior of the two forms of amorphous states, namely, as-deposited amorphous state and melt-quenched amorphous state, remains approximately same. We have also presented experiments showing the effect of the variation of the Sb/Te ratio and Ge doping on the crystallization behavior of these films.

  6. A Study of Structural and Photoluminescence for Al-Doped CdO Thin Films

    Directory of Open Access Journals (Sweden)

    Bong Ju Lee

    2016-01-01

    Full Text Available Al-doped CdO thin films were prepared by radio frequency magnetron sputtering at different deposition time and substrate temperature. X-ray diffraction showed that the changes in the intensities of the (200, (220, and (311 planes followed a similar trend with increase in deposition time. The surface of the thin film was examined by scanning electron microscopy. Grain sizes of Al-doped CdO thin films increased significantly with increasing deposition time. The film thicknesses were 0.09, 0.12, 0.20, and 0.225 μm for the deposition times of 1, 2, 3, and 4 h, respectively. The photoluminescence spectra of the Al-doped CdO thin films were measured at room temperature. The photoluminescence wavelength changed in the sequence, green, blue, green, and blue, with increasing deposition time, which indicates that blue light emitting films can be fabricated by adjusting the processing parameters.

  7. 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.

  8. Effect of ZDDP concentration on the thermal film formation on steel, hydrogenated non-doped and Si-doped DLC

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, S. [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia); Kovač, J. [Jozef Stefan Institute, Jamova 19, 1000 Ljubljana (Slovenia); Kalin, M., E-mail: mitjan.kalin@tint.fs.uni-lj.si [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia)

    2016-10-15

    Highlights: • The effect of the ZDDP concentrations onto the steel, H-DLC and Si-DLC surfaces is investigated. • ZDDP film structure on the DLC coatings is different from steel. • Different concentrations of ZDDP do not affect the final chemical structure of the ZDDP film on any of the studied surfaces. • The thickness of the thermal film is linear with the concentration for a given surface. • The reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings. - Abstract: This work focuses on the ZDDP concentration (1, 5 and 20 wt%) to form a ZDDP film on surfaces during static thermal tests at 150 °C. Silicon-doped and hydrogenated DLC coatings, as well as steel as reference, were studied using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The results show that, on the three surfaces, the structure of the ZDDP thermal film consists of identical groups of pyrophosphate and zinc oxide, while the sulphuric groups are dissimilar. On the steel surface, the sulphuric part consists of a mixture of organic sulphide and sulphohydryl groups, but on H-DLC and Si-DLC only organic sulphide groups are found; there are no sulphohydryl groups. Moreover, both ATR-FTIR and XPS show that different concentrations of ZDDP do not affect the final chemical structure of the ZDDP thermal film on any of the studied surfaces. In addition, the XPS results show that the thickness of the thermal film is linear with the concentration for the whole range from 1 to 20 wt%, supporting also its uniform chemical structure. These thicknesses further show that the reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings.

  9. Crystal orientation dependent thermoelectric properties of highly oriented aluminum-doped zinc oxide thin films

    KAUST Repository

    Abutaha, Anas I.

    2013-02-06

    We demonstrate that the thermoelectric properties of highly oriented Al-doped zinc oxide (AZO) thin films can be improved by controlling their crystal orientation. The crystal orientation of the AZO films was changed by changing the temperature of the laser deposition process on LaAlO3 (100) substrates. The change in surface termination of the LaAlO3 substrate with temperature induces a change in AZO film orientation. The anisotropic nature of electrical conductivity and Seebeck coefficient of the AZO films showed a favored thermoelectric performance in c-axis oriented films. These films gave the highest power factor of 0.26 W m−1 K−1 at 740 K.

  10. Barium titanate thin films deposited by electrophoresis on p-Doped Si (001) substrates.

    Science.gov (United States)

    Barbosa, J G; Pereira, M R; Moura, C; Mendes, J A; Almeida, B G

    2011-10-01

    Barium titanate (BaTiO3) thin films have been prepared by electrophoretic deposition on p-doped and platinum covered silicon (Si) substrates. Their structure, nanostructure and dielectric properties were characterized. The as-deposited films were polycrystalline and composed by barium titanate nanograins with an average grain size approximately 9 nm. Annealing at high temperatures promoted grain growth, so that the samples annealed at 600 degrees C presented average grain sizes approximately 24 nm. From Raman spectroscopy measurements it was found that the tetragonal (ferroelectric) BaTiO3 phase was stabilized on the films. Also, at higher annealing temperatures, cation disorder was reduced on the films. From measurements of the temperature dependence of the dielectric permittivity the corresponding paraelectric-ferroelectric phase transition was determined. The observed transition temperature (approximately 100 degrees C) was found to be below the BaTiO3 bulk or thick film values, due to the small nanosized grains composing the films.

  11. 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.

  12. 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.

  13. 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

  14. Multicomponent doped barium strontium titanate thin films for tunable microwave applications

    Science.gov (United States)

    Alema, Fikadu Legesse

    In recent years there has been enormous progress in the development of barium strontium titanate (BST) films for tunable microwave applications. However, the properties of BST films still remain inferior compared to bulk materials, limiting their use for microwave technology. Understanding the film/substrate mismatch, microstructure, and stoichiometry of BST films and finding the necessary remedies are vital. In this work, BST films were deposited via radio frequency magnetron sputtering method and characterized both analytically and electrically with the aim of optimizing their properties. The stoichiometry, crystal structure, and phase purity of the films were studied by varying the oxygen partial pressure (OPP) and total gas pressure (TGP) in the chamber. A better stoichiometric match between film and target was achieved when the TGP is high (> 30 mTorr). However, the O2/Ar ratio should be adjusted as exceeding a threshold of 2 mTorr in OPP facilitates the formation of secondary phases. The growth of crystalline film on platinized substrates was achieved only with a lower temperature grown buffer layer, which acts as a seed layer by crystallizing when the temperature increases. Concurrent Mg/Nb doping has significantly improved the properties of BST thin films. The doped film has shown an average tunability of 53%, which is only ˜8 % lower than the value for the undoped film. This drop is associated with the Mg ions whose detrimental effects are partially compensated by Nb ions. Conversely, the doping has reduced the dielectric loss by ˜40 % leading to a higher figure of merit. Moreover, the two dopants ensure a charge neutrality condition which resulted in significant leakage current reduction. The presence of large amounts of empty shallow traps related to Nb Ti localize the free carriers injected from the contacts; thus increase the device control voltage substantially (>10 V). A combinatorial thin film synthesis method based on co-sputtering of two BST

  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. A short literature survey on iron and cobalt ion doped TiO{sub 2} thin films and photocatalytic activity of these films against fungi

    Energy Technology Data Exchange (ETDEWEB)

    Tatl Latin-Small-Letter-Dotless-I dil, Ilknur [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bacaks Latin-Small-Letter-Dotless-I z, Emin [Department of Physics, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Buruk, Celal Kurtulus [Department of Microbiology, Faculty of Medicine, Karadeniz Technical University, 61080 Trabzon (Turkey); Breen, Chris [Materials and Engineering Research Institution, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Soekmen, Muenevver, E-mail: msokmen@ktu.edu.tr [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Co or Fe doped TiO{sub 2} thin films were prepared by sol-gel method. Black-Right-Pointing-Pointer We obtained lower E{sub g} values for Fe-doped and Co-TiO{sub 2} thin films. Black-Right-Pointing-Pointer Doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Black-Right-Pointing-Pointer Photocatalytic killing effect of the doped TiO{sub 2} thin films on C. albicans and A. niger was significantly higher than undoped TiO{sub 2} thin film for short exposure periods. - Abstract: In this study, a short recent literature survey which concentrated on the usage of Fe{sup 3+} or Co{sup 2+} ion doped TiO{sub 2} thin films and suspensions were summarized. Additionally, a sol-gel method was used for preparation of the 2% Co or Fe doped TiO{sub 2} thin films. The surface of the prepared materials was characterised using scanning-electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis and band gap of the films were calculated from the transmission measurements that were taken over the range of 190 and 1100 nm. The E{sub g} value was 3.40 eV for the pure TiO{sub 2}, 3.00 eV for the Fe-doped TiO{sub 2} film and 3.25 eV for Co-TiO{sub 2} thin film. Iron or cobalt doping at lower concentration produce more uniformed particles and doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Photocatalytic killing effect of the 2% Co doped TiO{sub 2} thin film on Candida albicans was significantly higher than Fe doped TiO{sub 2} thin film for short and long exposure periods. Doped thin films were more effective on Aspergillus niger for short exposure periods.

  17. Magnetism of carbon doped Mn5 Si3 and Mn5 Ge3 films

    Indian Academy of Sciences (India)

    Administrator

    2009-03-03

    Mar 3, 2009 ... -ion implantation are studied. The carbon-doped films exhibit ferromagnetic properties with Curie temperatures TC well above room temperature and metallic conductivity, making them possi- ble candidates for future magnetic semiconductor-based devices. In Mn5Si3Cx, the carbon gives rise to a.

  18. 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 ...

  19. Phosphorus-doped thin silica films characterized by magic-angle spinning nuclear magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Jacobsen, H.J.; Skibsted, J.; Kristensen, Martin

    2001-01-01

    Magic-angle spinning nuclear magnetic resonance spectra of 31P and 29Si have been achieved for a thin silica film doped with only 1.8% 31P and deposited by plasma enhanced chemical vapor deposition on a pure silicon wafer. The observation of a symmetric 31P chemical shift tensor is consistent...

  20. Synthesis of TiO 2-doped SiO 2 composite films and its applications

    Indian Academy of Sciences (India)

    In XRD, FT–IR, and TEM investigations of these TiO2-doped SiO2 composite films, the titanium oxide species are highly dispersed in the SiO2 matrixes and exist in a ... Anhui Key Laboratory of Functional Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, P.R. China ...

  1. Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

    International Nuclear Information System (INIS)

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Jiang, Weilin; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2010-01-01

    The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generated due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom% Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom% samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed

  2. Influence of In doping on electro-optical properties of ZnO films

    Indian Academy of Sciences (India)

    defects, surface roughness, presence of mixed phases, etc. (Song et al 2004; Luna-Arredondo et al 2005). Therefore, we presume that higher optical transmittances were obtained for doped films because of improved structure and different morphologies (see figure 4). It can be observed that all samples are characterized by.

  3. Optical spectroscopy of rare-earth ions doped KY(WO4)2 thin films

    NARCIS (Netherlands)

    García-Revilla, S.; Valiente, R.; Romanyuk, Y.E.; Utke, I.; Pollnau, Markus

    KY(WO4)2 thin films doped with Dy3+, Tb3+, Yb3+, were grown onto KY(WO4)2 substrates using liquid-phase epitaxy. Spectroscopic investigations of the grown layers were performed. Obtained results were compared with spectra given for bulk crystals. Upconversion experiments after direct Yb3+ excitation

  4. Effects of Ni doping on photocatalytic activity of TiO2 thin films ...

    Indian Academy of Sciences (India)

    Wintec

    Ni–TiO2 thin film; LPD technique; photodegradation. 1. Introduction. In the field of photocatalysis, the polycrystalline system formed by transition metal-ion-doped TiO2 has been the object of several studies (Palmisano et al 1988; Soria et al 1991; Karakitsou and Verykios 1993; Choi et al 1994;. Litter and Navio 1994, 1996).

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

    Indian Academy of Sciences (India)

    Administrator

    Li doping was done by adding lithium chloride in zinc acetate solution, Li concentration was calculated as; x = [Li]/[Zn] = [LiCl]/[Zn(CH3COO)2] and its values ... The sheet resistance (Rs) of the films was meas- ured by two-point probe method using thermally evapo- rated aluminum electrodes; the resistivity was calculated.

  6. Optical phase-conjugation in erioglaucine dye-doped thin film

    Indian Academy of Sciences (India)

    Abstract. Optical phase-conjugation (OPC) has been demonstrated in erioglaucine. (acid blue 9) dye-doped gelatin films via continuous-wave degenerate four-wave mixing. (DFWM) using a low-power He–Ne laser at 633 nm. DFWM and holographic processes are found to contribute to the observed phase-conjugate signal ...

  7. Synthesis of TiO2-doped SiO2 composite films and its applications

    Indian Academy of Sciences (India)

    Wintec

    And special attention has been focused on the relationship between the local structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactiv- ity in order to provide vital information for the design and application of such highly efficient photocatalytic systems in the degradation of ...

  8. Optical phase-conjugation in erioglaucine dye-doped thin film

    Indian Academy of Sciences (India)

    Optical phase-conjugation (OPC) has been demonstrated in erioglaucine (acid blue 9) dye-doped gelatin films via continuous-wave degenerate four-wave mixing (DFWM) using a low-power He-Ne laser at 633 nm. DFWM and holographic processes are found to contribute to the observed phase-conjugate signal.

  9. 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), ...

  10. Micromorphology, photophysical and electrical properties of pristine and ferric chloride doped poly(3-hexylthiophene) films

    International Nuclear Information System (INIS)

    Singh, Rajiv K.; Kumar, Jitendra; Singh, Ramadhar; Kant, Rama; Chand, Suresh; Kumar, Vikram

    2007-01-01

    Poly(3-hexylthiophene) (P3HT), synthesized by chemical oxidative polymerization at ∼258 K, has been probed by Fourier transform infrared (FT-IR), ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM) and by measuring the temperature dependence of DC conductivity (σ DC ) in both its pristine and partially doped state. FT-IR and UV-vis studies suggest the formation of polaronic charge species in both pristine and partially doped P3HT. SEM of pristine P3HT film exhibits the formation of randomly distributed polymer fibrils whereas ferric chloride doped P3HT film shows the formation of dopant islands (size ∼500 nm), some of which adhered to the polymer fibrils. The temperature dependence of DC conductivity in the range 77-300 K is well explained by Mott's 3-dimensional variable range hopping (3D-VRH) model

  11. Analysis of polypyrrole-coated stainless steel electrodes-Estimation ...

    Indian Academy of Sciences (India)

    Analysis of polypyrrole-coated stainless steel electrodes - Estimation of specific capacitances and construction of equivalent circuits. R Ramya M V Sangaranarayanan ... The galvanostatic polymerization of pyrrole is carried out on stainless steel electrodes using -toluene sulphonic acid. The morphology of the film is ...

  12. Effects of preparation temperature on the conductivity of polypyrrole ...

    Indian Academy of Sciences (India)

    An attempt has been made to investigate the effect of temperature on the conductivity of polypyrrole conducting polymer films prepared by an electrochemical method in an aqueous medium using camphor sulfonate as the dopant. The polymer was grown from aqueous solutions employing a range of temperatures (1-60°C).

  13. Effect of crystalline polarity on microstructure and optoelectronic properties of gallium-doped zinc oxide films deposited onto glass substrates

    International Nuclear Information System (INIS)

    Ogino, Tsuyoshi; Williams, Jesse R.; Watanabe, Ken; Sakaguchi, Isao; Hishita, Shunichi; Haneda, Hajime; Adachi, Yutaka; Ohgaki, Takeshi; Ohashi, Naoki

    2014-01-01

    The effect of crystalline polarity on the microstructure of gallium-doped zinc oxide (GZO) deposited using magnetron sputtering onto glass substrates was investigated. X-ray photoelectron spectroscopy was used to determine the crystalline polarity of c-axis textured GZO films. Grains whose radii were more than 1 μm grew abnormally in 0.2 mol% doped GZO when the film was thicker than ∼ 1 μm, and the radius of the grains was much smaller than 100 nm in the heavily (i.e., 4 mol%) doped GZO, regardless of the film thickness. Such abnormal growth of the grains in the 0.2 mol% doped GZO films coincided with a change in the crystalline polarity: the surfaces of unusually large GZO grains were terminated with the (0001 ¯ ) face, and those of normal GZO grains were terminated with the (0001) face. The results indicated that polarity flipping is a very important event for controlling the texture of doped zinc oxide films. - Highlights: • Ga-doped ZnO films were deposited using radiofrequency magnetron sputtering. • Abnormal grain growth was reproduced in lightly doped zinc oxide film. • Grains grew abnormally with polarity flipping. • Spatial fluctuations in compositions of gallium may trigger polarity flipping

  14. Anomalous magnetism of superconducting Mg-doped InN film

    Directory of Open Access Journals (Sweden)

    P. H. Chang

    2016-02-01

    Full Text Available We report on the Meissner effect of Mg-doped InN film with superconducting transition onset temperature Tc,onset of 5 K. Mg-doped InN is magnetically ordered and exhibits a simultaneous first-order magnetic and electric transition near 50 K. Its behavior is similar to that of iron-based superconductors. A strong correlation is proposed to exist between structural distortion and superconductivity when Mg is doped into InN. The suppression of magnetic ordering close to Tc by doping is further demonstrated by anisotropic magnetoresistance and M-H measurements. The findings suggest that the superconducting mechanism in the system may not be conventional BCS.

  15. The role of the dopant in the magnetism of Fe-doped SnO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Torres, C.E. Rodriguez [Departamento de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina)]. E-mail: torres@fisica.unlp.edu.ar; Errico, L. [Departamento de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Golmar, F. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Navarro, A.M. Mudarra [Departamento de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Cabrera, A.F. [Departamento de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Duhalde, S. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Sanchez, F.H. [Departamento de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Weissmann, M. [Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250, 1429 Buenos Aires (Argentina)

    2007-09-15

    Transparent pure and Fe-doped SnO{sub 2} thin films were grown by pulsed laser deposition technique on LaAlO{sub 3} substrates. X-ray diffraction shows that the films are polycrystalline and have the rutile structure. Surprisingly, the pure film presents magnetic-like behavior at room temperature with a saturated magnetization of almost one-third of the doped film ({approx}3.6 and 11.3 emu/g, respectively) and its magnetization could not be attributed to any impurity phase. Taking into account the magnetic moment measured in the pure film, the effective contribution of the impurity in the doped one can be inferred to be {approx}2 {mu} {sub B} per Fe atom. A large magnetic moment was also predicted by an ab initio calculation in the doped system, which increases if an oxygen vacancy is present near the Fe impurity.

  16. Stabilization and enhanced energy gap by Mg doping in ɛ-phase Ga2O3 thin films

    Science.gov (United States)

    Bi, Xiaoyu; Wu, Zhenping; Huang, Yuanqi; Tang, Weihua

    2018-02-01

    Mg-doped Ga2O3 thin films with different doping concentrations were deposited on sapphire substrates using laser molecular beam epitaxy (L-MBE) technique. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) absorption spectrum were used to characterize the crystal structure and optical properties of the as-grown films. Compared to pure Ga2O3 thin film, the Mg-doped thin films have transformed from the most stable β-phase into ɛ-phase. The absorption edge shifted to about 205 nm and the optical bandgap increased to ˜ 6 eV. These properties reveal that Mg-doped Ga2O3 films may have potential applications in the field of deep ultraviolet optoelectronic devices, such as deep ultraviolet photodetectors, short wavelength light emitting devices and so on.

  17. Morphological and optical comparison of the Si doped GaN thin film deposited onto the transparent substrates

    Science.gov (United States)

    Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan

    2016-04-01

    The aim of this paper is to expand the body of knowledge about the silicon doped gallium nitride thin films deposited on different substrates. The physical properties of the Si doped GaN thin films deposited on the glass and polyethylene terephthalate substrates by thermionic vacuum arc which is plasma production technique were investigated. Thermionic vacuum arc method is a method of producing pure material plasma. The Si doped GaN thin films were analyzed using the following methods and the devices: atomic force microscopy, x-ray diffraction device, spectroscopic ellipsometer and energy dispersive x-ray spectroscopy detector. The produced Si doped GaN thin films are in the (113) orientation. The thicknesses and refractive index were determined by using Cauchy dispersion model. Surface morphologies of produced thin films are homogenous and low roughness. Our analysis showed that the thermionic vacuum arc method present important advantages for optical and industrial applications.

  18. 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.

  19. Effect of tin doping on the optical properties of indium oxide films by a spray pyrolysis method

    International Nuclear Information System (INIS)

    Ibrahim Abu Talib; Muhammad Mat Salleh; Muhammad Yahya; Mod Noor Bader Sher

    1993-01-01

    Thin films of stannum doped indium oxide were deposited on glass by a X-ray pyrolysis method. The substrate temperature and the rate of flow of the carrier gas were fixed at 450 0 C and 2.5 litre/minute respectively during deposition. The dependence of the optical properties of the films on the doping concentration was studied. It is found that the transmission of the visible wavelengths (300 to 800 nm) through the films increases around 5% from 74.9% as the film was doped with 10% stannum. It is also found that the optical energy bandgap increases 0.2 eV from 3.16 to 3.36 eV by doping the film with 10% stannum. The increase is attributed to the Bernstein-Moss (1) and self-energy (2) effects

  20. Improved UV Photodetection by Indium Doped TiO₂ Thin Film Based Photodetector.

    Science.gov (United States)

    Sarkar, Mitra Barun; Choudhuri, Bijit; Bhattacharya, P; Barman, R N; Ghosh, A; Dwivedi, S M M Dhar; Chakrabartty, S; Mondal, Aniruddha

    2018-07-01

    Indium (In) was doped into TiO2 thin film (TF) using the electron beam evaporation technique followed by an annealing process. The high resolution X-ray diffraction (HRXRD) analysis revealed lower angle diffraction peak (2) shifting of Rutile (002) phases of TiO2 from 61.9 to 61.56 for an increased In doped samples. Calculated average grain size from FESEM (field emission scanning electron microscope) gradually decreased from 21.12 nm to 17.03 mm with an increase in In content ranging from 1.45~17.30 at%. HRXRD data revealed that crystallite sizes also reduced from 21.79 nm to 16.93 nm with an increased In doping concentration. Doping of In leads to the formation of inhomogeneous InxTiy O2 alloy that enhances the transition between 3.3-3.42 eV energy levels with variation in doping concentration. The photo-efficiencies for increased doping concentration of In with 3.47 at% and 17.30 at% were enhanced by 2.56 and 2.76 times, respectively, compared to the undoped TiO2 TF detector and both were larger than low doped In with 1.45 at% sample. The ratio of main band detection intensity to oxygen defect level was also increased from 0.22 to 2.22 with the gradual increase in In content.

  1. Electrostatic doping of graphene through ultrathin hexagonal boron nitride films.

    Science.gov (United States)

    Bokdam, Menno; Khomyakov, Petr A; Brocks, Geert; Zhong, Zhicheng; Kelly, Paul J

    2011-11-09

    When combined with graphene, hexagonal boron nitride (h-BN) is an ideal substrate and gate dielectric with which to build metal|h-BN|graphene field-effect devices. We use first-principles density functional theory (DFT) calculations for Cu|h-BN|graphene stacks to study how the graphene doping depends on the thickness of the h-BN layer and on a potential difference applied between Cu and graphene. We develop an analytical model that describes the doping very well, allowing us to identify the key parameters that govern the device behavior. A predicted intrinsic doping of graphene is particularly prominent for ultrathin h-BN layers and should be observable in experiment. It is dominated by novel interface terms that we evaluate from DFT calculations for the individual materials and for interfaces between h-BN and Cu or graphene.

  2. A strategy to enhance the thermal stability of a nanostructured polypyrrole-based coating for solid phase microextraction

    International Nuclear Information System (INIS)

    Mehdinia, A.; Bashour, F.; Roohi, F.; Jabbari, A.

    2012-01-01

    We report on a nanostructured self-doped polypyrrole (SPPy) film that was prepared by an electrochemical technique in an electrolyte containing fluorosulfonic acid as the sulfonation reagent. The film was applied as a new fiber material for solid-phase microextraction (SPME) of the pesticides lindane, heptachlor, aldrin, endosulfans I and II prior to their quantitation by GC with electron capture detection. The SPPy nanoparticles have a diameter of 0 C) and satisfactory extraction efficiency. The thermal stability of the SPPy fiber is superior to common polypyrrole fibers. Extraction was optimized by means of the Taguchi orthogonal array experimental design with an OA 16 (4 5 ) matrix including extraction temperature, extraction time, salt concentration, stirring rate, and headspace volume. The method displays good repeatability (RSD -1 ; with an R 2 of >0. 998. The detection limits are -1 . The method was successfully applied to the analysis of the pesticides in skimmed milk and fruit juice samples, and recoveries are from 84 ± 1 to 105 ± 1%. (author)

  3. 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.

  4. 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.

  5. An anode with aluminum doped on zinc oxide thin films for organic light emitting devices

    International Nuclear Information System (INIS)

    Xu Denghui; Deng Zhenbo; Xu Ying; Xiao Jing; Liang Chunjun; Pei Zhiliang; Sun Chao

    2005-01-01

    Doped zinc oxides are attractive alternative materials as transparent conducting electrode because they are nontoxic and inexpensive compared with indium tin oxide (ITO). Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by DC reactive magnetron sputtering method. Films were deposited at a substrate temperature of 150-bar o C in 0.03 Pa of oxygen pressure. The electrical and optical properties of the film with the Al-doping amount of 2 wt% in the target were investigated. For the 300-nm thick AZO film deposited using a ZnO target with an Al content of 2 wt%, the lowest electrical resistivity was 4x10 -4 Ωcm and the average transmission in the visible range 400-700 nm was more than 90%. The AZO film was used as an anode contact to fabricate organic light-emitting diodes. The device performance was measured and the current efficiency of 2.9 cd/A was measured at a current density of 100 mA/cm 2

  6. Properties of NiZnO Thin Films with Different Amounts of Al Doping

    Science.gov (United States)

    Kayani, Zohra N.; Fatima, Gulnaz; Zulfiqar, Bareera; Riaz, Saira; Naseem, Shahzad

    2017-10-01

    Transparent Al-doped NiZnO thin films have been fabricated by sol-gel dip coating and investigated using scanning electron microscopy, x-ray diffraction analysis, ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometry, vibrating-sample magnetometry, and Fourier-transform infrared spectroscopy. The Al-doped NiZnO films consisted of ZnO hexagonal and α-Al2O3 rhombohedral phases as the Al incorporation was gradually increased from 1 at.% up to 3 at.%. A decrease in the optical bandgap from 3.90 eV to 3.09 eV was observed for films grown with Al content of 1 at.% to 2.5 at.%, but at 3 at.% Al, the bandgap increased to 3.87 eV. Optical transmittance of 96% was achieved for these transparent oxide films. Study of their magnetic properties revealed that increasing Al percentage resulted in enhanced ferromagnetism. The saturated magnetization increased with increasing Al percentage. The ferromagnetic properties of Al-doped NiZnO are mediated by electrons. The surface of the deposited thin films consisted of nanowires, nanorods, porous surface, and grains.

  7. Deposition of Cu-doped PbS thin films with low resistivity using DC sputtering

    Directory of Open Access Journals (Sweden)

    Hariyadi Soetedjo

    2018-03-01

    Full Text Available Investigation of the electrical resistivity of Cu-doped PbS thin films has been carried out. The films were prepared using a DC sputtering technique. The doping was achieved by introducing the Cu dopant plate material directly on the surface of the PbS sputtering target plate. SEM-EDX data shows the Cu concentration in the PbS film to be proportional to the Cu plate diameter. The XRD pattern indicates the film is in crystalline cubic form. The Hall effect measurement shows that Cu doping yields an increase in the carrier concentration to 3.55 × 1019 cm−3 and a significant decrease in electrical resistivity. The lowest resistivity obtained was 0.13 Ωcm for a Cu concentration of 18.5%. Preferential orientation of (1 1 1 and (2 0 0 occurs during deposition. Keywords: Thin films, Lead sulfide, Sputtering, Resistivity, Semiconductor, Infrared

  8. Photoelectrochemical Performance Observed in Mn-Doped BiFeO3 Heterostructured Thin Films

    Directory of Open Access Journals (Sweden)

    Hao-Min Xu

    2016-11-01

    Full Text Available Pure BiFeO3 and heterostructured BiFeO3/BiFe0.95Mn0.05O3 (5% Mn-doped BiFeO3 thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO3 films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm−2. By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe0.95Mn0.05O3 layer and an internal field being built in the BiFeO3/BiFe0.95Mn0.05O3 interface. BiFeO3/BiFe0.95Mn0.05O3 and BiFe0.95Mn0.05O3 thin films demonstrated poor photo activity compared with pure BiFeO3 films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe0.95Mn0.05O3 layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.

  9. Opto-electronic properties of chromium doped indium-tin-oxide films deposited at room temperature

    International Nuclear Information System (INIS)

    Chang Weiche; Lee Shihchin; Yang Chihhao; Lin Tienchai

    2008-01-01

    Indium-tin-oxide (ITO) doped chromium films were deposited on Corning 7059 glass prepared by radio frequency (RF) magnetron sputtering under various levels of sputtering power for the chromium target. Experimental results show that the surface roughness slightly decreases by co-sputtering Cr. The pure ITO films deposited at room temperature were amorphous-like. At 15 W of chromium target power, the structure of ITO: Cr film mainly consists of (2 2 2) crystallization plane, with minority of (2 1 1), (4 4 0), (6 6 2) crystallization planes. The carrier concentration of the ITO films increases with increasing the doping of chromium, however the mobility of the carrier decreases. When the sputtering power of the chromium target is at 7.5 W, there has a maximum carrier mobility of 27.3 cm 2 V -1 s -1 , minimum carrier concentration of 2.47 x 10 20 cm -3 , and lowest resistivity of 7.32 x 10 -4 Ω cm. The transmittance of all the chromium doped ITO films at the 300-800 nm wavelength region in this experiment can reach up to 70-85%. In addition, the blue shift of UV-Vis spectrum is not observed with the increase of carrier concentration

  10. Effects of Surface Electron Doping and Substrate on the Superconductivity of Epitaxial FeSe Films.

    Science.gov (United States)

    Zhang, W H; Liu, X; Wen, C H P; Peng, R; Tan, S Y; Xie, B P; Zhang, T; Feng, D L

    2016-03-09

    Superconductivity in FeSe is greatly enhanced in films grown on SrTiO3 substrates, although the mechanism behind remains unclear. Recently, surface potassium (K) doping has also proven able to enhance the superconductivity of FeSe. Here, by using scanning tunneling microscopy, we compare the K doping dependence of the superconductivity in FeSe films grown on two substrates: SrTiO3 (001) and graphitized SiC (0001). For thick films (20 unit cells (UC)), the optimized superconducting (SC) gaps are of similar size (∼9 meV) regardless of the substrate. However, when the thickness is reduced to a few UC, the optimized SC gap is increased up to ∼15 meV for films on SrTiO3, whereas it remains unchanged for films on SiC. This clearly indicates that the FeSe/SrTiO3 interface can further enhance the superconductivity, beyond merely doping electrons. Intriguingly, we found that this interface enhancement decays exponentially as the thickness increases, with a decay length of 2.4 UC, which is much shorter than the length scale for relaxation of the lattice strain, pointing to interfacial electron-phonon coupling as the likely origin.

  11. Characterization of Cu-doped CdTe thin films prepared by closed space sublimation (css) techniques

    International Nuclear Information System (INIS)

    Abbas, N.; Shah, N.; Ali, A.; Maqsood, A.

    2005-01-01

    Cadmium telluride (CdTe) thin films of different thickness are deposited on the microscopic slides of water-white glass substrates using the close spaced sublimation (CSS) method. The films are doped with Cu by immersion in Cu (NO/sub 3/)2-H/sub 2/O solution for different times and the effect of immersion time and subsequent heating in vacuum on the electrical, structural and optical properties are presented. The XRD and SEM results show that appropriate Cu doping would be favorable to the growth of CdTe crystallite. The Hall Effect measurements indicate that the conductivity of the films could be improved by Cu doping. (author)

  12. Magnetic and structural study of Cu-doped TiO2 thin films

    International Nuclear Information System (INIS)

    Torres, C.E. Rodriguez; Golmar, F.; Cabrera, A.F.; Errico, L.; Navarro, A.M. Mudarra; Renteria, M.; Sanchez, F.H.; Duhalde, S.

    2007-01-01

    Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO 2 thin films were grown by pulsed laser deposition technique on LaAlO 3 substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO 2 . The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO 2

  13. Magnetic and structural study of Cu-doped TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Torres, C.E. Rodriguez [Dpto de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina)], E-mail: torres@fisica.unlp.edu.ar; Golmar, F. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Cabrera, A.F.; Errico, L.; Navarro, A.M. Mudarra; Renteria, M.; Sanchez, F.H. [Dpto de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Duhalde, S. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina)

    2007-10-31

    Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO{sub 2} thin films were grown by pulsed laser deposition technique on LaAlO{sub 3} substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO{sub 2}. The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO{sub 2}.

  14. Promising Cu-doped polyvinyl alcohol films for optical and photoconductive applications

    Science.gov (United States)

    Ali, F. M.; Ashraf, I. M.; Alqahtani, Sh. M.

    2017-12-01

    Pure and Cu-doped Poly Vinyl Alcohol (PVA) film samples with different concentrations of copper (5%, 10%, 15% and 20% weight percent) were prepared by the conventional castling technique. The structural, optical and photoconductive properties of pure and doped films were studied. X-ray diffraction pattern of the investigated samples reveals the interaction between the filler and polymer which leads to decrease the crystallinity with riching amorphous phase. Optical spectrophotometric measurements showed blocking of UV range in transmission spectra of 20% wt Cu-content where the determined indirect Optical energy gap strongly decrease from 4.96 eV for pure PVA to about 2.85 eV for this sample. Film samples exhibit positive photoconduction effect where the light reduce the resistance or increases its conduction in addition to that photosensitivity strongly increase by increasing both light intensity and copper concentration in the polymer matrix.

  15. Optical Properties of Al- and Sb-Doped CdTe Thin Films

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Nondoped and (Al, Sb-doped CdTe thin films with 0.5, 1.5, and 2.5  wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures ( of room temperature (RT and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n, extinction coefficient (, and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant as n, and real and imaginary parts of the dielectric coefficient increase.

  16. Electrically controlled drug release from nanostructured polypyrrole coated on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J, E-mail: Thomas_Webster@Brown.edu [School of Engineering, Brown University, Providence, RI 02912 (United States)

    2011-02-25

    Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s{sup -1}. Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

  17. Deposition and Tribological Properties of Sulfur-Doped DLC Films Deposited by PBII Method

    Directory of Open Access Journals (Sweden)

    Nutthanun Moolsradoo

    2010-01-01

    Full Text Available Sulfur-doped diamond-like carbon films (S-DLC fabricated from C2H2 and SF6 mixtures were used to study the effects of sulfur content and negative pulse bias voltage on the deposition and tribological properties of films prepared by plasma-based ion implantation (PBII. The structure and relative concentration of the films were analyzed by Raman spectroscopy and Auger electron spectroscopy. Hardness and elastic modulus of films were measured by nanoindentation hardness testing. Tribological characteristics of films were performed using a ball-on-disk friction tester. The results indicate that with the increasing sulfur content, the hardness and elastic modulus decrease. Additionally, by changing the negative pulse bias voltage from 0 kV to −5 kV, the hardness and elastic modulus increase, while the friction coefficient and specific wear rate tends to decrease. Moreover, at a negative pulse bias voltage of −5 kV and flow-rate ratio of 1 : 2, there is considerable improvement in friction coefficient of 0.05 under ambient air is due to the formation of a transfer films on the interface. The decrease in the friction coefficient of films doped with 4.9 at.% sulfur is greater under high vacuum (0.03 than under ambient air (>0.1.

  18. Spray deposited Mg-doped SnO{sub 2} thin film LPG sensor: XPS and EDX analysis in relation to deposition temperature and doping

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Boben, E-mail: dr.boben1@gmail.com; Skariah, Benoy

    2015-03-15

    Highlights: • Mg doped SnO{sub 2} thin film significantly improves the LPG response to 93%. • Mg doping concentration up to 0.9 wt% is helpful in decreasing the grain size. • The O/Sn ratio supports excess oxygen in films whereas XPS suggests dissimilar chemical states. • Doping leads to an enhanced oxygen adsorption by a favourable crystallite orientation. • Adsorbed oxygen ions responsible for enhanced response can be perceived at the grain boundaries or at the surface, on account of the absence in the crystalline matrix. - Abstract: Magnesium doped SnO{sub 2} polycrystalline thin films are deposited by Spray pyrolysis by adding small amount of Mg between 0.3 and 1.2 wt%. Mg doping significantly modifies the gas sensing properties of tin oxide thin films by yielding (1 1 0) and (1 0 1) crystallite orientation to accommodate oxygen vacancies which lead to enhanced oxygen adsorption. A correlation is established between the crystallite orientation and the gas sensing magnitude by plotting the texture coefficient. The structure, surface chemical composition, and the optical and electrical properties are studied in relation to the gas sensing magnitude. It is shown that the magnesium doping in SnO{sub 2} maintains tetragonal rutile structure in stable cassiterite phase over low doping concentrations. The grain dimensions are influenced by both doping concentration and substrate temperature. Electronic surface states identified by the XPS are deconvoluted to establish the constituent oxygen states, while the EDX compositional analysis indicates added oxygen adsorption. As the temperature is raised for the response measurement, the adsorbed oxygen may transform to O{sup −} or O{sup 2−} which is supported by the increase of film resistance. It is shown that the sensor response to LPG is improved significantly (93%) by the addition of minor amounts of Mg to SnO{sub 2} thin film sensors.

  19. Effect of ZDDP concentration on the thermal film formation on steel, hydrogenated non-doped and Si-doped DLC

    Science.gov (United States)

    Akbari, S.; Kovač, J.; Kalin, M.

    2016-10-01

    This work focuses on the ZDDP concentration (1, 5 and 20 wt%) to form a ZDDP film on surfaces during static thermal tests at 150 °C. Silicon-doped and hydrogenated DLC coatings, as well as steel as reference, were studied using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The results show that, on the three surfaces, the structure of the ZDDP thermal film consists of identical groups of pyrophosphate and zinc oxide, while the sulphuric groups are dissimilar. On the steel surface, the sulphuric part consists of a mixture of organic sulphide and sulphohydryl groups, but on H-DLC and Si-DLC only organic sulphide groups are found; there are no sulphohydryl groups. Moreover, both ATR-FTIR and XPS show that different concentrations of ZDDP do not affect the final chemical structure of the ZDDP thermal film on any of the studied surfaces. In addition, the XPS results show that the thickness of the thermal film is linear with the concentration for the whole range from 1 to 20 wt%, supporting also its uniform chemical structure. These thicknesses further show that the reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings.

  20. 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.

  1. A magenta polypyrrole derivatised with Methyl Red azo dye: synthesis and spectroelectrochemical characterisation

    International Nuclear Information System (INIS)

    Almeida, Andresa K.A.; Dias, Jéssica M.M.; Santos, Diego P.; Nogueira, Fred A.R.; Navarro, Marcelo; Tonholo, Josealdo; Lima, Dimas J.P.; Ribeiro, Adriana S.

    2017-01-01

    Highlights: • A pyrrole (Py) derivative functionalised with methyl red (MRPy) was synthesised. • MRPy was polymerised electrochemically in LiClO 4 /CH 3 CN with BFEE. • Electrochromic properties of PMRPy and PPy doped with methyl red (PPy/MR) were compared. • Colour of the PMRPy changes from magenta to yellow depending on the pH. • PMRPy films might be applicable in optoelectronic devices or in pH sensors. - Abstract: A pyrrole derivative bearing 2-(4-dimethylaminophenylazo)benzoic acid, also known as Methyl Red (MR), was prepared by a simple synthetic route, and electropolymerised onto ITO/glass electrodes in (C 4 H 9 ) 4 NBF 4 /CH 3 CN in presence of boron trifluoride diethyl etherate (BFEE). Films of polypyrrole (PPy) and PPy doped with MR (PPy/MR) were also deposited onto ITO/glass in order to compare their electrochromic properties with the films of PPy derivatised with MR. Cyclic voltammogram of the poly[3-(N-pyrrolyl)propyl 2-(4-dimethylaminophenylazo)benzoate] (PMRPy) film displayed a redox pair with anodic peak potential (Epa) at ca. 0.53 V and cathodic peak potential (Epc) at 0.25 V vs. Ag/Ag + , corresponding to the polymer p-doping, whilst the PPy/MR film shows capacitive behaviour with a redox pair in the cathodic region (Epa = −0.36 V and Epc = −0.62 V), similar to the PPy film (Epa = −0.10 V, and Epc = −0.15 V), and an anodic wave in the same potential range of that for PMRPy film. The electrochromic properties of the PMRPy film, such as chromatic contrast (Δ%T = 34.2%), switching time (τ = 10 s) and stability (Δ%T = 15% at the 100th cycle), were enhanced relative to the PPy/MR and PPy films. However, the colour of the PMRPy film changed from yellow (-0.8 V) to magenta (E = 1.0 V) in the first cycle and became light magenta at −0.8 V in the subsequent cycles. PMRPy films were also investigated in phosphate buffer solution (PBS, 2.0 ≤ pH ≤ 9.0) and after exposure to HCl vapour, in which the colour varied from magenta at p

  2. Surface roughness characterization of Al-doped zinc oxide thin films using rapid optical measurement

    Science.gov (United States)

    Kuo, Chil-Chyuan

    2011-07-01

    Transparent conductive oxide thin films have been widely investigated in photoelectric devices such as flat panel display (FPD) and solar cells. Al-doped zinc oxide (AZO) thin films have been widely employed in FPD. Measuring the surface roughness of AZO thin films is important before the manufacturing of photoelectric device using AZO thin films because surface roughness of AZO thin films will significantly affect the performance of photoelectric device. Traditional methods to measure surface roughness of AZO thin films are scanning electron microscopy and atomic force microscopy. The disadvantages of these approaches include long lead time and slow measurement speed. To solve this problem, an optical inspection system for rapid measurement of the surface roughness of AZO thin films is developed in this study. It is found that the incident angle of 60° is a good candidate to measure the surface roughness of AZO thin films. Based on the trend equation y=-3.6483 x+2.1409, the surface roughness of AZO thin films ( y) can be directly deduced from the peak power density ( x) using the optical inspection system developed. The maximum measurement-error rate of the optical inspection system developed is less than 8.7%.The saving in inspection time of the surface roughness of AZO thin films is up to 83%.

  3. Enhanced flux pinning properties in superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} films by a novel chemical doping approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T., E-mail: wtwang@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Pu, M.H.; Lei, M.; Zhang, H.; Wang, Z. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2013-10-15

    Highlights: • Pure and Co-doped YBCO films were prepared by newly-developed chemical method. • The doped films have much denser and smoother surface microstructures. • Significantly enhanced fux-pinning properties have been obtained for dilute Co-doped flm. -- Abstract: Pure and cobalt-doped superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} (YBCO) films were prepared on (0 0 l) LaAlO{sub 3} substrate by a newly developed polymer-assisted metal organic deposition method. The cobalt-doped YBCO films display much denser and smoother surface microstructures and the superconducting transition temperature T{sub c} spans a small range of 1.7 K with the doping levels. Significantly enhanced flux-pinning properties have been obtained for dilute cobalt-doped film. This may be attributed to the good grain connections and the effective flux pinning centers introduced by cobalt doping.

  4. Polypyrrole Actuators Working at 2 to 30 Hz

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; West, Keld

    2007-01-01

    “Soft actuators” based on the conducting polymer polypyrrole (PPy) may be especially suitable for use in combination with human limbs. A research project under the European Union Quality of Life program (DRIFTS, Dynamically Responsive Intervention for Tremor Suppression, http://www.gerontech.org.......“Soft actuators” based on the conducting polymer polypyrrole (PPy) may be especially suitable for use in combination with human limbs. A research project under the European Union Quality of Life program (DRIFTS, Dynamically Responsive Intervention for Tremor Suppression, http...... and in the electrolyte, a polypyrrole actuator able to yield significant force at up to 30 Hz has been made. The stiffness change turns out to be approximately 20 times faster than the change in length. Simple scaling up of the present data leads to a required total thickness of PPy (30 mm wide film) of 0.13 mm at 2 Hz...

  5. Translation Effects in Fluorine Doped Tin Oxide Thin Film Properties by Atmospheric Pressure Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Mohammad Afzaal

    2016-10-01

    Full Text Available In this work, the impact of translation rates in fluorine doped tin oxide (FTO thin films using atmospheric pressure chemical vapour deposition (APCVD were studied. We demonstrated that by adjusting the translation speeds of the susceptor, the growth rates of the FTO films varied and hence many of the film properties were modified. X-ray powder diffraction showed an increased preferred orientation along the (200 plane at higher translation rates, although with no actual change in the particle sizes. A reduction in dopant level resulted in decreased particle sizes and a much greater degree of (200 preferred orientation. For low dopant concentration levels, atomic force microscope (AFM studies showed a reduction in roughness (and lower optical haze with increased translation rate and decreased growth rates. Electrical measurements concluded that the resistivity, carrier concentration, and mobility of films were dependent on the level of fluorine dopant, the translation rate and hence the growth rates of the deposited films.

  6. Effects of process parameters on sheet resistance uniformity of fluorine-doped tin oxide thin films

    Science.gov (United States)

    Hudaya, Chairul; Park, Ji Hun; Lee, Joong Kee

    2012-01-01

    An alternative indium-free material for transparent conducting oxides of fluorine-doped tin oxide [FTO] thin films deposited on polyethylene terephthalate [PET] was prepared by electron cyclotron resonance - metal organic chemical vapor deposition [ECR-MOCVD]. One of the essential issues regarding metal oxide film deposition is the sheet resistance uniformity of the film. Variations in process parameters, in this case, working and bubbler pressures of ECR-MOCVD, can lead to a change in resistance uniformity. Both the optical transmittance and electrical resistance uniformity of FTO film-coated PET were investigated. The result shows that sheet resistance uniformity and the transmittance of the film are affected significantly by the changes in bubbler pressure but are less influenced by the working pressure of the ECR-MOCVD system.

  7. The effect of Nb doping on ferroelectric properties of PZT thin films prepared from polymeric precursors

    International Nuclear Information System (INIS)

    Souza, E.C.F.; Simoes, A.Z.; Cilense, M.; Longo, E.; Varela, J.A.

    2004-01-01

    Pure and Nb doped PbZr 0.4 Ti 0.6 O 3 thin films was prepared by the polymeric precursor method and deposited by spin coating on Pt/Ti/SiO 2 /Si (100) substrates and annealed at 700 deg. C. The films are oriented in (1 1 0) and (1 0 0) direction. The electric properties of PZT thin films show strong dependence of the crystallographic orientation. The P-E hysteresis loops for the thin film with composition PbZr 0.39 Ti 0.6 Nb 0.1 O 3 showed good saturation, with values for coercive field (E c ) equal to 60 KV cm -1 and for remanent polarization (P r ) equal to 20 μC cm -2 . The measured dielectric constant (ε) is 1084 for this film. These results show good potential for application in FERAM

  8. Indium-Doped Zinc Oxide Thin Films as Effective Anodes of Organic Photovoltaic Devices

    Directory of Open Access Journals (Sweden)

    Ziyang Hu

    2011-01-01

    Full Text Available Indium-doped zinc oxide (IZO thin films were prepared by low-cost ultrasonic spray pyrolysis (USP. Both a low resistivity (3.13×10−3 Ω cm and an average direct transmittance (400∼1500 nm about 80% of the IZO films were achieved. The IZO films were investigated as anodes in bulk-heterojunction organic photovoltaic (OPV devices based on poly(3-hexylthiophene and [6,6]-phenyl C61-butyric acid methyl ester. The device fabricated on IZO film-coated glass substrate showed an open circuit voltage of 0.56 V, a short circuit current of 8.49 mA cm-2, a fill factor of 0.40, and a power conversion efficiency of 1.91%, demonstrating that the IZO films prepared by USP technique are promising low In content and transparent electrode candidates of low-cost OPV devices.

  9. Properties of the Surface Layer of Thin Films of Polyaniline Doped With Phosphoric Acid

    Directory of Open Access Journals (Sweden)

    Almedina Modrić-Šahbazović

    2016-08-01

    Full Text Available This study deals with estimation of the surface free energy of thin films of polyaniline doped with phosphoric acid, by measuring contact angles. Synthesis of polyaniline (PANI with phosphoric acid (PA was performed at room temperature of 20°C, and at 0°C. Thin films were obtained by means of a spin coater, applying the synthetized mixture on a glass substrate. By measuring the contact angle, first between ethylene glycol and a film and then between distilled water and a film, we thus calculated the polar, dispersion and total surface free energy. It was proved and demonstrated that the surface free energy depends on the temperature at which the solution (from which the thin films are obtained later was synthesized.

  10. Synthesis, characterization and photovoltaic properties of Mn-doped Sb2S3 thin film

    Directory of Open Access Journals (Sweden)

    Horoz Sabit

    2018-03-01

    Full Text Available Synthesis and characterization of Mn-doped Sb2S3 thin films (TFs prepared by chemical bath deposition (CBD at room temperature have been documented and their structural, optical, morphological, magnetic and photovoltaic properties have been examined for the first time. Their structural properties reveal that the Mn-doped Sb2S3 TF has an orthorhombic phase structure of Sb2S3, and that the grain size of the Mn-doped Sb2S3 TF (72.9 nm becomes larger than that of undoped Sb2S3 TF (69.3 nm. It has been observed that Mn content causes the Sb2S3 TF band gap to decrease. This situation clearly correlates with band tailing due to the impurities that are involved. The morphological properties have revealed that the shape of the Mn-doped Sb2S3 TF is more uniform than the shape of its undoped counterpart. The study on its magnetic properties has demonstrated that the Mn-doped Sb2S3 TF exhibits paramagnetic behavior. Its paramagnetic Curie-Weiss temperature was found to be -4.1 K. This result suggests that there is an anti-ferromagnetic interaction between Mn moments in the Mn-doped Sb2S3 TF. Incident photon to electron conversion efficiency (IPCE and J-V measurements were also carried out for the Mn-doped Sb2S3 TF for the first time. The results have indicated that the Mn-doped Sb2S3 TF can be utilized as a sensitizer to improve the performance of solar cells. Another important observation on the photovoltaic properties of Mn-doped Sb2S3 TF is that the spectral response range is wider than that of undoped Sb2S3 TF. Our study suggests that the introduction of dopant could serve as an effective means of improving the device performance of solar cells.

  11. 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.

  12. Microstructure and high-temperature tribological properties of Si-doped hydrogenated diamond-like carbon films

    Science.gov (United States)

    Zhang, Teng Fei; Wan, Zhi Xin; Ding, Ji Cheng; Zhang, Shihong; Wang, Qi Min; Kim, Kwang Ho

    2018-03-01

    Si-doped DLC films have attracted great attention for use in tribological applications. However, their high-temperature tribological properties remain less investigated, especially in harsh oxidative working conditions. In this study, Si-doped hydrogenated DLC films with various Si content were synthesized and the effects of the addition of Si on the microstructural, mechanical and high-temperature tribological properties of the films were investigated. The results indicate that Si doping leads to an obvious increase in the sp3/sp2 ratio of DLC films, likely due to the silicon atoms preferentially substitute the sp2-hybridized carbon atoms and augment the number of sp3 sites. With Si doping, the mechanical properties, including hardness and adhesion strength, were improved, while the residual stress of the DLC films was reduced. The addition of Si leads to higher thermal and mechanical stability of DLC films because the Si atoms inhibit the graphitization of the films at an elevated temperature. Better high-temperature tribological properties of the Si-DLC films under oxidative conditions were observed, which can be attributed to the enhanced thermal stability and formation of a Si-containing lubricant layer on the surfaces of the wear tracks. The nano-wear resistance of the DLC films was also improved by Si doping.

  13. Cr doping induced negative transverse magnetoresistance in C d3A s2 thin films

    Science.gov (United States)

    Liu, Yanwen; Tiwari, Rajarshi; Narayan, Awadhesh; Jin, Zhao; Yuan, Xiang; Zhang, Cheng; Chen, Feng; Li, Liang; Xia, Zhengcai; Sanvito, Stefano; Zhou, Peng; Xiu, Faxian

    2018-02-01

    The magnetoresistance of a material conveys various dynamic information about charge and spin carriers, inspiring both fundamental studies in physics and practical applications such as magnetic sensors, data storage, and spintronic devices. Magnetic impurities play a crucial role in the magnetoresistance as they induce exotic states of matter such as the quantum anomalous Hall effect in topological insulators and tunable ferromagnetic phases in dilute magnetic semiconductors. However, magnetically doped topological Dirac semimetals are hitherto lacking. Here, we report a systematic study of Cr-doped C d3A s2 thin films grown by molecular-beam epitaxy. With the Cr doping, C d3A s2 thin films exhibit unexpected negative transverse magnetoresistance and strong quantum oscillations, bearing a trivial Berry's phase and an enhanced effective mass. More importantly, with ionic gating the magnetoresistance of Cr-doped C d3A s2 thin films can be drastically tuned from negative to positive, demonstrating the strong correlation between electrons and the localized spins of the Cr impurities, which we interpret through the formation of magnetic polarons. Such a negative magnetoresistance under perpendicular magnetic field and its gate tunability have not been observed previously in the Dirac semimetal C d3A s2 . The Cr-induced topological phase transition and the formation of magnetic polarons in C d3A s2 provide insights into the magnetic interaction in Dirac semimetals as well as their potential applications in spintronics.

  14. Development of polypyrrole coated copper nanowires for gas sensor application

    Directory of Open Access Journals (Sweden)

    H. Shokry Hassan

    2015-09-01

    Full Text Available Both polypyrrole (PPy and polypyrrole coated copper thin films were synthesized successfully via two-step methods. PPy nanorods films were first grown chemically, and then PPy thin films were fabricated on glass substrates using dip-coating technique. The resulting films were examined via various characterization methods such as X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR and Thermal Gravimetric Analysis (TGA. Gas sensor devices were fabricated and the gas sensitivity for (PPy coated copper was measured as a function of temperature for both O2 and CO2 gases. The maximum sensitivity for O2 gas was around 160% and the maximum sensitivity for CO2 was 300%.

  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. Electromagnetic and optical characteristics of Nb5+-doped double-crossover and salmon DNA thin films

    Science.gov (United States)

    Babu Mitta, Sekhar; Reddy Dugasani, Sreekantha; Jung, Soon-Gil; Vellampatti, Srivithya; Park, Tuson; Park, Sung Ha

    2017-10-01

    We report the fabrication and physical characteristics of niobium ion (Nb5+)-doped double-crossover DNA (DX-DNA) and salmon DNA (SDNA) thin films. Different concentrations of Nb5+ ([Nb5+]) are coordinated into the DNA molecules, and the thin films are fabricated via substrate-assisted growth (DX-DNA) and drop-casting (SDNA) on oxygen plasma treated substrates. We conducted atomic force microscopy to estimate the optimum concentration of Nb5+ ([Nb5+]O = 0.08 mM) in Nb5+-doped DX-DNA thin films, up to which the DX-DNA lattices maintain their structures without deformation. X-ray photoelectron spectroscopy (XPS) was performed to probe the chemical nature of the intercalated Nb5+ in the SDNA thin films. The change in peak intensities and the shift in binding energy were witnessed in XPS spectra to explicate the binding and charge transfer mechanisms between Nb5+ and SDNA molecules. UV-visible, Raman, and photoluminescence (PL) spectra were measured to determine the optical properties and thus investigate the binding modes, Nb5+ coordination sites in Nb5+-doped SDNA thin films, and energy transfer mechanisms, respectively. As [Nb5+] increases, the absorbance peak intensities monotonically increase until ˜[Nb5+]O and then decrease. However, from the Raman measurements, the peak intensities gradually decrease with an increase in [Nb5+] to reveal the binding mechanism and binding sites of metal ions in the SDNA molecules. From the PL, we observe the emission intensities to reduce them at up to ˜[Nb5+]O and then increase after that, expecting the energy transfer between the Nb5+ and SDNA molecules. The current-voltage measurement shows a significant increase in the current observed as [Nb5+] increases in the SDNA thin films when compared to that of pristine SDNA thin films. Finally, we investigate the temperature dependent magnetization in which the Nb5+-doped SDNA thin films reveal weak ferromagnetism due to the existence of tiny magnetic dipoles in the Nb5+-doped SDNA

  17. Electromagnetic and optical characteristics of Nb5+-doped double-crossover and salmon DNA thin films.

    Science.gov (United States)

    Mitta, Sekhar Babu; Dugasani, Sreekantha Reddy; Jung, Soon-Gil; Vellampatti, Srivithya; Park, Tuson; Park, Sung Ha

    2017-10-06

    We report the fabrication and physical characteristics of niobium ion (Nb 5+ )-doped double-crossover DNA (DX-DNA) and salmon DNA (SDNA) thin films. Different concentrations of Nb 5+ ([Nb 5+ ]) are coordinated into the DNA molecules, and the thin films are fabricated via substrate-assisted growth (DX-DNA) and drop-casting (SDNA) on oxygen plasma treated substrates. We conducted atomic force microscopy to estimate the optimum concentration of Nb 5+ ([Nb 5+ ] O  = 0.08 mM) in Nb 5+ -doped DX-DNA thin films, up to which the DX-DNA lattices maintain their structures without deformation. X-ray photoelectron spectroscopy (XPS) was performed to probe the chemical nature of the intercalated Nb 5+ in the SDNA thin films. The change in peak intensities and the shift in binding energy were witnessed in XPS spectra to explicate the binding and charge transfer mechanisms between Nb 5+ and SDNA molecules. UV-visible, Raman, and photoluminescence (PL) spectra were measured to determine the optical properties and thus investigate the binding modes, Nb 5+ coordination sites in Nb 5+ -doped SDNA thin films, and energy transfer mechanisms, respectively. As [Nb 5+ ] increases, the absorbance peak intensities monotonically increase until ∼[Nb 5+ ] O and then decrease. However, from the Raman measurements, the peak intensities gradually decrease with an increase in [Nb 5+ ] to reveal the binding mechanism and binding sites of metal ions in the SDNA molecules. From the PL, we observe the emission intensities to reduce them at up to ∼[Nb 5+ ] O and then increase after that, expecting the energy transfer between the Nb 5+ and SDNA molecules. The current-voltage measurement shows a significant increase in the current observed as [Nb 5+ ] increases in the SDNA thin films when compared to that of pristine SDNA thin films. Finally, we investigate the temperature dependent magnetization in which the Nb 5+ -doped SDNA thin films reveal weak ferromagnetism due to the existence of tiny

  18. Hydrogen diffusion and induced-crystallization in intrinsic and doped hydrogenated amorphous silicon films

    International Nuclear Information System (INIS)

    Kail, F.; Hadjadj, A.; Roca i Cabarrocas, P.

    2005-01-01

    We have studied the evolution of the structure of intrinsic and doped hydrogenated amorphous silicon films exposed to a hydrogen plasma. For this purpose, we combine in situ spectroscopic ellipsometry and secondary ion mass spectrometry measurements. We show that hydrogen diffuses faster in boron-doped hydrogenated amorphous silicon than in intrinsic samples, leading to a thicker subsurface layer from the early stages of hydrogen plasma exposure. At longer times, hydrogen plasma leads to the formation of a microcrystalline layer via chemical transport, but there is no evidence for crystallization of the a-Si:H substrate. Moreover, we observe that once the microcrystalline layer is formed, hydrogen diffuses out of the sample

  19. Alkaline-doped manganese perovskite thin films grown by MOCVD

    International Nuclear Information System (INIS)

    Bibes, M.; Gorbenko, O.; Martinez, B.; Kaul, A.; Fontcuberta, J.

    2000-01-01

    We report on the preparation and characterization of La 1-x Na x MnO 3 thin films grown by MOCVD on various single-crystalline substrates. Under appropriate conditions epitaxial thin films have been obtained. The Curie temperatures of the films, which are very similar to those of bulk samples of similar composition, reflect the residual strain caused by the substrate. The anisotropic magnetoresistance AMR of the films has been analyzed in some detail, and it has been found that it has a two-fold symmetry at any temperature. Its temperature dependence mimics that of the electrical resistivity and magnetoresistance measured at similar fields, thus suggesting that the real structure of the material contributes to the measured AMR besides the intrinsic component

  20. Amorphous silicon films doped with BF3 and PF5

    International Nuclear Information System (INIS)

    Ortiz, A.; Muhl, S.; Sanchez, A.; Monroy, R.; Pickin, W.

    1984-01-01

    By using gaseous discharge process, thin films of hydrogenated amorphous silicon (a-Si:H) were produced. This process consists of Silane (SiH 4 ) decomposition at low pressure, in a chamber. (A.C.A.S.) [pt

  1. 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.

  2. Preparation and chemical characterization of neodymium-doped molybdenum oxide films grown using spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, J. E. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia Materiales y Superficies, AA 5997 Bogota DC (Colombia); Moreno, L. C., E-mail: jealfonsoo@unal.edu.co [Universidad Nacional de Colombia, Departamento de Quimica, AA 5997 Bogota DC (Colombia)

    2014-07-01

    We studied the crystalline, morphology, and surface composition of Nd-doped molybdenum oxide films grown on glass slides through spray pyrolysis. After fabrication, the films were subjected to thermal treatment in oxygen for periods ranging from 2 to 20 hours. The films were structurally characterized though X-ray diffraction (XRD), their bulk chemical composition was determined using Energy-Dispersive X-ray analysis (EDX), and their surface composition was determined using X-ray Photoelectron Spectroscopy (XP S). The XRD results show that the films obtained from different dissolution volumes and at substrate temperature of 300 grades C exhibit the characteristics of the oxygen-deficient molybdenum trioxide Mo{sub 9}O{sub 26} phase. The films subjected to different thermal treatments exhibit a mixture of Mo{sub 9}O{sub 26} and Mo{sub 17}O{sub 47} phases. EDX study shows the energy belonging to the L line of Nd. Finally, films doped with Nd and subjected to a thermal treatment of 20 h were analyzed through XP S, showing the binding energies at the crystalline lattice correspond to Nd{sub 2} (MoO{sub 4}){sub 3} and Nd{sub 2}Mo{sub 2}O{sub 7}. (Author)

  3. Preparation and properties of KCl-doped Cu2O thin film by electrodeposition

    International Nuclear Information System (INIS)

    Yu, Xiaojiao; Li, Xinming; Zheng, Gang; Wei, Yuchen; Zhang, Ama; Yao, Binghua

    2013-01-01

    With the indium tin oxide-coated glass as working electrode, cuprous oxide thin film is fabricated by means of electrodeposition. The effects of KCl doped and annealing treatment upon Cu 2 O thin film morphology, surface resistivity, open-circuit voltage, electric conduction types and visible light response are studied. The research results indicate that KCl doped has a great effect upon Cu 2 O crystal morphology, thus, making Cu 2 O thin film surface resistivity drop, and the open-circuit voltage increase and that electric conduction types are transformed from p type into n type, and the visible light (400–500 nm) absorption rate is slightly reduced. Annealing treatment can obviously decrease Cu 2 O thin film surface resistivity and improve its open-circuit voltage. When KCl concentration in electrolytic solution reaches 7 mmol/L, Cu 2 O thin film morphology can be changed from the dendritic crystal into the cubic crystal and Cu 2 O thin film surface resistivity decreases from the initial 2.5 × 10 6 Ω cm to 8.5 × 10 4 Ω cm. After annealing treatment at 320 °C for 30 min, the surface resistivity decreases to 8.5 × 10 2 Ω cm, and the open-circuit voltage increases from the initial 3.1 mV to 79.2 mV.

  4. Chemical bath deposition of Hg doped CdSe thin films and their characterization

    International Nuclear Information System (INIS)

    Bhuse, V.M.

    2005-01-01

    The deliberate addition of Hg in CdSe thin film have been carried out using a simple, modified, chemical bath deposition technique with the objective to study the effect of Hg doping on properties of CdSe thin films. Synthesis was initiated at 278 K temperature using complexed cadmium sulphate, mercuric nitrate and sodium selenosulphate in an aqueous ammonical medium at pH 10. Films were characterized by XRD, SEM, optical absorption, electrical and thermoelectric techniques. The 'as deposited' films were uniform, well adherent, nearly stoichiometric and polycrystalline in a single cubic phase (zinc blende). Crystallite size determined from XRD and SEM was found to increase slightly with addition of Hg. The optical band gap of CdSe remains constant upto 0.05 mol% Hg doping, while it decreases monotonically with further increase in mercury content. Dark dc electrical resistivity and conduction activation energy of CdSe were found to decrease initially upto 0.05 mol% of Hg, thereafter increased for higher values of Hg but remains less than those of CdSe. All the films showed n-type of conductivity. A CdSe film containing 0.05 mol% of Hg showed higher absorption coefficient, and conductivity

  5. Doping and controllable pore size enhanced electrochemical performance of free-standing 3D graphene films

    Science.gov (United States)

    Wang, Liping; Qin, Kaiqiang; Li, Jiajun; Zhao, Naiqin; Shi, Chunsheng; Ma, Liying; He, Chunnian; He, Fang; Liu, Enzuo

    2018-01-01

    High quality free-standing 3D nanoporous graphene (3DNG) films were fabricated using nanoporous nickel as template and catalyst. The effect of heteroatom doping and pore size on the electrochemical performance of the 3D graphene films as supercapacitor electrodes are systematically studied. Compared with macroporous graphene films, nanoporous graphene films exhibit an extraordinarily large operational window in neutral, acidic and alkaline aqueous electrolytes, as well as high packing density. Nitrogen and oxygen doping play different roles in different aqueous electrolytes on the electrical conductivity and pseudocapacitance of 3DNG. The realization of both high packing density, 3.65 mg/cm2, and the maximum working window, as well as the synergistic effect between N and O doping, gives rise to a high areal capacitance of 435 mF/cm2 in neutral electrolyte and excellent cycle stability up to 5000 cycles. The results provide a potential strategy to further increase the volumetric or areal energy density of carbon-based aqueous supercapacitor.

  6. Characterization of Sn Doped ZnS thin films synthesized by CBD

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Ayan; Mitra, Partha, E-mail: mitrapartha1@rediffmail.com [Department of Physics, The University of Burdwan, Burdwan (India)

    2017-03-15

    Zinc sulphide (ZnS) thin film were prepared using chemical bath deposition (CBD) process and tin (Sn) doping was successfully carried out in ZnS. Structural, morphological and microstructural characterization was carried out using XRD, TEM, FESEM and EDX. XRD and SAED pattern confirms presence of hexagonal phase. Rietveld analysis using MAUD software was used for particle size estimation. A constantly decreasing trend in particle size was observed with increasing tin incorporation in ZnS film which was due to enhanced microstrain resulting for tin incorporation. The particle size of prepared hexagonal wurtzite ZnS was around 14-18 nm with average size of ~16.5 nm. The bandgap of the film increases from ~ 3.69 eV for ZnS to ~ 3.90 eV for 5% Sn doped ZnS film which might be due to more ordered hexagonal structure as a result of tin incorporation. Band gap tenability property makes Sn doped ZnS suitable for application in different optoelectronics devices. PL study shows variation of intensity with excitation wavelength and a red shift is noticed for increasing excitation wavelength. (author)

  7. Synthesis and characterization of Ag doped TiO{sub 2} heterojunction films and their photocatalytic performances

    Energy Technology Data Exchange (ETDEWEB)

    Demirci, Selim, E-mail: selim.demirci@marmara.edu.tr [Marmara University, Department of Metallurgical and Materials Engineering, Kadiköy, 34722 Istanbul (Turkey); Dikici, Tuncay [Izmir Katip Celebi University, Department of Materials Science and Engineering, Cigli, 35620 Izmir (Turkey); Yurddaskal, Metin [Department of Metallurgical and Materials Engineering, Dokuz Eylul University, 35390 Izmir (Turkey); Center for Fabrication and Application of Electronic Materials, Dokuz Eylul University, 35390 Izmir (Turkey); Gultekin, Serdar [Department of Nanoscience and Nanoengineering, Dokuz Eylul University, 35390 İzmir (Turkey); Experimental Science Applications and Research Center, Celal Bayar University, 45140 Manisa (Turkey); Toparli, Mustafa; Celik, Erdal [Department of Metallurgical and Materials Engineering, Dokuz Eylul University, 35390 Izmir (Turkey); Department of Nanoscience and Nanoengineering, Dokuz Eylul University, 35390 İzmir (Turkey); Center for Fabrication and Application of Electronic Materials, Dokuz Eylul University, 35390 Izmir (Turkey)

    2016-12-30

    Highlights: • Ag doped TiO{sub 2} films were successfully synthesized by sol–gel spin coating method. • Ag in TiO{sub 2} lattice enters in intermediate states to decrease TiO{sub 2} bandgap energy. • Ag dopants increase the photoactivity and superhydrophilicity. • The degradation kinetics of methylene blue was studied. • The 0.7 mol% of Ag was found to be the optimum concentration. - Abstract: In this study, undoped and silver (Ag) doped titanium dioxide (TiO{sub 2}) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO{sub 2} films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO{sub 2} films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO{sub 2} films calcined at 500 °C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO{sub 2} matrix enhanced the photocatalytic activity of TiO{sub 2} films under UV light irradiation as compared to the undoped TiO{sub 2} film. Furthermore, the results indicated that the 0.7% Ag doped TiO{sub 2} film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO{sub 2} films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water.

  8. Novel doped hydroxyapatite thin films obtained by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duta, L. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, 409 Atomistilor Street, Magurele (Romania); Oktar, F.N. [Department of Bioengineering, Faculty of Engineering, Marmara University, Goztepe, Istanbul 34722 (Turkey); Department of Medical Imaging Technics, Vocational School of Health Services, Marmara University, Uskudar, Istanbul 34668 (Turkey); Nanotechnology and Biomaterials Application and Research Centre, Marmara University, Istanbul (Turkey); Stan, G.E. [National Institute of Materials Physics, 105 Bis Atomistilor Street, Magurele (Romania); Popescu-Pelin, G.; Serban, N.; Luculescu, C. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, 409 Atomistilor Street, Magurele (Romania); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, 409 Atomistilor Street, Magurele (Romania)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer HA coatings synthesized by pulsed laser deposition. Black-Right-Pointing-Pointer Comparative study of commercial vs. animal origin materials. Black-Right-Pointing-Pointer HA coatings of animal origin were rougher and more adherent to substrates. Black-Right-Pointing-Pointer Animal origin films can be considered as promising candidates for implant coatings. - Abstract: We report on the synthesis of novel ovine and bovine derived hydroxyapatite thin films on titanium substrates by pulsed laser deposition for a new generation of implants. The calcination treatment applied to produce the hydroxyapatite powders from ovine/bovine bones was intended to induce crystallization and to prohibit the transmission of diseases. The deposited films were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. Pull-off adherence and profilometry measurements were also carried out. X-ray diffraction ascertained the polycrystalline hydroxyapatite nature of the powders and films. Fourier transform infrared spectroscopy evidenced the vibrational bands characteristic to a hydroxyapatite material slightly carbonated. The micrographs of the films showed a uniform distribution of spheroidal particulates with a mean diameter of {approx}2 {mu}m. Pull-off measurements demonstrated excellent bonding strength values between the hydroxyapatite films and the titanium substrates. Because of their physical-chemical properties and low cost fabrication from renewable resources, we think that these new coating materials could be considered as a prospective competitor to synthetic hydroxyapatite used for implantology applications.

  9. Evaluation of the Antimicrobial Activity of Different Antibiotics Enhanced with Silver-Doped Hydroxyapatite Thin Films

    Directory of Open Access Journals (Sweden)

    Daniela Predoi

    2016-09-01

    Full Text Available The inhibitory and antimicrobial effects of silver particles have been known since ancient times. In the last few years, a major health problem has arisen due to pathogenic bacteria resistance to antimicrobial agents. The antibacterial activities of new materials including hydroxyapatite (HAp, silver-doped hydroxyapatite (Ag:HAp and various types of antibiotics such as tetracycline (T-HAp and T-Ag:HAp or ciprofloxacin (C-HAp and C-Ag:HAp have not been studied so far. In this study we reported, for the first time, the preparation and characterization of various thin films based on hydroxyapatite and silver-doped hydroxyapatite combined with tetracycline or ciprofloxacin. The structural and chemical characterization of hydroxyapatite and silver-doped hydroxyapatite thin films has been evaluated by X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FTIR. The morphological studies of the HAp, Ag:HAp, T-HAp, T-Ag:HAp, C-HAp and C-Ag:HAp thin solid films were performed using scanning electron microscopy (SEM. In order to study the chemical composition of the coatings, energy dispersive X-ray analysis (EDX and glow discharge optical emission spectroscopy (GDOES measurements have been used, obtaining information on the distribution of the elements throughout the film. These studies have confirmed the purity of the prepared hydroxyapatite and silver-doped hydroxyapatite thin films obtained from composite targets containing Ca10−xAgx(PO46(OH2 with xAg = 0 (HAp and xAg = 0.2 (Ag:HAp. On the other hand, the major aim of this study was the evaluation of the antibacterial activities of ciprofloxacin and tetracycline in the presence of HAp and Ag:HAp thin layers against Staphylococcus aureus and Escherichia coli strains. The antibacterial activities of ciprofloxacin and tetracycline against Staphylococcus aureus and Escherichia coli test strains increased in the presence of HAp and Ag:HAp thin layers.

  10. Cobalt Doped SnO2 Thick Film Gas Sensors: Conductance and Gas Response Characteristics for LPG and CNG Gas

    OpenAIRE

    V. Kumar; S. K. Srivastava; Kiran Jain

    2009-01-01

    Cobalt doped thick films tin oxide sensors were studied for their LPG and CNG gas sensitivity. SnO2 powder was synthesized by precipitation technique and doped with cobalt sulphate (0 to 10 wt %) by impregnation technique. The sensing characteristics were found to depend on the cobalt concentration and operating temperature. Best performance for LPG and CNG detection was obtained for 3 wt % addition of cobalt sulphate. Cobalt doped SnO2 sensors showed a decrease in the optimum temperature for...

  11. Photo-catalytic studies of transition metal doped titanium dioxide thin films processed by metalorganic decomposition (MOD) method

    Science.gov (United States)

    Talagala, P.; Marko, X.; Padmanabhan, K. R.; Naik, R.; Rodak, D.; Cheng, Y. T.

    2006-03-01

    We have synthesized pure and transition element (Fe, Co and V) doped Titanium oxide thin films of thickness ˜ 350 nm on sapphire, Si, and stainless steel substrates by Metalorganic Decomposition (MOD) method. The films were subsequently annealed at appropriate temperatures ( 500-750C) to obtain either anatase or the rutile phase of TiO2. Analysis of the composition of the films were performed by energy dispersive X-ray(EDAX) and Rutherford backscattering spectrometry(RBS). Ion channeling was used to identify possible epitaxial growth of the films on sapphire. Both XRD and Raman spectra of the films exhibit that the films annealed at 550C are of anatase phase, while those annealed at 700C seem to prefer a rutile structure. The water contact angle measurements of the films before and after photoactivation, demonstrate a significant reduction in the contact angle for the anatase phase. However, the variation in contact angle was observed for films exposed to UV (<10^o-30^o) and dark (25^o-50^o). Films doped with Fe show a trend towards lower contact angle than those doped with Co. Results with films doped with V will also be included.

  12. Elucidating doping driven microstructure evolution and optical properties of lead sulfide thin films grown from a chemical bath

    Science.gov (United States)

    Mohanty, Bhaskar Chandra; Bector, Keerti; Laha, Ranjit

    2018-03-01

    Doping driven remarkable microstructural evolution of PbS thin films grown by a single-step chemical bath deposition process at 60 °C is reported. The undoped films were discontinuous with octahedral-shaped crystallites after 30 min of deposition, whereas Cu doping led to a distinctly different surface microstructure characterized by densely packed elongated crystallites. A mechanism, based on the time sequence study of microstructural evolution of the films, and detailed XRD and Raman measurements, has been proposed to explain the contrasting microstructure of the doped films. The incorporation of Cu forms an interface layer, which is devoid of Pb. The excess Cu ions in this interface layer at the initial stages of film growth strongly interact and selectively stabilize the charged {111} faces containing either Pb or S compared to the uncharged {100} faces that contain both Pb and S. This interaction interferes with the natural growth habit resulting in the observed surface features of the doped films. Concurrently, the Cu-doping potentially changed the optical properties of the films: A significant widening of the bandgap from 1.52 eV to 1.74 eV for increase in Cu concentration from 0 to 20% was observed, making it a highly potential absorber layer in thin film solar cells.

  13. Effect of cobalt doping and annealing on properties of titania thin films prepared by sol-gel process

    Science.gov (United States)

    Pärna, R.; Joost, U.; Nõmmiste, E.; Käämbre, T.; Kikas, A.; Kuusik, I.; Hirsimäki, M.; Kink, I.; Kisand, V.

    2011-05-01

    Undoped and cobalt doped titania (TiO 2) thin films have been prepared on Si(1 0 0) monocrystal and quartz substrate using the sol-gel deposition method and annealed in air at 450, 550, 650, 750, 850, 950 and 1050 °C. Several experimental techniques (AFM, XRD, Raman spectroscopy, XRR, EDX, XPS, XAS, UV-VIS spectroscopy) have been used to characterize these films. Further more the degree of light induced hydrophilicity was estimated by measuring the contact angle of a water droplet on the film. Increase of the annealing temperature and in smaller degree also cobalt doping predispose titania crystallite growth. The rutile phase was detected at lower temperatures in the cobalt doped films than in the undoped titania films. Cobalt in the cobalt doped TiO 2 was seen to be in Co 2+ oxidation state, mainly in CoTiO 3 phase when films were annealed at temperatures higher than 650 °C. Cobalt compounds segregated into the sub-surface region and to the surface of the titania, where they formed islands. Cobalt doping red-shifted the fundamental absorption edge further into the visible range, however it did not enhance the light induced hydrophilicity of the thin film surface as compared to the undoped titania thin films.

  14. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    Science.gov (United States)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti

  15. Synthesis and characterization of Cu-doped TiO2 thin films produced by the inert gas condensation technique

    Science.gov (United States)

    Ahmed, H. A.; Abu-Eishah, S. I.; Ayesh, A. I.; Mahmoud, S. T.

    2017-07-01

    The bandgap of thin films Cu-doped TiO2 nanoclusters prepared using the inert gas condensation (IGC) technique have been investigated at various Cu contents. The samples were characterized using XRD, SEM/EDS and UV-visible spectrophotometer. It was found that doping of TiO2 thin film nanoclusters with Cu enhance its optical activity and shift it to the visible region; which makes it useful in photocatalytic applications.

  16. Electroluminescence properties of In-doped Zn2SiO4 thin films prepared by sol-gel process

    International Nuclear Information System (INIS)

    Ogawa, Hirotaka; Kan, Akinori; Ikeda, Norihiro; Fujita, Akihiro

    2012-01-01

    The effect of In doping on the electroluminescence (EL) properties of Zn 2 SiO 4 :In thin films was investigated. In-doped Zn 2 SiO 4 thin films were deposited on BaTiO 3 substrates and their EL properties were characterized in this study. X-ray powder diffraction patterns of In-doped Zn 2 SiO 4 powders revealed a single phase of Zn 2 SiO 4 for In concentrations up to approximately 1.5 mol%, whereas a secondary phase of In 2 O 3 was observed for In concentrations in the range of 2-10 mol%. The maximum luminance of thin film electroluminescent (TFEL) devices varied significantly with the amount of In doping. The highest luminance with blue emission was obtained when 2 mol% In was doped. The blue emission of In-doped Zn 2 SiO 4 thin film may be related to the In substitution for Zn. The 2 mol% In-doped Zn 2 SiO 4 thin film exhibited blue emission with CIE color coordinates of x=0.208 and y=0.086.

  17. Transparent Conducting Mo-Doped CdO Thin Films by Spray Pyrolysis Method for Solar Cell Applications

    Science.gov (United States)

    Helen, S. J.; Devadason, Suganthi; Haris, M.; Mahalingam, T.

    2018-04-01

    Pure and 3%, 5%, and 7% molybdenum-doped cadmium oxide (CdO) thin films have been prepared on glass substrates preheated to 400°C using a spray pyrolysis technique, then analyzed using x-ray diffraction analysis, field-emission scanning electron microscopy, ultraviolet-visible spectroscopy, and photoluminescence and Hall measurements. The films were found to have polycrystalline nature with cubic structure. The crystallite size was calculated to be ˜ 12 nm for various doping concentrations. Doping improved the optical transparency of the CdO thin film, with the 5% Mo-doped film recording the highest transmittance in the optical region. The energy bandgap deduced from optical studies ranged from 2.38 eV and 2.44 eV for different Mo doping levels. The electrical conductivity was enhanced on Mo doping, with the highest conductivity of 1.74 × 103 (Ω cm)-1 being achieved for the 5% Mo-doped CdO thin film.

  18. 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.

  19. Cu doping concentration effect on the physical properties of CdS thin films obtained by the CBD technique

    Science.gov (United States)

    Albor Aguilera, M. L.; Flores Márquez, J. M.; Remolina Millan, A.; Matsumoto Kuwabara, Y.; González Trujillo, M. A.; Hernández Vásquez, C.; Aguilar Hernandez, J. R.; Hernández Pérez, M. A.; Courel-Piedrahita, M.; Madeira, H. T. Yee

    2017-08-01

    Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnS4 (CZTS) semiconductors are direct band gap materials; when these types of material are used in solar cells, they provide efficiencies of 22.1% and 12.6%, respectively. Most traditional fabrication methods involve expensive vacuum processes including co-evaporation and sputtering techniques, where films and doping are conducted separately. On the other hand, the chemical bath deposition (CBD) technique allows an in situ process. Cu-doped CdS thin films working as a buffer layer on solar cells provide good performing devices and they may be deposited by low cost techniques such as chemical methods. In this work, Cu-doped CdS thin films were deposited using the CBD technique on SnO2:F (FTO) substrates. The elemental analysis and mapping reconstruction were conducted by EDXS. Morphological, optical and electrical properties were studied, and they revealed that Cu doping modified the CdS structure, band-gap value and the electrical properties. Cu-doped CdS films show high resistivity compared to the non-doped CdS. The appropriate parameters of Cu-doped CdS films were determined to obtain an adequate window or buffer layer on CIGS and CZTS photovoltaic solar cells.

  20. Phosphorous doped p-type MoS2 polycrystalline thin films via direct sulfurization of Mo film

    Directory of Open Access Journals (Sweden)

    Tomohiro Momose

    2018-02-01

    Full Text Available We report on the successful synthesis of a p-type, substitutional doping at S-site, MoS2 thin film using Phosphorous (P as the dopant. MoS2 thin films were directly sulfurized for molybdenum films by chemical vapor deposition technique. Undoped MoS2 film showed n-type behavior and P doped samples showed p-type behavior by Hall-effect measurements in a van der Pauw (vdP configuration of 10×10 mm2 area samples and showed ohmic behavior between the silver paste contacts. The donor and the acceptor concentration were detected to be ∼2.6×1015 cm-3 and ∼1.0×1019 cm-3, respectively. Hall-effect mobility was 61.7 cm2V-1s-1 for undoped and varied in the range of 15.5 ∼ 0.5 cm2V-1s-1 with P supply rate. However, the performance of field-effect transistors (FETs declined by double Schottky barrier contacts where the region between Ni electrodes on the source/drain contact and the MoS2 back-gate cannot be depleted and behaves as a 3D material when used in transistor geometry, resulting in poor on/off ratio. Nevertheless, the FETs exhibit hole transport and the field-effect mobility showed values as high as the Hall-effect mobility, 76 cm2V-1s-1 in undoped MoS2 with p-type behavior and 43 cm2V-1s-1 for MoS2:P. Our findings provide important insights into the doping constraints for transition metal dichalcogenides.

  1. Optical characterization of hydrogen-free CeO2 doped DLC films deposited by unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang Zhenyu; Zhou Hongxiu; Guo Dongming; Gao Hang; Kang Renke

    2008-01-01

    A novel kind of hydrogen-free CeO 2 doped diamond-like carbon (DLC) films with thickness of 180-200 nm were deposited on silicon by unbalanced magnetron sputtering. Reduced reflectance and increased lifetime are expected with respect to pure DLC films, making these coatings good candidates as optical protective coatings for IR windows and solar cells. X-ray photoelectron spectroscopy confirms that CeO 2 is formed within the DLC films. Auger electron spectroscopy exhibits that the C, O, and Ce elements distribute uniformly across the film thickness, and C element diffuses into the Si substrate at the interface between the substrate and film. AFM shows that nanoparticles with diameter of around 50 nm are formed on the surface of deposited films, whose surface roughness is in the range of 1.3-2.3 nm. Raman spectra show the CeO 2 doped DLC films are amorphous DLC films, and both the G frequency and relative intensity ratio I D /I G are higher than those of pure DLC films. The photoluminescence of CeO 2 doped DLC films is obviously more intense than that of a pure DLC film, which indicates a promising potential as optical protective films for solar cells and IR window

  2. 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.

  3. Effect of Gaussian doping profile on the performance of a thin film polycrystalline solar cell

    Directory of Open Access Journals (Sweden)

    Ouali A.

    2012-06-01

    Full Text Available A two-dimensional (2D analytical model based on the Green’s function method is applied to an n+-p thin film polycrystalline solar cell that allows us to calculate the conversion efficiency. This model considers the effective Gaussian doping profile in the p region in order to improve cell efficiency. The dependence of mobility and lifetime on grain doping is also investigated. This model is implemented through a simulation program in order to optimize conversion efficiency while varying thickness and doping profile in the base region of the cell. Compared with n+-p standard structure, our proposed structure shows a 43% improvement in conversion efficiency for a polycrystalline solar cell.

  4. Effects of Ba doping on physical properties of La-Ca-Mn-O thin films

    CERN Document Server

    Hong, N H; Sakai, J; Iwasaki, H

    2003-01-01

    Transport and magnetic properties of La-Ba-Ca-Mn-O thin films fabricated by the pulsed laser deposition technique had been investigated systematically to see the effects of substitution of the small atom Ca by Ba which is much bigger. The induced insulator-to-metal (IM) transition was obtained not only in compositions near 0.5 and 0.18 which are boundaries between metallic and insulating phases but also in the heavily doped region. In the region of x > 0.5, the Ba doping causes an anomalous response of the system to the magnetic field and a positive magnetoresistance was observed. Besides, our results concerning the vicinity of 0.5 imply the existence of phase separation. As for x < 0.5, the doping enhances remarkably the paramagnetism-ferromagnetism transition and the IM transition temperatures.

  5. 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.

  6. Deep-level optical spectroscopy investigation of N-doped TiO2 films

    International Nuclear Information System (INIS)

    Nakano, Yoshitaka; Morikawa, Takeshi; Ohwaki, Takeshi; Taga, Yasunori

    2005-01-01

    N-doped TiO 2 films were deposited on n + -GaN/Al 2 O 3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 deg. C in flowing N 2 gas. The N-doping concentration was ∼8.8%, as determined from x-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at ∼1.18 and ∼2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N doping and contributes to band-gap narrowing by mixing with the O 2p valence band

  7. Band-gap narrowing of TiO2 films induced by N-doping

    International Nuclear Information System (INIS)

    Nakano, Y.; Morikawa, T.; Ohwaki, T.; Taga, Y.

    2006-01-01

    N-doped TiO 2 films were deposited on n + -GaN/Al 2 O 3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 o C in flowing N 2 gas. The N-doping concentration was ∼8.8%, as determined from X-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at 1.18 and 2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N-doping and contributes to band-gap narrowing by mixing with the O 2p valence band

  8. Effect of boron doping on optical properties of sol–gel based nanostructured zinc oxide films on glass

    International Nuclear Information System (INIS)

    Jana, Sunirmal; Vuk, Angela Surca; Mallick, Aparajita; Orel, Boris; Biswas, Prasanta Kumar

    2011-01-01

    Graphical abstract: Room temperature fine structured UV–vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: ► Sol–gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. ► Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). ► Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. ► The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films (∼80 nm) were deposited onto pure silica glass by sol–gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24–2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

  9. Aluminum-doped zinc oxide thin films grown on various substrates using facing target sputtering system

    Science.gov (United States)

    Kim, Hwa-Min; Lee, Chang Hyun; Shon, Sun Young; Kim, Bong Hwan

    2017-11-01

    Aluminum-doped zinc oxide (AZO) films were fabricated on various substrates, such as glass, polyethylene naphthalate (PEN), and polyethylene terephthalate (PET), at room temperature using a facing target sputtering (FTS) system with hetero ZnO and Al2O3 targets, and their electrical and optical properties were investigated. The AZO film on glass exhibited compressive stress while the films on the plastic substrates showed tensile stress. These stresses negatively affected the crystalline quality of the AZO films, and it is suggested that the poor crystalline quality of the films may be related to the neutral Al-based defect complexes formed in the films; these complexes act as neutral impurity scattering centers. AZO films with good optoelectronic properties could be formed on the glass and plastic substrates by the FTS technique using the hetero targets. The AZO films deposited on the glass, PEN, and PET substrates showed very low resistivities, of 5.0 × 10-4 Ω cm, 7.0 × 10-4 Ω cm, and 7.4 × 10-4 Ω cm, respectively. Further, the figure merit of the AZO film formed on the PEN substrate in the visible range (400-700 nm) was significantly higher than that of the AZO film on PET and similar to that of the AZO film on glass. Finally, the average transmittances of the films in the visible range (400-700 nm) were 83.16% (on glass), 76.3% (on PEN), and 78.16% (on PET).

  10. Luminescent down shifting effect of Ce-doped yttrium aluminum garnet thin films on solar cells

    International Nuclear Information System (INIS)

    Shao, Guojian; Lou, Chaogang; Kang, Jian; Zhang, Hao

    2015-01-01

    Ce-doped yttrium aluminum garnet (YAG:Ce) thin films as luminescent down shifting (LDS) materials are introduced into the module of crystalline silicon solar cells. The films are deposited by RF magnetron sputtering on the lower surface of the quartz glass. They convert ultraviolet and blue light into yellow light. Experiments show that the introduction of YAG:Ce films improves the conversion efficiency from 18.45% of the cells to 19.27% of the module. The increasing efficiency is attributed to LDS effect of YAG:Ce films and the reduced reflection of short wavelength photons. Two intentionally selected samples with similar reflectivities are used to evaluate roughly the effect of LDS alone on the solar cells, which leads to a relative increase by 2.68% in the conversion efficiency

  11. Oxygen reduction activity of N-doped carbon-based films prepared by pulsed laser deposition

    Science.gov (United States)

    Hakoda, Teruyuki; Yamamoto, Shunya; Kawaguchi, Kazuhiro; Yamaki, Tetsuya; Kobayashi, Tomohiro; Yoshikawa, Masahito

    2010-12-01

    Carbon-based films with nitrogen species on their surface were prepared on a glassy carbon (GC) substrate for application as a non-platinum cathode catalyst for polymer electrolyte fuel cells. Cobalt and carbon were deposited in the presence of N 2 gas using a pulsed laser deposition method and then the metal Co was removed by HCl-washing treatment. Oxygen reduction reaction (ORR) activity was electrochemically determined using a rotating disk electrode system in which the film samples on the GC substrate were replaceable. The ORR activity increased with the temperature of the GC substrate during deposition. A carbon-based film prepared at 600 °C in the presence of N 2 at 66.7 Pa showed the highest ORR activity among the tested samples (0.66 V vs. NHE). This film was composed of amorphous carbons doped with pyridine type nitrogen atoms on its surface.

  12. High-mobility transparent conductive thin films of cerium-doped hydrogenated indium oxide

    Science.gov (United States)

    Kobayashi, Eiji; Watabe, Yoshimi; Yamamoto, Tetsuya

    2015-01-01

    We have developed 100-nm-thick cerium-doped hydrogenated indium oxide (ICO:H) films with a superior Hall mobility of 130-145 cm2 V-1 s-1. The ICO:H films deposited at 150 °C by dc arc-discharge ion plating were post-annealed at 200 °C. The relationship between the Hall mobility and carrier density of the polycrystalline ICO:H films shows that the carrier transport is limited by an ionized impurity scattering mechanism inside the grains. The surfaces of the ICO:H films were found to be very smooth and clear grain-boundary areas were not observed.

  13. Characterization of photoluminescent europium doped yttrium oxide thin-films prepared by metallorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A.; Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M.

    1998-01-01

    Europium doped yttrium oxide, (Y 1-x Eu x ) 2 O 3 , thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y 2 O 3 , grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y 2 O 3 :Eu 3+ was observed in x-ray diffraction for deposition temperatures ≥600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra

  14. GALVANIC MAGNETIC PROPERTIES OF BISMUTH THIN FILMS DOPED WITH TELLURIUM MADE BY THERMAL VACUUM EVAPORATION

    Directory of Open Access Journals (Sweden)

    V. A. Komarov

    2013-01-01

    Full Text Available The influence of n-type impurity of tellurium (concentration range from 0.005 atomic % Te to 0.15 atomic % Te on galvanic magnetic properties (resistivity, magnetic resistance and Hall constant of Bi thin films with various thicknesses was studied. The properties were measured in temperature range from 77 to 300 K. It was established that the classical size effect in the films is significant and decreases with higher concentration of Te impurity. The analysis of experimental results was carried out in approximation of the law of Jones-Schoenberg dispersion for Bi films doped with tellurium. Calculation of concentration and mobility of charge carriers in the studied films was made.

  15. Participation of the Third Order Optical Nonlinearities in Nanostructured Silver Doped Zinc Oxide Thin Solid Films

    Directory of Open Access Journals (Sweden)

    C. Torres-Torres

    2012-01-01

    Full Text Available We report the transmittance modulation of optical signals in a nanocomposite integrated by two different silver doped zinc oxide thin solid films. An ultrasonic spray pyrolysis approach was employed for the preparation of the samples. Measurements of the third-order nonlinear optical response at a nonresonant 532 nm wavelength of excitation were performed using a vectorial two-wave mixing. It seems that the separated contribution of the optical nonlinearity associated with each film noticeable differs in the resulting nonlinear effects with respect to the additive response exhibited by the bilayer system. An enhancement of the optical Kerr nonlinearity is predicted for prime number arrays of the studied nanoclusters in a two-wave interaction. We consider that the nanostructured morphology of the thin solid films originates a strong modification of the third-order optical phenomena exhibited by multilayer films based on zinc oxide.

  16. Sn Doped In2S3 Films Elaborated by Spray Technique

    Directory of Open Access Journals (Sweden)

    M. KRAINI

    2014-05-01

    Full Text Available Tin doped In2S3 films were grown by the chemical spray pyrolysis (CSP method using the pneumatic spray set-up and compressed air as a carrier gas. The spraying solution contained indium chloride (InCl3, thiourea [CS(NH22] and (SnCl4 at a molar ratio of S/In = 2.5. The deposition was carried out at 350 °C on glass substrates. The Sn doping level was changed with Sn/In = 0-8 % in solution. The effect of Sn concentration on electrical, optical and structural properties of In2S3:Sn thin films have been investigated.

  17. Metal Oxides Doped PPY-PVA Blend Thin Films Based Gas Sensor

    Directory of Open Access Journals (Sweden)

    D. B. DUPARE

    2009-02-01

    Full Text Available Synthesis of metal oxides doped polypyrrole–polyvinyl alcohol blend thin films by in situ chemical oxidative polymerization, using microwave oven on glass substrate for development of Ammonia and Trimethyl ammine hazardous gas sensor. The all experimental process carried out at room temperature(304 K. These polymer materials were characterized by Chemical analyses, spectral studies (UV-visible and IR and conductivity measurement by four –probe technique. The surface morphology as observed in the SEM image was observed to be uniformly covering the entire substrate surface. The sensor was used for different concentration (ppm of TMA and Ammonia gas investigation at room temperature (304 k. This study found to possess improved electrical, mechanical and environmental stability metal oxides doped PPY-PVA films.

  18. Chromium doped TiO2 sputtered thin films synthesis, physical investigations and applications

    CERN Document Server

    Hajjaji, Anouar; Gaidi, Mounir; Bessais, Brahim; El Khakani, My Ali

    2014-01-01

    This book presents co-sputtered processes ways to produce chrome doped TiO2 thin films onto various substrates such as quartz, silicon and porous silicon. Emphasis is given on the link between the experimental preparation and physical characterization in terms of Cr content. Moreover, the structural, optical and optoelectronic investigations are emphasized throughout. The book explores the potencial applications of devices based on Cr doped TiO2 thin films as gas sensors and in photocatalysis and in the photovoltaic industry. Also, this book provides extensive leads into research literature, and each chapter contains details which aim to develop awareness of the subject and the methods used. The content presented here will be useful for graduate students as well as researchers in materials science, physics, chemistry and engineering.

  19. Uniform fabrication of Ge nanocrystals embedded into SiO2 film via neutron transmutation doping

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2014-06-01

    Full Text Available Nanocrystalline 74Ge embedded SiO2 films were prepared by employing ion implantation and neutron transmutation doping methods. Transmission electron microscopy, energy dispersive x-ray spectroscopy, and photoluminescence of the obtained samples were measured. The existence of As dopants transmuted from 74Ge is significant to guarantee the uniformity and higher volume density of Ge nanocrystals by tuning the system׳s crystallinity and activating mass transfer process. It was observed that the photoluminescence intensity of Ge nanocrystals increased first then decreased with the increase of arsenic concentration. The optimized fluence of neutron transmutation doping was found to be 5.5×1017 cm−2 to achieve maximum photoluminescence emission in Ge embedded SiO2 film. This work opens a route in the three-dimensional nanofabrication of uniform Ge nanocrystals.

  20. 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 (

  1. Electrodeposition and characterization of undoped and nitrogen-doped ZnSe films

    International Nuclear Information System (INIS)

    Manzoli, A.; Eguiluz, K.I.B.; Salazar-Banda, G.R.; Machado, S.A.S.

    2010-01-01

    Semiconducting films of (n-type) ZnSe and (p-type) nitrogen-doped ZnSe were electrodeposited by a linear-sweep voltammetric technique on to a substrate of fluorine-tin oxide (FTO) glass ceramics. The films were characterized by scanning electron microscopy, energy-dispersive X-ray analysis and grazing-incidence X-ray diffraction. The results indicated that the material was deposited uniformly over the substrate, forming clusters when the Zn content of the bath was 0.1 mol L -1 and a film when it was 0.2 or 0.3 mol L -1 . The effectiveness of doping the films with nitrogen by adding ammonium sulfate to the deposition solution was assessed by measuring the film-electrolyte interface capacitance (C) at various applied potentials (E ap ) and plotting Mott-Schottky curves (C -2 vs E ap ), whose slope sign was used to identify p-type ZnSe.

  2. Doping-tunable thermal emission from plasmon polaritons in semiconductor epsilon-near-zero thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Young Chul [Inha Univ., Incheon (Korea, Republic of). Dept. of Physics; Luk, Ting S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies; Robert Ellis, A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klem, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brener, Igal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies

    2014-09-29

    Here, we utilize the unique dispersion properties of leaky plasmon polaritons in epsilon-near-zero (ENZ) thin films to demonstrate thermal radiation control. Owing to its highly flat dispersion above the light line, a thermally excited leaky wave at the ENZ frequency out-couples into free space without any scattering structures, resulting in a narrowband, wide-angle, p-polarized thermal emission spectrum. We demonstrate this idea by measuring angle- and polarization-resolved thermal emission spectra from a single layer of unpatterned, doped semiconductors with deep-subwavelength film thickness (d/λ0 ~ 6 ×10-3, where d is the film thickness and λ0 is the free space wavelength). We show that this semiconductor ENZ film effectively works as a leaky wave thermal radiation antenna, which generates far-field radiation from a thermally excited mode. The use of semiconductors makes the radiation frequency highly tunable by controlling doping densities and also facilitates device integration with other components. Therefore, this leaky plasmon polariton emission from semiconductor ENZ films provides an avenue for on-chip control of thermal radiation.

  3. On-line monitoring of CO2 quality using doped WO3 thin film sensors

    International Nuclear Information System (INIS)

    Stankova, M.; Vilanova, X.; Llobet, E.; Calderer, J.; Vinaixa, M.; Gracia, I.; Cane, C.; Correig, X.

    2006-01-01

    Thin films of either pure or doped tungsten oxide were grown by radiofrequency (rf) sputtering onto silicon micromachined substrates. Up to 7 different dopant materials (noble metals or metal oxides) were deposited by rf sputtering or by evaporation onto the tungsten oxide films. The responsiveness of the resulting micromachined sensors towards sulfur dioxide and hydrogen sulfide was studied. Other pollutants in CO 2 such as ethylene and methane were also tested. It was found that Au-doped tungsten oxide sensors were highly sensitive to H 2 S, poorly sensitive to SO 2 and almost insensitive to hydrocarbons. On the other hand, Pt-doped tungsten oxide was highly sensitive to SO 2 , poorly responsive to H 2 S and nearly insensitive to hydrocarbons. By applying a principal component analysis (PCA), we show that it would be possible to selectively detect traces of H 2 S and SO 2 in a CO 2 stream using doped WO 3 microsensors. These sensors could be used in a low-cost analyzer of beverage-grade CO 2

  4. Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

    KAUST Repository

    Han, Yang

    2018-03-13

    Molecular doping is an important strategy to improve the charge transport properties of organic semiconductors in various electronic devices. Compared to p-type dopants, the development of n-type dopants is especially challenging due to poor dopant stability against atmospheric conditions. In this article, we report the n-doping of the milestone naphthalenediimide-based conjugated polymer P(NDI2OD-T2) in organic thin film transistor devices by soluble anion dopants. The addition of the dopants resulted in the formation of stable radical anions in thin films, as confirmed by EPR spectroscopy. By tuning the dopant concentration via simple solution mixing, the transistor parameters could be readily controlled. Hence the contact resistance between the electrodes and the semiconducting polymer could be significantly reduced, which resulted in the transistor behaviour approaching the desirable gate voltage-independent model. Reduced hysteresis was also observed, thanks to the trap filling by the dopant. Under optimal doping concentrations the channel on-current was increased several fold whilst the on/off ratio was simultaneously increased by around one order of magnitude. Hence doping with soluble organic salts appears to be a promising route to improve the charge transport properties of n-type organic semiconductors.

  5. Suppression of vacancy defects in epitaxial La-doped SrTiO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Keeble, D. J.; Kanda, G. [Carnegie Laboratory of Physics, SUPA, School of Engineering, Physics, and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); Jalan, B.; Stemmer, S. [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Ravelli, L.; Egger, W. [Universitaet Bundeswehr Muenchen, D-85577 Neubiberg (Germany)

    2011-12-05

    Variable energy positron annihilation lifetime spectroscopy of high-mobility La-doped SrTiO{sub 3} grown by molecular beam epitaxy found that the films contained sufficiently low concentrations of Sr vacancies and vacancy cluster defects to allow the observation of positron annihilation events from the perfect lattice. This enabled the concentrations of charged cation vacancies to be estimated, and these were found to be at least an order of magnitude below the La-dopant concentrations.

  6. 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.

  7. 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.

  8. 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.

  9. Electronic properties of intrinsic and doped amorphous silicon carbide films

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, M. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain)]. E-mail: mvetter@eel.upc.edu; Voz, C. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain); Ferre, R. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain); Martin, I. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain); Orpella, A. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain); Puigdollers, J. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain); Andreu, J. [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, E-08028 Barcelona (Spain); Alcubilla, R. [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, Gran Capita s/n, Modul C4, E-08034 Barcelona (Spain)

    2006-07-26

    Hydrogenated amorphous silicon carbide (a-SiC{sub x} : H) films have shown excellent surface passivation of crystalline silicon. With the aim of large area deposition of these films the influence of the rf plasma power was investigated. It is found that homogenous deposition with effective surface recombination velocity lower than 100 cms{sup -1} is possible up to 6'' diameter in a simple parallel plate reactor by optimizing deposition parameters. For application in solar cell processes the conductivity of these a-SiC{sub x} : H films might become of importance since good surface passivation results from field-effect passivation which needs an insulating dielectric layer. Therefore, the temperature dependence of the dark dc conductivity of these films was investigated in the temperature range from - 20 to 260 deg. C. Two transition temperatures, T {sub s}{approx}80 deg. C and T {sub s}{approx}170 deg. C, were found where conductivity increases, resp. decreases over-exponential. From Arrhenius plots activation energy (E {sub a}) and conductivity pre-factor ({sigma} {sub 0}) were calculated for a large number of samples with different composition. A correlation between E {sub a} and {sigma} {sub 0} was found giving a Meyer-Neldel relation with a slope of 59 mV, corresponding to a material characteristic temperature T {sub m} = 400 deg. C, and an intercept at {sigma} {sub 00} = 0.1 {omega}{sup -1}cm{sup -1}.

  10. Metal nanoparticle-doped coloured films on glass and ...

    Indian Academy of Sciences (India)

    In a program on the development of metal (e.g. Au, Ag, Cu and their alloy) nanoparticles in sol{gel derived films, attempts were made to synthesize different coloured coatings on glasses and plastics. The absorption position of surface plasmon resonance (SPR) band arising from the embedded metal nanoparticles was ...

  11. Electronic properties of intrinsic and doped amorphous silicon carbide films

    International Nuclear Information System (INIS)

    Vetter, M.; Voz, C.; Ferre, R.; Martin, I.; Orpella, A.; Puigdollers, J.; Andreu, J.; Alcubilla, R.

    2006-01-01

    Hydrogenated amorphous silicon carbide (a-SiC x : H) films have shown excellent surface passivation of crystalline silicon. With the aim of large area deposition of these films the influence of the rf plasma power was investigated. It is found that homogenous deposition with effective surface recombination velocity lower than 100 cms -1 is possible up to 6'' diameter in a simple parallel plate reactor by optimizing deposition parameters. For application in solar cell processes the conductivity of these a-SiC x : H films might become of importance since good surface passivation results from field-effect passivation which needs an insulating dielectric layer. Therefore, the temperature dependence of the dark dc conductivity of these films was investigated in the temperature range from - 20 to 260 deg. C. Two transition temperatures, T s ∼80 deg. C and T s ∼170 deg. C, were found where conductivity increases, resp. decreases over-exponential. From Arrhenius plots activation energy (E a ) and conductivity pre-factor (σ 0 ) were calculated for a large number of samples with different composition. A correlation between E a and σ 0 was found giving a Meyer-Neldel relation with a slope of 59 mV, corresponding to a material characteristic temperature T m = 400 deg. C, and an intercept at σ 00 = 0.1 Ω -1 cm -1

  12. Rotational reorganization of doped cholesteric liquid crystalline films

    NARCIS (Netherlands)

    Eelkema, R.; M. Pollard, M.; Katsonis, N.; Vicario, J.; J. Broer, D.; Feringa, B.L.

    2006-01-01

    In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric

  13. Characterization and electrocatalytic application of silver modified polypyrrole electrodes

    Directory of Open Access Journals (Sweden)

    A. DEKANSKI

    2005-02-01

    Full Text Available Silver modified polypyrrole electrodeswere preparedwith the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS. The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electrochemical and spectroscopic examinations show that immersion of a polypyrrole electrode in a AgNO3 solution results in its modificationwith silver, which is deposited in the elemental state on the surface. The quantity of silver deposited depends not only on the immersion time but also on the thickness of the polymer film. A modified PPy/Ag electrode exhibits catalytic activity for the electrooxidation of CH2O in NaOH. In spite of the low quantity of silver, the activity of the electrode for this reaction is comparable to that of a polycrystalline silver electrode.

  14. Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

    Directory of Open Access Journals (Sweden)

    Wei Xun

    2017-07-01

    Full Text Available Based on first-principles calculations, the BaTiO3(BTO film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investigation can provide an alternative avenue in modification of surface property and surface screening effect in polar materials.

  15. Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

    Science.gov (United States)

    Xun, Wei; Hao, Xiang; Pan, Tao; Zhong, Jia-Lin; Ma, Chun-Lan; Hou, Fang; Wu, Yin-Zhong

    2017-07-01

    Based on first-principles calculations, the BaTiO3(BTO) film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investigation can provide an alternative avenue in modification of surface property and surface screening effect in polar materials.

  16. Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

    OpenAIRE

    Wei Xun; Xiang Hao; Tao Pan; Jia-Lin Zhong; Chun-Lan Ma; Fang Hou; Yin-Zhong Wu

    2017-01-01

    Based on first-principles calculations, the BaTiO3(BTO) film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investiga...

  17. Visible light carrier generation in co-doped epitaxial titanate films

    Energy Technology Data Exchange (ETDEWEB)

    Comes, Ryan B.; Smolin, Sergey Y.; Kaspar, Tiffany C.; Gao, Ran; Apgar, Brent A.; Martin, Lane W.; Bowden, Mark E.; Baxter, Jason; Chambers, Scott A.

    2015-03-02

    Perovskite titanates such as SrTiO3 (STO) exhibit a wide range of important functional properties, including high electron mobility, ferroelectricity—which may be valuable in photovoltaic applications—and excellent photocatalytic performance. The wide optical band gap of titanates limits their use in these applications, however, making them ill-suited for integration into solar energy harvesting technologies. Our recent work has shown that by doping STO with equal concentrations of La and Cr we can enhance visible light absorption in epitaxial thin films while avoiding any compensating defects. In this work, we explore the optical properties of photoexcited carriers in these films. Using spectroscopic ellipsometry, we show that the Cr3+ dopants, which produce electronic states immediately above the top of the O 2p valence band in STO reduce the direct band gap of the material from 3.75 eV to between 2.4 and 2.7 eV depending on doping levels. Transient reflectance measurements confirm that optically generated carriers have a recombination lifetime comparable to that of STO and are in agreement with the observations from ellipsometry. Finally, through photoelectrochemical yield measurements, we show that these co-doped films exhibit enhanced visible light photocatalysis when compared to pure STO.

  18. Visible light carrier generation in co-doped epitaxial titanate films

    Energy Technology Data Exchange (ETDEWEB)

    Comes, Ryan B., E-mail: ryan.comes@pnnl.gov; Kaspar, Tiffany C.; Chambers, Scott A. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States); Smolin, Sergey Y.; Baxter, Jason B. [Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Gao, Ran [Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, California 94720 (United States); Apgar, Brent A. [Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801 (United States); Martin, Lane W. [Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, California 94720 (United States); Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bowden, Mark E. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States)

    2015-03-02

    Perovskite titanates such as SrTiO{sub 3} (STO) exhibit a wide range of important functional properties, including ferroelectricity and excellent photocatalytic performance. The wide optical band gap of titanates limits their use in these applications; however, making them ill-suited for integration into solar energy harvesting technologies. Our recent work has shown that by doping STO with equal concentrations of La and Cr, we can enhance visible light absorption in epitaxial thin films while avoiding any compensating defects. In this work, we explore the optical properties of photoexcited carriers in these films. Using spectroscopic ellipsometry, we show that the Cr{sup 3+} dopants, which produce electronic states immediately above the top of the O 2p valence band in STO reduce the direct band gap of the material from 3.75 eV to 2.4–2.7 eV depending on doping levels. Transient reflectance spectroscopy measurements are in agreement with the observations from ellipsometry and confirm that optically generated carriers are present for longer than 2 ns. Finally, through photoelectrochemical methylene blue degradation measurements, we show that these co-doped films exhibit enhanced visible light photocatalysis when compared to pure STO.

  19. Air-stable n-type doping of graphene from overlying Si3N4 film

    International Nuclear Information System (INIS)

    Wang, Zegao; Li, Pingjian; Chen, Yuanfu; Liu, Jingbo; Qi, Fei; Tian, Hongjun; Zheng, Binjie; Zhou, Jinhao

    2014-01-01

    In this study, we report a facile method to obtain air-stable n-type graphene by plasma-enhanced chemical vapor depositing Si 3 N 4 film on the surface of graphene. We have demonstrated that the overlying Si 3 N 4 film can not only act as the penetration-barrier against H 2 O and O 2 adsorbed on the graphene surface, but also cause an effective n-type doping due to the amine groups at the interface of graphene/Si 3 N 4 . Furthermore, the studies reveal that the Dirac point of graphene can be modulated by the thickness of Si 3 N 4 film, which is due to competing effects of Si 3 N 4 -induced doping (n-type) and penetrating H 2 O (O 2 )-induced doping (p-type). We expect this method to be used for obtaining stable n-type graphene field-effect transistors in air, which will be widely used in graphene electronic devices.

  20. Nonlinear optical studies on 1,3-disubstituent chalcones doped polymer films

    Science.gov (United States)

    Poornesh, P.; Shettigar, Seetharam; Umesh, G.; Manjunatha, K. B.; Prakash Kamath, K.; Sarojini, B. K.; Narayana, B.

    2009-04-01

    We report the measurements of the third-order nonlinear optical properties of recently synthesized and characterized two different 1,3-disubstituent chalcones doped PMMA films, with the prospective of reaching a good compromise between processability and high nonlinear optical properties. The measurements were done using nanosecond Z-scan at 532 nm. The Z-scan spectra reveal a large negative nonlinear refraction coefficient n2 of the order 10 -11 esu and the molecular two photon absorption cross section is 10 -46 cm 4 s/photon. The doped films exhibit good optical power limiting property under nanosecond regime and the two photon absorption (TPA) is the dominating process leading to the nonlinear behavior. The improvement in the nonlinear properties has been observed when methylenedioxy group is replaced by dimethoxy group due to increase in conjugation length. The observed nonlinear parameters of chalcone derivatives doped PMMA film is comparable with stilbazolieum derivatives, a well-known class of optical materials for photonics and biophotonics applications, which suggests that, these moieties have potential for the application of all-optical limiting and switching devices.

  1. Optical, structural and photocatalysis properties of Cu-doped TiO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bensouici, F., E-mail: fbensouici@yahoo.fr [Department of Physics, URMPE Unite, UMBB University, 35000 Boumerdes (Algeria); Bououdina, M.; Dakhel, A.A. [Department of Physics, College of Science, University of Bahrain, PO Box 32038 (Bahrain); Tala-Ighil, R.; Tounane, M.; Iratni, A. [Department of Physics, URMPE Unite, UMBB University, 35000 Boumerdes (Algeria); Souier, T. [Department of Physics, College of Science, Sultan Qaboos University, PO Box 36 (Oman); Liu, S.; Cai, W. [Key laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Technology, Center for Environmental and Energy Nanomaterials, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2017-02-15

    Highlights: • A simple chemical route to obtain thin layers of Cu doped TiO{sub 2}. • Detailed structure analysis was carried out by Rietveld refinements. • Forming the CuO phase decreases the efficiency photocatalysis of TiO{sub 2}. - Abstract: Pure and Cu{sup +2} doped TiO{sub 2} thin films have been successfully deposited onto glass substrate by sol–gel dip-coating. The films were annealed at 450 °C for 1 h and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), UV–vis spectrophotometer and photocatalytic degradation of methylene blue. XRD confirmed the presence of two phases at higher Cu concentration; TiO{sub 2} anatase and CuO. AFM analysis showed that the surface roughness increases within increasing Cu content as well as the presence of large aggregates at higher Cu content. SEM observations confirmed the granular structure of the films, and EDX analysis revealed a low solubility limit (effective doping) of Cu into TiO{sub 2} lattice. It was found that the optical band gap energy decreases with increasing Cu content. At constant irradiation time, the photo-degradation of methylene blue rate decreased with increasing concentration of Cu{sup +2}.

  2. Influence of doping on the properties of vanadium oxide gel films

    Energy Technology Data Exchange (ETDEWEB)

    Pergament, A L; Velichko, A A; Berezina, O Ya; Kazakova, E L; Kuldin, N A; Artyukhin, D V [Physics and Technology Department, Petrozavodsk State University, Petrozavodsk 185910 (Russian Federation)], E-mail: aperg@psu.karelia.ru

    2008-10-22

    The effect of doping with H and W on the properties of V{sub 2}O{sub 5} and VO{sub 2} derived from V{sub 2}O{sub 5} gel has been studied. It is shown that the treatment of V{sub 2}O{sub 5} in low-temperature RF hydrogen plasma for 1-10 min leads to either hydration of vanadium pentoxide or its reduction (depending on the treatment conditions) to lower vanadium oxides. For some samples, which are subject to plasma treatment in the discharge active zone, a non-ordinary temperature dependence of resistance, with a maximum at T{approx}100 K, is observed. For W-doped VO{sub 2} films, it is shown that substitution of V{sup 4+} with W{sup 6+} results in a decrease of the temperature of the metal-insulator transition. Also, it has been shown that the doping of initial films with {approx}3 at.% of W reduces the statistical scatter in the threshold parameters of the switching devices with S-shaped I-V characteristics on the basis of V{sub 2}O{sub 5} gel films. (fast track communication)

  3. Exciting transition metal doped dilute magnetic thin films: MgO:Er and ZnO:Er

    Science.gov (United States)

    Ćakıcı, T.; Sarıtaş, S.; Muǧlu, G. Merhan; Yıldırım, M.

    2017-02-01

    Erbium doped MgO and doped ZnO thin films have reasonably important properties applications in spintronic devices. These films were synthesized on glass substrates by Chemical Spray Pyrolysis (CSP) method. In the literature there has been almost no report on preparation of MgO:Er dilute magnetic thin films by means of CSP. Because doped thin films show different magnetic behaviors, depending upon the type of magnetic material ions, concentration of them, synthesis route and experimental conditions, synthesized MgO:Er and ZnO:Er films were compared to thin film properties. Optical analyses of the synthesized thin films were examined spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Structural analysis of the thin films was examined by using XRD, Raman Analysis, FE-SEM, EDX and AFM techniques. Also, magnetic properties of the MgO:Er and ZnO:Er films were investigated by vibrating sample magnetometer (VSM) which show that diamagnetic behavior of the MgO:Er thin film and ferromagnetic (FM) behavior of the ZnO:Er film were is formed.

  4. Carbon and nitrogen co-doping self-assembled MoS{sub 2} multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoqin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Xu, Jiao; Chai, Liqiang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); He, Tengfei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Yu, Fucheng [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Wang, Peng, E-mail: pengwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2017-06-01

    Highlights: • Mo–S–C–N composite films were synthesized by using reactive magnetron sputtering. • A self-assembled multilayer structure with periodicity in the nanometer scale was formed in the composite film. • The hardness of Mo–S–C–N film deposited at optimized parameter reaches up to 9.76 GPa. • The wear rate of deposited Mo–S–C–N film both in vacuum and ambient atmosphere decreases dramatically. - Abstract: Mo–S–C–N composite films were prepared using reactive magnetron sputtering of graphite and MoS{sub 2} targets in argon and nitrogen atmospheres. The effects of carbon/nitrogen co-doping and carbon concentration on the composition, microstructure, mechanical and tribological properties of deposited films have been investigated by various characterization techniques. The results show that the deposited films comprise MoS{sub 2} nanocrystalline and amorphous carbon, and the incorporating nitrogen forms Mo-N and C–N chemical bonds. Increasing carbon concentration leads to the increase of sp{sup 2} carbon fraction in the films. Furthermore, the high-resolution transmission electron microscopy reveals that a self-assembled multilayer structure with periodicity in the nanometer scale is formed in the Mo–S–C–N film. Benefiting from the composite and self-assembled multilayer structures, the hardness of Mo–S–C–N film deposited at optimized parameter reaches up to 9.76 GPa, and corresponding friction experiment indicates that this composite films display low friction coefficient and high wear resistance both in vacuum and ambient air conditions.

  5. Different threshold and bipolar resistive switching mechanisms in reactively sputtered amorphous undoped and Cr-doped vanadium oxide thin films

    Science.gov (United States)

    Rupp, Jonathan A. J.; Querré, Madec; Kindsmüller, Andreas; Besland, Marie-Paule; Janod, Etienne; Dittmann, Regina; Waser, Rainer; Wouters, Dirk J.

    2018-01-01

    This study investigates resistive switching in amorphous undoped and Cr-doped vanadium oxide thin films synthesized by sputtering deposition at low oxygen partial pressure. Two different volatile threshold switching characteristics can occur as well as a non-volatile bipolar switching mechanism, depending on device stack symmetry and Cr-doping. The two threshold switching types are associated with different crystalline phases in the conduction filament created during an initial forming step. The first kind of threshold switching, observed for undoped vanadium oxide films, was, by its temperature dependence, proven to be associated with a thermally triggered insulator-to-metal transition in a crystalline VO2 phase, whereas the threshold switch observed in chromium doped films is stable up to 90 °C and shows characteristics of an electronically induced Mott transition. This different behaviour for undoped versus doped films has been attributed to an increased stability of V3+ due to the Cr3+ doping (as evidenced by X-ray photoelectron spectroscopy analysis), probably favouring the creation of a crystalline Cr-doped V2O3 phase (rather than a Cr-doped VO2 phase) during the energetic forming step. The symmetric Pt/a-(VCr)Ox/Pt device showing high temperature stable threshold switching may find interesting applications as a possible new selector device for resistive switching memory (ReRAM) crossbar arrays.

  6. Copper doped nickel ferrite nano-crystalline thin films: A potential gas sensor towards reducing gases

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Pratibha; Godbole, R.V.; Bhagwat, Sunita, E-mail: smb.agc@gmail.com

    2016-03-01

    NiFe{sub 2}O{sub 4} and (1 wt% and 3 wt%) Cu:NiFe{sub 2}O{sub 4} thin films have been fabricated using spray pyrolysis deposition technique at 350 °C and then sintered at 650 °C for 3 h. X-ray diffraction, SEM, EDAX, UV-VIS spectroscopy, SQUID VSM were carried out to investigate phase formation, microstructural and influence of Cu doping on magnetic properties of NiFe{sub 2}O{sub 4} thin films. The gas response towards various gases viz. ethanol, Liquid Petroleum Gas (LPG), methanol and hydrogen sulfide (H{sub 2}S) is investigated. The results of XRD revealed that all samples had shown the principal phase of nickel ferrite and the lattice parameter was found to vary from 8.294 Å to 8.314 Å on an incorporation of Cu, and the crystalline sizes were about 40–45 nm. The effect of Cu concentration on saturation magnetization and coercive force were studied. The maximum value of saturation magnetization calculated from hysteresis loop was 89.16 emu/g at room temperature and 96.88 emu/g at 50 K. Cu content on the film surface was found to be maximum for 1 wt% Cu:NiFe{sub 2}O{sub 4} thin film and this film showed an improved response towards all gases. Response of ethanol for NiFe{sub 2}O{sub 4} thin film was found to be higher as compared to all the other gases. The lowering of the optimum operating temperature is observed in 1 wt% Cu:NiFe{sub 2}O{sub 4} thin film with higher selectivity towards ethanol than other gases. All results indicated that the Cu doping in nickel ferrite thin films has a significant influence on the properties. - Highlights: • Cu:NiFe{sub 2}O{sub 4} thin films are synthesized by low cost spray pyrolysis technique. • Addition of Cu content improves magnetic properties. • Cu content on the surface of the film enhances the gas response. • NiFe{sub 2}O{sub 4} thin films exhibit predominant selectivity towards ethanol. • 1 wt% Cu:NiFe{sub 2}O{sub 4} film responses towards ethanol at lower optimum temperature.

  7. Structural, optical and magnetic properties of Mn diffusion-doped CdS thin films prepared by vacuum evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Aksu, S. [SoloPower, Inc., 5981 Optical Ct., San Jose, CA 95138 (United States); Bacaksiz, E., E-mail: eminb@ktu.edu.tr [Department of Physics, Karadeniz Technical University, 61080 Trabzon (Turkey); Parlak, M. [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Yilmaz, S.; Polat, I.; Altunbas, M. [Department of Physics, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuerksoy, M.; Topkaya, R. [Department of Physics, Gebze Institute of Technology, Gebze, 41400 Kocaeli (Turkey); Ozdogan, K. [Department of Physics, Yildiz Technical University, 34210 Istanbul (Turkey)

    2011-10-17

    Highlights: {yields} Cadmium sulphide thin films were deposited by vacuum evaporation. {yields} Elemental Mn was deposited onto CdS thin films by using electron beam evaporation and annealed under vacuum at different temperatures. {yields} Structural, optical and magnetic studies of Mn-doped CdS have been investigated. {yields} X-ray diffraction results showed that the undoped CdS film had a zinc-blende structure with a strong preferred orientation along the (1 1 1) direction. {yields} Magnetic measurements show that Mn-doped CdS thin films exhibit a ferromagnetism behavior at room temperature. - Abstract: The effect of Mn-doping on the vacuum deposited CdS thin films has been investigated by studying the changes in the structural, optical and magnetic properties of the films. A thin Mn layer evaporated on the CdS film surface served as the source layer for the diffusion doping. Doping was accomplished by annealing the CdS/Mn stack layers at the temperature range from 300 deg. C to 400 deg. C in step of 50 deg. C for 30 min under vacuum. The X-ray diffraction results showed that the undoped CdS film had a zinc-blende structure with a strong preferred orientation along the (1 1 1) direction. The incorporation of Mn did not cause any change in the texture but reduced the peak intensity and lead to a smaller crystallite size. Investigation of surface morphology using atomic force microscopy confirmed the decrease in the grain size with the Mn diffusion. In addition, a more uniform grain size distribution was observed in the doped films. X-ray photoelectron spectroscopy analysis showed that Mn atoms on the surface of the films were bounded to either sulphur or oxygen atoms. Auger electron spectroscopy of the diffusion-doped CdS sample at 350 deg. C indicated that the atomic Mn concentration was higher close to the surface region and Mn was distributed with a steadily decreasing profile through the bulk of the film with an average atomic concentration value around few

  8. Low-temperature preparation of rutile-type TiO2 thin films for optical coatings by aluminum doping

    Science.gov (United States)

    Ishii, Akihiro; Kobayashi, Kosei; Oikawa, Itaru; Kamegawa, Atsunori; Imura, Masaaki; Kanai, Toshimasa; Takamura, Hitoshi

    2017-08-01

    A rutile-type TiO2 thin film with a high refractive index (n), a low extinction coefficient (k) and small surface roughness (Ra) is required for use in a variety of optical coatings to improve the controllability of the reflection spectrum. In this study, Al-doped TiO2 thin films were prepared by pulsed laser deposition, and the effects of Al doping on their phases, optical properties, surface roughness and nanoscale microstructure, including Al distribution, were investigated. By doping 5 and 10 mol%Al, rutile-type TiO2 was successfully prepared under a PO2 of 0.5 Pa at 350-600 °C. The nanoscale phase separation in the Al-doped TiO2 thin films plays an important role in the formation of the rutile phase. The 10 mol%Al-doped rutile-type TiO2 thin film deposited at 350 °C showed excellent optical properties of n ≈ 3.05, k ≈ 0.01 (at λ = 400 nm) and negligible surface roughness, at Ra ≈ 0.8 nm. The advantages of the superior optical properties and small surface roughness of the 10 mol%Al-doped TiO2 thin film were confirmed by fabricating a ten-layered dielectric mirror.

  9. Metal-Doped Oxide Electrodes for Transparent Thin-Film Transistors Fabricated by Direct Co-Sputtering Method

    Science.gov (United States)

    Cheong, Woo-Seok; Shin, Jae-Heon; Byun, Chun-Won; Ryu, Minki; Hwang, Chi-Sun

    2009-04-01

    In this study, for the first time, Ag-doped SnO2 and Mo-doped ZnO films for transparent electrodes was explored by using a direct co-sputtering method in a non-oxidizing atmosphere, and successfully applied to source and drain electrodes of transparent thin-film transistors. Ag (˜4%)-doped SnO2 films has the low resistivity of 3.8 ×10-4 Ω cm, but the relatively low transmittance of ˜50%, after 300 °C for 1 h post-annealing in an O2 ambient. On the other hand, a shallow coating of Mo (2.3 nm) on Mo-doped ZnO electrode caused a hard-saturation behavior even at the low drain voltage (˜2 V), which can provide effective tools to current-driving devices, for example, active matrix-organic light emitting display (AM-OLED).

  10. Effects of Nb and Sr doping on crystal structure of epitaxial BaTiO3 thin films on MgO substrates

    International Nuclear Information System (INIS)

    Kim, Yongsam; Chen, Chunhua; Saiki, Atsushi; Wakiya, Naoki; Shinozaki, Kazuo; Mizutani, Nobuyasu

    2002-01-01

    Niobium (Nb) and strontium (Sr) doped barium titanate (BT) films were deposited by radio frequency (RF) magnetron sputtering with Nb and Sr doped BT ceramic targets, respectively. The effect of Nb and Sr doping on the crystal structure of epitaxial BaTiO 3 thin films on MgO substrates was investigated. The crystal structure of the films was examined using the reciprocal space mapping measurement. All the films exhibit a cube-on-cube relation with respect to the substrates. As the amount of doped Sr increased, both of the in-plane and out-of-plane lattice constants of Sr doped BT films slowly approached the BT bulk values. On the other hand, the lattice constants of Nb doped BT films were rapidly coming close to the bulk values. These indicated that the lattices of doped BT films were relaxed as the amount of doped elements increased. In addition, Nb doping had greater influence on the relaxation of the films than Sr doping for the same content of dopant. (author)

  11. Mn doped GaN thin films and nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Šofer, Z.; Sedmidubský, D.; Huber, Š.; Hejtmánek, Jiří; Macková, Anna; Fiala, R.

    2012-01-01

    Roč. 9, 8-9 (2012), s. 809-824 ISSN 1475-7435 R&D Projects: GA ČR GA104/09/0621 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10480505 Keywords : GaN nanoparticles * GaN thin films * manganese * transition metals * MOVPE * ion implantations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.087, year: 2012

  12. Characterization of molybdenum-doped indium oxide thin films by ...

    Indian Academy of Sciences (India)

    Rozati S M and Akesteh Sh 2008 Cryst. Res. Technol. 43 273. Rozati S M, Moradi S, Golshahi S, Martins R and Fortunato E 2009. Thin Solid Films 518 1279. Ryu H, Kang J, Han Y, Kim D, Park J J, Park W K and Yang M S. 2003 J. Electron. Mater. 23 919. Tahar R B H, Ban T, Ohya Y and Takahashi Y 1997 J. Appl. Phys.

  13. 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.

  14. Superconductivity in transparent zinc-doped In2O3 films having low carrier density

    Directory of Open Access Journals (Sweden)

    Kazumasa Makise, Nobuhito Kokubo, Satoshi Takada, Takashi Yamaguti, Syunsuke Ogura, Kazumasa Yamada, Bunjyu Shinozaki, Koki Yano, Kazuyoshi Inoue and Hiroaki Nakamura

    2008-01-01

    Full Text Available Thin polycrystalline zinc-doped indium oxide (In2O3–ZnO films were prepared by post-annealing amorphous films with various weight concentrations x of ZnO in the range 0≤x ≤0.06. We have studied the dependences of the resistivity ρ and Hall coefficient on temperature T and magnetic field H in the range 0.5≤T ≤300 K, H≤6 Tfor 350 nm films annealed in air. Films with 0≤x≤0.03 show the superconducting resistive transition. The transition temperature Tc is below 3.3 K and the carrier density n is about 1025–1026 m−3. The annealed In2O3–ZnO films were examined by transmission electron microscopy and x-ray diffraction analysis revealing that the crystallinity of the films depends on the annealing time. We studied the upper critical magnetic field Hc2 (T for the film with x = 0.01. From the slope of dHc2 /dT, we obtain the coherence length ξ (0 ≈ 10 nm at T = 0 K and a coefficient of electronic heat capacity that is small compared with those of other oxide materials.

  15. Properties of Nitrogen-Doped Zinc Telluride Films for Back Contact to Cadmium Telluride Photovoltaics

    Science.gov (United States)

    Shimpi, Tushar M.; Drayton, Jennifer; Swanson, Drew E.; Sampath, Walajabad S.

    2017-08-01

    Zinc telluride (ZnTe) films have been deposited onto uncoated glass superstrates by reactive radiofrequency (RF) sputtering with different amounts of nitrogen introduced into the process gas, and the structural and electronic transport properties of the resulting nitrogen-doped ZnTe (ZnTe:N) films characterized. Based on transmission and x-ray diffraction measurements, it was observed that the crystalline quality of the ZnTe:N films decreased with increasing nitrogen in the deposition process. The bulk carrier concentration of the ZnTe:N films determined from Hall-effect measurements showed a slight decrease at 4% nitrogen flow rate. The effect of ZnTe:N films as back contact to cadmium telluride (CdTe) solar cells was also investigated. ZnTe:N films were deposited before or after CdCl2 passivation on CdTe/CdS samples. Small-area devices were characterized for their electronic properties. Glancing-angle x-ray diffraction measurements and energy-dispersive spectroscopy analysis confirmed substantial loss of zinc from the samples where CdCl2 passivation was carried out after ZnTe:N film deposition.

  16. Incorporation mechanism for doping of metal ions into a passivating film at the lithium/thionyl chloride interface

    Science.gov (United States)

    Danilov, V. G.; Shikin, V. I.

    1993-05-01

    Effects of iron and titanium ions on corrosion processes of lithium in thionyl chloride electrolytes have been studied. Laws for the growth of the passivating film on the type and concentration of doped ions have been established, and equations for these are suggested. A stepwise mechanism of dopant incorporation into passivating film structure is presented.

  17. Incorporation mechanism for doping of metal ions into a passive film at the lithium/thionyl chloride interface

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, V.G. (Siberian Inst. of Tech., Krasnoyarsk (Russian Federation). Lab. of Electrochemistry); Shilkin, V.I. (Siberian Inst. of Tech., Krasnoyarsk (Russian Federation). Lab. of Electrochemistry)

    1993-05-01

    Effects of iron and titanium ions on corrosion processes of lithium in thionyl chloride electrolytes have been studied. Laws for the growth of the passivating film on the type and concentration of doped ions have been established, and equations for these are suggested. A stepwise mechanism of dopant incorporation into passivating film structure is presented. (orig.)

  18. Microstructure and magnetism of sol–gel synthesized Co-doped PbPdO{sub 2} nanograin film

    Energy Technology Data Exchange (ETDEWEB)

    Song, T.T.; Tang, F.L. [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Su, H.L., E-mail: hailinsu@hfut.edu.cn [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Chuang, P.Y. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Liu, J.; Mei, C. [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China); Huang, S.Y. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Lee, M.K. [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); MoST Instrument Center at NCKU, Tainan 70101, Taiwan (China); Huang, J.C.A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (China); Wu, Y.C., E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering and Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei 230009 (China)

    2016-06-01

    The single-phase body-centered-orthorhombic-structured Co-doped PbPdO{sub 2} thin film was obtained using the sol–gel spin-coating method and an oxidation treatment. The film had a nanograin microstructure with an average grain size of about 56 nm and a thickness of about 150 nm. The adoption of a moderate calcination temperature of 650 °C was found to be very important for preparing the single-phase-PbPdO{sub 2}-based film with a high crystalline quality. The magnetic studies exhibited that the ferromagnetism and the paramagnetism coexist within the formed Co-doped PbPdO{sub 2} film and the ferromagnetism can be maintained above room temperature. The saturation magnetization of the ferromagnetism increasing with the temperature, as the peculiar characteristic of the spin gapless semiconductor, was found within the film. The investigation on the film's X-ray absorption near-edge structure revealed that the ferromagnetism of the Co-doped PbPdO{sub 2} is intrinsic. - Highlights: • High-quality single-phase body-centered-orthorhombic-structured Co-doped PbPdO{sub 2} nanograin film was synthesized by the sol–gel spin-coating method and an oxidation treatment. • The magnetic constitution of Co-doped PbPdO{sub 2} nanograin film was clarified. • The saturation magnetization of the ferromagnetism increasing with the temperature, as the peculiar characteristic of the spin gapless semiconductor, was found within the Co-doped PbPdO{sub 2} nanograin film. • The obtained ferromagnetism can be retained to high temperature and was demonstrated to be intrinsic.

  19. Electrodeposition of gold nanoclusters on overoxidized polypyrrole film modified glassy carbon electrode and its application for the simultaneous determination of epinephrine and uric acid under coexistence of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li Jing [Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China); Lin Xiangqin [Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China)]. E-mail: xqlin@ustc.edu.cn

    2007-07-23

    A novel biosensor was fabricated by electrochemical deposition of gold nanoclusters on ultrathin overoxidized polypyrrole (PPyox) film, formed a nano-Au/PPyox composite on glassy carbon electrode (nano-Au/PPyox/GCE). The properties of the nanocomposite have been characterized by field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD) and electrochemical investigations. The nano-Au/PPyox/GCE had strongly catalytic activity toward the oxidation of epinephrine (EP), uric acid (UA) and ascorbic acid (AA), and resolved the overlapping voltammetric response of EP, UA and AA into three well-defined peaks with a large anodic peak difference. The catalytic peak currents obtained from differential pulse voltammetry increased linearly with increasing EP and UA concentrations in the range of 3.0 x 10{sup -7} to 2.1 x 10{sup -5} M and 5.0 x 10{sup -8} to 2.8 x 10{sup -5} M with a detection limit of 3.0 x 10{sup -8} and 1.2 x 10{sup -8} M (s/n = 3), respectively. The results showed that the modified electrode can selectively determine EP and UA in the coexistence of a large amount of AA. In addition, the sensor exhibited excellent sensitivity, selectivity and stability. The nano-Au/PPyox/GCE has been applied to determination of EP in epinephrine hydrochloride injection and UA in urine samples with satisfactory results.

  20. Electrochemically Controlled Ion-exchange Property of Carbon Nanotubes/Polypyrrole Nanocomposite in Various Electrolyte Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Daiwon [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Lin, Yuehe [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States

    2016-09-15

    The electrochemically controlled ion-exchange properties of multi-wall carbon nanotube (MWNT)/electronically conductive polypyrrole (PPy) polymer composite in the various electrolyte solutions have been investigated. The ion-exchange behavior, rate and capacity of the electrochemically deposited polypyrrole with and without carbon nanotube (CNT) were compared and characterized using cyclic voltammetry (CV), chronoamperometry (CA), electrochemical quartz crystal microbalance (EQCM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that the presence of carbon nanotube backbone resulted in improvement in ion-exchange rate, stability of polypyrrole, and higher anion loading capacity per PPy due to higher surface area, electronic conductivity, porous structure of thin film, and thinner film thickness providing shorter diffusion path. Chronoamperometric studies show that electrically switched anion exchange could be completed more than 10 times faster than pure PPy thin film. The anion selectivity of CNT/PPy film is demonstrated using X-ray photoelectron spectroscopy (XPS).

  1. Heavily-doped ZnO:Al thin films prepared by using magnetron Co-sputtering: Optical and electrical properties

    Science.gov (United States)

    Moon, Eun-A.; Jun, Young-Kil; Kim, Nam-Hoon; Lee, Woo-Sun

    2016-07-01

    Photovoltaic applications require transparent conducting-oxide (TCO) thin films with high optical transmittance in the visible spectral region (380 - 780 nm), low resistivity, and high thermal/chemical stability. The ZnO thin film is one of the most common alternatives to the conventional indium-tin-oxide (ITO) thin film TCO. Highly transparent and conductive ZnO thin films can be prepared by doping with group III elements. Heavily-doped ZnO:Al (AZO) thin films were prepared by using the RF magnetron co-sputtering method with ZnO and Al targets to obtain better characteristics at a low cost. The RF sputtering power to each target was varied to control the doping concentration in fixed-thickness AZO thin films. The crystal structures of the AZO thin films were analyzed by using X-ray diffraction. The morphological microstructure was observed by using scanning electron microscopy. The optical transmittance and the band gap energy of the AZO thin films were examined with an UV-visible spectrophotometer in the range of 300 - 1800 nm. The resistivity and the carrier concentration were examined by using a Hall-effect measurement system. An excellent optical transmittance > 80% with an appropriate band gap energy (3.26 - 3.27 eV) and an improved resistivity (~10 -1 Ω·cm) with high carrier concentration (1017 - 1019 cm -3) were demonstrated in 350-nm-thick AZO thin films for thin-film photovoltaic applications.

  2. Tribochemical interactions of Si-doped DLC film against steel in sliding contact

    International Nuclear Information System (INIS)

    Yoon, Eui Sung; Pham, Duc Cuong; Ahn, Hyo Sok; Oh, Jae Eung

    2007-01-01

    This study concerns the effects of tribochemical interactions at the interface of Si-DLC (silicon-doped diamond-like carbon) film and steel ball in sliding contact on tribological properties of the film. The Si-DLC film was over-coated on pure DLC coating by radio frequency plasma-assisted chemical vapor deposition (r.f. PACVD) with different Si concentration. Friction tests against steel ball using a reciprocating type tribotester were performed in ambient environment. X-Ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES) were used to study the chemical characteristics and elemental composition of the films and mating balls after tests. Results showed a darkgray film consisting of carbon, oxygen and silicon on the worn steel ball surface with different thickness. On the contrary, such film was not observed on the surface of the ball slid against pure DLC coating. The oxidation of Si-DLC surface and steel ball was also found at particular regions of contact area. This demonstrates that tribochemical interactions occurred at the contact area of Si-DLC and steel ball during sliding to form a tribofilm (so called transfer film) on the ball specimen. While the pure DLC coating exhibited high coefficient of friction (∼0.06), the Si-DLC film showed a significant lower coefficient of friction (∼0.022) with the presence of tribofilm on mating ball surface. However, the Si-DLC film possesses a very high wear rate in comparison with the pure DLC. It was found that the tribochemical interactions strongly affected tribological properties of the Si-DLC film in sliding against steel

  3. On the doping problem of CdTe films: The bismuth case

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Galan, O. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Brown, M. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Ruiz, C.M. [Depto. Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Vidal-Borbolla, M.A. [Instituto de Investigacion en Comunicacion Optica, Av. Karakorum 1470, Lomas 4a. Secc., 78210 San Luis Potosi, SLP (Mexico); Ramirez-Bon, R. [CINVESTAV-IPN, U. Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Santiago de Queretaro, Qro. (Mexico); Sanchez-Meza, E. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Tufino-Velazquez, M. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)], E-mail: mtufinovel@yahoo.com.mx; Calixto, M. Estela [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico); Compaan, A.D. [Department of Physics and Astronomy, The University of Toledo, 43606 Toledo, OH (United States); Contreras-Puente, G. [Escuela Superior de Fisica y Matematicas del IPN, Edif. 9, UPALM, 07738 Mexico, D. F. (Mexico)

    2008-08-30

    The controlled increase of hole concentration is an important issue and still an unsolved problem for polycrystalline CdTe-based solar cells. The typical hole concentration of as-grown CdTe thin-films goes up to 10{sup 13} cm{sup -3}, depending on the specific growth technique. The highest electron concentration obtained for CdS, the suitable window partner material of CdTe, is around 10{sup 15} cm{sup -3}. Thus, the PV-performance of a CdS/CdTe device can be optimized if the hole concentration in CdTe is increased. We have faced up this problem by studying the electrical properties of two types of CdTe films: CdTe films grown by Close Space Vapor Transport using a CdTe:Bi powder as the starting material and CdTe sputtered films doped by implantation with different Bi-doses. Temperature-dependent resistivity and Hall effect measurements and a discussion on the efficiency of both doping processes are presented.

  4. On the doping problem of CdTe films: The bismuth case

    International Nuclear Information System (INIS)

    Vigil-Galan, O.; Brown, M.; Ruiz, C.M.; Vidal-Borbolla, M.A.; Ramirez-Bon, R.; Sanchez-Meza, E.; Tufino-Velazquez, M.; Calixto, M. Estela; Compaan, A.D.; Contreras-Puente, G.

    2008-01-01

    The controlled increase of hole concentration is an important issue and still an unsolved problem for polycrystalline CdTe-based solar cells. The typical hole concentration of as-grown CdTe thin-films goes up to 10 13 cm -3 , depending on the specific growth technique. The highest electron concentration obtained for CdS, the suitable window partner material of CdTe, is around 10 15 cm -3 . Thus, the PV-performance of a CdS/CdTe device can be optimized if the hole concentration in CdTe is increased. We have faced up this problem by studying the electrical properties of two types of CdTe films: CdTe films grown by Close Space Vapor Transport using a CdTe:Bi powder as the starting material and CdTe sputtered films doped by implantation with different Bi-doses. Temperature-dependent resistivity and Hall effect measurements and a discussion on the efficiency of both doping processes are presented

  5. High-Quality Fe-doped TiO2 films with Superior Visible-Light Performance

    DEFF Research Database (Denmark)

    Su, Ren; Bechstein, Ralf; Kibsgaard, Jakob

    2012-01-01

    We report on high-quality polycrystalline Fe-doped TiO2 (Fe–TiO2) porous films synthesized via one-step electrochemical oxidation. We demonstrate that delicate properties such as the impurity concentration and the microstructure that strongly influence the performance of the material...... for photovoltaic and photocatalysis applications can be controlled by adjusting the electrolyte composition. Compared to Fe-doped TiO2 films prepared with traditional phosphate- or silicate-based electrolytes, our newly synthesised Fe–TiO2 films contain solely Fe dopants, which results in excellent photocatalytic...... and photovoltaic performance under visible light irradiation....

  6. Electrochemical Study of Unmodified and Inhibitor Doped Silane Films for Corrosion Protection of AA2024-T3

    Science.gov (United States)

    Mubarak, Nauman; Hu, Jin; Tang, Shawei

    2017-09-01

    Aluminum alloy was coated with unmodified and rare-earth inhibitor doped silane films. The role of number of hydrolysable groups, functional group and cerium ions towards film protective quality was investigated. The anti-corrosion performance was evaluated using electrochemical impedance spectroscopy (EIS), d.c. potentiodynamic polarization and energy dispersive x-ray spectroscopy (EDS). The morphology was studied using scanning electron microscopy (SEM). Results indicate improved corrosion protection performance especially for cerium modified silane films with higher number of hydrolysable groups. Inhibitor doped silanes present a facile method for pre-treatment of aluminium alloys prior to deposition of top coat.

  7. 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.

  8. Resistivity Effects of Cation Ordering in Highly-Doped La2-xSrxCu4 Epitaxial Thin Films

    Science.gov (United States)

    Burquest, Franklin; Marmol, Rodrigo; Cox, Nicholas; Nelson-Cheeseman, Brittany

    Highly-doped La2-xSrxCuO4 (LSCO) films (0.5 causes internal polar electrostatic forces, which have been shown to cause stretching of the apical oxygen bond in analogous epitaxial nickelate films. Thin film samples are grown concurrently to minimize extraneous effects on film structure and properties. Atomic force microscopy and x-ray reflectivity demonstrate that the films are single crystalline, epitaxial, and smooth. X-ray diffraction is used to measure the c-axis of the films as a function of doping and dopant cation ordering. Electrical transport data of the ordered samples is compared with transport data of conventional disordered cation samples. Preliminary data indicates significant differences in resistivity at both 300K and 10K between the cation-ordered and cation-disordered samples. This work indicates that dopant cation ordering within the layered cuprates could significantly modify the conduction mechanisms at play in these materials.

  9. Fabrication of p-type conductivity in SnO{sub 2} thin films through Ga doping

    Energy Technology Data Exchange (ETDEWEB)

    Tsay, Chien-Yie, E-mail: cytsay@fcu.edu.tw; Liang, Shan-Chien

    2015-02-15

    Highlights: • P-type Ga-doped SnO{sub 2} semiconductor films were prepared by sol-gel spin coating. • Optical bandgaps of the SnO{sub 2}:Ga films are narrower than that of the SnO{sub 2} film. • SnO{sub 2}:Ga films exhibited p-type conductivity as Ga doping content higher than 10%. • A p-n heterojunction composed of p-type SnO{sub 2}:Ga and n-type ZnO:Al was fabricated. - Abstract: P-type transparent tin oxide (SnO{sub 2}) based semiconductor thin films were deposited onto alkali-free glass substrates by a sol-gel spin-coating method using gallium (Ga) as acceptor dopant. In this study, we investigated the influence of Ga doping concentration ([Ga]/[Sn] + [Ga] = 0%, 5%, 10%, 15%, and 20%) on the structural, optical and electrical properties of SnO{sub 2} thin films. XRD analysis results showed that dried Ga-doped SnO{sub 2} (SnO{sub 2}:Ga) sol-gel films annealed in oxygen ambient at 520 °C for 1 h exhibited only the tetragonal rutile phase. The average optical transmittance of as-prepared thin film samples was higher than 87.0% in the visible light region; the optical band gap energy slightly decreased from 3.92 eV to 3.83 eV with increases in Ga doping content. Hall effect measurement showed that the nature of conductivity of SnO{sub 2}:Ga thin films changed from n-type to p-type when the Ga doping level was 10%, and when it was at 15%, Ga-doped SnO{sub 2} thin films exhibited the highest mean hole concentration of 1.70 × 10{sup 18} cm{sup -3}. Furthermore, a transparent p-SnO{sub 2}:Ga (Ga doping level of 15%)/n-ZnO:Al (Al doping level of 2%) heterojunction was fabricated on alkali-free glass. The I-V curve measurement for the p-n heterojunction diode showed a typical rectifying characteristic with a forward turn-on voltage of 0.65 V.

  10. Photoactive thin films of polycaprolactam doped with europium (III) complex using phenylalanine as ligand

    Energy Technology Data Exchange (ETDEWEB)

    Santos Garcia, Irene Teresinha, E-mail: irene@iq.ufrgs.br [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil); Velleda Ribeiro, Patricia; Silva Correa, Diogo; Neto da Cunha, Igor Michel; Lenin Villarreal Carreno, Neftali [Instituto de Quimica e Geociencias, Universidade Federal de Pelotas, Campus Capao do Leao, s/n. CEP 96010-900, Pelotas, RS (Brazil); Ceretta Moreira, Eduardo [PPGEE, Universidade Federal do Pampa, Campus Bage, Bage- RS (Brazil); Severo Rodembusch, Fabiano [Departamento de Quimica Organica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil)

    2011-12-01

    A photoactive complex based on europium(III) using the amino acid phenylalanine as ligand was prepared and characterized. The obtained europium(III)/phenylalanine complex presents an effective energy transfer from ligands to the rare earth center. The observed photoluminescent behavior for europium(III)/phenylalanine complex was similar to the well known europium(III)/ acetyl-{beta}-acetonate hydrate. New photoactive polyamide thin films were prepared using polycaprolactam as host of these complexes. The structural characterizations of the films were studied through Rutherford backscattering (RBS), Fourier transform infrared (FTIR) and Raman spectroscopies. The polyamide films doped with the amino acid and acetyl-{beta}-acetonate rare earth complexes maintain the original photoluminescent behavior, narrow emission bands corresponding to transitions {sup 5}D{sub 0} {yields} {sup 7}F{sub 0-4}, which indicates that this polymer is an excellent host to these complexes.

  11. OSL and TL dosimeter characterization of boron doped CVD diamond films

    Science.gov (United States)

    Gonçalves, J. A. N.; Sandonato, G. M.; Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; De la Rosa, E.; Rodríguez, R. A.; Salas, P.; Barboza-Flores, M.

    2005-04-01

    Natural diamond is an exceptional prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality CVD diamond has renewed the interest in using diamond films as radiation dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by the HFCVD method. The thermoluminescence and the optically stimulated luminescence of beta exposed diamond sample containing a B/C 4000 ppm doping presents excellent properties suitable for dosimetric applications with β-ray doses up to 3.0 kGy. The observed OSL and TL performance is reasonable appropriate to justify further investigation of diamond films as dosimeters for ionizing radiation, specially in the radiotherapy field where very well localized and in vivo and real time radiation dose applications are essential.

  12. Defects in heavily phosphorus-doped Si epitaxial films probed by monoenergetic positron beams

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Suzuki, Ryoichi; Ohgaki, Hideaki; Mikado, Tomohisa.

    1994-01-01

    Vacancy-type defects in heavily phosphorus-doped Si epitaxial films were probed by monoenergetic positron beams. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured for the epitaxial films grown on the Si substrates by plasma chemical vapor deposition. For the as-deposited film, divacancy-phosphorus complexes were found with high concentration. After 600degC annealing, vacancy clusters were formed near the Si/Si interface, while no drastic change in the depth distribution of the divacancy-phosphorus complexes was observed. By 900degC annealing, the vacancy clusters were annealed out; however, the average number of phosphorus atoms coupled with divacancies increased. The relationship between the vacancy-type defects probed by the positron annihilation technique and the carrier concentration was confirmed. (author)

  13. Defects in heavily phosphorus-doped Si epitaxial films probed by monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Suzuki, Ryoichi; Ohgaki, Hideaki; Mikado, Tomohisa

    1994-11-01

    Vacancy-type defects in heavily phosphorus-doped Si epitaxial films were probed by monoenergetic positron beams. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured for the epitaxial films grown on the Si substrates by plasma chemical vapor deposition. For the as-deposited film, divacancy-phosphorus complexes were found with high concentration. After 600degC annealing, vacancy clusters were formed near the Si/Si interface, while no drastic change in the depth distribution of the divacancy-phosphorus complexes was observed. By 900degC annealing, the vacancy clusters were annealed out; however, the average number of phosphorus atoms coupled with divacancies increased. The relationship between the vacancy-type defects probed by the positron annihilation technique and the carrier concentration was confirmed. (author).

  14. Dual acceptor doping and aging effect of p-ZnO:(Na, N) nanorod thin films by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Swapna, R., E-mail: swapna.ramella@yahoo.com, E-mail: santhoshmc@nitt.edu; Amiruddin, R., E-mail: swapna.ramella@yahoo.com, E-mail: santhoshmc@nitt.edu; Santhosh Kumar, M. C., E-mail: swapna.ramella@yahoo.com, E-mail: santhoshmc@nitt.edu [Advanced Materials Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli-620 015 (India)

    2014-01-28

    An attempt has been made to realize p-type ZnO by dual acceptor doping (Na-N) into ZnO thin films. Na and N doped ZnO thin films of different concentrations (0 to 8 at.%) have been grown by spray pyrolysis at 623 K. The grown films on glass substrate have been characterized by X-ray diffraction (XRD), Hall measurement, UV-Vis spectrophotometer, Photoluminescence (PL) and Energy dispersive spectroscopy (EDS) to validate the p-type conduction. The surface morphology and roughness of the ZnO:(Na, N) films are studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Hall measurement shows that all the films exhibit p-type conductivity except for 0 at.% Na-N doped ZnO film. The obtained resistivity (5.60×10{sup −2} Ω cm) and hole concentration (3.15×10{sup 18} cm{sup −3}) for the best dual acceptor doped film is 6 at.%. It has been predicted that (Na{sub Zn}−N{sub O}) acceptor complex is responsible for the p-type conduction. The p-type conductivity of the ZnO:(Na, N) films is stable even after 6 months. The crystallinity of the films has been studied by XRD. Energy dispersive spectroscopy (EDS) confirms the presence of Na and N in 6 at.% ZnO:(Na, N) film. Photoluminescence (PL) spectra of ZnO:(Na, N) films show NBE and deep level emissions in the UV and visible regions, respectively. The ZnO:(Na, N) films exhibit a high transmittance about 90% in the visible region.

  15. Zinc oxide doped graphene oxide films for gas sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Chetna,, E-mail: chetna2288@gmail.com; Kumar, Shani; Chaudhary, S.; Kapoor, A. [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India); Garg, A.; Chowdhuri, A.; Dhingra, V. [Department of Electronic Science, Acharya Narendra Dev College, University of Delhi, Kalkaji, New Delhi- 110019 (India)

    2016-05-06

    Graphene Oxide (GO) is analogous to graphene, but presence of many functional groups makes its physical and chemical properties essentially different from those of graphene. GO is found to be a promising material for low cost fabrication of highly versatile and environment friendly gas sensors. Selectivity, reversibility and sensitivity of GO based gas sensor have been improved by hybridization with Zinc Oxide nanoparticles. The device is fabricated by spin coating of deionized water dispersed GO flakes (synthesized using traditional hummer’s method) doped with Zinc Oxide on standard glass substrate. Since GO is an insulator and functional groups on GO nanosheets play vital role in adsorbing gas molecules, it is being used as an adsorber. Additionally, on being exposed to certain gases the electric and optical characteristics of GO material exhibit an alteration in behavior. For the conductivity, we use Zinc Oxide, as it displays a high sensitivity towards conduction. The effects of the compositions, structural defects and morphologies of graphene based sensing layers and the configurations of sensing devices on the performances of gas sensors were investigated by Raman Spectroscopy, X-ray diffraction(XRD) and Keithley Sourcemeter.

  16. Boron Doped Nanocrystalline Diamond Films for Biosensing Applications

    Directory of Open Access Journals (Sweden)

    V. Petrák

    2011-01-01

    Full Text Available With the rise of antibiotic resistance of pathogenic bacteria there is an increased demand for monitoring the functionality of bacteria membranes, the disruption of which can be induced by peptide-lipid interactions. In this work we attempt to construct and disrupt supported lipid membranes (SLB on boron doped nanocrystalline diamond (B-NCD. Electrochemical Impedance Spectroscopy (EIS was used to study in situ changes related to lipid membrane formation and disruption by peptide-induced interactions. The observed impedance changes were minimal for oxidized B-NCD samples, but were still detectable in the low frequency part of the spectra. The sensitivity for the detection of membrane formation and disruption was significantly higher for hydrogenated B-NCD surfaces. Data modeling indicates large changes in the electrical charge when an electrical double layer is formed at the B-NCD/SLB interface, governed by ion absorption. By contrast, for oxidized B-NCD surfaces, these changes are negligible indicating little or no change in the surface band bending profile.

  17. Cathodoluminescence of Cr-doped diamond-like carbon film by filtered cathodic vacuum arc plasma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Meng-Wen; Jao, Jui-Yun [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Lin, Chun-Chun; Hsieh, Wei-Jen; Yang, Yu-Hsiang [Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300, Taiwan (China); Cheng, Li-Shin; Shieu, F.S. [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Shih, Han C., E-mail: hcshih@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300, Taiwan (China); Institute of Materials Science and Nanotechnology, Chinese Culture University, 55 Hwa Kang Road, Yang Ming Shan, Taipei 111, Taiwan (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The formation of the DLC:Cr films dependent on the flow rates of C{sub 2}H{sub 2}/Ar have been achieved in our FCVA plasma. Black-Right-Pointing-Pointer The amorphous DLC:Cr have high sp{sup 2} content can be completely converted to nanocrystalline Cr{sub 3}C{sub 2}. Black-Right-Pointing-Pointer The effect of doping with Cr is apparently to change the band structure of the DLC and its consequent cathodoluminescence property. - Abstract: Cr doped diamond-like carbon (DLC:Cr) film was synthesized in various flow rates of C{sub 2}H{sub 2}/Ar under a substrate voltage of -50 V at 500 Degree-Sign C by a filtered cathodic vacuum arc plasma. This work has found that the structure of the films was correlated to the flow rate of C{sub 2}H{sub 2}/Ar but the luminescence properties are similar. The cathodoluminescence spectra of DLC:Cr films obtained at 1.9-2.4 eV verifies that the luminescence from the films is in the visible region. The incorporation of Cr into the carbon network results in red emission shifted to 1.99 eV and the orange emission (2.03 eV) also appeared due to the transitions between chromium-related electron levels and {sigma}* states. The peak at 2.10 eV may result from the defects of the structures in DLC:Cr films.

  18. Solution processed Al doped ZnO film fabrication through electrohydrodynamic atomization

    International Nuclear Information System (INIS)

    Muhammad, Nauman Malik; Duraisamy, Navaneethan; Dang, Hyun-Woo; Jo, Jeongdai; Choi, Kyung-Hyun

    2012-01-01

    In this study, highly transparent, 250 nm thick films of Aluminum doped Zinc-oxide (ZnO:Al) are achieved on glass substrates at ambient conditions through a solution processing technique called electrohydrodynamic atomization. A 10 wt.% monodispersed solution containing 6% ZnO:Al nanoparticles (ZnO/Al 2 O 3 ) in ethanol has been synthesized first and then used in the deposition process as the working solution. Pure and uniform transparent films with an average transmittance of 93% have been deposited with crystal structure exhibiting both zincite and gahnite phases. Surface composition purity has been confirmed using X-ray photoelectron spectroscopy technique and the clear indication of Zn-2p and Al-2p peaks confirms surface integrity. Fourier Transform Infrared analysis further confirms the presence of aluminum in the samples. The electrical properties are studied by recording and analyzing the current–voltage (I–V) measurements and the resistivity has been estimated from the slope of the IV-curve which is approximately 25 mΩ.cm. The layer roughness has been characterized using atomic force microscopy. - Highlights: ►Aluminum doped Zinc oxide (ZnO:Al) films are made via electrohydrodynamic atomization. ►ZnO:Al nano-particle ink is used to form thin films in single step at room conditions. ►Scanning electron and atomic force microscopes confirm fine layer characteristics. ►X-ray photoelectron and Fourier Transform-Infrared spectroscope confirm film purity. ►Transparent and conductive films have been fabricated with wurtzite structure.

  19. Defect mediated reversible ferromagnetism in Co and Mn doped zinc oxide epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Mal, Siddhartha; Nori, Sudhakar; Narayan, J. [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Mula, Suhrit [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008 (India); Prater, J. T. [Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709 (United States)

    2012-12-01

    We have introduced defects in ZnO (undoped and doped with Co and Mn) epitaxial thin films using laser irradiation from nanosecond laser pulses and thermal annealing in oxygen ambient. In contrast to the as grown samples, the laser irradiated films show a significant increase in conductivity, enhancement in UV emission, while maintaining the same wurtzite crystal structure. Room-temperature ferromagnetism (RTFM) is observed in laser-irradiated samples, which increased with the number of laser pulses up to a certain value where magnetic moment saturates. The induced ferromagnetism as well as the enhanced electrical conductivity can be reversed with thermal annealing in oxygen ambient. The magnetization in Co and Mn doped films was found to be strong function of growth conditions and defect concentration. X-ray diffraction and optical absorption experiments suggested a 2+ valance state and tetrahedral coordination for both Co and Mn ions. There is a simultaneous increase in n-type electrical conductivity with the number of laser pulses and continue to exhibit semiconducting behavior in both undoped and doped films. The saturation magnetization was found to be 0.08 {mu}{sub B}/Co and 0.05 {mu}{sub B}/Mn, much lower than 3.0 {mu}{sub B}/Co and 5.0 {mu}{sub B}/Mn, indicating the prominent role of intrinsic defects in RTFM with some contribution from Co{sup 2+}-oxygen vacancy complexes. We propose a unified mechanism based upon introduction of intrinsic defects to explain RTFM and n-type conductivity enhancements during pulsed laser and thermal annealing.

  20. Phase Coexistence near a Morphotropic Phase Boundary in Sm-doped BiFeO3 Films

    Energy Technology Data Exchange (ETDEWEB)

    S Emery; C Cheng; D Kan; F Rueckert; S Alpay; V Nagarajan; I Takeuchi; B Wells

    2011-12-31

    We have investigated heteroepitaxial films of Sm-doped BiFeO{sub 3} with a Sm-concentration near a morphotropic phase boundary. Our high-resolution synchrotron x-ray diffraction, carried out in a temperature range of 25 to 700 C, reveals substantial phase coexistence as one changes temperature to crossover from a low-temperature PbZrO{sub 3}-like phase to a high-temperature orthorhombic phase. We also examine changes due to strain for films exhibiting anisotropic misfit between film and substrate. Additionally, thicker films exhibit a substantial volume collapse associated with the structural transition that is suppressed in thinner films.

  1. Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazir, Adnan, E-mail: adnan.nazir@iit.it [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Toma, Andrea [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Shah, Nazar Abbas [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Panaro, Simone [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Butt, Sajid [Department of Materials Science and Engineering, Institute of Space Technology (IST), Islamabad 44000 (Pakistan); School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Sagar, Rizwan ur Rehman [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Raja, Waseem [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Rasool, Kamran [Micro and Nano Devices Group, Department of Metallurgy and Materials Engineering Pakistan, Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 45650 (Pakistan); Maqsood, Asghari [Department of Physics, Air University, Islamabad (Pakistan)

    2014-10-01

    Highlights: • Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. • Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. • Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (50–70% transmission) in visible range and a highly resistive behavior (10{sup 6} Ω cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (10{sup 3} Ω cm) against a 20% cut in optical transmission.

  2. Synthesis of Ag doped SnO2 thin films for the evaluation of H2S gas sensing properties

    Science.gov (United States)

    Kolhe, Pankaj S.; Koinkar, Pankaj M.; Maiti, Namita; Sonawane, Kishor M.

    2017-11-01

    The Tin Oxide (SnO2) based thin films doped with 1.5, 3.0 and 4.5 mol% of Ag were deposited on the glass substrates using the advanced chemical spray pyrolysis technique. All the films were deposited at temperature 400 °C. The crystalline structure of the samples was analyzed by X-ray diffraction (XRD). All the XRD patterns of the films showed a well-defined polycrystalline phase, fitting well with the SnO2 tetragonal rutile type structure. The optical properties of the Ag doped SnO2 films were studied using UV-Visible absorption spectroscopy. The surface morphological analysis of as-synthesized Ag doped SnO2 films have been carried out using scanning electron microscope (SEM). The sensor response was estimated by the change in the electrical resistance of the film in the absence and presence of H2S gas. The sensor response and sensitivity in relation to, operation temperature and the gas concentration have been systematically studied. A significant response (∼ 1.38) and with a short response and recovery time (46 s, 110 s) towards 450 ppm H2S at 100 °C operating temperature is observed for the 3 mol% Ag-doped SnO2 film. This method offers a highly promising candidate for development of materials sensors due to facile fabrication route and desirable sensing performance.

  3. PHOTOCATALYTIC PROPERTIES OF Cr DOPED TiO2–SiO2 NANOSTRUCTURE THIN FILM

    Directory of Open Access Journals (Sweden)

    Akbar Eshaghi

    2012-07-01

    Full Text Available Cr doped TiO2–SiO2 nanostructure thin film on glass substrates was prepared by a sol-gel dip coating method. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and UV-vis spectrophotometer were used to characterize the structural, chemical and optical properties of the thin film. The XRD showed that thin films contain only anatase phase. FE-SEM images illustrated that anatase average crystallite size in the pure TiO2 and Cr doped TiO2–SiO2 thin films are 15 nm and 10 nm, respectively. XPS spectra confirmed the presence of Cr3+ in the thin film. UV-vis absorption spectra indicated that absorption edge in Cr doped TiO2–SiO2 thin film shifted to the visible light region. The photocatalytic results pointed that Cr doping in TiO2–SiO2 improved decoloring rate of methyl orange in comparison to pure TiO2 thin film.

  4. Influence of doping fluorine on the structural, surface morphological and optical properties of CdO films

    Energy Technology Data Exchange (ETDEWEB)

    Aydogu, S.; Cabuk, G. [Dumlupinar University, Department of Physics, Faculty of Science and Art, Kutahya (Turkey); Coban, M.B. [Balikesir University, Department of Physics, Faculty of Science and Art, Balikesir (Turkey)

    2017-06-15

    CdO and CdO:F films were prepared by ultrasonic spray pyrolysis method on glass substrates at temperature of 250 ± 5 C. The structural and optical properties of pure and fluorine doped CdO films were characterized by XRD measurements and UV-VIS spectra, respectively. X-ray diffraction patterns show that the films have the polycrystalline structure with preferred orientation along (111) plane. Scherrer Method and Williamson Hall Method were used for calculating of the crystalline grains and strains of films. It is observed that the films at 8% F doped has better crystallinity level, and F doping decreases the defects in CdO films and improves crystallite quality. By UV-VIS spectra, it is revealed that the film with 8% F doped has a high transmittance about 65% in the visible region together with a direct band gap of 2.70 eV. Thicknesses, refractive indices and extinction coefficient values are determined by spectroscopic ellipsometry technique using Cauchy-Urbach model. (orig.)

  5. Elaboration and characterization of doped barium titanate films for gas sensing

    Energy Technology Data Exchange (ETDEWEB)

    Romh, M. A. El, E-mail: Mohamad.romh@univ-littoral.fr; Fasquelle, D., E-mail: Mohamad.romh@univ-littoral.fr; Mascot, M. [Unité de Dynamique et Structure des Matériaux Moléculaires (UDSMM), Université du Littoral Côte d' Opale (ULCO), BP717, 62228 Calais (France); Députier, S. [UMR CNRS no. 6226 ISCR, Université de Rennes 1, Equipe Chimie du Solide et Matériaux (CSM), CS 74205, 35042 RENNES Cedex (France)

    2014-11-05

    Barium titanate (BaTiO{sub 3}) thick films were prepared from commercial powder to develop and optimize the film elaboration. Then, BaTiO{sub 3} was doped by strontium and iron to increase the conductivity by a double substitution on site A and B of the perovskite structure in view to develop semiconductor gas sensors. Film inks were prepared by mixing BT and BSTF powder with an organic vehicle, using a ratio of 50:50; 60:40, respectively and deposited on alumina substrates. The BT and BSTF films were sintered at 1100°C for 2h. The structural and physical properties of the films have been studied by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The dielectric measurements showed a huge increase in the a.c. conductivity for the BSTF films, by a factor of 10000 at low frequency, when the temperature ranges from 25°C to 500°C.

  6. Photoconductivity studies on amorphous and crystalline TiO{sub 2} films doped with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Valverde-Aguilar, G.; Garcia-Macedo, J.A. [Universidad Nacional Autonoma de Mexico, Departamento de Estado Solido, Instituto de Fisica, Mexico D.F. (Mexico); Renteria-Tapia, V. [Universidad de Guadalajara, Centro Universitario de los Valles, Departamento de Ciencias Naturales y Exactas, Ameca, Jalisco (Mexico); Aguilar-Franco, M. [Universidad Nacional Autonoma de Mexico, Departamento de Fisica Quimica, Instituto de Fisica, Mexico D.F. (Mexico)

    2011-06-15

    In this work, amorphous and crystalline TiO{sub 2} films were synthesized by the sol-gel process at room temperature. The TiO{sub 2} films were doped with gold nanoparticles. The films were spin-coated on glass wafers. The crystalline samples were annealed at 100 C for 30 minutes and sintered at 520 C for 2 h. All films were characterized using X-ray diffraction, transmission electronic microscopy and UV-Vis absorption spectroscopy. Two crystalline phases, anatase and rutile, were formed in the matrix TiO{sub 2} and TiO{sub 2}/Au. An absorption peak was located at 570 nm (amorphous) and 645 nm (anatase). Photoconductivity studies were performed on these films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm. This indicates an ohmic behavior. Crystalline TiO{sub 2}/Au films are more photoconductive than the amorphous ones. (orig.)

  7. 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.

  8. Preparation of B-doped Si quantum dots embedded in SiNx films for Si quantum dot solar cells

    Science.gov (United States)

    Chen, Xiaobo; Yang, Peizhi

    2018-01-01

    Silicon quantum dots (Si-QDs) embedded B-doped SiNx films were fabricated by magnetron co-sputtering. The effects of B content on the structural, optical and electrical properties of the films were studied. The study found that the amount of B dopant has no significant effect on the crystallization characteristics of the films. B atoms may be doped in the Si-QDs or exist in the silicon nitride or the interface between Si-QDs and the matrix. PL intensity increases with increasing B content, but increases at first and then decreases. The conductivity as a function of the dopant concentration increases at first from a value of 2.71 × 10-4 S/cm to 5.83 × 10-2 S/cm until 0.9 at.% and then decreases. By employing B-doped Si-QDs films, Si-QDs/c-Si heterojunction solar cells were fabricated and the effect of B doping concentration on the photovoltaic properties was studied. It was found that, with the increase of B doping amount, the photovoltaic performance is improved, when the B doping amount is 0.9 at.%, the efficiency reaches the highest value of 4.26%.

  9. The effect of Bi3+ and Li+ co-doping on the luminescence characteristics of Eu3+-doped aluminum oxide films

    International Nuclear Information System (INIS)

    Padilla-Rosales, I.; Martinez-Martinez, R.; Cabañas, G.; Falcony, C.

    2015-01-01

    The incorporation of Bi 3+ and Li + as co-dopants in Eu 3+ -doped aluminum oxide films deposited by the ultrasonic spray pyrolysis technique and its effect on the luminescence characteristics of this material are described. Both Bi 3+ and Li + do not introduce new luminescence features but affect the luminescence intensity of the Eu 3+ related emission spectra as well as the excitation spectra. The introduction of Bi 3+ generates localized states in the aluminum oxide host that result in a quenching of the luminescence intensity, while Li + and Bi 3+ co-doping increase the luminescence intensity of these films. - Highlights: • Li and Bi co-doping increase the luminescence. • Bi creates localized states in the Al 2 O 3 host. • Li was incorporated as a co-activator

  10. The effect of Bi{sup 3+} and Li{sup +} co-doping on the luminescence characteristics of Eu{sup 3+}-doped aluminum oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Padilla-Rosales, I., E-mail: ipadilla@cinvestav.mx [Centro de Investigación y de Estudios Avanzados del IPN, Nanociencias y Nanotecnología, Av. IPN 2508, Col. San Pedro Zacatenco, CP 07360 México D.F. (Mexico); Martinez-Martinez, R. [Instituto de Física y Matemáticas, Universidad Tecnológica de la Mixteca, Carretera a Acatlima Km. 2.5, CP 69000 Huajuapan de León, Oax, México (Mexico); Cabañas, G. [Centro de Investigación y de Estudios Avanzados del IPN, Nanociencias y Nanotecnología, Av. IPN 2508, Col. San Pedro Zacatenco, CP 07360 México D.F. (Mexico); Falcony, C. [Centro de Investigación y de Estudios Avanzados del IPN, Departamento de Física, Av. IPN 2508, Col. San Pedro Zacatenco, CP 07360 México D.F. (Mexico)

    2015-09-15

    The incorporation of Bi{sup 3+} and Li{sup +} as co-dopants in Eu{sup 3+}-doped aluminum oxide films deposited by the ultrasonic spray pyrolysis technique and its effect on the luminescence characteristics of this material are described. Both Bi{sup 3+} and Li{sup +} do not introduce new luminescence features but affect the luminescence intensity of the Eu{sup 3+} related emission spectra as well as the excitation spectra. The introduction of Bi{sup 3+} generates localized states in the aluminum oxide host that result in a quenching of the luminescence intensity, while Li{sup +} and Bi{sup 3+} co-doping increase the luminescence intensity of these films. - Highlights: • Li and Bi co-doping increase the luminescence. • Bi creates localized states in the Al{sub 2}O{sub 3} host. • Li was incorporated as a co-activator.

  11. Origin of visible-light sensitivity in N-doped TiO2 films

    International Nuclear Information System (INIS)

    Nakano, Yoshitaka; Morikawa, Takeshi; Ohwaki, Takeshi; Taga, Yasunori

    2007-01-01

    We report on visible-light sensitivity in N-doped TiO 2 (TiO 2 :N) films that were deposited on n + -GaN/Al 2 O 3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 deg. C in flowing N 2 gas. The N-doping concentration was ∼8.8%, as determined by X-ray photoelectron spectroscopy measurements. From transmission electron microscopic observations and optical absorption measurements, yellow-colored TiO 2 :N samples showed an enhanced granular structure and strong absorption in the visible-light region. Photoelectron spectroscopy in air measurements showed a noticeable decrease in ionization energy of TiO 2 by the N doping. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at ∼1.18 and ∼2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. The pronounced 2.48 eV band is newly introduced by the N doping and contributes to band-gap narrowing of TiO 2 by mixing with the O 2p valence band. Therefore, this localized intraband is probably one origin of visible-light sensitivity in TiO 2 :N

  12. EuO and Gd-doped EuO thin films. Epitaxial growth and properties

    Energy Technology Data Exchange (ETDEWEB)

    Sutarto, Ronny

    2009-07-06

    Europium oxide (EuO) based materials exhibit a wealth of spectacular phenomena, including half-metallic ferromagnetism, metal-insulator transition, colossal magneto-resistance, large magneto-optical Kerr effect, tunable ferromagnetic ordering temperatures, and large and long-lived photo-induced conductivity. These extraordinary properties make EuO an ideal candidate for implementation in device applications, in particular, for spintronics. Most of the work in the past has been carried out on bulk EuO, but for device applications it is preferred to have the EuO in thin lm form. A urry of studies have therefore emerged in the last decade in order to explore a wide variety of preparation routes and to investigate the properties of the resulting EuO thin films. A recent highlight is the demonstration that doped EuO films can be fabricated on Si and GaN, thereby exhibiting the expected spin-polarized transport effects. Nevertheless, it is still far from a trivial task to prepare EuO thin films with well de ned properties. For bulk EuO, it is already known that stoichiometry is the key issue, and that the presence of small amounts of defects or impurities quickly lead to very large deviations of the material properties. In fact, to make bulk EuO to be stoichiometric one needs temperatures as high as 1800 C. It is obvious that such high temperatures are not compatible with device engineering processes. The preparation of thin films must therefore involve much lower temperatures, preferably not higher than 400-500 C. The consequences are very dear. It turned out that many of the recent studies on EuO thin films are suffering from sample quality problems, due to the presence of, e.g., trivalent Eu species (Eu{sub 3}O{sub 4}, Eu{sub 2}O{sub 3}), oxygen vacancies, or even Eu metal clusters. Controlled doping of the EuO with trivalent rare-earth ions is also not trivial, since most often even the actual doping concentrations were not known. In fact, one could also question in

  13. EuO and Gd-doped EuO thin films. Epitaxial growth and properties

    International Nuclear Information System (INIS)

    Sutarto, Ronny

    2009-01-01

    Europium oxide (EuO) based materials exhibit a wealth of spectacular phenomena, including half-metallic ferromagnetism, metal-insulator transition, colossal magneto-resistance, large magneto-optical Kerr effect, tunable ferromagnetic ordering temperatures, and large and long-lived photo-induced conductivity. These extraordinary properties make EuO an ideal candidate for implementation in device applications, in particular, for spintronics. Most of the work in the past has been carried out on bulk EuO, but for device applications it is preferred to have the EuO in thin lm form. A urry of studies have therefore emerged in the last decade in order to explore a wide variety of preparation routes and to investigate the properties of the resulting EuO thin films. A recent highlight is the demonstration that doped EuO films can be fabricated on Si and GaN, thereby exhibiting the expected spin-polarized transport effects. Nevertheless, it is still far from a trivial task to prepare EuO thin films with well de ned properties. For bulk EuO, it is already known that stoichiometry is the key issue, and that the presence of small amounts of defects or impurities quickly lead to very large deviations of the material properties. In fact, to make bulk EuO to be stoichiometric one needs temperatures as high as 1800 C. It is obvious that such high temperatures are not compatible with device engineering processes. The preparation of thin films must therefore involve much lower temperatures, preferably not higher than 400-500 C. The consequences are very dear. It turned out that many of the recent studies on EuO thin films are suffering from sample quality problems, due to the presence of, e.g., trivalent Eu species (Eu 3 O 4 , Eu 2 O 3 ), oxygen vacancies, or even Eu metal clusters. Controlled doping of the EuO with trivalent rare-earth ions is also not trivial, since most often even the actual doping concentrations were not known. In fact, one could also question in this respect the

  14. Effect of Cd-doping level on the electrical, structural and photoconductivity properties of GaSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Colakoglu, T. [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Parlak, M. [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey)]. E-mail: parlak@metu.edu.tr

    2005-12-01

    GaSe thin films were deposited by thermal evaporation technique with and without Cd doping. X-ray diffraction analysis showed that the crystallinity of doped and undoped films increases in (1014) preferred orientation direction upon annealing. Addition of cadmium dopant with excess selenium in the GaSe structure gives rise to the possibility for the existence of a CdSe phase in the highly Cd-doped samples. The room temperature conductivity and mobility values of the samples were found to be lying in between 1.3 x 10{sup 1}-3.4 x 10{sup 2} ({omega} cm){sup -1}, (1.2-1.5) x 10{sup -6} ({omega} cm){sup -1} and 5.9-20.9 (cm{sup 2}/V s) for doped and undoped films, respectively. Dominant conduction mechanisms in doped films were determined to be thermionic emission in the high temperature region (250-400 K), tunneling in the range 160-250 K and variable range hopping mechanism between 100 and 150 K. For undoped films, thermionic emission was the dominant conduction mechanism above 250 K. Photocurrent-illumination intensity dependences indicated that the power exponent of the illumination intensity with values n > 1 implied that two recombination centers exist in the studied samples.

  15. Effect of Ag-Nanoparticles Doped in Polyvinyl Alcohol on the Structural and Optical Properties of PVA Films

    Directory of Open Access Journals (Sweden)

    Mahshad Ghanipour

    2013-01-01

    Full Text Available The effect of silver nanoparticles doped in PVA on the structural and optical properties of composite films is studied experimentally. Samples are PVA films of 0.14 mm thickness doped with different sizes and concentrations of silver nanoparticles. Structural properties are studied using X-ray diffraction and FTIR spectrum. Using the reflectance and transmittance of samples, the effect of doped nanoparticles and their concentration on optical parameters of PVA films include absorption coefficient, optical bandgap energy, complex refractive index, complex dielectric function, complex optical conductivity, and relaxation time is extracted and discussed. The dispersion of the refractive index of films in terms of the single oscillator Wemple-DiDomenico (WD model is investigated and the dispersion parameters are calculated. Results show that by doping silver nanoparticles in PVA, number of Bragg’s planes in the structure of polymer and its crystallinity are increased noticeably. Ag–O bonds are formed in the films and the bandgap energy of samples is decreased. Calculations based on WD model confirm that by doping nanoparticles, the anion strength of PVA as a dielectric medium is decreased.

  16. 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.

  17. Effects of Iodine Doping on Optoelectronic and Chemical Properties of Polyterpenol Thin Films

    Directory of Open Access Journals (Sweden)

    Kateryna Bazaka

    2017-01-01

    Full Text Available Owing to their amorphous, highly cross-liked nature, most plasma polymers display dielectric properties. This study investigates iodine doping as the means to tune optoelectronic properties of plasma polymer derived from a low-cost, renewable resource, i.e., Melaleuca alternifolia oil. In situ exposure of polyterpenol to vapors of electron-accepting dopant reduced the optical band gap to 1.5 eV and increased the conductivity from 5.05 × 10−8 S/cm to 1.20 × 10−6 S/cm. The increased conductivity may, in part, be attributed to the formation of charge-transfer complexes between the polymer chain and halogen, which act as a cation and anion, respectively. Higher levels of doping notably increased the refractive index, from 1.54 to 1.70 (at 500 nm, and significantly reduced the transparency of films.

  18. Study of sub band gap absorption of Sn doped CdSe thin films

    International Nuclear Information System (INIS)

    Kaur, Jagdish; Rani, Mamta; Tripathi, S. K.

    2014-01-01

    The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively

  19. Study of sub band gap absorption of Sn doped CdSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jagdish; Rani, Mamta [Department of Physics, Panjab University, Chandigarh- 160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Panjab University, Chandigarh- 160014 (India)

    2014-04-24

    The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively.

  20. Relation between secondary doping and phase separation in PEDOT:PSS films

    Energy Technology Data Exchange (ETDEWEB)

    Donoval, Martin; Micjan, Michal; Novota, Miroslav; Nevrela, Juraj; Kovacova, Sona; Pavuk, Milan; Juhasz, Peter; Jagelka, Martin; Kovac, Jaroslav; Jakabovic, Jan [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Cigan, Marek [Institute of Chemistry, Faculty of Natural Science, Comenius University, Mlynska dolina CH-2, Ilkovicova 6, Bratislava 84215 (Slovakia); Weis, Martin, E-mail: martin.weis@stuba.sk [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia)

    2017-02-15

    Highlights: • Surface morphology of highly conductive polymer was investigated. • Phase separation due to secondary doping is an origin of conductivity enhancement. • Phase separation is not dependent on secondary dopant type. - Abstract: Conductive copolymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative to transparent conductive oxides because of its flexibility, transparency, and low-cost production. Four different secondary dopants, namely N,N-dimethylformamide, ethyleneglycol, sorbitol, and dimethyl sulfoxide, have been used to improve the conductivity. The relation between the structure changes and conductivity enhancement is studied in detail. Atomic force microscopy study of the thin film surface reveals the phase separation of PEDOT and PSS. We demonstrate that secondary doping induces the phase separation as well as the conductivity enhancement.

  1. Gd-Doped BaSnO3 Thin Films: High Mobility in a Magnetically-Doped Transparent Conducting Oxide

    Science.gov (United States)

    Alaan, Urusa; Shafer, Padraic; N'diaye, Alpha; Arenholz, Elke; Suzuki, Yuri

    It has recently been shown that when the perovskite-structure BaSnO3 (BSO) is doped with LaBa', the result is a transparent conducting oxide with room-temperature electron mobilities that are much higher than conventional ternary oxides. The ability to achieve high carrier mobilities in BSO is promising for future perovskite-structure devices. We have used pulsed laser deposition to grow epitaxial thin films of Ba0.96Gd0.04SnO3 (Gd:BSO) and Ba0.96La0.04SnO3 (La:BSO) on (001) SrTiO3 and (001) MgO substrates. At 300 K, Gd:BSO films have ρ ~2 m Ω .cm, μe ~28 cm2/V .s and n ~1.0 × 1020cm-3. At the same temperature, La:BSO films have ρ ~0.4 m Ω .cm, μe ~58 cm2/V .s and n ~2.5 × 1020 cm-3. While La:BSO is diamagnetic, Gd:BSO is paramagnetic with a clear magnetic response that saturates at ~7 μB/Gd3+, and a negative ordinary magnetoresistance at low temperatures. Like La:BSO, Gd:BSO is transparent and colorless in the visible regime. Thus, we have shown that Gd is good dopant for BSO in order to achieve transparency and metallicity that is coincident with a magnetic response. We acknowledge support from the Army Research Office under Grant # W911NF-14-1-0611, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and the National Science Foundation Graduate Research Fellowship Program.

  2. 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.

  3. 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.

  4. Electrical current at micro-/macro-scale of undoped and nitrogen-doped MWPECVD diamond films

    Science.gov (United States)

    Cicala, G.; Velardi, L.; Senesi, G. S.; Picca, R. A.; Cioffi, N.

    2017-12-01

    Chemical, structural, morphological and micro-/macro-electrical properties of undoped and nitrogen-(N-)doped diamond films are determined by X-ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, field emission scanning electron microscopy, atomic force microscopy, scanning capacitance microscopy (SCM) and two points technique for I-V characteristics, respectively. The characterization results are very useful to examine and understand the relationship among these properties. The effect of the nitrogen incorporation in diamond films is investigated through the evolution of the chemical, structural, morphological and topographical features and of the electrical behavior. The distribution of the electrical current is first assessed at millimeter scale on the surface of diamond films and then at micrometer scale on small regions in order to establish the sites where the carriers preferentially move. Specifically, the SCM images indicate a non-uniform distribution of carriers on the morphological structures mainly located along the grain boundaries. A good agreement is found by comparing the electrical currents at the micro- and macro-scale. This work aims to highlight phenomena such as photo- and thermionic emission from N-doped diamond useful for microelectronic engineering.

  5. Photoluminescent study of Polycarbonate (PC) and Poly(9-vinylcarbazole) (PVK) doped films with europium complex

    International Nuclear Information System (INIS)

    Forster, Pedro Lima

    2010-01-01

    Polymers doped with rare earth complexes are advantaged in film production for many applications in the luminescent field. In this study luminescent polymer obtained from polycarbonate (PC) and poly(9-vinylcarbazole) films doped with diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(tta) 3 (H 2 0) 2 ] were prepared and their calorimetric and luminescent properties in the solid state are reported. The thermal behavior was investigated by differential scanning calorimetry (OSC) and thermogravimetry analysis (TGA). Due of the addition of rare earth Eu(tta) 3 (H 2 0) 2 ] into PC and PVK matrices, changes were observed in the thermal behavior concerning the glass transition and thermal stability. Characteristic broadened narrow bands arising from the 5 D 0 -→ 7 F J transitions (J = 0-4) of Eu 3+ ion indicate the incorporation of the Eu 3+ ions into those polymers. The luminescent films show enhancement emission intensity with an increase in the rare earth concentration in polymeric matrix accompanied by decrease in thermal stability. (author)

  6. Structural and electrical properties of the europium-doped indium zinc oxide thin film transistors

    International Nuclear Information System (INIS)

    Ting, Chu-Chi; Li, Wei-Yang; Wang, Ching-Hua; Yong, Hua-En

    2014-01-01

    The EuInZnO (EIZO) thin film transistor (TFT) devices were fabricated by the sol–gel spin-coating technique. The EIZO TFT operates in the n-channel depletion mode and exhibits a well-defined pinch-off and saturation region. Because europium ion possesses lower electronegativity (1.2) and standard electrode potential (− 1.991 V), it can act as the carrier suppressor to reduce the carrier concentrations of the IZO (In:Zn = 1:1) thin film. Eu 3+ (13 mol%)-doped IZO TFT possesses the optimum performance, and its field-effect mobility in the saturated regime, threshold voltage, on–off ratio, and S-factor are 1.23 cm 2 /Vs, 3.28 V, 1.07 × 10 6 , and 2.28 V/decade, respectively. - Highlights: • Europium ions can act as the carrier suppressor in the InZnO system. • The EuInZnO forms an n-channel material for the thin film transistor (TFT) device. • The optimum performance of the EuInZnO TFT is the sample with 13 mol% Eu 3+ doping

  7. Growth parameter control toward mobility enchancement in doped BaSnO3 thin films

    Science.gov (United States)

    Singh, Prastuti; Swartz, Adrian; Lu, Di; Nishio, Kazunori; Hikita, Yasuyuki; Hwang, Harold

    Doped BaSnO3 is known to exhibit high electron mobility at room temperature, showing great prospects as an transparent conducting oxide. However, when grown epitaxially on perovskite substrates, thin films exhibit reduced mobilities compared with bulk single crystals due to scattering from the formation of dislocations at the interface of the thin film and substrate. In this emerging field, correlating synthesis growth regimes, structure, and stoichiometry with transport properties is critical for developing next level oxide electronic devices. Here, we will discuss our results linking growth conditions and transport properties of La-doped BaSnO3 (BLSO) to enhance mobility. In addition to varying standard growth parameters, we deposited BLSO on a hygroscopic pseudo-perovskite buffer layer. The pseudo-perovskite buffer acts as a sacrificial layer that can be selectively etched to produce conductive free-standing BLSO membranes, free of the underlying substrate. This allows us to minimize film dislocation density and examine BLSO transport properties in the limit of no substrate.

  8. Silica doped with lanthanum sol-gel thin films for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Abuin, M. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Serrano, A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); Llopis, J. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Garcia, M.A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); IMDEA Nanoscience, Fco. Tomas y Valiente 7, 28049 Madrid (Spain); Carmona, N., E-mail: n.carmona@fis.ucm.es [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain)

    2012-06-01

    We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol-gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: Black-Right-Pointing-Pointer Silica sol-gel films doped with lanthanum ions were synthesized. Black-Right-Pointing-Pointer Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. Black-Right-Pointing-Pointer La-acetate is an affordable chemical reactive preferred for the industry. Black-Right-Pointing-Pointer Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. Black-Right-Pointing-Pointer An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

  9. 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.

  10. Properties of Al- and Ga-doped thin zinc oxide films treated with UV laser radiation

    Science.gov (United States)

    Al-Asedy, Hayder J.; Al-Khafaji, Shuruq A.; Bakhtiar, Hazri; Bidin, Noriah

    2018-03-01

    This paper reports the Nd:YAG laser irradiation treated modified properties of aluminum (Al) and gallium (Ga) co-doped zinc oxide (ZnO) (AGZO) films prepared on Si-substrate via combined sol-gel and spin-coating method. The impact of varying laser energy (150-200 mJ) on the structure, morphology, electrical and optical properties of such AGZO films were determined. Laser-treated samples were characterized using various analytical tools. Present techniques could achieve a high-quality polycrystalline films compared with those produced via conventional high temperature processing. AGZO films irradiated with third harmonics UV radiation (355 nm) from Nd:YAG laser source revealed very low resistivity of 4.02 × 10- 3 Ω cm. The structural properties grain size was calculated firm the X-ray diffraction spectra using the Scherrer equation that increased from 12.7 to 22.5 nm as the annealing laser energy increased from (150-200) mJ. The differences in crystallinity and orientation are explained in terms of the thermal effect caused by laser irradiation. (FESEM) images have been demonstrated that Nd:YAG laser annealing can significantly improve the crystallinity level, densification, and surface flatness of sol-gel derived AGZO thin films that occurred as a result of laser processing. Synthesized AGZO films displayed favorable growth orientation along (101) lattice direction. AGZO films with energy band gap of 3.37-3.41 eV were obtained. Results on the crystallinity, surface morphology, roughness, bonding vibration, absorption, photoluminescence, and resistivity of the laser-irradiated films were analyzed and discussed.

  11. Heavy-ion elastic-recoil detection analysis of doped-silica films for integrated photonics

    International Nuclear Information System (INIS)

    Weijers, T.D.M.; Timmers, H.; Gaff, K.; Ophel, T.R.; Elliman, R.G.

    1999-01-01

    Photosensitive silica films, in which a permanent refractive index change is induced by exposure to ultra-violet (UV) light, are of interest for the fabrication of integrated photonic devices and circuits. Such films, consisting of Ge- and Sn-doped silica, are being fabricated at the Australian National University (ANU) by a plasma assisted deposition technique known as Helicon Assisted Reactive Evaporation (HARE). The initial refractive index of these films is related to their stoichiometry and can be altered further by controlled exposure to UV light . Contaminants introduced into the films during deposition can degrade their optical properties and are therefore also of interest. Hydrogen is of particular concern as it causes optical absorption in the wavelength range of interest for communications applications (1.3-1.5μm). High-energy heavy ion elastic recoil detection (ERD) analysis enables the detection of a broad range of elements with almost constant sensitivity. A variety of recoil detection systems have been developed for this purpose, including time-of-flight systems, magnetic spectrometers, and quadrupole spectrometers. However, these are often restricted to small acceptance solid angles. Beam-induced sample modification, such as hydrogen release, can therefore be a serious limitation. The use of a position sensitive gas ionization detector overcomes these limitations for a range of import ant applications by operating with a large solid angle and correcting the kinematic energy spread of the ions over large acceptance angles to provide ≤1% energy resolution. In this study, heavy-ion ERD employing a novel position sensitive gas ionization detector is used to characterize the composition, thickness, uniformity and hydrogen content of Ge- and Sn- doped silica films. The technique is shown to provide this information in a single measurement

  12. Effect of yttrium-doping on the microstructures and semiconductor-metal phase transition characteristics of polycrystalline VO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Deen, E-mail: gudeen@163.com; Sun, Zhanhong; Zhou, Xin; Guo, Rui; Wang, Tao; Jiang, Yadong

    2015-12-30

    Highlights: • Modulating the microstructures and phase transition characteristics of VO{sub 2} thin films by Y-doping. • Y-doping greatly reduces the grain size of polycrystalline VO{sub 2} thin films. • Y{sup 3+} ions hardly influence the chemical states of V and O elements in the Y-doped VO{sub 2} films. • Y-doped VO{sub 2} films have a notably narrower ΔT (4.6 °C) than undoped VO{sub 2} films (10.7 °C). - Abstract: We investigate the effect of yttrium-doping on the microstructures and semiconductor-metal phase transition characteristics of polycrystalline VO{sub 2} thin films prepared by reactively co-sputtering process. XPS analyses indicate the existence of Y{sup 3+} in the Y-doped VO{sub 2} films, but Y-doping hardly influences the chemical states of V and O elements. X-ray diffraction patterns and Raman spectra reveal that both undoped and Y-doped VO{sub 2} thin films have a polycrystalline structure of monoclinic VO{sub 2}. The introduction of Y greatly reduces the grain size of VO{sub 2} thin films as evidenced by scanning electron microscopy analyses. The relationship between the hysteresis width and doping level is not monotonic although the grain size is monotonically reduced with increasing the doping level. Y-doped VO{sub 2} films with optimal doping level (1.82 at%) have a notably narrower hysteresis width (4.6 °C) than undoped VO{sub 2} films (10.7 °C). This is ascribed to increased heterogeneous nucleation centers due to Y in the VO{sub 2} lattice. With the further increase of doping level, the size effect gradually plays a prominent role in SMPT, and the hysteresis width of Y-doped VO{sub 2} films increases instead. The SMPT temperature of Y-doped VO{sub 2} films obviously decreases compared with undoped VO{sub 2} films due to reduced grain size and deformation of local structure around Y atom.

  13. Effect of Na doping on structural, optical, and electrical properties of Cu2Se thin films prepared by chemical bath deposition method

    Science.gov (United States)

    Sudha, A. P.; Henry, J.; Mohanraj, K.; Sivakumar, G.

    2018-02-01

    In this work, pure and monovalent Na+ ion-doped Cu2Se thin films were deposited on glass substrates using a simple chemical bath deposition method and the films were annealed at 200 °C. The effect of Na+ doping on the structural, surface morphological, compositional, optical, and electrical properties of the Cu2Se thin films was investigated using X-ray diffraction, field-emission scanning electron microscopy (FESEM), diffuse reflectance spectra, and Hall effect analysis. The X-ray pattern reveals that both pure and Na+-doped Cu2Se thin films crystallized in cubic structure with a shift for Na-doped films indicating the incorporation of Na into host Cu2Se site. FESEM images show uniformly distributed multi geometrical shape particles. Na-doped films show higher absorption in the visible region. The energy bandgap is about 2.5-1.52 eV for Na-doped films. The films were found to be p type and the electrical conductivity of the doped films is found to be less than the Cu2Se films.

  14. Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    F. de Moure-Flores

    2012-06-01

    Full Text Available Cu-doped CdTe thin films were prepared by pulsed laser deposition on Corning glass substrates using powders as target. Films were deposited at substrate temperatures ranging from 100 to 300 °C. The X-ray diffraction shows that both the Cu-doping and the increase in the substrate temperature promote the presence of the hexagonal CdTe phase. For a substrate temperature of 300 °C a CdTe:Cu film with hexagonal phase was obtained. Raman and EDS analysis indicate that the films grew with an excess of Te, which indicates that CdTe:Cu films have p-type conductivity.

  15. Up-conversion emission in rare earth-doped Y2Ti2O7 sol-gel thin films

    International Nuclear Information System (INIS)

    Jenouvrier, P.; Boccardi, G.; Fick, J.; Jurdyc, A.-M.; Langlet, M.

    2005-01-01

    Yttrium titanate (YTO) thin films doped with rare earth elements have been deposited using the aerosol-gel process. The up-conversion emission (UPE) of films doped with erbium and/or thulium has been studied with respect to the film crystallization degree and rare earth concentration. The effects of ytterbium codoping have been considered as well. Mechanisms that control UPE of YTO films are discussed with respect to the experimental conditions. It is shown that films, which selectively emit in the blue ( 1 G 4 → 3 H 6 transition of thulium ions), green ( 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions of erbium ions), or red ( 4 F 9/2 → 4 I 15/2 transition of erbium ions), can readily be achieved

  16. 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.