WorldWideScience

Sample records for thin silicon layers

  1. Transparent conducting oxide layers for thin film silicon solar cells

    NARCIS (Netherlands)

    Rath, J.K.; Liu, Y.; de Jong, M.M.; de Wild, J.; Schuttauf, J.A.; Brinza, M.; Schropp, R.E.I.

    2009-01-01

    Texture etching of ZnO:1%Al layers using diluted HCl solution provides excellent TCOs with crater type surface features for the front contact of superstrate type of thin film silicon solar cells. The texture etched ZnO:Al definitely gives superior performance than Asahi SnO2:F TCO in case of

  2. Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.

    Science.gov (United States)

    Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

    2011-01-01

    A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

  3. Charged particle detectors made from thin layers of amorphous silicon

    International Nuclear Information System (INIS)

    Morel, J.R.

    1986-05-01

    A series of experiments was conducted to determine the feasibility of using hydrogenated amorphous silicon (α-Si:H) as solid state thin film charged particle detectors. 241 Am alphas were successfully detected with α-Si:H devices. The measurements and results of these experiments are presented. The problems encountered and changes in the fabrication of the detectors that may improve the performance are discussed

  4. Effect of p-layer properties on nanocrystalline absorber layer and thin film silicon solar cells

    International Nuclear Information System (INIS)

    Chowdhury, Amartya; Adhikary, Koel; Mukhopadhyay, Sumita; Ray, Swati

    2008-01-01

    The influence of the p-layer on the crystallinity of the absorber layer and nanocrystalline silicon thin film solar cells has been studied. Boron doped Si : H p-layers of different crystallinities have been prepared under different power pressure conditions using the plasma enhanced chemical vapour deposition method. The crystalline volume fraction of p-layers increases with the increase in deposition power. Optical absorption of the p-layer reduces as the crystalline volume fraction increases. Structural studies at the p/i interface have been done by Raman scattering studies. The crystalline volume fraction of the i-layer increases as that of the p-layer increases, the effect being more prominent near the p/i interface. Grain sizes of the absorber layer decrease from 9.2 to 7.2 nm and the density of crystallites increases as the crystalline volume fraction of the p-layer increases and its grain size decreases. With increasing crystalline volume fraction of the p-layer solar cell efficiency increases

  5. Ion beam studied of silicon oxynitride and silicon nitroxide thin layers

    International Nuclear Information System (INIS)

    Oude Elferink, J.B.

    1989-01-01

    In this the processes occurring during high temperature treatments of silicon oxynitride and silicon oxide layers are described. Oxynitride layers with various atomic oxygen to nitrogen concentration ration (O/N) are considered. The high energy ion beam techniques Rutherford backscattering spectroscopy, elastic recoil detection and nuclear reaction analysis have been used to study the layer structures. A detailed discussion of these ion beam techniques is given. Numerical methods used to obtain quantitative data on elemental compositions and depth profiles are described. The electrical compositions and depth profiles are described. The electrical properties of silicon nitride films are known to be influenced by the behaviour of hydrogen in the film during high temperature anneling. Investigations of the behaviour of hydrogen are presented. Oxidation of silicon (oxy)nitride films in O 2 /H 2 0/HCl and nitridation of silicon dioxide films in NH 3 are considered since oxynitrides are applied as an oxidation mask in the LOCOS (Local oxidation of silicon) process. The nitridation of silicon oxide layers in an ammonia ambient is considered. The initial stage and the dependence on the oxide thickness of nitrogen and hydrogen incorporation are discussed. Finally, oxidation of silicon oxynitride layers and of silicon oxide layers are compared. (author). 76 refs.; 48 figs.; 1 tab

  6. Thin-Film layers with Interfaces that reduce RF Losses on High-Resistivity Silicon Substrates

    NARCIS (Netherlands)

    Evseev, S. B.; Milosavljevic, S.; Nanver, L. K.

    2017-01-01

    Radio-Frequency (RF) losses on High-Resistivity Silicon (HRS) substrates were studied for several different surface passivation layers comprising thin-films of SiC, SiN and SiO2 In many combinations, losses from conductive surface channels were reduced and increasing the number of interfaces between

  7. Characterization of the porosity of silicon nitride thin layers by Electrochemical Impedance Spectroscopy

    International Nuclear Information System (INIS)

    Barrès, T.; Tribollet, B.; Stephan, O.; Montigaud, H.; Boinet, M.; Cohin, Y.

    2017-01-01

    Silicon nitride thin films are widely used as diffusion barriers within stacks in the glass industry but turn out to be porous at the nanometric scale. EIS measurements were conducted on SiNx thin layers deposited on a gold layer. An electrochemical model was established to fit the EIS measurements making use of data from other complementary techniques. In particular, Transmission Electron Microscopy was performed on these thin layers to determine the diameter and the qualitative morphology of the pores. A quantitative determination of the through-porosity of the layer was deduced from the EIS model and was in good agreement with TEM measurements. Moreover, combining EIS with local observations enabled inhomogeneities in the layer to be probed by highlighting a specific region in the layer.

  8. Complex boron redistribution kinetics in strongly doped polycrystalline-silicon/nitrogen-doped-silicon thin bi-layers

    Energy Technology Data Exchange (ETDEWEB)

    Abadli, S. [Department of Electrical Engineering, University Aout 1955, Skikda, 21000 (Algeria); LEMEAMED, Department of Electronics, University Mentouri, Constantine, 25000 (Algeria); Mansour, F. [LEMEAMED, Department of Electronics, University Mentouri, Constantine, 25000 (Algeria); Pereira, E. Bedel [CNRS-LAAS, 7 avenue du colonel Roche, 31077 Toulouse (France)

    2012-10-15

    We have investigated the complex behaviour of boron (B) redistribution process via silicon thin bi-layers interface. It concerns the instantaneous kinetics of B transfer, trapping, clustering and segregation during the thermal B activation annealing. The used silicon bi-layers have been obtained by low pressure chemical vapor deposition (LPCVD) method at 480 C, by using in-situ nitrogen-doped-silicon (NiDoS) layer and strongly B doped polycrystalline-silicon (P{sup +}) layer. To avoid long-range B redistributions, thermal annealing was carried out at relatively low-temperatures (600 C and 700 C) for various times ranging between 30 min and 2 h. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of two thin layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the complex B redistribution profiles-shoulders. The increasing kinetics of the B peak concentration near the bi-layers interface is well reproduced by the established model. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Structural, optical and electrical properties of quasi-monocrystalline silicon thin films obtained by rapid thermal annealing of porous silicon layers

    International Nuclear Information System (INIS)

    Hajji, M.; Khardani, M.; Khedher, N.; Rahmouni, H.; Bessais, B.; Ezzaouia, H.; Bouchriha, H.

    2006-01-01

    Quasi-mono-crystalline silicon (QMS) layers have a top surface like crystalline silicon with small voids in the body. Such layers are reported to have a higher absorption coefficient than crystalline silicon at the interesting range of the solar spectrum for photovoltaic application. In this work we present a study of the structural, optical and electrical properties of quasimonocrystalline silicon thin films. Quasimonocrystalline silicon thin films were obtained from porous silicon, which has been annealed at a temperature ranging from 950 to 1050 deg. C under H 2 atmosphere for different annealing durations. The porous layers were prepared by conventional electrochemical anodization using a double tank cell and a HF / Ethanol electrolyte. Porous silicon is formed on highly doped p + -type silicon substrates that enable us to prevent back contacts for the anodization. Atomic Force Microscope (AFM) was used to study the morphological quality of the prepared layers. Optical properties were extracted from transmission and reflectivity spectra. Dark I-V characteristics were used to determine the electrical conductivity of quasimonocrystalline silicon thin films. Results show an important improvement of the absorption coefficient of the material and electrical conductivity reaches a value of twenty orders higher than that of starting mesoporous silicon

  10. Highly Sensitive Bulk Silicon Chemical Sensors with Sub-5 nm Thin Charge Inversion Layers.

    Science.gov (United States)

    Fahad, Hossain M; Gupta, Niharika; Han, Rui; Desai, Sujay B; Javey, Ali

    2018-03-27

    There is an increasing demand for mass-producible, low-power gas sensors in a wide variety of industrial and consumer applications. Here, we report chemical-sensitive field-effect-transistors (CS-FETs) based on bulk silicon wafers, wherein an electrostatically confined sub-5 nm thin charge inversion layer is modulated by chemical exposure to achieve a high-sensitivity gas-sensing platform. Using hydrogen sensing as a "litmus" test, we demonstrate large sensor responses (>1000%) to 0.5% H 2 gas, with fast response (<60 s) and recovery times (<120 s) at room temperature and low power (<50 μW). On the basis of these performance metrics as well as standardized benchmarking, we show that bulk silicon CS-FETs offer similar or better sensing performance compared to emerging nanostructures semiconductors while providing a highly scalable and manufacturable platform.

  11. Silicon surface passivation using thin HfO2 films by atomic layer deposition

    International Nuclear Information System (INIS)

    Gope, Jhuma; Vandana; Batra, Neha; Panigrahi, Jagannath; Singh, Rajbir; Maurya, K.K.; Srivastava, Ritu; Singh, P.K.

    2015-01-01

    Graphical abstract: - Highlights: • HfO 2 films using thermal ALD are studied for silicon surface passivation. • As-deposited thin film (∼8 nm) shows better passivation with surface recombination velocity (SRV) <100 cm/s. • Annealing improves passivation quality with SRV ∼20 cm/s for ∼8 nm film. - Abstract: Hafnium oxide (HfO 2 ) is a potential material for equivalent oxide thickness (EOT) scaling in microelectronics; however, its surface passivation properties particularly on silicon are not well explored. This paper reports investigation on passivation properties of thermally deposited thin HfO 2 films by atomic layer deposition system (ALD) on silicon surface. As-deposited pristine film (∼8 nm) shows better passivation with <100 cm/s surface recombination velocity (SRV) vis-à-vis thicker films. Further improvement in passivation quality is achieved with annealing at 400 °C for 10 min where the SRV reduces to ∼20 cm/s. Conductance measurements show that the interface defect density (D it ) increases with film thickness whereas its value decreases after annealing. XRR data corroborate with the observations made by FTIR and SRV data.

  12. Electrochemical lithiation of thin silicon based layers potentiostatically deposited from ionic liquid

    International Nuclear Information System (INIS)

    Vlaic, Codruta Aurelia; Ivanov, Svetlozar; Peipmann, Ralf; Eisenhardt, Anja; Himmerlich, Marcel; Krischok, Stefan; Bund, Andreas

    2015-01-01

    Thin silicon layers containing about 20% carbon and 20% oxygen were deposited on copper substrates by potentiostatic electroreduction from a 1 M SiCl 4 1-butyl-1-methyl-pyrrolidinium bis (trifluoromethyl) sulfonylimide [BMP][TFSI] electrolyte. The electrodeposition process was investigated by means of voltammetric techniques, coupled with in-situ microgravimetry (quartz crystal microbalance, QCM). The electrochemical and QCM data suggest a possible contribution of a partial Si 4+ to Si 2+ reduction and/or a restructuring of the metallic substrate. Considerable impact of side reactions parallel to the deposition process was indicated by QCM measurements performed under potentiostatic and potentiodynamic conditions. The deposition of silicon-based films was confirmed by energy dispersive X-ray analysis (EDX). Analysis of the chemical composition of the deposit and its elemental distribution were achieved by depth profiling X-ray photoelectron spectroscopy (XPS). The electrodeposited silicon containing layers showed stable lithiation and delithiation with capacity values of about 1200 mAhg −1 and 80% capacity retention after 300 cycles in standard EC/DMC electrolytes. In ionic liquid (IL) the material displayed lower capacity of ca. 500 mAhg −1 , which can be attributed to the higher viscosity of this electrolyte and deposition of IL decomposition products during lithiation

  13. The kinetics of dewetting ultra-thin Si layers from silicon dioxide

    International Nuclear Information System (INIS)

    Aouassa, M; Favre, L; Ronda, A; Berbezier, I; Maaref, H

    2012-01-01

    In this study, we investigate the kinetically driven dewetting of ultra-thin silicon films on silicon oxide substrate under ultra-high vacuum, at temperatures where oxide desorption and silicon lost could be ruled out. We show that in ultra-clean experimental conditions, the three different regimes of dewetting, namely (i) nucleation of holes, (ii) film retraction and (iii) coalescence of holes, can be quantitatively measured as a function of temperature, time and thickness. For a nominal flat clean sample these three regimes co-exist during the film retraction until complete dewetting. To discriminate their roles in the kinetics of dewetting, we have compared the dewetting evolution of flat unpatterned crystalline silicon layers (homogeneous dewetting), patterned crystalline silicon layers (heterogeneous dewetting) and amorphous silicon layers (crystallization-induced dewetting). The first regime (nucleation) is described by a breaking time which follows an exponential evolution with temperature with an activation energy E H ∼ 3.2 eV. The second regime (retraction) is controlled by surface diffusion of matter from the edges of the holes. It involves a very fast redistribution of matter onto the flat Si layer, which prevents the formation of a rim on the edges of the holes during both heterogeneous and homogeneous dewetting. The time evolution of the linear dewetting front measured during heterogeneous dewetting follows a characteristic power law x ∼ t 0.45 consistent with a surface diffusion-limited mechanism. It also evolves as x ∼ h -1 as expected from mass conservation in the absence of thickened rim. When the surface energy is isotropic (during dewetting of amorphous Si) the dynamics of dewetting is considerably modified: firstly, there is no measurable breaking time; secondly, the speed of dewetting is two orders of magnitude larger than for crystalline Si; and thirdly, the activation energy of dewetting is much smaller due to the different driving

  14. Influence of intermediate layers on the surface condition of laser crystallized silicon thin films and solar cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Höger, Ingmar, E-mail: ingmar.hoeger@ipht-jena.de; Gawlik, Annett; Brückner, Uwe; Andrä, Gudrun [Leibniz-Institut für Photonische Technologien, PF 100239, 07702 Jena (Germany); Himmerlich, Marcel; Krischok, Stefan [Institut für Mikro-und Nanotechnologien, Technische Universität Ilmenau, PF 100565, 98684 Ilmenau (Germany)

    2016-01-28

    The intermediate layer (IL) between glass substrate and silicon plays a significant role in the optimization of multicrystalline liquid phase crystallized silicon thin film solar cells on glass. This study deals with the influence of the IL on the surface condition and the required chemical surface treatment of the crystallized silicon (mc-Si), which is of particular interest for a-Si:H heterojunction thin film solar cells. Two types of IL were investigated: sputtered silicon nitride (SiN) and a layer stack consisting of silicon nitride and silicon oxide (SiN/SiO). X-ray photoelectron spectroscopy measurements revealed the formation of silicon oxynitride (SiO{sub x}N{sub y}) or silicon oxide (SiO{sub 2}) layers at the surface of the mc-Si after liquid phase crystallization on SiN or SiN/SiO, respectively. We propose that SiO{sub x}N{sub y} formation is governed by dissolving nitrogen from the SiN layer in the silicon melt, which segregates at the crystallization front during crystallization. This process is successfully hindered, when additional SiO layers are introduced into the IL. In order to achieve solar cell open circuit voltages above 500 mV, a removal of the formed SiO{sub x}N{sub y} top layer is required using sophisticated cleaning of the crystallized silicon prior to a-Si:H deposition. However, solar cells crystallized on SiN/SiO yield high open circuit voltage even when a simple wet chemical surface treatment is applied. The implementation of SiN/SiO intermediate layers facilitates the production of mesa type solar cells with open circuit voltages above 600 mV and a power conversion efficiency of 10%.

  15. Suppression of interfacial voids formation during silane (SiH4)-based silicon oxide bonding with a thin silicon nitride capping layer

    Science.gov (United States)

    Lee, Kwang Hong; Bao, Shuyu; Wang, Yue; Fitzgerald, Eugene A.; Seng Tan, Chuan

    2018-01-01

    The material properties and bonding behavior of silane-based silicon oxide layers deposited by plasma-enhanced chemical vapor deposition were investigated. Fourier transform infrared spectroscopy was employed to determine the chemical composition of the silicon oxide films. The incorporation of hydroxyl (-OH) groups and moisture absorption demonstrates a strong correlation with the storage duration for both as-deposited and annealed silicon oxide films. It is observed that moisture absorption is prevalent in the silane-based silicon oxide film due to its porous nature. The incorporation of -OH groups and moisture absorption in the silicon oxide films increase with the storage time (even in clean-room environments) for both as-deposited and annealed silicon oxide films. Due to silanol condensation and silicon oxidation reactions that take place at the bonding interface and in the bulk silicon, hydrogen (a byproduct of these reactions) is released and diffused towards the bonding interface. The trapped hydrogen forms voids over time. Additionally, the absorbed moisture could evaporate during the post-bond annealing of the bonded wafer pair. As a consequence, defects, such as voids, form at the bonding interface. To address the problem, a thin silicon nitride capping film was deposited on the silicon oxide layer before bonding to serve as a diffusion barrier to prevent moisture absorption and incorporation of -OH groups from the ambient. This process results in defect-free bonded wafers.

  16. Microcrystalline silicon carbide alloys prepared with HWCVD as highly transparent and conductive window layers for thin film solar cells

    International Nuclear Information System (INIS)

    Finger, F.; Astakhov, O.; Bronger, T.; Carius, R.; Chen, T.; Dasgupta, A.; Gordijn, A.; Houben, L.; Huang, Y.; Klein, S.; Luysberg, M.; Wang, H.; Xiao, L.

    2009-01-01

    Crystalline silicon carbide alloys have a very high potential as transparent conductive window layers in thin-film solar cells provided they can be prepared in thin-film form and at compatible deposition temperatures. The low-temperature deposition of such material in microcrystalline form (μc-Si:C:H) was realized by use of monomethylsilane precursor gas diluted in hydrogen with the Hot-Wire Chemical Vapor Deposition process. A wide range of deposition parameters has been investigated and the structural, electronic and optical properties of the μc-SiC:H thin films have been studied. The material, which is strongly n-type from unintentional doping, has been used as window layer in n-side illuminated microcrystalline silicon solar cells. High short-circuit current densities are obtained due to the high transparency of the material resulting in a maximum solar cell conversion efficiency of 9.2%.

  17. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei, E-mail: weili.unsw@gmail.com; Varlamov, Sergey; Xue, Chaowei

    2014-09-30

    Highlights: • Crystallisation kinetic is used to analyse seed layer surface cleanliness. • Simplified RCA cleaning for the seed layer can shorten the epitaxy annealing duration. • RTA for the seed layer can improve the quality for both seed layer and epi-layer. • Epitaxial poly-Si solar cell performance is improved by RTA treated seed layer. - Abstract: This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, V{sub oc} and J{sub sc} than the one on the seed layer without RTA treatment.

  18. Vanadium oxide thin films deposited on silicon dioxide buffer layers by magnetron sputtering

    International Nuclear Information System (INIS)

    Chen Sihai; Ma Hong; Wang Shuangbao; Shen Nan; Xiao Jing; Zhou Hao; Zhao Xiaomei; Li Yi; Yi Xinjian

    2006-01-01

    Thin films made by vanadium oxide have been obtained by direct current magnetron sputtering method on SiO 2 buffer layers. A detailed electrical and structural characterization has been performed on the deposited films by four-point probe method and scanning electron microscopy (SEM). At room temperature, the four-point probe measurement result presents the resistance of the film to be 25 kU/sheet. The temperature coefficient of resistance is - 2.0%/K. SEM image indicates that the vanadium oxide exhibits a submicrostructure with lamella size ranging from 60 nm to 300 nm. A 32 x 32-element test microbolometer was fabricated based on the deposited thin film. The infrared response testing showed that the response was 200 mV. The obtained results allow us to conclude that the vanadium oxide thin films on SiO 2 buffer layers is suitable for uncooled focal plane arrays applications

  19. Microscratch testing method for systematic evaluation of the adhesion of atomic layer deposited thin films on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kilpi, Lauri, E-mail: Lauri.Kilpi@vtt.fi; Ylivaara, Oili M. E.; Vaajoki, Antti; Puurunen, Riikka L.; Ronkainen, Helena [VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT (Finland); Malm, Jari [Department of Physics, University of Jyväskylä, P.O. Box 35, Jyväskylä 40014 (Finland); Sintonen, Sakari [Department of Micro- and Nanosciences, Aalto University School of Electrical Engineering, P.O. Box 13500, FI-00076 AALTO (Finland); Tuominen, Marko [ASM Microchemistry Oy, Pietari Kalmin katu 1 F 2, FIN-00560 Helsinki (Finland)

    2016-01-15

    The scratch test method is widely used for adhesion evaluation of thin films and coatings. Usual critical load criteria designed for scratch testing of coatings were not applicable to thin atomic layer deposition (ALD) films on silicon wafers. Thus, the bases for critical load evaluation were established and the critical loads suitable for ALD coating adhesion evaluation on silicon wafers were determined in this paper as L{sub CSi1}, L{sub CSi2}, L{sub CALD1}, and L{sub CALD2}, representing the failure points of the silicon substrate and the coating delamination points of the ALD coating. The adhesion performance of the ALD Al{sub 2}O{sub 3}, TiO{sub 2}, TiN, and TaCN+Ru coatings with a thickness range between 20 and 600 nm and deposition temperature between 30 and 410 °C on silicon wafers was investigated. In addition, the impact of the annealing process after deposition on adhesion was evaluated for selected cases. The tests carried out using scratch and Scotch tape test showed that the coating deposition and annealing temperature, thickness of the coating, and surface pretreatments of the Si wafer had an impact on the adhesion performance of the ALD coatings on the silicon wafer. There was also an improved load carrying capacity due to Al{sub 2}O{sub 3}, the magnitude of which depended on the coating thickness and the deposition temperature. The tape tests were carried out for selected coatings as a comparison. The results show that the scratch test is a useful and applicable tool for adhesion evaluation of ALD coatings, even when carried out for thin (20 nm thick) coatings.

  20. Surface Passivation of Silicon Using HfO2 Thin Films Deposited by Remote Plasma Atomic Layer Deposition System.

    Science.gov (United States)

    Zhang, Xiao-Ying; Hsu, Chia-Hsun; Lien, Shui-Yang; Chen, Song-Yan; Huang, Wei; Yang, Chih-Hsiang; Kung, Chung-Yuan; Zhu, Wen-Zhang; Xiong, Fei-Bing; Meng, Xian-Guo

    2017-12-01

    Hafnium oxide (HfO 2 ) thin films have attracted much attention owing to their usefulness in equivalent oxide thickness scaling in microelectronics, which arises from their high dielectric constant and thermodynamic stability with silicon. However, the surface passivation properties of such films, particularly on crystalline silicon (c-Si), have rarely been reported upon. In this study, the HfO 2 thin films were deposited on c-Si substrates with and without oxygen plasma pretreatments, using a remote plasma atomic layer deposition system. Post-annealing was performed using a rapid thermal processing system at different temperatures in N 2 ambient for 10 min. The effects of oxygen plasma pretreatment and post-annealing on the properties of the HfO 2 thin films were investigated. They indicate that the in situ remote plasma pretreatment of Si substrate can result in the formation of better SiO 2 , resulting in a better chemical passivation. The deposited HfO 2 thin films with oxygen plasma pretreatment and post-annealing at 500 °C for 10 min were effective in improving the lifetime of c-Si (original lifetime of 1 μs) to up to 67 μs.

  1. Growth of nanocrystalline silicon thin film with layer-by-layer technique for fast photo-detecting applications

    International Nuclear Information System (INIS)

    Lin, C.-Y.; Fang, Y.-K.; Chen, S.-F.; Lin, P.-C.; Lin, C.-S.; Chou, T.-H; Hwang, J.S.; Lin, K.I.

    2006-01-01

    High mobility nanocrystalline silicon (nc-Si) films with layer-by-layer technique for fast photo-detecting applications were studied. The structure and morphology of films were studied by means of XRD, micro-Raman scattering, SEM and AFM. The Hall mobility and absorption properties have been investigated and found they were seriously affected by the number of layers in growing, i.e., with increasing of layer number, Hall mobility increased but absorption coefficient decreased. The optimum layer number of nc-Si films for fast near-IR photo-detecting is 7 with film thickness of 1400 nm, while that for fast visible photo-detecting is 17 with film thickness of 3400 nm

  2. Influence of germanium on thermal dewetting and agglomeration of the silicon template layer in thin silicon-on-insulator

    International Nuclear Information System (INIS)

    Zhang, P P; Yang, B; Rugheimer, P P; Roberts, M M; Savage, D E; Lagally, M G; Liu Feng

    2009-01-01

    We investigate the influence of heteroepitaxially grown Ge on the thermal dewetting and agglomeration of the Si(0 0 1) template layer in ultrathin silicon-on-insulator (SOI). We show that increasing Ge coverage gradually destroys the long-range ordering of 3D nanocrystals along the (1 3 0) directions and the 3D nanocrystal shape anisotropy that are observed in the dewetting and agglomeration of pure SOI(0 0 1). The results are qualitatively explained by Ge-induced bond weakening and decreased surface energy anisotropy. Ge lowers the dewetting and agglomeration temperature to as low as 700 0 C.

  3. Uniform GaN thin films grown on (100) silicon by remote plasma atomic layer deposition

    International Nuclear Information System (INIS)

    Shih, Huan-Yu; Chen, Miin-Jang; Lin, Ming-Chih; Chen, Liang-Yih

    2015-01-01

    The growth of uniform gallium nitride (GaN) thin films was reported on (100) Si substrate by remote plasma atomic layer deposition (RP-ALD) using triethylgallium (TEG) and NH 3 as the precursors. The self-limiting growth of GaN was manifested by the saturation of the deposition rate with the doses of TEG and NH 3 . The increase in the growth temperature leads to the rise of nitrogen content and improved crystallinity of GaN thin films, from amorphous at a low deposition temperature of 200 °C to polycrystalline hexagonal structures at a high growth temperature of 500 °C. No melting-back etching was observed at the GaN/Si interface. The excellent uniformity and almost atomic flat surface of the GaN thin films also infer the surface control mode of the GaN thin films grown by the RP-ALD technique. The GaN thin films grown by RP-ALD will be further applied in the light-emitting diodes and high electron mobility transistors on (100) Si substrate. (paper)

  4. Nickel silicide thin films as masking and structural layers for silicon bulk micro-machining by potassium hydroxide wet etching

    International Nuclear Information System (INIS)

    Bhaskaran, M; Sriram, S; Sim, L W

    2008-01-01

    This paper studies the feasibility of using titanium and nickel silicide thin films as mask materials for silicon bulk micro-machining. Thin films of nickel silicide were found to be more resistant to wet etching in potassium hydroxide. The use of nickel silicide as a structural material, by fabricating micro-beams of varying dimensions, is demonstrated. The micro-structures were realized using these thin films with wet etching using potassium hydroxide solution on (1 0 0) and (1 1 0) silicon substrates. These results show that nickel silicide is a suitable alternative to silicon nitride for silicon bulk micro-machining

  5. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  6. Epitaxial growth of silicon for layer transfer

    Science.gov (United States)

    Teplin, Charles; Branz, Howard M

    2015-03-24

    Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

  7. Questing and the application for silicon based ternary compound within ultra-thin layer of SIS intermediate region

    International Nuclear Information System (INIS)

    Chen, Shumin; Gao, Ming; Wan, Yazhou; Du, Huiwei; Li, Yong; Ma, Zhongquan

    2016-01-01

    Highlights: • A new kind of functional material with plasticity of dielectric was obtained. • Powerful characterization methods was exploited to determine this ultra-thin layer. • The electronic structures and properties of this intermediate layer were analyzed. • A potential application of this structure were investigated. - Abstract: A silicon based ternary compound was supposed to be solid synthesized with In, Si and O elements by magnetron sputtering of indium tin oxide target (ITO) onto crystal silicon substrate at 250 °C. To make clear the configuration of the intermediate region, a potential method to obtain the chemical bonding of Si with other existing elements was exploited by X-ray photoelectron spectroscopy (XPS) instrument combined with other assisted techniques. The phase composition and solid structure of the interfacial region between ITO and Si substrate were investigated by X-ray diffraction (XRD) and high resolution cross sectional transmission electron microscope (HR-TEM). A photovoltaic device with structure of Al/Ag/ITO/SiOx/p-Si/Al was assembled by depositing ITO films onto the p-Si substrate by using magnetron sputtering. The new matter has been assumed to be a buffer layer for semiconductor-insulator-semiconductor (SIS) photovoltaic device and plays critical role for the promotion of optoelectronic conversion performance from the view point of device physics.

  8. Questing and the application for silicon based ternary compound within ultra-thin layer of SIS intermediate region

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shumin; Gao, Ming; Wan, Yazhou; Du, Huiwei; Li, Yong [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai 200444 (China); Ma, Zhongquan, E-mail: zqma@shu.edu.cn [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai 200444 (China); Instrumental Analysis & Research Center, Shanghai University, Shanghai 200444 (China)

    2016-12-01

    Highlights: • A new kind of functional material with plasticity of dielectric was obtained. • Powerful characterization methods was exploited to determine this ultra-thin layer. • The electronic structures and properties of this intermediate layer were analyzed. • A potential application of this structure were investigated. - Abstract: A silicon based ternary compound was supposed to be solid synthesized with In, Si and O elements by magnetron sputtering of indium tin oxide target (ITO) onto crystal silicon substrate at 250 °C. To make clear the configuration of the intermediate region, a potential method to obtain the chemical bonding of Si with other existing elements was exploited by X-ray photoelectron spectroscopy (XPS) instrument combined with other assisted techniques. The phase composition and solid structure of the interfacial region between ITO and Si substrate were investigated by X-ray diffraction (XRD) and high resolution cross sectional transmission electron microscope (HR-TEM). A photovoltaic device with structure of Al/Ag/ITO/SiOx/p-Si/Al was assembled by depositing ITO films onto the p-Si substrate by using magnetron sputtering. The new matter has been assumed to be a buffer layer for semiconductor-insulator-semiconductor (SIS) photovoltaic device and plays critical role for the promotion of optoelectronic conversion performance from the view point of device physics.

  9. Experimental studies of thorium ion implantation from pulse laser plasma into thin silicon oxide layers

    Science.gov (United States)

    Borisyuk, P. V.; Chubunova, E. V.; Lebedinskii, Yu Yu; Tkalya, E. V.; Vasilyev, O. S.; Yakovlev, V. P.; Strugovshchikov, E.; Mamedov, D.; Pishtshev, A.; Karazhanov, S. Zh

    2018-05-01

    We report the results of experimental studies related to implantation of thorium ions into thin silicon dioxide by pulsed plasma flux expansion. Thorium ions were generated by laser ablation from a metal target, and the ionic component of the laser plasma was accelerated in an electric field created by the potential difference (5, 10 and 15 kV) between the ablated target and a SiO2/Si (0 0 1) sample. The laser ablation system installed inside the vacuum chamber of the electron spectrometer was equipped with a YAG:Nd3  +  laser having a pulse energy of 100 mJ and time duration of 15 ns in the Q-switched regime. The depth profile of thorium atoms implanted into the 10 nm thick subsurface areas together with their chemical state as well as the band gap of the modified silicon oxide at different conditions of implantation processes were studied by means of x-ray photoelectron spectroscopy and reflected electron energy loss spectroscopy methods. Analysis of the chemical composition showed that the modified silicon oxide film contains complex thorium silicates. Depending on the local concentration of thorium atoms, the experimentally established band gaps were located in the range 6.0–9.0 eV. Theoretical studies of the optical properties of the SiO2 and ThO2 crystalline systems were performed by ab initio calculations within hybrid functional. The optical properties of the SiO2/ThO2 composite were interpreted on the basis of the Bruggeman effective medium approximation. A quantitative assessment of the yield of isomeric nuclei in ‘hot’ laser plasma at the early stages of expansion was performed. The estimates made with experimental results demonstrated that the laser implantation of thorium ions into the SiO2 matrix can be useful for further research of low-lying isomeric transitions in a 229Th isotope with energy of 7.8 +/- 0.5 eV.

  10. Surface texture of single-crystal silicon oxidized under a thin V{sub 2}O{sub 5} layer

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, S. E., E-mail: nikitin@mail.ioffe.ru; Verbitskiy, V. N.; Nashchekin, A. V.; Trapeznikova, I. N.; Bobyl, A. V.; Terukova, E. E. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2017-01-15

    The process of surface texturing of single-crystal silicon oxidized under a V{sub 2}O{sub 5} layer is studied. Intense silicon oxidation at the Si–V{sub 2}O{sub 5} interface begins at a temperature of 903 K which is 200 K below than upon silicon thermal oxidation in an oxygen atmosphere. A silicon dioxide layer 30–50 nm thick with SiO{sub 2} inclusions in silicon depth up to 400 nm is formed at the V{sub 2}O{sub 5}–Si interface. The diffusion coefficient of atomic oxygen through the silicon-dioxide layer at 903 K is determined (D ≥ 2 × 10{sup –15} cm{sup 2} s{sup –1}). A model of low-temperature silicon oxidation, based on atomic oxygen diffusion from V{sub 2}O{sub 5} through the SiO{sub 2} layer to silicon, and SiO{sub x} precipitate formation in silicon is proposed. After removing the V{sub 2}O{sub 5} and silicon-dioxide layers, texture is formed on the silicon surface, which intensely scatters light in the wavelength range of 300–550 nm and is important in the texturing of the front and rear surfaces of solar cells.

  11. The Effect of High Temperature Annealing on the Grain Characteristics of a Thin Chemical Vapor Deposition Silicon Carbide Layer.

    Energy Technology Data Exchange (ETDEWEB)

    Isabella J van Rooyen; Philippus M van Rooyen; Mary Lou Dunzik-Gougar

    2013-08-01

    The unique combination of thermo-mechanical and physiochemical properties of silicon carbide (SiC) provides interest and opportunity for its use in nuclear applications. One of the applications of SiC is as a very thin layer in the TRi-ISOtropic (TRISO) coated fuel particles for high temperature gas reactors (HTGRs). This SiC layer, produced by chemical vapor deposition (CVD), is designed to withstand the pressures of fission and transmutation product gases in a high temperature, radiation environment. Various researchers have demonstrated that macroscopic properties can be affected by changes in the distribution of grain boundary plane orientations and misorientations [1 - 3]. Additionally, various researchers have attributed the release behavior of Ag through the SiC layer as a grain boundary diffusion phenomenon [4 - 6]; further highlighting the importance of understanding the actual grain characteristics of the SiC layer. Both historic HTGR fission product release studies and recent experiments at Idaho National Laboratory (INL) [7] have shown that the release of Ag-110m is strongly temperature dependent. Although the maximum normal operating fuel temperature of a HTGR design is in the range of 1000-1250°C, the temperature may reach 1600°C under postulated accident conditions. The aim of this specific study is therefore to determine the magnitude of temperature dependence on SiC grain characteristics, expanding upon initial studies by Van Rooyen et al, [8; 9].

  12. Growth of light-emitting SiGe heterostructures on strained silicon-on-insulator substrates with a thin oxide layer

    Energy Technology Data Exchange (ETDEWEB)

    Baidakova, N. A., E-mail: banatale@ipmras.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Bobrov, A. I. [University of Nizhny Novgorod (Russian Federation); Drozdov, M. N.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Pavlov, D. A. [University of Nizhny Novgorod (Russian Federation); Shaleev, M. V.; Yunin, P. A.; Yurasov, D. V.; Krasilnik, Z. F. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2015-08-15

    The possibility of using substrates based on “strained silicon on insulator” structures with a thin (25 nm) buried oxide layer for the growth of light-emitting SiGe structures is studied. It is shown that, in contrast to “strained silicon on insulator” substrates with a thick (hundreds of nanometers) oxide layer, the temperature stability of substrates with a thin oxide is much lower. Methods for the chemical and thermal cleaning of the surface of such substrates, which make it possible to both retain the elastic stresses in the thin Si layer on the oxide and provide cleaning of the surface from contaminating impurities, are perfecte. It is demonstrated that it is possible to use the method of molecular-beam epitaxy to grow light-emitting SiGe structures of high crystalline quality on such substrates.

  13. Mocvd Growth of Group-III Nitrides on Silicon Carbide: From Thin Films to Atomically Thin Layers

    Science.gov (United States)

    Al Balushi, Zakaria Y.

    Group-III nitride semiconductors (AlN, GaN, InN and their alloys) are considered one of the most important class of materials for electronic and optoelectronic devices. This is not limited to the blue light-emitting diode (LED) used for efficient solid-state lighting, but other applications as well, such as solar cells, radar and a variety of high frequency power electronics, which are all prime examples of the technological importance of nitride based wide bandgap semiconductors in our daily lives. The goal of this dissertation work was to explore and establish new growth schemes to improve the structural and optical properties of thick to atomically thin films of group-III nitrides grown by metalorganic chemical vapor deposition (MOCVD) on SiC substrates for future novel devices. The first research focus of this dissertation was on the growth of indium gallium nitride (InGaN). This wide bandgap semiconductor has attracted much research attention as an active layer in LEDs and recently as an absorber material for solar cells. InGaN has superior material properties for solar cells due to its wavelength absorption tunability that nearly covers the entire solar spectrum. This can be achieved by controlling the indium content in thick grown material. Thick InGaN films are also of interest as strain reducing based layers for deep-green and red light emitters. The growth of thick films of InGaN is, however, hindered by several combined problems. This includes poor incorporation of indium in alloys, high density of structural and morphological defects, as well as challenges associated with the segregation of indium in thick films. Overcoming some of these material challenges is essential in order integrate thick InGaN films into future optoelectronics. Therefore, this dissertation research investigated the growth mechanism of InGaN layers grown in the N-polar direction by MOCVD as a route to improve the structural and optical properties of thick InGaN films. The growth

  14. Silicon epitaxy on textured double layer porous silicon by LPCVD

    International Nuclear Information System (INIS)

    Cai Hong; Shen Honglie; Zhang Lei; Huang Haibin; Lu Linfeng; Tang Zhengxia; Shen Jiancang

    2010-01-01

    Epitaxial silicon thin film on textured double layer porous silicon (DLPS) was demonstrated. The textured DLPS was formed by electrochemical etching using two different current densities on the silicon wafer that are randomly textured with upright pyramids. Silicon thin films were then grown on the annealed DLPS, using low-pressure chemical vapor deposition (LPCVD). The reflectance of the DLPS and the grown silicon thin films were studied by a spectrophotometer. The crystallinity and topography of the grown silicon thin films were studied by Raman spectroscopy and SEM. The reflectance results show that the reflectance of the silicon wafer decreases from 24.7% to 11.7% after texturing, and after the deposition of silicon thin film the surface reflectance is about 13.8%. SEM images show that the epitaxial silicon film on textured DLPS exhibits random pyramids. The Raman spectrum peaks near 521 cm -1 have a width of 7.8 cm -1 , which reveals the high crystalline quality of the silicon epitaxy.

  15. Quality Evaluation for Microcrystalline Silicon Thin-Film Solar Cells by Single-Layer Absorption

    Directory of Open Access Journals (Sweden)

    Sheng-Hui Chen

    2012-01-01

    Full Text Available The absorption coefficient at 1.4 eV is divided by the value at 0.9 eV to obtain the factor used to judge the quality of μc-Si:H. PV device performance can be predicted by multiplying Voc with Isc when using this layer as an intrinsic layer. The results show a good relationship between the quality factor and the product of open-circuit voltage and short-circuit current. However, the final efficiency is influenced by the identities of the interface in the multilayer structure.

  16. Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    Jiao Bao-Chen; Zhang Xiao-Dan; Wei Chang-Chun; Sun Jian; Ni Jian; Zhao Ying

    2011-01-01

    Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82×10 −3 Ω·cm and particle grains. The double-layers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.58×10 −3 Ω·cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substrate-layer, and the second-layer plays a large part in the resistivity of the double-layer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Improving the Microstructure and Electrical Properties of Aluminum Induced Polysilicon Thin Films Using Silicon Nitride Capping Layer

    Directory of Open Access Journals (Sweden)

    Min-Hang Weng

    2014-01-01

    Full Text Available We investigated the capping layer effect of SiNx (silicon nitride on the microstructure, electrical, and optical properties of poly-Si (polycrystalline silicon prepared by aluminum induced crystallization (AIC. The primary multilayer structure comprised Al (30 nm/SiNx (20 nm/a-Si (amorphous silicon layer (100 nm/ITO coated glass and was then annealed in a low annealing temperature of 350°C with different annealing times, 15, 30, 45, and 60 min. The crystallization properties were analyzed and verified by X-ray diffraction (XRD and Raman spectra. The grain growth was analyzed via optical microscope (OM and scanning electron microscopy (SEM. The improved electrical properties such as Hall mobility, resistivity, and dark conductivity were investigated by using Hall and current-voltage (I-V measurements. The results show that the amorphous silicon film has been effectively induced even at a low temperature of 350°C and a short annealing time of 15 min and indicate that the SiNx capping layer can improve the grain growth and reduce the metal content in the induced poly-Si film. It is found that the large grain size is over 20 μm and the carrier mobility values are over 80 cm2/V-s.

  18. Use of XPS to clarify the Hall coefficient sign variation in thin niobium layers buried in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Demchenko, Iraida N., E-mail: demch@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw (Poland); Lisowski, Wojciech [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Syryanyy, Yevgen [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw (Poland); Melikhov, Yevgen [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw (Poland); School of Engineering, Cardiff University, Newport Rd., Cardiff, CF24 3AA (United Kingdom); Zaytseva, Iryna; Konstantynov, Pavlo [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw (Poland); Chernyshova, Maryna [Institute of Plasma Physics and Laser Microfusion, Hery Street 23, 01-497 Warsaw (Poland); Cieplak, Marta Z. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw (Poland)

    2017-03-31

    Highlights: • HR XPS spectra of Nb 3d, Si 2p, O 1s were probed for Si/Nb/Si trilayers prepared by magnetron sputtering to clarify the Hall coefficient variation as a function of Nb layer thickness. • Strong boundary scattering, enhanced by the presence of silicon ions in the layer close to the interface/s is a main factor leading to sign change of the Hall coefficient. • Theoretical concentration/depth profile as a function of sputtering determined by SESSA after optimization of the model system gives good agreement with experiment. - Abstract: Si/Nb/Si trilayers formed with 9.5 and 1.3 nm thick niobium layer buried in amorphous silicon were prepared by magnetron sputtering and studied using XPS depth-profile techniques in order to investigate the change of Hall coefficient sign with thickness. The analysis of high-resolution (HR) XPS spectra revealed that the thicker layer sample has sharp top interface and metallic phase of niobium, thus holes dominate the transport. In contrast, the analysis indicates that the thinner layer sample has a Nb-rich mixed alloy formation at the top interface. The authors suggest that the main effect leading to a change of sign of the Hall coefficient for the thinner layer sample (which is negative contrary to the positive sign for the thicker layer sample) may be related to strong boundary scattering enhanced by the presence of silicon ions in the layer close to the interface/s. The depth-profile reconstruction was performed by SESSA software tool confirming that it can be reliably used for quantitative analysis/interpretation of experimental XPS data.

  19. Silver nanoparticle formation in thin oxide layer on silicon by silver-negative-ion implantation for Coulomb blockade at room temperature

    International Nuclear Information System (INIS)

    Tsuji, Hiroshi; Arai, Nobutoshi; Matsumoto, Takuya; Ueno, Kazuya; Gotoh, Yasuhito; Adachi, Kouichiro; Kotaki, Hiroshi; Ishikawa, Junzo

    2004-01-01

    Formation of silver nanoparticles formed by silver negative-ion implantation in a thin SiO 2 layer and its I-V characteristics were investigated for development single electron devices. In order to obtain effective Coulomb blockade phenomenon at room temperature, the isolated metal nanoparticles should be in very small size and be formed in a thin insulator layer such as gate oxide on the silicon substrate. Therefore, conditions of a fine particles size, high particle density and narrow distribution should be controlled at their formation without any electrical breakdown of the thin insulator layer. We have used a negative-ion implantation technique with an advantage of 'charge-up free' for insulators, with which no breakdown of thin oxide layer on Si was obtained. In the I-V characteristics with Au electrode, the current steps were observed with a voltage interval of about 0.12 V. From the step voltage the corresponded capacitance was calculated to be 0.7 aF. In one nanoparticle system, this value of capacitance could be given by a nanoparticle of about 3 nm in diameter. This consideration is consistent to the measured particle size in the cross-sectional TEM observation. Therefore, the observed I-V characteristics with steps are considered to be Coulomb staircase by the Ag nanoparticles

  20. Optimization of Recombination Layer in the Tunnel Junction of Amorphous Silicon Thin-Film Tandem Solar Cells

    Directory of Open Access Journals (Sweden)

    Yang-Shin Lin

    2011-01-01

    Full Text Available The amorphous silicon/amorphous silicon (a-Si/a-Si tandem solar cells have attracted much attention in recent years, due to the high efficiency and low manufacturing cost compared to the single-junction a-Si solar cells. In this paper, the tandem cells are fabricated by high-frequency plasma-enhanced chemical vapor deposition (HF-PECVD at 27.1 MHz. The effects of the recombination layer and the i-layer thickness matching on the cell performance have been investigated. The results show that the tandem cell with a p+ recombination layer and i2/i1 thickness ratio of 6 exhibits a maximum efficiency of 9.0% with the open-circuit voltage (Voc of 1.59 V, short-circuit current density (Jsc of 7.96 mA/cm2, and a fill factor (FF of 0.70. After light-soaking test, our a-Si/a-Si tandem cell with p+ recombination layer shows the excellent stability and the stabilized efficiency of 8.7%.

  1. On the use of a charged tunnel layer as a hole collector to improve the efficiency of amorphous silicon thin-film solar cells

    International Nuclear Information System (INIS)

    Ke, Cangming; Sahraei, Nasim; Aberle, Armin G.; Stangl, Rolf; Peters, Ian Marius

    2015-01-01

    A new concept, using a negatively charged tunnel layer as a hole collector, is proposed and theoretically investigated for application in amorphous silicon thin-film solar cells. The concept features a glass/transparent conductive oxide/ultra-thin negatively charged tunnel layer/intrinsic a-Si:H/n-doped a-Si:H/metal structure. The key feature of this so called t + -i-n structure is the introduction of a negatively charged tunnel layer (attracting holes from the intrinsic absorber layer), which substitutes the highly recombination active p-doped a-Si:H layer in a conventional p-i-n configuration. Atomic layer deposited aluminum oxide (ALD AlO x ) is suggested as a potential candidate for such a tunnel layer. Using typical ALD AlO x parameters, a 27% relative efficiency increase (i.e., from 9.7% to 12.3%) is predicted theoretically for a single-junction a-Si:H solar cell on a textured superstrate. This prediction is based on parameters that reproduce the experimentally obtained external quantum efficiency and current-voltage characteristics of a conventional processed p-i-n a-Si:H solar cell, reaching 9.7% efficiency and serving as a reference. Subsequently, the p-doped a-Si:H layer is replaced by the tunnel layer (studied by means of numerical device simulation). Using a t + -i-n configuration instead of a conventional p-i-n configuration will not only increase the short-circuit current density (from 14.4 to 14.9 mA/cm 2 , according to our simulations), it also enhances the open-circuit voltage and the fill factor (from 917 mV to 1.0 V and from 74% to 83%, respectively). For this concept to work efficiently, a high work function front electrode material or a high interface charge is needed

  2. Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

    Directory of Open Access Journals (Sweden)

    Kae Dal Kwack

    2011-01-01

    Full Text Available A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

  3. Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

    Science.gov (United States)

    Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

    2011-01-01

    A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light. PMID:22319353

  4. A buffer-layer/a-SiO{sub x}:H(p) window-layer optimization for thin film amorphous silicon based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jinjoo; Dao, Vinh Ai [College of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Shin, Chonghoon [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Park, Hyeongsik [College of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Minbum; Jung, Junhee [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Doyoung [School of Electricity and Electronics, Ulsan College West Campus, Ulsan 680-749 (Korea, Republic of); Yi, Junsin, E-mail: yi@yurim.skku.ac.kr [College of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2013-11-01

    Amorphous silicon based (a-Si:H-based) solar cells with a buffer-layer/boron doped hydrogenated amorphous silicon oxide (a-SiO{sub x}:H(p)) window-layer were fabricated and investigated. In the first part, in order to reduce the Schottky barrier height at the fluorine doped tin oxide (FTO)/a-SiO{sub x}:H(p) window-layer heterointerface, we have used buffer-layer/a-SiO{sub x}:H(p) for the window-layer, in which boron doped hydrogenated amorphous silicon (a-Si:H(p)) or boron doped microcrystalline silicon (μc-Si:H(p)) is introduced as a buffer layer between the a-SiO{sub x}:H(p) and FTO of the a-Si:H-based solar cells. The a-Si:H-based solar cell using a μc-Si:H(p) buffer-layer shows the highest efficiency compared to the optimized bufferless, and a-Si:H(p) buffer-layer in the a-Si:H-based solar cells. This highest performance was attributed not only to the lower absorption of the μc-Si:H(p) buffer-layer but also to the lower Schottky barrier height at the FTO/window-layer interface. Then, we present the dependence of the built-in potential (V{sub bi}) and blue response of the devices on the inversion of activation energy (ξ) of the a-SiO{sub x}:H(p), in the μc-Si:H(p)/a-SiO{sub x}:H(p) window-layer. The enhancement of both V{sub bi} and blue response is observed, by increasing the value of ξ. The improvement of V{sub bi} and blue response can be ascribed to the enlargement of the optical gap of a-SiO{sub x}:H(p) films in the μc-Si:H(p)/a-SiO{sub x}:H(p) window-layer. Finally, the conversion efficiency was increased by 22.0%, by employing μc-Si:H(p) as a buffer-layer and raising the ξ of the a-SiO{sub x}:H(p), compared to the optimized bufferless case, with a 10 nm-thick a-SiO{sub x}:H(p) window-layer. - Highlights: • Low Schottky barrier height benefits fill factor, and open-circuit voltage (V{sub oc}). • High band gap is beneficial for short-circuit current density (J{sub sc}). • Boron doped microcrystalline silicon is a suitable buffer-layer for

  5. High-rate deposition of epitaxial layers for efficient low-temperature thin film epitaxial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, L.; Schmidt, J.; Wagner, T.A.; Bergmann, R.B. [Stuttgart Univ. (Germany). Inst. of Physical Electronics

    2001-07-01

    Low-temperature deposition of Si for thin-film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open-circuit voltage of these solar cells. In contrast, ion-assisted deposition produces Si films with a minority-carrier diffusion length of 40 {mu}m, obtained at a record deposition rate of 0.8 {mu}m/min and a deposition temperature of 650{sup o}C with a prebake at 810{sup o}C. A thin-film Si solar cell with a 20-{mu}m-thick epitaxial layer achieves an open-circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high-temperature solar cell process steps. (author)

  6. Effect of atomic layer deposited Al2O3:ZnO alloys on thin-film silicon photovoltaic devices

    Science.gov (United States)

    Abdul Hadi, Sabina; Dushaq, Ghada; Nayfeh, Ammar

    2017-12-01

    In this work, we present the effects of the Al2O3:ZnO ratio on the optical and electrical properties of aluminum doped ZnO (AZO) layers deposited by atomic layer deposition, along with AZO application as the anti-reflective coating (ARC) layer and in heterojunction configurations. Here, we report complex refractive indices for AZO layers with different numbers of aluminum atomic cycles (ZnO:Al2O3 = 1:0, 39:1, 19:1, and 9:1) and we confirm their validity by fitting models to experimental data. Furthermore, the most conductive layer (ZnO:Al2O3 = 19:1, conductivity ˜4.6 mΩ cm) is used to fabricate AZO/n+/p-Si thin film solar cells and AZO/p-Si heterojunction devices. The impact of the AZO layer on the photovoltaic properties of these devices is studied by different characterization techniques, resulting in the extraction of recombination and energy band parameters related to the AZO layer. Our results confirm that AZO 19:1 can be used as a low cost and effective conductive ARC layer for solar cells. However, AZO/p-Si heterojunctions suffer from an insufficient depletion region width (˜100 nm) and recombination at the interface states, with an estimated potential barrier of ˜0.6-0.62 eV. The work function of AZO (ZnO:Al2O3 = 19:1) is estimated to be in the range between 4.36 and 4.57 eV. These material properties limit the use of AZO as an emitter in Si solar cells. However, the results imply that AZO based heterojunctions could have applications as low-cost photodetectors or photodiodes, operating under relatively low reverse bias.

  7. Thin epitaxial silicon detectors

    International Nuclear Information System (INIS)

    Stab, L.

    1989-01-01

    Manufacturing procedures of thin epitaxial surface barriers will be given. Some improvements have been obtained: larger areas, lower leakage currents and better resolutions. New planar epitaxial dE/dX detectors, made in a collaboration work with ENERTEC-INTERTECHNIQUE, and a new application of these thin planar diodes to EXAFS measurements, made in a collaboration work with LURE (CNRS,CEA,MEN) will also be reported

  8. Thinning of Inner Retinal Layers after Vitrectomy with Silicone Oil versus Gas Endotamponade in Eyes with Macula-Off Retinal Detachment.

    Science.gov (United States)

    Purtskhvanidze, Konstantine; Hillenkamp, Jost; Tode, Jan; Junge, Olaf; Hedderich, Jürgen; Roider, Johann; Treumer, Felix

    2017-01-01

    To evaluate retinal layer thickness with optical coherence tomography (OCT) in eyes with macula-off retinal detachment after silicone oil (SiO) or gas endotamponade. Cross-sectional study of 40 eyes with macula-off rhegmatogenous retinal detachment that underwent vitrectomy. 20 eyes received SiO tamponade and 20 matched eyes received gas. 33 healthy fellow eyes served as controls. Macular spectral domain OCT was performed with automated layer detection in the 5 inner subfields of the Early Treatment Diabetic Retinopathy Study (ETDRS) map. Comparing the SiO group with the gas group, the ganglion cell layer showed a significant thinning in all fields of the inner ring of the ETDRS map, the inner plexiform layer in the nasal, superior and temporal quadrants, and the outer plexiform layer in the nasal quadrant. Inner retinal layers in the fovea/parafovea were significantly thinner in the SiO group. Prospective studies are warranted to further elucidate possible retinal adverse effects of SiO tamponade. © 2017 S. Karger AG, Basel.

  9. Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers

    Science.gov (United States)

    Betz, Michael A.; Büchele, Patric; Brünnler, Manfred; Deml, Sonja; Lechner, Alfred

    2017-01-01

    Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30-50 µl · min-1. For spray coating an active area of 25 cm2 a 2.45-4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of ~750 nm using a single micronozzle at a coating speed of 1.7 cm2 · min-1 reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of ~7.4 · 10-5 mA · cm-2, both measured at  -2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning.

  10. Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers

    International Nuclear Information System (INIS)

    Betz, Michael A; Brünnler, Manfred; Deml, Sonja; Lechner, Alfred; Büchele, Patric

    2017-01-01

    Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30–50 µ l · min −1 . For spray coating an active area of 25 cm 2 a 2.45–4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of ∼750 nm using a single micronozzle at a coating speed of 1.7 cm 2 · min −1 reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of ∼7.4 · 10 −5 mA · cm −2 , both measured at  −2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning. (paper)

  11. Polycystalline silicon thin films for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Christian Claus

    2012-01-15

    For the thin polycrystalline Si films fabricated with the aluminium-induced-layer-exchange (ALILE) process a good structural quality up to a layer-thickness value of 10 nm was determined. For 5 nm thick layers however after the layer exchange no closes poly-silicon film was present. In this case the substrate was covered with spherically arranged semiconductor material. Furthermore amorphous contributions in the layer could be determined. The electrical characterization of the samples at room temperature proved a high hole concentration in the range 10{sup 18} cm{sup -3} up to 9.10{sup 19} cm{sup -3}, which is influenced by the process temperature and the layer thickness. Hereby higher hole concentrations at higher process temperatures and thinner films were observed. Furthermore above 150-200 K a thermically activated behaviour of the electrical conductivity was observed. At lower temperatures a deviation of the measured characteristic from the exponential Arrhenius behaviour was determined. For low temperatures (below 20 K) the conductivity follows the behaviour {sigma}{proportional_to}[-(T{sub 0}/T){sup 1/4}]. The hole mobility in the layers was lowered by a passivation step, which can be explained by defect states at the grain boundaries. The for these very thin layers present situation was simulated in the framework of the model of Seto, whereby both the defect states at the grain boundaries (with an area density Q{sub t}) and the defect states at the interfaces (with an area density Q{sub it}) were regarded. By this the values Q{sub t}{approx}(3-4).10{sup 12} cm{sup -2} and Q{sub it}{approx}(2-5).10{sup 12} cm{sup -2} could be determined for these thin ALILE layers on quartz substrates. Additionally th R-ALILE process was studied, which uses the reverse precursor-layer sequence substrate/amorphous silicon/oxide/aluminium. Hereby two steps in the crystallization process of the R-ALILE process were found. First a substrate/Al-Si mixture/poly-Si layer structure

  12. Thin layer activation

    International Nuclear Information System (INIS)

    Schweickert, H.; Fehsenfeld, P.

    1995-01-01

    The reliability of industrial equip ment is substantially influenced by wear and corrosion; monitoring can prevent accidents and avoid down-time. One powerful tool is thin layer activation analysis (TLA) using accelerator systems. The information is used to improve mechanical design and material usage; the technology is used by many large companies, particularly in the automotive industry, e.g. Daimler Benz. A critical area of a machine component receives a thin layer of radioactivity by irradiation with charged particles from an accelerator - usually a cyclotron. The radioactivity can be made homogeneous by suitable selection of particle, beam energy and angle of incidence. Layer thickness can be varied from 20 microns to around 1 mm with different depth distributions; the position and size of the wear zone can be set to within 0.1 mm. The machine is then reassembled and operated so that wear can be measured. An example is a combustion engine comprising piston ring, cylinder wall, cooling water jacket and housing wall, where wear measurements on the cylinder wall are required in a critical zone around the dead-point of the piston ring. Proton beam bombardment creates a radioactive layer whose thickness is known accurately, and characteristic gamma radiation from this radioactive zone penetrates through the engine and is detected externally. Measurements can be made either of the activity removed from the surface, or of the (reduced) residual activity; wear measurement of the order of 10 -9 metres is possible

  13. Fabrication of functional structures on thin silicon nitride membranes

    NARCIS (Netherlands)

    Ekkels, P.; Tjerkstra, R.W.; Krijnen, Gijsbertus J.M.; Berenschot, Johan W.; Brugger, J.P.; Elwenspoek, Michael Curt

    A process to fabricate functional polysilicon structures above large (4×4 mm2) thin (200 nm), very flat LPCVD silicon rich nitride membranes was developed. Key features of this fabrication process are the use of low-stress LPCVD silicon nitride, sacrificial layer etching, and minimization of

  14. "Silicon millefeuille": From a silicon wafer to multiple thin crystalline films in a single step

    Science.gov (United States)

    Hernández, David; Trifonov, Trifon; Garín, Moisés; Alcubilla, Ramon

    2013-04-01

    During the last years, many techniques have been developed to obtain thin crystalline films from commercial silicon ingots. Large market applications are foreseen in the photovoltaic field, where important cost reductions are predicted, and also in advanced microelectronics technologies as three-dimensional integration, system on foil, or silicon interposers [Dross et al., Prog. Photovoltaics 20, 770-784 (2012); R. Brendel, Thin Film Crystalline Silicon Solar Cells (Wiley-VCH, Weinheim, Germany 2003); J. N. Burghartz, Ultra-Thin Chip Technology and Applications (Springer Science + Business Media, NY, USA, 2010)]. Existing methods produce "one at a time" silicon layers, once one thin film is obtained, the complete process is repeated to obtain the next layer. Here, we describe a technology that, from a single crystalline silicon wafer, produces a large number of crystalline films with controlled thickness in a single technological step.

  15. Highly Oriented Growth of Piezoelectric Thin Films on Silicon Using Two-Dimensional Nanosheets as Growth Template Layer.

    Science.gov (United States)

    Nguyen, Minh D; Yuan, Huiyu; Houwman, Evert P; Dekkers, Matthijn; Koster, Gertjan; Ten Elshof, Johan E; Rijnders, Guus

    2016-11-16

    Ca 2 Nb 3 O 10 (CNOns) and Ti 0.87 O 2 (TiOns) metal oxide nanosheets (ns) are used as a buffer layer for epitaxial growth of piezoelectric capacitor stacks on Si and Pt/Ti/SiO 2 /Si (Pt/Si) substrates. Highly (001)- and (110)-oriented Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) films are achieved by utilizing CNOns and TiOns, respectively. The piezoelectric capacitors are characterized by polarization and piezoelectric hysteresis loops and by fatigue measurements. The devices fabricated with SrRuO 3 top and bottom electrodes directly on nanosheets/Si have ferroelectric and piezoelectric properties well comparable with devices that use more conventional oxide buffer layers (stacks) such as YSZ, CeO 2 /YSZ, or SrTiO 3 on Si. The devices grown on nanosheets/Pt/Si with Pt top electrodes show significantly improved polarization fatigue properties over those of similar devices grown directly on Pt/Si. The differences in properties are ascribed to differences in the crystalline structures and the density of the films. These results show a route toward the fabrication of single crystal piezoelectric thin films and devices with high quality, long-lifetime piezoelectric capacitor structures on nonperovskite and even noncrystalline substrates such as glass or polished metal surfaces.

  16. On the use of a charged tunnel layer as a hole collector to improve the efficiency of amorphous silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Cangming; Sahraei, Nasim; Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Stangl, Rolf [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); Peters, Ian Marius

    2015-06-28

    A new concept, using a negatively charged tunnel layer as a hole collector, is proposed and theoretically investigated for application in amorphous silicon thin-film solar cells. The concept features a glass/transparent conductive oxide/ultra-thin negatively charged tunnel layer/intrinsic a-Si:H/n-doped a-Si:H/metal structure. The key feature of this so called t{sup +}-i-n structure is the introduction of a negatively charged tunnel layer (attracting holes from the intrinsic absorber layer), which substitutes the highly recombination active p-doped a-Si:H layer in a conventional p-i-n configuration. Atomic layer deposited aluminum oxide (ALD AlO{sub x}) is suggested as a potential candidate for such a tunnel layer. Using typical ALD AlO{sub x} parameters, a 27% relative efficiency increase (i.e., from 9.7% to 12.3%) is predicted theoretically for a single-junction a-Si:H solar cell on a textured superstrate. This prediction is based on parameters that reproduce the experimentally obtained external quantum efficiency and current-voltage characteristics of a conventional processed p-i-n a-Si:H solar cell, reaching 9.7% efficiency and serving as a reference. Subsequently, the p-doped a-Si:H layer is replaced by the tunnel layer (studied by means of numerical device simulation). Using a t{sup +}-i-n configuration instead of a conventional p-i-n configuration will not only increase the short-circuit current density (from 14.4 to 14.9 mA/cm{sup 2}, according to our simulations), it also enhances the open-circuit voltage and the fill factor (from 917 mV to 1.0 V and from 74% to 83%, respectively). For this concept to work efficiently, a high work function front electrode material or a high interface charge is needed.

  17. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    Science.gov (United States)

    Li, Hongbo

    2007-09-01

    With the worldwide growing concern about reliable energy supply and the environmental problems of fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic systems, can play a major role in the urgently needed energy transition in electricity production. Solar cells based on thin film silicon and its alloys are a promising candidate that is capable of fulfilling the fast increasing demand of a reliable solar cell supply. The conventional method to deposit silicon thin films is based on plasma enhanced chemical vapour deposition (PECVD) techniques, which have the disadvantage of increasing film inhomogeneity at a high deposition rate when scaling up for the industrial production. In this thesis, we study the possibility of making high efficiency single and multijunction thin film silicon solar cells with the so-called hot-wire CVD technique, in which no strong electromagnetic field is involved in the deposition. Therefore, the up-scaling for industrial production is straightforward. We report and discuss our findings on the correlation of substrate surface rms roughness and the main output parameter of a solar cell, the open circuit voltage Voc of c-Si:H n i p cells. By considering all the possible reasons that could influence the Voc of such cells, we conclude that the near linear correlation of Voc and substrate surface rms roughness is the result the two most probable reasons: the unintentional doping through the cracks originated near the valleys of the substrate surface due to the in-diffusion of impurities, and the high density electrical defects formed by the collision of columnar silicon structures. Both of them relate to the morphology of substrate surface. Therefore, to have the best cell performance on a rough substrate surface, a good control on the substrate surface morphology is necessary. Another issue influencing the performance of c-Si:H solar cells is the

  18. Comprehensive Die Shear Test of Silicon Packages Bonded by Thermocompression of Al Layers with Thin Sn Capping or Insertions

    Directory of Open Access Journals (Sweden)

    Shiro Satoh

    2018-04-01

    Full Text Available Thermocompression bonding for wafer-level hermetic packaging was demonstrated at the lowest temperature of 370 to 390 °C ever reported using Al films with thin Sn capping or insertions as bonding layer. For shrinking the chip size of MEMS (micro electro mechanical systems, a smaller size of wafer-level packaging and MEMS–ASIC (application specific integrated circuit integration are of great importance. Metal-based bonding under the temperature of CMOS (complementary metal-oxide-semiconductor backend process is a key technology, and Al is one of the best candidates for bonding metal in terms of CMOS compatibility. In this study, after the thermocompression bonding of two substrates, the shear fracture strength of dies was measured by a bonding tester, and the shear-fractured surfaces were observed by SEM (scanning electron microscope, EDX (energy dispersive X-ray spectrometry, and a surface profiler to clarify where the shear fracture took place. We confirmed two kinds of fracture mode. One mode is Si bulk fracture mode, where the die shear strength is 41.6 to 209 MPa, proportionally depending on the area of Si fracture. The other mode is bonding interface fracture mode, where the die shear strength is 32.8 to 97.4 MPa. Regardless of the fracture modes, the minimum die shear strength is practical for wafer-level MEMS packaging.

  19. Atomic-layer deposition of silicon nitride

    CERN Document Server

    Yokoyama, S; Ooba, K

    1999-01-01

    Atomic-layer deposition (ALD) of silicon nitride has been investigated by means of plasma ALD in which a NH sub 3 plasma is used, catalytic ALD in which NH sub 3 is dissociated by thermal catalytic reaction on a W filament, and temperature-controlled ALD in which only a thermal reaction on the substrate is employed. The NH sub 3 and the silicon source gases (SiH sub 2 Cl sub 2 or SiCl sub 4) were alternately supplied. For all these methods, the film thickness per cycle was saturated at a certain value for a wide range of deposition conditions. In the catalytic ALD, the selective deposition of silicon nitride on hydrogen-terminated Si was achieved, but, it was limited to only a thin (2SiO (evaporative).

  20. Ultra-thin silicon oxide layers on crystalline silicon wafers: Comparison of advanced oxidation techniques with respect to chemically abrupt SiO{sub 2}/Si interfaces with low defect densities

    Energy Technology Data Exchange (ETDEWEB)

    Stegemann, Bert, E-mail: bert.stegemann@htw-berlin.de [HTW Berlin - University of Applied Sciences, 12459 Berlin (Germany); Gad, Karim M. [University of Freiburg, Department of Microsystems Engineering - IMTEK, 79110 Freiburg (Germany); Balamou, Patrice [HTW Berlin - University of Applied Sciences, 12459 Berlin (Germany); Helmholtz Center Berlin for Materials and Energy (HZB), 12489 Berlin (Germany); Sixtensson, Daniel [Helmholtz Center Berlin for Materials and Energy (HZB), 12489 Berlin (Germany); Vössing, Daniel; Kasemann, Martin [University of Freiburg, Department of Microsystems Engineering - IMTEK, 79110 Freiburg (Germany); Angermann, Heike [Helmholtz Center Berlin for Materials and Energy (HZB), 12489 Berlin (Germany)

    2017-02-15

    Highlights: • Fabrication of ultrathin SiO{sub 2} tunnel layers on c-Si. • Correlation of electronic and chemical SiO{sub 2}/Si interface properties revealed by XPS/SPV. • Chemically abrupt SiO{sub 2}/Si interfaces generate less interface defect states considerable. - Abstract: Six advanced oxidation techniques were analyzed, evaluated and compared with respect to the preparation of high-quality ultra-thin oxide layers on crystalline silicon. The resulting electronic and chemical SiO{sub 2}/Si interface properties were determined by a combined x-ray photoemission (XPS) and surface photovoltage (SPV) investigation. Depending on the oxidation technique, chemically abrupt SiO{sub 2}/Si interfaces with low densities of interface states were fabricated on c-Si either at low temperatures, at short times, or in wet-chemical environment, resulting in each case in excellent interface passivation. Moreover, the beneficial effect of a subsequent forming gas annealing (FGA) step for the passivation of the SiO{sub 2}/Si interface of ultra-thin oxide layers has been proven. Chemically abrupt SiO{sub 2}/Si interfaces have been shown to generate less interface defect states.

  1. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    Science.gov (United States)

    Caridi, F.; Picciotto, A.; Vanzetti, L.; Iacob, E.; Scolaro, C.

    2015-10-01

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.

  2. Study on structural properties of epitaxial silicon films on annealed double layer porous silicon

    International Nuclear Information System (INIS)

    Yue Zhihao; Shen Honglie; Cai Hong; Lv Hongjie; Liu Bin

    2012-01-01

    In this paper, epitaxial silicon films were grown on annealed double layer porous silicon by LPCVD. The evolvement of the double layer porous silicon before and after thermal annealing was investigated by scanning electron microscope. X-ray diffraction and Raman spectroscopy were used to investigate the structural properties of the epitaxial silicon thin films grown at different temperature and different pressure. The results show that the surface of the low-porosity layer becomes smooth and there are just few silicon-bridges connecting the porous layer and the substrate wafer. The qualities of the epitaxial silicon thin films become better along with increasing deposition temperature. All of the Raman peaks of silicon films with different deposition pressure are situated at 521 cm -1 under the deposition temperature of 1100 °C, and the Raman intensity of the silicon film deposited at 100 Pa is much closer to that of the monocrystalline silicon wafer. The epitaxial silicon films are all (4 0 0)-oriented and (4 0 0) peak of silicon film deposited at 100 Pa is more symmetric.

  3. Single-crystal-like GdNdO{sub x} thin films on silicon substrates by magnetron sputtering and high-temperature annealing for crystal seed layer application

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ziwei; Xiao, Lei; Liang, Renrong, E-mail: wang-j@tsinghua.edu.cn, E-mail: liangrr@tsinghua.edu.cn; Shen, Shanshan; Xu, Jun; Wang, Jing, E-mail: wang-j@tsinghua.edu.cn, E-mail: liangrr@tsinghua.edu.cn [Tsinghua National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

    2016-06-15

    Single-crystal-like rare earth oxide thin films on silicon (Si) substrates were fabricated by magnetron sputtering and high-temperature annealing processes. A 30-nm-thick high-quality GdNdO{sub x} (GNO) film was deposited using a high-temperature sputtering process at 500°C. A Gd{sub 2}O{sub 3} and Nd{sub 2}O{sub 3} mixture was used as the sputtering target, in which the proportions of Gd{sub 2}O{sub 3} and Nd{sub 2}O{sub 3} were controlled to make the GNO’s lattice parameter match that of the Si substrate. To further improve the quality of the GNO film, a post-deposition annealing process was performed at a temperature of 1000°C. The GNO films exhibited a strong preferred orientation on the Si substrate. In addition, an Al/GNO/Si capacitor was fabricated to evaluate the dielectric constant and leakage current of the GNO films. It was determined that the single-crystal-like GNO films on the Si substrates have potential for use as an insulator layer for semiconductor-on-insulator and semiconductor/insulator multilayer applications.

  4. Single-crystal-like GdNdOx thin films on silicon substrates by magnetron sputtering and high-temperature annealing for crystal seed layer application

    Directory of Open Access Journals (Sweden)

    Ziwei Wang

    2016-06-01

    Full Text Available Single-crystal-like rare earth oxide thin films on silicon (Si substrates were fabricated by magnetron sputtering and high-temperature annealing processes. A 30-nm-thick high-quality GdNdOx (GNO film was deposited using a high-temperature sputtering process at 500°C. A Gd2O3 and Nd2O3 mixture was used as the sputtering target, in which the proportions of Gd2O3 and Nd2O3 were controlled to make the GNO’s lattice parameter match that of the Si substrate. To further improve the quality of the GNO film, a post-deposition annealing process was performed at a temperature of 1000°C. The GNO films exhibited a strong preferred orientation on the Si substrate. In addition, an Al/GNO/Si capacitor was fabricated to evaluate the dielectric constant and leakage current of the GNO films. It was determined that the single-crystal-like GNO films on the Si substrates have potential for use as an insulator layer for semiconductor-on-insulator and semiconductor/insulator multilayer applications.

  5. Solar cell fabricated on welded thin flexible silicon

    Directory of Open Access Journals (Sweden)

    Hessmann Maik Thomas

    2015-01-01

    Full Text Available We present a thin-film crystalline silicon solar cell with an AM1.5 efficiency of 11.5% fabricated on welded 50 μm thin silicon foils. The aperture area of the cell is 1.00 cm2. The cell has an open-circuit voltage of 570 mV, a short-circuit current density of 29.9 mA cm-2 and a fill factor of 67.6%. These are the first results ever presented for solar cells on welded silicon foils. The foils were welded together in order to create the first thin flexible monocrystalline band substrate. A flexible band substrate offers the possibility to overcome the area restriction of ingot-based monocrystalline silicon wafers and the feasibility of a roll-to-roll manufacturing. In combination with an epitaxial and layer transfer process a decrease in production costs can be achieved.

  6. Highly Oriented Growth of Piezoelectric Thin Films on Silicon using Two-Dimensional Nanosheets as Growth Template Layer

    NARCIS (Netherlands)

    Nguyen, Duc Minh; Yuan, H.; Houwman, Evert Pieter; Dekkers, Jan M.; Koster, Gertjan; ten Elshof, Johan E.; Rijnders, Augustinus J.H.M.

    2016-01-01

    Ca2Nb3O10 (CNOns) and Ti0.87O2 (TiOns) metal oxide nanosheets (ns) are used as a buffer layer for epitaxial growth of piezoelectric capacitor stacks on Si and Pt/Ti/SiO2/Si (Pt/Si) substrates. Highly (001)- and (110)-oriented Pb(Zr0.52Ti0.48)O3 (PZT) films are achieved by utilizing CNOns and TiOns,

  7. Thin pentacene layer under pressure

    International Nuclear Information System (INIS)

    Srnanek, R.; Jakabovic, J.; Kovac, J.; Donoval, D.; Dobrocka, E.

    2011-01-01

    Organic semiconductors have got a lot of interest during the last years, due to their usability for organic thin film transistor. Pentacene, C 22 H 14 , is one of leading candidates for this purpose. While we obtain the published data about pressure-induced phase transition only on single crystal of pentacene we present pressure-induced phase transition in pentacene thin layers for the first time. Changes in the pentacene structure, caused by the pressure, were detected by micro-Raman spectroscopy. Applying the defined pressure to the pentacene layer it can be transformed from thin phase to bulk phase. Micro-Raman spectroscopy was found as useful method for detection of changes and phases identification in the pentacene layer induced by mechanical pressure. Such a pressure-induced transformation of pentacene thin layers was observed and identified for the first time. (authors)

  8. Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Guy Beaucarne

    2007-01-01

    with plasma-enhanced chemical vapor deposition (PECVD. In spite of the fundamental limitation of this material due to its disorder and metastability, the technology is now gaining industrial momentum thanks to the entry of equipment manufacturers with experience with large-area PECVD. Microcrystalline Si (also called nanocrystalline Si is a material with crystallites in the nanometer range in an amorphous matrix, and which contains less defects than amorphous silicon. Its lower bandgap makes it particularly appropriate as active material for the bottom cell in tandem and triple junction devices. The combination of an amorphous silicon top cell and a microcrystalline bottom cell has yielded promising results, but much work is needed to implement it on large-area and to limit light-induced degradation. Finally thin-film polysilicon solar cells, with grain size in the micrometer range, has recently emerged as an alternative photovoltaic technology. The layers have a grain size ranging from 1 μm to several tens of microns, and are formed at a temperature ranging from 600 to more than 1000∘C. Solid Phase Crystallization has yielded the best results so far but there has recently been fast progress with seed layer approaches, particularly those using the aluminum-induced crystallization technique.

  9. Characterization of dielectric materials in thin layers for the development of S.O.I. (Silicon on Insulator) substrates

    International Nuclear Information System (INIS)

    Gruber, Olivier

    1999-01-01

    This thesis deals with the characterization of oxide layer placed inside S.O.I. substrates and submitted to irradiation. This type of material is used for the development of hardened electronic components, that is to say components able to be used in a radiative environment. The irradiation induces charges (electrons or holes) in the recovered oxide. A part of these charges is trapped which leads to changes of the characteristics of the electronic components made on these substrates. The main topic of this study is the characterization of trapping properties of recovered oxides and more particularly of 'Unibond' material carried out with a new fabrication process: the 'smart-cut' process. This work is divided into three parts: - study with one carrier: this case is limited to low radiation doses where is only observed holes trapping. The evolution of the physical and chemical properties of the 'Unibond' material recovered oxide has been revealed, this evolution being due to the fabrication process. - Study with two carriers: in this case, there is trapping of holes and electrons. This type of trapping is observed in the case of strong radiation doses. A new type of electrons traps has been identified with the 'Unibond' material oxide. The transport and the trapping of holes and electrons have been studied in the case of transient phenomena created by short radiative pulses. This study has been carried out using a new measurement method. - Study with three carriers: here are added to holes and electrons the protons introduced in the recovered oxide by the annealing under hydrogen. These protons are movable when they are submitted to the effect of an electric field and they induce a memory effect according to their position in the oxide. These different works show that the 'Unibond' material is a very good solution for the future development of S.O.I. (author) [fr

  10. Role of SiNx Barrier Layer on the Performances of Polyimide Ga2O3-doped ZnO p-i-n Hydrogenated Amorphous Silicon Thin Film Solar Cells

    Science.gov (United States)

    Wang, Fang-Hsing; Kuo, Hsin-Hui; Yang, Cheng-Fu; Liu, Min-Chu

    2014-01-01

    In this study, silicon nitride (SiNx) thin films were deposited on polyimide (PI) substrates as barrier layers by a plasma enhanced chemical vapor deposition (PECVD) system. The gallium-doped zinc oxide (GZO) thin films were deposited on PI and SiNx/PI substrates at room temperature (RT), 100 and 200 °C by radio frequency (RF) magnetron sputtering. The thicknesses of the GZO and SiNx thin films were controlled at around 160 ± 12 nm and 150 ± 10 nm, respectively. The optimal deposition parameters for the SiNx thin films were a working pressure of 800 × 10−3 Torr, a deposition power of 20 W, a deposition temperature of 200 °C, and gas flowing rates of SiH4 = 20 sccm and NH3 = 210 sccm, respectively. For the GZO/PI and GZO-SiNx/PI structures we had found that the GZO thin films deposited at 100 and 200 °C had higher crystallinity, higher electron mobility, larger carrier concentration, smaller resistivity, and higher optical transmittance ratio. For that, the GZO thin films deposited at 100 and 200 °C on PI and SiNx/PI substrates with thickness of ~000 nm were used to fabricate p-i-n hydrogenated amorphous silicon (α-Si) thin film solar cells. 0.5% HCl solution was used to etch the surfaces of the GZO/PI and GZO-SiNx/PI substrates. Finally, PECVD system was used to deposit α-Si thin film onto the etched surfaces of the GZO/PI and GZO-SiNx/PI substrates to fabricate α-Si thin film solar cells, and the solar cells’ properties were also investigated. We had found that substrates to get the optimally solar cells’ efficiency were 200 °C-deposited GZO-SiNx/PI. PMID:28788494

  11. Role of SiNx Barrier Layer on the Performances of Polyimide Ga2O3-doped ZnO p-i-n Hydrogenated Amorphous Silicon Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Fang-Hsing Wang

    2014-02-01

    Full Text Available In this study, silicon nitride (SiNx thin films were deposited on polyimide (PI substrates as barrier layers by a plasma enhanced chemical vapor deposition (PECVD system. The gallium-doped zinc oxide (GZO thin films were deposited on PI and SiNx/PI substrates at room temperature (RT, 100 and 200 °C by radio frequency (RF magnetron sputtering. The thicknesses of the GZO and SiNx thin films were controlled at around 160 ± 12 nm and 150 ± 10 nm, respectively. The optimal deposition parameters for the SiNx thin films were a working pressure of 800 × 10−3 Torr, a deposition power of 20 W, a deposition temperature of 200 °C, and gas flowing rates of SiH4 = 20 sccm and NH3 = 210 sccm, respectively. For the GZO/PI and GZO-SiNx/PI structures we had found that the GZO thin films deposited at 100 and 200 °C had higher crystallinity, higher electron mobility, larger carrier concentration, smaller resistivity, and higher optical transmittance ratio. For that, the GZO thin films deposited at 100 and 200 °C on PI and SiNx/PI substrates with thickness of ~1000 nm were used to fabricate p-i-n hydrogenated amorphous silicon (α-Si thin film solar cells. 0.5% HCl solution was used to etch the surfaces of the GZO/PI and GZO-SiNx/PI substrates. Finally, PECVD system was used to deposit α-Si thin film onto the etched surfaces of the GZO/PI and GZO-SiNx/PI substrates to fabricate α-Si thin film solar cells, and the solar cells’ properties were also investigated. We had found that substrates to get the optimally solar cells’ efficiency were 200 °C-deposited GZO-SiNx/PI.

  12. Method of forming buried oxide layers in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2000-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  13. Ion beam deposited epitaxial thin silicon films

    International Nuclear Information System (INIS)

    Orrman-Rossiter, K.G.; Al-Bayati, A.H.; Armour, D.G.; Donnelly, S.E.; Berg, J.A. van den

    1991-01-01

    Deposition of thin films using low energy, mass-separated ion beams is a potentially important low temperature method of producing epitaxial layers. In these experiments silicon films were grown on Si (001) substrates using 10-200 eV 28 Si + and 30 Si + ions at substrate temperatures in the range 273-1073 K, under ultrahigh-vacuum conditions (deposition pressure -7 Pa). The film crystallinity was assessed in situ using medium energy ion scattering (MEIS). Films of crystallinity comparable to bulk samples were grown using 10-40 eV 28 Si + and 30 Si + ions at deposition temperatures in the range 623-823 K. These experiments confirmed the role of key experimental parameters such as ion energy, substrate temperature during deposition, and the surface treatment prior to deposition. It was found that a high temperature in situ anneal (1350-1450 K) gave the best results for epitaxial nucleation, whereas low energy (20-40 eV) Cl + ion bombardment resulted in amorphous film growth. The deposition energy for good epitaxial growth indicates that it is necessary to provide enough energy to induce local mobility but not to cause atomic displacements leading to the buildup of stable defects, e.g. divacancies, below the surface layer of the growing film. (orig.)

  14. Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-12-15

    Magnetoelectric M-type hexaferrite thin films (SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10{sup −9} s m{sup −1} in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} thin films.

  15. Ion beam heating of thin silicon membranes

    International Nuclear Information System (INIS)

    Tissot, P.E.; Hart, R.R.

    1993-01-01

    For silicon membranes irradiated by an ion beam in a vacuum environment, such as the masks used for ion beam lithography and the membranes used for thin film self-annealing, the heat transfer modes are radiation and limited conduction through the thin membrane. The radiation component depends on the total hemispherical emissivity which varies with the thickness and temperature of the membrane. A semiempirical correlation for the absorption coefficient of high resistivity silicon was derived and the variation of the total emissivity with temperature was computed for membranes with thicknesses between 0.1 and 10 μm. Based on this result, the temperatures reached during exposure to ion beams of varying intensities were computed. A proper modeling of the emissivity is shown to be important for beam heating of thin silicon membranes. (orig.)

  16. Barrier layer arrangement for conductive layers on silicon substrates

    International Nuclear Information System (INIS)

    Hung, L.S.; Agostinelli, J.A.

    1990-01-01

    This patent describes a circuit element comprised of a silicon substrate and a conductive layer located on the substrate. It is characterized in that the conductive layer consists essentially of a rare earth alkaline earth copper oxide and a barrier layer triad is interposed between the silicon substrate and the conductive layer comprised of a first triad layer located adjacent the silicon substrate consisting essentially of silica, a third triad layer remote from the silicon substrate consisting essentially of a least one Group 4 heavy metal oxide, and a second triad layer interposed between the first and third triad layers consisting essentially of a mixture of silica and at lease one Group 4 heavy metal oxide

  17. Thin-film silicon solar cell technology

    Czech Academy of Sciences Publication Activity Database

    Shah, A. V.; Schade, H.; Vaněček, Milan; Meier, J.; Vallat-Sauvain, E.; Wyrsch, N.; Kroll, U.; Droz, C.; Bailat, J.

    2004-01-01

    Roč. 12, - (2004), s. 113-142 ISSN 1062-7995 R&D Projects: GA MŽP SN/320/11/03 Institutional research plan: CEZ:AV0Z1010914 Keywords : thin-film silicon modules * hydrogenerated amorphous silicon(a-Si:H) * hydrogenerated microcrystalline (ćc-Si:H) * transparent conductive oxydes(TCOs) * building-integrated photovoltaics(BIPV) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.196, year: 2004

  18. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Chin-Yi Tsai

    2014-01-01

    Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications. Novel and key technologies of reflective layers and 4-step laser scribing were researched, developed, and introduced into the production line to produce solar panels with various colors, such as purple, dark blue, light blue, silver, golden, orange, red wine, and coffee. The highest module power is 105 W and the highest visible light transmittance is near 20%.

  19. Atomic-Layer-Deposited Transparent Electrodes for Silicon Heterojunction Solar Cells

    International Nuclear Information System (INIS)

    Demaurex, Benedicte; Seif, Johannes P.; Smit, Sjoerd; Macco, Bart; Kessels, W. M.; Geissbuhler, Jonas; De Wolf, Stefaan; Ballif, Christophe

    2014-01-01

    We examine damage-free transparent-electrode deposition to fabricate high-efficiency amorphous silicon/crystalline silicon heterojunction solar cells. Such solar cells usually feature sputtered transparent electrodes, the deposition of which may damage the layers underneath. Using atomic layer deposition, we insert thin protective films between the amorphous silicon layers and sputtered contacts and investigate their effect on device operation. We find that a 20-nm-thick protective layer suffices to preserve, unchanged, the amorphous silicon layers beneath. Insertion of such protective atomic-layer-deposited layers yields slightly higher internal voltages at low carrier injection levels. However, we identify the presence of a silicon oxide layer, formed during processing, between the amorphous silicon and the atomic-layer-deposited transparent electrode that acts as a barrier, impeding hole and electron collection

  20. Infrared analysis of thin films amorphous, hydrogenated carbon on silicon

    CERN Document Server

    Jacob, W; Schwarz-Selinger, T

    2000-01-01

    The infrared analysis of thin films on a thick substrate is discussed using the example of plasma-deposited, amorphous, hydrogenated carbon layers (a-C:H) on silicon substrates. The framework for the optical analysis of thin films is presented. The main characteristic of thin film optics is the occurrence of interference effects due to the coherent superposition of light multiply reflected at the various internal and external interfaces of the optical system. These interference effects lead to a sinusoidal variation of the transmitted and reflected intensity. As a consequence, the Lambert-Beer law is not applicable for the determination of the absorption coefficient of thin films. Furthermore, observable changes of the transmission and reflection spectra occur in the vicinity of strong absorption bands due to the Kramers-Kronig relation. For a sound data evaluation these effects have to be included in the analysis. To be able to extract the full information contained in a measured optical thin film spectrum, ...

  1. Surface segregation as a means of gettering Cu in liquid-phase-epitaxy silicon thin layers grown from Al-Cu-Si solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.H.; Ciszek, T.F.; Reedy, R.; Asher, S.; King, D. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    The authors demonstrate that, by using the natural surface segregation phenomenon, Cu can be gettered to the surface from the bulk of silicon layers so that its concentrations in the liquid-phase-epitaxy (LPE) layers are much lower than its solubility at the layer growth temperature and the reported 10{sup 17} cm{sup {minus}3} degradation threshold for solar-cell performance. Secondary-ion mass spectroscopy (SIMS) analysis indicates that, within a micron-deep sub-surface region, Cu accumulates even in as-grown LPE samples. Slower cooling after growth to room temperature enhances this Cu enrichment. X-ray photoelectron spectroscopy (XPS) measurement shows as much as 3.2% Cu in a surface region of about 50 {Angstrom}. More surface-sensitive, ion-scattering spectroscopy (ISS) analysis further reveals about 7% of Cu at the top surface. These results translate to an areal gettering capacity of about 1.0 x 10{sup 16} cm{sup {minus}2}, which is higher than the available total-area density of Cu in the layer and substrate (3.6 x 10{sup 15} cm{sup {minus}2} for a uniform 1.2 x 10{sup 17}cm{sup {minus}3} Cu throughout the layer and substrate with a total thickness of 300 {mu}m).

  2. Oxygen measurements in thin ribbon silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hyland, S L; Ast, D G; Baghdadi, A

    1987-03-01

    The oxygen content of thin silicon ribbons grown by the dendritic web technique was measured using a modification of the ASTM method based on Fourier transform infrared spectroscopy. Web silicon was found to have a high oxygen content, ranging from 13 to 19 ppma, calculated from the absorption peak associated with interstitial oxygen and using the new ASTM conversion coefficient. The oxygen concentration changed by about 10% along the growth direction of the ribbon. In some samples, a shoulder was detected on the absorption peak. A similar shoulder in Czochralski grown material has been variously interpreted in the literature as due to a complex of silicon, oxygen, and vacancies, or to a phase of SiO/sub 2/ developed along dislocations in the material. In the case of web silicon, it is not clear which is the correct interpretation.

  3. Buried Porous Silicon-Germanium Layers in Monocrystalline Silicon Lattices

    Science.gov (United States)

    Fathauer, Robert W. (Inventor); George, Thomas (Inventor); Jones, Eric W. (Inventor)

    1998-01-01

    Monocrystalline semiconductor lattices with a buried porous semiconductor layer having different chemical composition is discussed and monocrystalline semiconductor superlattices with a buried porous semiconductor layers having different chemical composition than that of its monocrystalline semiconductor superlattice are discussed. Lattices of alternating layers of monocrystalline silicon and porous silicon-germanium have been produced. These single crystal lattices have been fabricated by epitaxial growth of Si and Si-Ge layers followed by patterning into mesa structures. The mesa structures are strain etched resulting in porosification of the Si-Ge layers with a minor amount of porosification of the monocrystalline Si layers. Thicker Si-Ge layers produced in a similar manner emitted visible light at room temperature.

  4. Hopping absorption edge in silicon inversion layers

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1983-09-01

    The low frequency gap observed in the absorption spectrum of silicon inversion layers is related to the AC variable range hopping. The frequency dependence of the absorption coefficient is calculated. (author)

  5. Optical, Electrical, and Crystal Properties of TiO2 Thin Films Grown by Atomic Layer Deposition on Silicon and Glass Substrates

    Science.gov (United States)

    Kupa, I.; Unal, Y.; Cetin, S. S.; Durna, L.; Topalli, K.; Okyay, A. K.; Ates, H.

    2018-05-01

    TiO2 thin films have been deposited on glass and Si(100) by atomic layer deposition (ALD) technique using tetrakis(diethylamido)titanium(IV) and water vapor as reactants. Thorough investigation of the properties of the TiO2/glass and TiO2/Si thin films was carried out, varying the deposition temperature in the range from 100°C to 250°C while keeping the number of reaction cycles fixed at 1000. Physical and material property analyses were performed to investigate optical and electrical properties, composition, structure, and morphology. TiO2 films grown by ALD may represent promising materials for future applications in optoelectronic devices.

  6. Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

    OpenAIRE

    Lee, Youngseok; Oh, Woongkyo; Dao, Vinh Ai; Hussain, Shahzada Qamar; Yi, Junsin

    2012-01-01

    It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT) solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO) process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get high Voc by lowering the leakage current (I0) which improves the efficie...

  7. Mechanical properties of silicon in subsurface damage layer from nano-grinding studied by atomistic simulation

    Science.gov (United States)

    Zhang, Zhiwei; Chen, Pei; Qin, Fei; An, Tong; Yu, Huiping

    2018-05-01

    Ultra-thin silicon wafer is highly demanded by semi-conductor industry. During wafer thinning process, the grinding technology will inevitably induce damage to the surface and subsurface of silicon wafer. To understand the mechanism of subsurface damage (SSD) layer formation and mechanical properties of SSD layer, atomistic simulation is the effective tool to perform the study, since the SSD layer is in the scale of nanometer and hardly to be separated from underneath undamaged silicon. This paper is devoted to understand the formation of SSD layer, and the difference between mechanical properties of damaged silicon in SSD layer and ideal silicon. With the atomistic model, the nano-grinding process could be performed between a silicon workpiece and diamond tool under different grinding speed. To reach a thinnest SSD layer, nano-grinding speed will be optimized in the range of 50-400 m/s. Mechanical properties of six damaged silicon workpieces with different depths of cut will be studied. The SSD layer from each workpiece will be isolated, and a quasi-static tensile test is simulated to perform on the isolated SSD layer. The obtained stress-strain curve is an illustration of overall mechanical properties of SSD layer. By comparing the stress-strain curves of damaged silicon and ideal silicon, a degradation of Young's modulus, ultimate tensile strength (UTS), and strain at fracture is observed.

  8. Mechanical properties of silicon in subsurface damage layer from nano-grinding studied by atomistic simulation

    Directory of Open Access Journals (Sweden)

    Zhiwei Zhang

    2018-05-01

    Full Text Available Ultra-thin silicon wafer is highly demanded by semi-conductor industry. During wafer thinning process, the grinding technology will inevitably induce damage to the surface and subsurface of silicon wafer. To understand the mechanism of subsurface damage (SSD layer formation and mechanical properties of SSD layer, atomistic simulation is the effective tool to perform the study, since the SSD layer is in the scale of nanometer and hardly to be separated from underneath undamaged silicon. This paper is devoted to understand the formation of SSD layer, and the difference between mechanical properties of damaged silicon in SSD layer and ideal silicon. With the atomistic model, the nano-grinding process could be performed between a silicon workpiece and diamond tool under different grinding speed. To reach a thinnest SSD layer, nano-grinding speed will be optimized in the range of 50-400 m/s. Mechanical properties of six damaged silicon workpieces with different depths of cut will be studied. The SSD layer from each workpiece will be isolated, and a quasi-static tensile test is simulated to perform on the isolated SSD layer. The obtained stress-strain curve is an illustration of overall mechanical properties of SSD layer. By comparing the stress-strain curves of damaged silicon and ideal silicon, a degradation of Young’s modulus, ultimate tensile strength (UTS, and strain at fracture is observed.

  9. Enhanced Electroluminescence from Silicon Quantum Dots Embedded in Silicon Nitride Thin Films Coupled with Gold Nanoparticles in Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Ana Luz Muñoz-Rosas

    2018-03-01

    Full Text Available Nowadays, the use of plasmonic metal layers to improve the photonic emission characteristics of several semiconductor quantum dots is a booming tool. In this work, we report the use of silicon quantum dots (SiQDs embedded in a silicon nitride thin film coupled with an ultra-thin gold film (AuNPs to fabricate light emitting devices. We used the remote plasma enhanced chemical vapor deposition technique (RPECVD in order to grow two types of silicon nitride thin films. One with an almost stoichiometric composition, acting as non-radiative spacer; the other one, with a silicon excess in its chemical composition, which causes the formation of silicon quantum dots imbibed in the silicon nitride thin film. The ultra-thin gold film was deposited by the direct current (DC-sputtering technique, and an aluminum doped zinc oxide thin film (AZO which was deposited by means of ultrasonic spray pyrolysis, plays the role of the ohmic metal-like electrode. We found that there is a maximum electroluminescence (EL enhancement when the appropriate AuNPs-spacer-SiQDs configuration is used. This EL is achieved at a moderate turn-on voltage of 11 V, and the EL enhancement is around four times bigger than the photoluminescence (PL enhancement of the same AuNPs-spacer-SiQDs configuration. From our experimental results, we surmise that EL enhancement may indeed be due to a plasmonic coupling. This kind of silicon-based LEDs has the potential for technology transfer.

  10. Formation and properties of porous silicon layers

    International Nuclear Information System (INIS)

    Vitanov, P.; Kamenova, M.; Dimova-Malinovska, D.

    1993-01-01

    Preparation, properties and application of porous silicon films are investigated. Porous silicon structures were formed by an electrochemical etching process resulting in selective dissolution of the silicon substrate. The silicon wafers used with a resistivity of 5-10Ω.cm were doped with B to concentrations 6x10 18 -1x10 19 Ω.cm -3 in the temperature region 950 o C-1050 o C. The density of each porous films was determined from the weight loss during the anodization and it depends on the surface resistivity of the Si wafer. The density decreases with decreasing of the surface resistivity. The surface of the porous silicon layers was studied by X-ray photoelectron spectroscopy which indicates the presence of SiF 4 . The kinetic dependence of the anode potential and the porous layer thickness on the time of anodization in a galvanostatic regime for the electrolytes with various HF concentration were studied. In order to compare the properties of the resulting porous layers and to establish the dependence of the porosity on the electrolyte, three types of electrolytes were used: concentrated HF, diluted HF:H 2 O=1:1 and ethanol-hydrofluoric solutions HF:C 2 H 5 OH:H 2 O=2:1:1. High quality uniform and reproducible layers were formed using aqueous-ethanol-hydrofluoric electrolyte. Both Kikuchi's line and ring patterns were observed by TEM. The porous silicon layer was single crystal with the same orientation as the substrate. The surface shows a polycrystalline structure only. The porous silicon layers exhibit visible photoluminescence (PL) at room temperature under 480 nm Ar + laser line excitation. The peak of PL was observed at about 730 nm with FWHM about 90 nm. Photodiodes was made with a W-porous silicon junction. The current voltage and capacity voltage characteristics were similar to those of an isotype heterojunction diode. (orig.)

  11. Thin film silicon modules on plastic superstrates

    NARCIS (Netherlands)

    Rath, J.K.; Liu, Y; Borreman, A.; Hamers, E.A.G.; Schlatmann, R.; Jongerden, G.J.; Schropp, R.E.I.

    2008-01-01

    The aim of this research is to fabricate high efficiency a-Si/μc-Si tandem solar cell modules on flexible (polymer) superstrates using the Helianthos concept. As a first step we began by depositing the top cell which contains an amorphous silicon (a-Si:H) i-layer of 350 nm made by VHF PECVD at 50

  12. Laterally inherently thin amorphous-crystalline silicon heterojunction photovoltaic cell

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Zahidur R., E-mail: zr.chowdhury@utoronto.ca; Kherani, Nazir P., E-mail: kherani@ecf.utoronto.ca [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada)

    2014-12-29

    This article reports on an amorphous-crystalline silicon heterojunction photovoltaic cell concept wherein the heterojunction regions are laterally narrow and distributed amidst a backdrop of well-passivated crystalline silicon surface. The localized amorphous-crystalline silicon heterojunctions consisting of the laterally thin emitter and back-surface field regions are precisely aligned under the metal grid-lines and bus-bars while the remaining crystalline silicon surface is passivated using the recently proposed facile grown native oxide–plasma enhanced chemical vapour deposited silicon nitride passivation scheme. The proposed cell concept mitigates parasitic optical absorption losses by relegating amorphous silicon to beneath the shadowed metallized regions and by using optically transparent passivation layer. A photovoltaic conversion efficiency of 13.6% is obtained for an untextured proof-of-concept cell illuminated under AM 1.5 global spectrum; the specific cell performance parameters are V{sub OC} of 666 mV, J{sub SC} of 29.5 mA-cm{sup −2}, and fill-factor of 69.3%. Reduced parasitic absorption, predominantly in the shorter wavelength range, is confirmed with external quantum efficiency measurement.

  13. Materials and Light Management for High-Efficiency Thin-Film Silicon Solar Cells

    OpenAIRE

    Tan, H.

    2015-01-01

    Direct conversion of sunlight into electricity is one of the most promising approaches to provide sufficient renewable energy for humankind. Solar cells are such devices which can efficiently generate electricity from sunlight through the photovoltaic effect. Thin-film silicon solar cells, a type of photovoltaic (PV) devices which deploy the chemical-vapor-deposited hydrogenated amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) and their alloys as the absorber layers and doped ...

  14. Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications

    KAUST Repository

    Ghoneim, Mohamed T.; Zidan, Mohammed A.; Al-Nassar, Mohammed Y.; Hanna, Amir; Kosel, Jü rgen; Salama, Khaled N.; Hussain, Muhammad Mustafa

    2015-01-01

    A flexible version of traditional thin lead zirconium titanate ((Pb1.1Zr0.48Ti0.52O3)-(PZT)) based ferroelectric random access memory (FeRAM) on silicon shows record performance in flexible arena. The thin PZT layer requires lower operational

  15. TXRF analysis of trace metals in thin silicon nitride films

    International Nuclear Information System (INIS)

    Vereecke, G.; Arnauts, S.; Verstraeten, K.; Schaekers, M.; Heyrts, M.M.

    2000-01-01

    As critical dimensions of integrated circuits continue to decrease, high dielectric constant materials such as silicon nitride are being considered to replace silicon dioxide in capacitors and transistors. The achievement of low levels of metal contamination in these layers is critical for high performance and reliability. Existing methods of quantitative analysis of trace metals in silicon nitride require high amounts of sample (from about 0.1 to 1 g, compared to a mass of 0.2 mg for a 2 nm thick film on a 8'' silicon wafer), and involve digestion steps not applicable to films on wafers or non-standard techniques such as neutron activation analysis. A novel approach has recently been developed to analyze trace metals in thin films with analytical techniques currently used in the semiconductor industry. Sample preparation consists of three steps: (1) decomposition of the silicon nitride matrix by moist HF condensed at the wafer surface to form ammonium fluosilicate. (2) vaporization of the fluosilicate by a short heat treatment at 300 o C. (3) collection of contaminants by scanning the wafer surface with a solution droplet (VPD-DSC procedure). The determination of trace metals is performed by drying the droplet on the wafer and by analyzing the residue by TXRF, as it offers the advantages of multi-elemental analysis with no dilution of the sample. The lower limits of detection for metals in 2 nm thick films on 8'' silicon wafers range from about 10 to 200 ng/g. The present study will focus on the matrix effects and the possible loss of analyte associated with the evaporation of the fluosilicate salt, in relation with the accuracy and the reproducibility of the method. The benefits of using an internal standard will be assessed. Results will be presented from both model samples (ammonium fluoride contaminated with metallic salts) and real samples (silicon nitride films from a production tool). (author)

  16. The influence of the electrical asymmetry effect on deposition uniformity of thin silicon film

    Energy Technology Data Exchange (ETDEWEB)

    Hrunski, D., E-mail: Dzmitry.Hrunski@leyboldoptics.com; Janssen, A.; Fritz, T.; Hegemann, T.; Clark, C.; Schreiber, U.; Grabosch, G.

    2013-04-01

    The deposition of amorphous and microcrystalline silicon is an important step in the production of thin silicon film solar panels. Deposition rate, layer uniformity and material quality are key attributes for achieving high efficiency in such panels. Due to the multilayer structure of tandem solar cells (more than 6 thin silicon layers), it is becoming increasingly important to improve the uniformity of deposition without sacrificing deposition rate and material quality. This paper reports the results of an investigation into the influence of the electrical asymmetry effect (EAE) on the uniformity of deposited layers. 13.56 MHz + 27.12 MHz excitation frequencies were used for thin silicon film deposition in a Gen5 reactor (1100 × 1400 mm). To change the plasma properties, the DC self bias voltage on the RF electrode was varied by adjustment of the phase angle between the two frequencies applied. It was found that the layers deposited by EAE method have better uniformity than layers deposited in single frequency 27.12 MHz discharge. The EAE provides additional opportunities for improvement of uniformity, deposition rate and material quality. - Highlights: ► The electrical asymmetry effect technique tested for thin silicon film deposition ► Bias voltage has an influence on film uniformity. ► Minimized the deterioration of layer uniformity while increasing discharge frequency.

  17. Infrared analysis of thin films: amorphous, hydrogenated carbon on silicon

    International Nuclear Information System (INIS)

    Jacob, Wolfgang; Keudell, Achim von; Schwarz-Selinger, Thomas

    2000-01-01

    The infrared analysis of thin films on a thick substrate is discussed using the example of plasma-deposited, amorphous, hydrogenated carbon layers (a-C:H) on silicon substrates. The framework for the optical analysis of thin films is presented. The main characteristic of thin film optics is the occurrence of interference effects due to the coherent superposition of light multiply reflected at the various internal and external interfaces of the optical system. These interference effects lead to a sinusoidal variation of the transmitted and reflected intensity. As a consequence, the Lambert-Beer law is not applicable for the determination of the absorption coefficient of thin films. Furthermore, observable changes of the transmission and reflection spectra occur in the vicinity of strong absorption bands due to the Kramers-Kronig relation. For a sound data evaluation these effects have to be included in the analysis. To be able to extract the full information contained in a measured optical thin film spectrum, an experimentally measured spectrum has to be simulated using the full formalism including the Kramers-Kronig relation. Infrared absorption spectra and the resulting k spectra in the range of the CH vibrational bands around 3000 cm -1 are presented for a variety of a-C:H layers. The shape and the total intensity of the peak are quite sensitive to the film structure. Soft, polymerlike hydrocarbon layers are characterized by a well structured, intense IR absorption band, while hard, amorphous, hydrogenated carbon layers exhibit a structureless, broad IR absorption band with relative low intensity. The k spectra of the CH vibrational bands can be considered as fingerprint for the type of a-C:H film. (author)

  18. Ferroelectric and piezoelectric responses of (110) and (001)-oriented epitaxial Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} thin films on all-oxide layers buffered silicon

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Hien Thu [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Nguyen, Minh Duc, E-mail: minh.nguyen@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); SolMateS B.V., Drienerlolaan 5, Building 6, 7522 NB Enschede (Netherlands); Houwman, Evert; Boota, Muhammad [Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Dekkers, Matthijn [SolMateS B.V., Drienerlolaan 5, Building 6, 7522 NB Enschede (Netherlands); Vu, Hung Ngoc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Rijnders, Guus [Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2015-12-15

    Graphical abstract: The cross sections show a very dense structure in the (001)-oriented films (c,d), while an open columnar growth structure is observed in the case of the (110)-oriented films (a,b). The (110)-oriented PZT films show a significantly larger longitudinal piezoelectric coefficient (d33{sub ,f}), but smaller transverse piezoelectric coefficient (d31{sub ,f}) than the (001) oriented films. - Highlights: • We fabricate all-oxide, epitaxial piezoelectric PZT thin films on Si. • The orientation of the films can be controlled by changing the buffer layer stack. • The coherence of the in-plane orientation of the grains and grain boundaries affects the ferroelectric properties. • Good cycling stability of the ferroelectric properties of (001)-oriented PZT thin films. The (110)-oriented PZT thin films show a larger d33{sub ,f} but smaller d31{sub ,f} than the (001)-oriented films. - Abstract: Epitaxial ferroelectric Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) thin films were fabricated on silicon substrates using pulsed laser deposition. Depending on the buffer layers and perovskite oxide electrodes, epitaxial films with different orientations were grown. (110)-oriented PZT/SrRuO{sub 3} (and PZT/LaNiO{sub 3}) films were obtained on YSZ-buffered Si substrates, while (001)-oriented PZT/SrRuO{sub 3} (and PZT/LaNiO{sub 3}) were fabricated with an extra CeO{sub 2} buffer layer (CeO{sub 2}/YSZ/Si). There is no effect of the electrode material on the properties of the films. The initial remnant polarizations in the (001)-oriented films are higher than those of (110)-oriented films, but it increases to the value of the (001) films upon cycling. The longitudinal piezoelectric d33{sub ,f} coefficients of the (110) films are larger than those of the (001) films, whereas the transverse piezoelectric d31{sub ,f} coefficients in the (110)-films are less than those in the (001)-oriented films. The difference is ascribed to the lower density (connectivity between

  19. Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Youngseok Lee

    2012-01-01

    Full Text Available It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get high Voc by lowering the leakage current (I0 which improves the efficiency of HIT solar cell. The ultrathin thermal passivation silicon oxide (SiO2 layer was deposited by RTO system in the temperature range 500–950°C for 2 to 6 minutes. The thickness of the silicon oxide layer was affected by RTO annealing temperature and treatment time. The best value of surface recombination velocity was recorded for the sample treated at a temperature of 850°C for 6 minutes at O2 flow rate of 3 Lpm. A surface recombination velocity below 25 cm/s was obtained for the silicon oxide layer of 4 nm thickness. This ultrathin SiO2 layer was employed for the fabrication of HIT solar cell structure instead of a-Si:H, (i layer and the passivation and tunneling effects of the silicon oxide layer were exploited. The photocurrent was decreased with the increase of illumination intensity and SiO2 thickness.

  20. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  1. Spontaneous layering of porous silicon layers formed at high current densities

    Energy Technology Data Exchange (ETDEWEB)

    Parkhutik, Vitali; Curiel-Esparza, Jorge; Millan, Mari-Carmen [R and D Center MTM, Technical University of Valencia, Valencia (Spain); Albella, Jose [Institute of Materials Science (ICMM CSIC) Madrid (Spain)

    2005-06-01

    We report here a curious effect of spontaneous fracturing of the silicon layers formed in galvanostatic conditions at medium and high current densities. Instead of formation of homogeneous p-Si layer as at low currents, a stack of thin layers is formed. Each layer is nearly separated from others and possesses rather flat interfaces. The effects is observed using p{sup +}-Si wafers for the p-Si formation and starts being noticeable at above 100 mA/cm{sup 2}. We interpret these results in terms of the porous silicon growth model where generation of dynamic mechanical stress during the p-Si growth causes sharp changes in Si dissolution mechanism from anisotropic etching of individual needle-like pores in silicon to their branching and isotropic etching. At this moment p-Si layer loses its adhesion to the surface of Si wafer and another p-Si layer starts growing. One of the mechanisms triggering on the separation of p-Si layers from one another is a fluctuation of local anodic current in the pore bottoms associated with gas bubble evolution during the p-Si formation. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Fabrication of amorphous silicon nanoribbons by atomic force microscope tip-induced local oxidation for thin film device applications

    International Nuclear Information System (INIS)

    Pichon, L; Rogel, R; Demami, F

    2010-01-01

    We demonstrate the feasibility of induced local oxidation of amorphous silicon by atomic force microscopy. The resulting local oxide is used as a mask for the elaboration of a thin film silicon resistor. A thin amorphous silicon layer deposited on a glass substrate is locally oxidized following narrow continuous lines. The corresponding oxide line is then used as a mask during plasma etching of the amorphous layer leading to the formation of a nanoribbon. Such an amorphous silicon nanoribbon is used for the fabrication of the resistor

  3. The Refractive Index Measurement Of Silicon Dioxide Thin Film by the Coupling Prism Method

    International Nuclear Information System (INIS)

    Budianto, Anwar; Hariyanto, Sigit; Subarkah

    1996-01-01

    Refractive index of silicon dioxide thin film that doped with phosphor (SiO 2 :P) above the pure silicon dioxide substrate has been measured by light coupling prism method. The method principle is focusing the light on coupling prism base so that the light propagates into the waveguide layer while the reflected one forms a mode in the observation plane. The SiO 2 thin film as waveguide layer has a refractive index that give the thick and refractive index relation. The He-Ne laser as light source has the wavelength λ 0,6328 μm. The refractive index measurement of the thin film with the substrate refractive index n sb = 1,47 and the thin film thick d = 2μm gives n g = 1,5534 ± 0,01136. This method can distinguish the refractive index of thin film about 6% to the refractive index of substrate

  4. Suppression of photo-leakage current in amorphous silicon thin-film transistors by n-doped nanocrystalline silicon

    International Nuclear Information System (INIS)

    Lin, Hung-Chien; Ho, King-Yuan; Hsu, Chih-Chieh; Yan, Jing-Yi; Ho, Jia-Chong

    2011-01-01

    The reduction of photo-leakage current of amorphous silicon thin-film transistors (a-Si TFTs) is investigated and is found to be successfully suppressed by the use of an n-doped nanocrystalline silicon layer (n+ nc-Si) as an ohmic contact layer. The shallow-level defects of n+ nc-Si can become trapping centres of photo-induced electrons as the a-Si TFT is operated under light illumination. A lower oxygen concentration during n+ nc-Si deposition can increase the creation of shallow-level defects and improve the contrast ratio of active matrix organic light-emitting diode panels.

  5. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim D.; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat s...... layers, Fracture mechanics, Crack closure, Steady state crack propagation.......An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...... results for the fracture mechanical properties have been obtained, and these are applied in a study of the effect of contacting crack faces. Special attention has been given to analyse conditions under which steady state propagation of buckling driven delamination takes place. Keywords: Delamination, Thin...

  6. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim D.; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...

  7. Thin Single Crystal Silicon Solar Cells on Ceramic Substrates: November 2009 - November 2010

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.; Ravi, K. V.

    2011-06-01

    In this program we have been developing a technology for fabricating thin (< 50 micrometres) single crystal silicon wafers on foreign substrates. We reverse the conventional approach of depositing or forming silicon on foreign substrates by depositing or forming thick (200 to 400 micrometres) ceramic materials on high quality single crystal silicon films ~ 50 micrometres thick. Our key innovation is the fabrication of thin, refractory, and self-adhering 'handling layers or substrates' on thin epitaxial silicon films in-situ, from powder precursors obtained from low cost raw materials. This 'handling layer' has sufficient strength for device and module processing and fabrication. Successful production of full sized (125 mm X 125 mm) silicon on ceramic wafers with 50 micrometre thick single crystal silicon has been achieved and device process flow developed for solar cell fabrication. Impurity transfer from the ceramic to the silicon during the elevated temperature consolidation process has resulted in very low minority carrier lifetimes and resulting low cell efficiencies. Detailed analysis of minority carrier lifetime, metals analysis and device characterization have been done. A full sized solar cell efficiency of 8% has been demonstrated.

  8. Nano-Photonic Structures for Light Trapping in Ultra-Thin Crystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Prathap Pathi

    2017-01-01

    Full Text Available Thick wafer-silicon is the dominant solar cell technology. It is of great interest to develop ultra-thin solar cells that can reduce materials usage, but still achieve acceptable performance and high solar absorption. Accordingly, we developed a highly absorbing ultra-thin crystalline Si based solar cell architecture using periodically patterned front and rear dielectric nanocone arrays which provide enhanced light trapping. The rear nanocones are embedded in a silver back reflector. In contrast to previous approaches, we utilize dielectric photonic crystals with a completely flat silicon absorber layer, providing expected high electronic quality and low carrier recombination. This architecture creates a dense mesh of wave-guided modes at near-infrared wavelengths in the absorber layer, generating enhanced absorption. For thin silicon (<2 μm and 750 nm pitch arrays, scattering matrix simulations predict enhancements exceeding 90%. Absorption approaches the Lambertian limit at small thicknesses (<10 μm and is slightly lower (by ~5% at wafer-scale thicknesses. Parasitic losses are ~25% for ultra-thin (2 μm silicon and just 1%–2% for thicker (>100 μm cells. There is potential for 20 μm thick cells to provide 30 mA/cm2 photo-current and >20% efficiency. This architecture has great promise for ultra-thin silicon solar panels with reduced material utilization and enhanced light-trapping.

  9. Structural, optical and mechanical properties of thin diamond and silicon carbide layers grown by low pressure microwave linear antenna plasma enhanced chemical vapour deposition

    Czech Academy of Sciences Publication Activity Database

    Taylor, Andrew; Drahokoupil, Jan; Fekete, Ladislav; Klimša, Ladislav; Kopeček, Jaromír; Purkrt, Adam; Remeš, Zdeněk; Čtvrtlík, Radim; Tomáštík, Jan; Frank, Otakar; Janíček, P.; Mistrík, J.; Mortet, Vincent

    2016-01-01

    Roč. 69, Oct (2016), s. 13-18 ISSN 0925-9635 R&D Projects: GA MŠk LO1409; GA TA ČR TA03010743; GA ČR GA13-31783S; GA MŠk(CZ) LD14011; GA MŠk LM2015088 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568; AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 ; RVO:61388955 Keywords : diamond * silicon carbide * adherence * mechanical properties * optical properties Subject RIV: BM - Solid Matter Physics ; Magnetism; CG - Electrochemistry (UFCH-W) Impact factor: 2.561, year: 2016

  10. Experimental investigation of the excess charge and time constant of minority carriers in the thin diffused layer of 0.1 Ohm-cm silicon solar cells

    Science.gov (United States)

    Godlewski, M. P.; Brandhorst, H. W., Jr.; Lindholm, F. A.; Sah, C. T.

    1976-01-01

    The observed low open-circuit voltage in 0.1 Ohm-cm solar cells is probably related to an excessively high diode saturation current. Theoretical studies conducted by Lindholm et al. (1975) and by Godlewski et al. (1975) have shown that a high saturation current could be produced by either high recombination rates or bandgap narrowing effects. A description is given of an investigation which shows that bandgap narrowing effects have a first order significance in determining the charge carrier transport controlling the open-circuit voltage of 0.1 Ohm-cm silicon solar cells.

  11. Photo and electroluminescence of porous silicon layers

    International Nuclear Information System (INIS)

    Keshmini, S.H.; Samadpour, S.; Haji-Ali, E.; Rokn-Abadi, M.R.

    1995-01-01

    Porous silicon (PSi) layers were prepared by both chemical and electrochemical methods on n- and p-type Si substrates. In the former technique, light emission was obtained from p-type and n-type samples. It was found that intense light illumination during the preparation process was essential for PSi formation on n-type substrates. An efficient electrochemical cell with some useful features was designed for electrochemical etching of silicon. Various preparation parameters were studied and photoluminescence emissions ranging from dark red to light blue were obtained from PSi samples prepared on p-type substrates. N-type samples produced emission ranging from dark red to orange yellow. Electroluminescence of porous silicon samples showed that the color of the emission was the same as the photoluminescence color of the sample, and its intensity and duration depended on the current density passed through the sample. The effects of exposure of samples to air, storage in vacuum and heat treatment in air on luminescence intensity of the samples and preparation of patterned porous layers were also studied. (author)

  12. Application of plasma silicon nitride to crystalline thin-film silicon solar cells. Paper

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, J.; Oberbeck, L.; Rinke, T.J.; Berge, C.; Bergmann, R.B.

    2002-07-01

    We use plasma-enhanced chemical vapour deposition to deposit silicon nitride (SiN{sub x}) films at low temperature(400 C) onto the front surface of two different types of crystalline thin-film Si solar cells. The silicon nitride acts as an excellent antireflection coating on Si and provides a very high degree of electronic surface passivation over a wide range of compositions, including near-stoichiometric and Si-rich SiN{sub x}. Application of stoichiometric SiN{sub x} to non-textured thin-film cells, epitaxially grown at low temperature by ion-assisted deposition onto a monocrystalline Si substrate, results in an open-circuit voltage of 622 mV, a short-circuit current density of 26.6 mA/cm{sup 2} and an efficiency of 12.7%. It is shown that the SiN{sub x}-passivated in-situ grown n{sup +}-emitter of this cell type allows to reach open-circuit voltages of up to 667 mV. Silicon-rich SiN{sub x} is applied to the phosphorus-diffused n{sup +}-emitter of a textured thin-film cell on a glass superstrate fabricated by layer-transfer. The emitter saturation current density of these cells is only 40-64 fA/cm{sup 2}, which allows for open-circuit voltages of up to 699 mV. An impressively high open-circuit voltage of 638 mV and a short-circuit current density of 32.0 mA/cm{sup 2} are obtained for a 25 {mu}m thick SiN{sub x}-passivated, random pyramid-textured transfer cell. A transfer cell efficiency of 15.3% is independently confirmed.

  13. Thin film silicon modules: contributions to low cost industrial production

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A. [Universite de Neuchatel, Neuchatel (Switzerland)

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses the research work done during the two-year period 2003-04 at the Thin-Film Solar Cell Laboratory of the Institute of Microtechnology (IMT) at the University of Neuchatel in Switzerland. The transition from fundamental research work to concrete industrialisation issues, and changes within the research staff are discussed. The main results of the work done are presented, including basic techniques for the production of p-i-n solar cells on glass, new technologies for the deposition of n-i-p cells on low-cost flexible substrates and the optimisation of zinc oxide deposition methods. The key role played by substrate chemistry and roughness in the nucleation and growth of micro-crystalline silicon layers is looked at and diagnostic tools for the analysis of micro-crystalline solar cells are discussed.

  14. Optical characterisation of sputtered hydrogenated amorphous silicon thin films

    International Nuclear Information System (INIS)

    Mellassi, K.; Chafik El Idrissi, M.; Chouiyakh, A.; Rjeb, A.; Barhdadi, A.

    2000-09-01

    The present work is devoted to the study of some optical properties of hydrogenated amorphous silicon (a-Si:H) thin films prepared by radio-frequency cathodic sputtering technique. It is essentially focused on investigating separately the effects of increasing partial hydrogen pressure during the deposition stage, and the effects of post deposition thermal annealing on the main optical parameters of the deposited layers (refraction index, optical gap Urbach energy, etc.). We show that low hydrogen pressures allow a saturation of the dangling bonds in the material, while high pressures lead to the creation of new defects. We also show that thermal annealing under moderate temperatures allows a good improvement of the structural quality of deposited films. (author)

  15. Thin layers in actinide research

    International Nuclear Information System (INIS)

    Gouder, T.

    1998-01-01

    Surface science research at the ITU is focused on the synthesis and surface spectroscopy studies of thin films of actinides and actinide compounds. The surface spectroscopies used are X-ray and ultra violet photoelectron spectroscopy (XPS and UPS, respectively), and Auger electron spectroscopy (AES). Thin films of actinide elements and compounds are prepared by sputter deposition from elemental targets. Alloy films are deposited from corresponding alloy targets and could be used, in principle, as replicates of these targets. However, there are deviations between alloy film and target composition, which depend on the deposition conditions, such as pressure and target voltage. Mastering of these effects may allow us to study stoichiometric film replicates instead of thick bulk compounds. As an example, we discuss the composition of U-Ni films prepared from a UNi 5 target. (orig.)

  16. Laser process for extended silicon thin film solar cells

    International Nuclear Information System (INIS)

    Hessmann, M.T.; Kunz, T.; Burkert, I.; Gawehns, N.; Schaefer, L.; Frick, T.; Schmidt, M.; Meidel, B.; Auer, R.; Brabec, C.J.

    2011-01-01

    We present a large area thin film base substrate for the epitaxy of crystalline silicon. The concept of epitaxial growth of silicon on large area thin film substrates overcomes the area restrictions of an ingot based monocrystalline silicon process. Further it opens the possibility for a roll to roll process for crystalline silicon production. This concept suggests a technical pathway to overcome the limitations of silicon ingot production in terms of costs, throughput and completely prevents any sawing losses. The core idea behind these thin film substrates is a laser welding process of individual, thin silicon wafers. In this manuscript we investigate the properties of laser welded monocrystalline silicon foils (100) by micro-Raman mapping and spectroscopy. It is shown that the laser beam changes the crystalline structure of float zone grown silicon along the welding seam. This is illustrated by Raman mapping which visualizes compressive stress as well as tensile stress in a range of - 147.5 to 32.5 MPa along the welding area.

  17. Atomic Layer Deposition Alumina-Passivated Silicon Nanowires: Probing the Transition from Electrochemical Double-Layer Capacitor to Electrolytic Capacitor.

    Science.gov (United States)

    Gaboriau, Dorian; Boniface, Maxime; Valero, Anthony; Aldakov, Dmitry; Brousse, Thierry; Gentile, Pascal; Sadki, Said

    2017-04-19

    Silicon nanowires were coated by a 1-5 nm thin alumina layer by atomic layer deposition (ALD) in order to replace poorly reproducible and unstable native silicon oxide by a highly conformal passivating alumina layer. The surface coating enabled probing the behavior of symmetric devices using such electrodes in the EMI-TFSI electrolyte, allowing us to attain a large cell voltage up to 6 V in ionic liquid, together with very high cyclability with less than 4% capacitance fade after 10 6 charge/discharge cycles. These results yielded fruitful insights into the transition between an electrochemical double-layer capacitor behavior and an electrolytic capacitor behavior. Ultimately, thin ALD dielectric coatings can be used to obtain hybrid devices exhibiting large cell voltage and excellent cycle life of dielectric capacitors, while retaining energy and power densities close to the ones displayed by supercapacitors.

  18. Optical absorption in silicon layers in the presence of charge inversion/accumulation or ion implantation

    International Nuclear Information System (INIS)

    Alloatti, L.; Lauermann, M.; Koos, C.; Freude, W.; Sürgers, C.; Leuthold, J.

    2013-01-01

    We determine the optical losses in gate-induced charge accumulation/inversion layers at a Si/SiO 2 interface. Comparison between gate-induced charge layers and ion-implanted thin silicon films having an identical sheet resistance shows that optical losses can be significantly lower for gate-induced layers. For a given sheet resistance, holes produce higher optical loss than electrons. Measurements have been performed at λ = 1550 nm

  19. Thin film silicon by a microwave plasma deposition technique: Growth and devices, and, interface effects in amorphous silicon/crystalline silicon solar cells

    Science.gov (United States)

    Jagannathan, Basanth

    Thin film silicon (Si) was deposited by a microwave plasma CVD technique, employing double dilution of silane, for the growth of low hydrogen content Si films with a controllable microstructure on amorphous substrates at low temperatures (prepared by this technique. Such films showed a dark conductivity ˜10sp{-6} S/cm, with a conduction activation energy of 0.49 eV. Film growth and properties have been compared for deposition in Ar and He carrier systems and growth models have been proposed. Low temperature junction formation by undoped thin film silicon was examined through a thin film silicon/p-type crystalline silicon heterojunctions. The thin film silicon layers were deposited by rf glow discharge, dc magnetron sputtering and microwave plasma CVD. The hetero-interface was identified by current transport analysis and high frequency capacitance methods as the key parameter controlling the photovoltaic (PV) response. The effect of the interface on the device properties (PV, junction, and carrier transport) was examined with respect to modifications created by chemical treatment, type of plasma species, their energy and film microstructure interacting with the substrate. Thermally stimulated capacitance was used to determine the interfacial trap parameters. Plasma deposition of thin film silicon on chemically clean c-Si created electron trapping sites while hole traps were seen when a thin oxide was present at the interface. Under optimized conditions, a 10.6% efficient cell (11.5% with SiOsb2 A/R) with an open circuit voltage of 0.55 volts and a short circuit current density of 30 mA/cmsp2 was fabricated.

  20. Material Properties of Laser-Welded Thin Silicon Foils

    Directory of Open Access Journals (Sweden)

    M. T. Hessmann

    2013-01-01

    Full Text Available An extended monocrystalline silicon base foil offers a great opportunity to combine low-cost production with high efficiency silicon solar cells on a large scale. By overcoming the area restriction of ingot-based monocrystalline silicon wafer production, costs could be decreased to thin film solar cell range. The extended monocrystalline silicon base foil consists of several individual thin silicon wafers which are welded together. A comparison of three different approaches to weld 50 μm thin silicon foils is investigated here: (1 laser spot welding with low constant feed speed, (2 laser line welding, and (3 keyhole welding. Cross-sections are prepared and analyzed by electron backscatter diffraction (EBSD to reveal changes in the crystal structure at the welding side after laser irradiation. The treatment leads to the appearance of new grains and boundaries. The induced internal stress, using the three different laser welding processes, was investigated by micro-Raman analysis. We conclude that the keyhole welding process is the most favorable to produce thin silicon foils.

  1. Photonic intermediate layer for silicon tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bielawny, Andreas; Miclea, Paul-Tiberiu; Wehrspohn, Ralf [Martin-Luther Universitaet Halle-Wittenberg (Germany). Inst. fuer Physik, Mikro-MD; Lee, Seuong-Mo; Knez, Mato [Max-Planck-Inst. fuer Mikrostrukturphysik, Halle (Germany); Carius, Reinhard [Forschungszentrum Juelich (DE). Inst. fuer Photovoltaik (IEF-5); Lisca, Marian; Rockstuhl, Carsten; Lederer, Falk [Universitaet Jena (Germany). Dept. Physik

    2008-07-01

    The concept of incorporation of a 3D photonic crystal as diffractive spectral filter within a-Si/mc-Si tandem solar cells has been investigated as a promising application. Our intermediate reflective filter enhances the pathway of spectrally selected light within an amorphous silicon top cell in its spectral region of low absorption. From our previous work, we expect a significant improvement of the tandem's efficiency of about 1.2%(absolute). This increases efficiency for a typical silicon tandem cell from 11.2% to 12.4%, as a result of the optical current-matching of the two junctions. Our wavelength-selective optical element is a 3D-structured optical thin-film - prepared by self-organized artificial opal templates and finalized with atomic layer deposition techniques. The resulting samples are highly periodical thin-film inverted opals made of zinc-oxide. We compare recent experimental data on the optical properties with our simulations and photonic bandstructure calculations.

  2. Thin film silicon photovoltaics: Architectural perspectives and technological issues

    Energy Technology Data Exchange (ETDEWEB)

    Mercaldo, Lucia Vittoria; Addonizio, Maria Luisa; Noce, Marco Della; Veneri, Paola Delli; Scognamiglio, Alessandra; Privato, Carlo [ENEA, Portici Research Center, Piazzale E. Fermi, 80055 Portici (Napoli) (Italy)

    2009-10-15

    Thin film photovoltaics is a particularly attractive technology for building integration. In this paper, we present our analysis on architectural issues and technological developments of thin film silicon photovoltaics. In particular, we focus on our activities related to transparent and conductive oxide (TCO) and thin film amorphous and microcrystalline silicon solar cells. The research on TCO films is mainly dedicated to large-area deposition of zinc oxide (ZnO) by low pressure-metallorganic chemical vapor deposition. ZnO material, with a low sheet resistance (<8 {omega}/sq) and with an excellent transmittance (>82%) in the whole wavelength range of photovoltaic interest, has been obtained. ''Micromorph'' tandem devices, consisting of an amorphous silicon top cell and a microcrystalline silicon bottom cell, are fabricated by using the very high frequency plasma enhanced chemical vapor deposition technique. An initial efficiency of 11.1% (>10% stabilized) has been obtained. (author)

  3. Light-Induced Degradation of Thin Film Silicon Solar Cells

    International Nuclear Information System (INIS)

    Hamelmann, F U; Weicht, J A; Behrens, G

    2016-01-01

    Silicon-wafer based solar cells are still domination the market for photovoltaic energy conversion. However, most of the silicon is used only for mechanical stability, while only a small percentage of the material is needed for the light absorption. Thin film silicon technology reduces the material demand to just some hundred nanometer thickness. But even in a tandem stack (amorphous and microcrystalline silicon) the efficiencies are lower, and light-induced degradation is an important issue. The established standard tests for characterisation are not precise enough to predict the performance of thin film silicon solar cells under real conditions, since many factors do have an influence on the degradation. We will show some results of laboratory and outdoor measurements that we are going to use as a base for advanced modelling and simulation methods. (paper)

  4. Analysis of the silicon market: Will thin films profit?

    International Nuclear Information System (INIS)

    Sark, W.G.J.H.M. van; Brandsen, G.W.; Fleuster, M.; Hekkert, M.P.

    2007-01-01

    The photovoltaic industry has been growing with astonishing rates over the past years. The supply of silicon to the wafer-based industry has recently become a problem. This paper presents a thorough analysis of the PV industry and quantifies the silicon shortage. It is expected that this leads to a decrease in production in 2006 rather than the usual increase. Due to a mismatch in expansion plans of silicon feedstock manufacturers and solar cell manufacturers, a large cell overcapacity will persist up to 2010. The thin-film PV market is expected to profit from the silicon shortage problem; its market share may substantially increase to about 25% in 2010

  5. Analysis of the silicon market: Will thin films profit?

    Energy Technology Data Exchange (ETDEWEB)

    Sark, W.G.J.H.M. van; Brandsen, G.W. [Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Utrecht (Netherlands). Department of Science, Technology and Society; Fleuster, M. [Solland Solar Energy, Heerlen (Netherlands); Hekkert, M.P. [Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Utrecht (Netherlands). Department of Innovation Studies

    2007-06-15

    The photovoltaic industry has been growing with astonishing rates over the past years. The supply of silicon to the wafer-based industry has recently become a problem. This paper presents a thorough analysis of the PV industry and quantifies the silicon shortage. It is expected that this leads to a decrease in production in 2006 rather than the usual increase. Due to a mismatch in expansion plans of silicon feedstock manufacturers and solar cell manufacturers, a large cell overcapacity will persist up to 2010. The thin-film PV market is expected to profit from the silicon shortage problem; its market share may substantially increase to about 25% in 2010. (author)

  6. Surface Plasmon Enhanced Light Trapping in Metal/Silicon Nanobowl Arrays for Thin Film Photovoltaics

    Directory of Open Access Journals (Sweden)

    Ruinan Sun

    2017-01-01

    Full Text Available Enhancing the light absorption in thin film silicon solar cells with nanophotonic and plasmonic structures is important for the realization of high efficiency solar cells with significant cost reduction. In this work, we investigate periodic arrays of conformal metal/silicon nanobowl arrays (MSNBs for light trapping applications in silicon solar cells. They exhibited excellent light-harvesting ability across a wide range of wavelengths up to infrared regimes. The optimized structure (MSNBsH covered by SiO2 passivation layer and hemisphere Ag back reflection layer has a maximal short-circuit density (Jsc 25.5 mA/cm2, which is about 88.8% higher than flat structure counterpart, and the light-conversion efficiency (η is increased two times from 6.3% to 12.6%. The double-side textures offer a promising approach to high efficiency ultrathin silicon solar cells.

  7. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.; Hoogland, Sjoerd; Adachi, Michael M.; Kanjanaboos, Pongsakorn; Wong, Chris T. O.; McDowell, Jeffrey J.; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J.; Sargent, Edward H.

    2014-01-01

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  8. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  9. Implanted Silicon Resistor Layers for Efficient Terahertz Absorption

    Science.gov (United States)

    Chervenak, J. A.; Abrahams, J.; Allen, C. A.; Benford, D. J.; Henry, R.; Stevenson, T.; Wollack, E.; Moseley, S. H.

    2005-01-01

    Broadband absorption structures are an essential component of large format bolometer arrays for imaging GHz and THz radiation. We have measured electrical and optical properties of implanted silicon resistor layers designed to be suitable for these absorbers. Implanted resistors offer a low-film-stress, buried absorber that is robust to longterm aging, temperature, and subsequent metals processing. Such an absorber layer is readily integrated with superconducting integrated circuits and standard micromachining as demonstrated by the SCUBA II array built by ROE/NIST (1). We present a complete characterization of these layers, demonstrating frequency regimes in which different recipes will be suitable for absorbers. Single layer thin film coatings have been demonstrated as effective absorbers at certain wavelengths including semimetal (2,3), thin metal (4), and patterned metal films (5,6). Astronomical instrument examples include the SHARC II instrument is imaging the submillimeter band using passivated Bi semimetal films and the HAWC instrument for SOFIA, which employs ultrathin metal films to span 1-3 THz. Patterned metal films on spiderweb bolometers have also been proposed for broadband detection. In each case, the absorber structure matches the impedance of free space for optimal absorption in the detector configuration (typically 157 Ohms per square for high absorption with a single or 377 Ohms per square in a resonant cavity or quarter wave backshort). Resonant structures with -20% bandwidth coupled to bolometers are also under development; stacks of such structures may take advantage of instruments imaging over a wide band. Each technique may enable effective absorbers in imagers. However, thin films tend to age, degrade or change during further processing, can be difficult to reproduce, and often exhibit an intrinsic granularity that creates complicated frequency dependence at THz frequencies. Thick metal films are more robust but the requirement for

  10. Enhancement of photovoltaic properties of multicrystalline silicon solar cells by combination of buried metallic contacts and thin porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ben Rabha, M.; Bessais, B. [Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2010-03-15

    Photovoltaic properties of buried metallic contacts (BMCs) with and without application of a front porous silicon (PS) layer on multicrystalline silicon (mc-Si) solar cells were investigated. A Chemical Vapor Etching (CVE) method was used to perform front PS layer and BMCs of mc-Si solar cells. Good electrical performance for the mc-Si solar cells was observed after combination of BMCs and thin PS films. As a result the current-voltage (I-V) characteristics and the internal quantum efficiency (IQE) were improved, and the effective minority carrier diffusion length (Ln) increases from 75 to 110 {mu}m after BMCs achievement. The reflectivity was reduced to 8% in the 450-950 nm wavelength range. This simple and low cost technology induces a 12% conversion efficiency (surface area = 3.2 cm{sup 2}). The obtained results indicate that the BMCs improve charge carrier collection while the PS layer passivates the front surface. (author)

  11. Preparation of Ferroelectric Thin Films of Bismuth Layer Structured Compounds

    Science.gov (United States)

    Watanabe, Hitoshi; Mihara, Takashi; Yoshimori, Hiroyuki; Araujo, Carlos

    1995-09-01

    Ferroelectric thin films of bismuth layer structured compounds, SrBi2Ta2O9, SrBi2Nb2O9, SrBi4Ti4O15 and their solid solutions, were formed onto a sputtered platinum layer on a silicon substrate using spin-on technique and metal-organic decomposition (MOD) method. X-ray diffraction (XRD) analysis and some electrical measurements were performed on the prepared thin films. XRD results of SrBi2(Ta1- x, Nb x)2O9 films (0≤x≤1) showed that niobium ions substitute for tantalum ions in an arbitrary ratio without any change of the layer structure and lattice constants. Furthermore, XRD results of SrBi2 xTa2O9 films (0≤x≤1.5) indicated that the formation of the bismuth layer structure does not always require an accurate bismuth content. The layer structure was formed above 50% of the stoichiometric bismuth content in the general formula. SrBi2(Ta1- x, Nb x)2O9 films with various Ta/Nb ratios have large enough remanent polarization for nonvolatile memory application and have shown high fatigue resistance against 1011 cycles of full switching of the remanent polarization. Mixture films of the three compounds were also investigated.

  12. Method of producing buried porous silicon-geramanium layers in monocrystalline silicon lattices

    Science.gov (United States)

    Fathauer, Robert W. (Inventor); George, Thomas (Inventor); Jones, Eric W. (Inventor)

    1997-01-01

    Lattices of alternating layers of monocrystalline silicon and porous silicon-germanium have been produced. These single crystal lattices have been fabricated by epitaxial growth of Si and Si--Ge layers followed by patterning into mesa structures. The mesa structures are stain etched resulting in porosification of the Si--Ge layers with a minor amount of porosification of the monocrystalline Si layers. Thicker Si--Ge layers produced in a similar manner emitted visible light at room temperature.

  13. Superlattice doped layers for amorphous silicon photovoltaic cells

    Science.gov (United States)

    Arya, Rajeewa R.

    1988-01-12

    Superlattice doped layers for amorphous silicon photovoltaic cells comprise a plurality of first and second lattices of amorphous silicon alternatingly formed on one another. Each of the first lattices has a first optical bandgap and each of the second lattices has a second optical bandgap different from the first optical bandgap. A method of fabricating the superlattice doped layers also is disclosed.

  14. Layer-by-layer assembly of thin film oxygen barrier

    International Nuclear Information System (INIS)

    Jang, Woo-Sik; Rawson, Ian; Grunlan, Jaime C.

    2008-01-01

    Thin films of sodium montmorillonite clay and cationic polyacrylamide were grown on a polyethylene terephthalate film using layer-by-layer assembly. After 30 clay-polymer layers are deposited, with a thickness of 571 nm, the resulting transparent film has an oxygen transmission rate (OTR) below the detection limit of commercial instrumentation ( 2 /day/atm). This low OTR, which is unprecedented for a clay-filled polymer composite, is believed to be due to a brick wall nanostructure comprised of completely exfoliated clay in polymeric mortar. With an optical transparency greater than 90% and potential for microwaveability, this thin composite is a good candidate for foil replacement in food packaging and may also be useful for flexible electronics packaging

  15. Study of Nitrogen Effect on the Boron Diffusion during Heat Treatment in Polycrystalline Silicon/Nitrogen-Doped Silicon Thin Films

    Science.gov (United States)

    Saci, Lynda; Mahamdi, Ramdane; Mansour, Farida; Boucher, Jonathan; Collet, Maéva; Bedel Pereira, Eléna; Temple-Boyer, Pierre

    2011-05-01

    The present paper studies the boron (B) diffusion in nitrogen (N) doped amorphous silicon (a-Si) layer in original bi-layer B-doped polycrystalline silicon (poly-Si)/in-situ N-doped Si layers (NIDOS) thin films deposited by low pressure chemical vapor deposition (LPCVD) technique. The B diffusion in the NIDOS layer was investigated by secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectroscopy (FTIR) analysis. A new extended diffusion model is proposed to fit the SIMS profile of the bi-layer films. This model introduces new terms which take into account the effect of N concentration on the complex diffusion phenomena of B atoms in bi-layer films. SIMS results show that B diffusion does not exceed one third of NIDOS layer thickness after annealing. The reduction of the B diffusion in the NIDOS layer is due to the formation of complex B-N as shown by infrared absorption measurements. Electrical measurements using four-probe and Hall effect techniques show the good conductivity of the B-doped poly-Si layer after annealing treatment.

  16. Design criteria for XeF{sub 2} enabled deterministic transformation of bulk silicon (100) into flexible silicon layer

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Aftab M.; Shaikh, Sohail F.; Hussain, Muhammad M., E-mail: muhammadmustafa.hussain@kaust.edu.sa [Integrated Nanotechnology Laboratory (INL) and Integrated Disruptive Electronics Applications (IDEA) Laboratory, Computer Electrical Mathematical Science and Engineering Division, King Abdullah University of Science and Technology - KAUST, Thuwal 23955-6900 (Saudi Arabia)

    2016-07-15

    Isotropic etching of bulk silicon (100) using Xenon Difluoride (XeF{sub 2}) gas presents a unique opportunity to undercut and release ultra-thin flexible silicon layers with pre-fabricated state-of-the-art Complementary Metal Oxide Semiconductor (CMOS) electronics. In this work, we present design criteria and mechanism with a comprehensive mathematical model for this method. We consider various trench geometries and parametrize important metrics such as etch time, number of cycles and area efficiency in terms of the trench diameter and spacing so that optimization can be done for specific applications. From our theoretical analysis, we conclude that a honeycomb-inspired hexagonal distribution of trenches can produce the most efficient release of ultra-thin flexible silicon layers in terms of the number of etch cycles, while a rectangular distribution of circular trenches provides the most area efficient design. The theoretical results are verified by fabricating and releasing (varying sizes) flexible silicon layers. We observe uniform translation of design criteria into practice for etch distances and number of etch cycles, using reaction efficiency as a fitting parameter.

  17. Design criteria for XeF2 enabled deterministic transformation of bulk silicon (100) into flexible silicon layer

    KAUST Repository

    Hussain, Aftab M.

    2016-07-15

    Isotropic etching of bulk silicon (100) using Xenon Difluoride (XeF2) gas presents a unique opportunity to undercut and release ultra-thin flexible silicon layers with pre-fabricated state-of-the-art Complementary Metal Oxide Semiconductor (CMOS) electronics. In this work, we present design criteria and mechanism with a comprehensive mathematical model for this method. We consider various trench geometries and parametrize important metrics such as etch time, number of cycles and area efficiency in terms of the trench diameter and spacing so that optimization can be done for specific applications. From our theoretical analysis, we conclude that a honeycomb-inspired hexagonal distribution of trenches can produce the most efficient release of ultra-thin flexible silicon layers in terms of the number of etch cycles, while a rectangular distribution of circular trenches provides the most area efficient design. The theoretical results are verified by fabricating and releasing (varying sizes) flexible silicon layers. We observe uniform translation of design criteria into practice for etch distances and number of etch cycles, using reaction efficiency as a fitting parameter.

  18. Design criteria for XeF2 enabled deterministic transformation of bulk silicon (100) into flexible silicon layer

    KAUST Repository

    Hussain, Aftab M.; Shaikh, Sohail F.; Hussain, Muhammad Mustafa

    2016-01-01

    Isotropic etching of bulk silicon (100) using Xenon Difluoride (XeF2) gas presents a unique opportunity to undercut and release ultra-thin flexible silicon layers with pre-fabricated state-of-the-art Complementary Metal Oxide Semiconductor (CMOS) electronics. In this work, we present design criteria and mechanism with a comprehensive mathematical model for this method. We consider various trench geometries and parametrize important metrics such as etch time, number of cycles and area efficiency in terms of the trench diameter and spacing so that optimization can be done for specific applications. From our theoretical analysis, we conclude that a honeycomb-inspired hexagonal distribution of trenches can produce the most efficient release of ultra-thin flexible silicon layers in terms of the number of etch cycles, while a rectangular distribution of circular trenches provides the most area efficient design. The theoretical results are verified by fabricating and releasing (varying sizes) flexible silicon layers. We observe uniform translation of design criteria into practice for etch distances and number of etch cycles, using reaction efficiency as a fitting parameter.

  19. HOLE-BLOCKING LAYERS FOR SILICON/ORGANIC HETEROJUNCTIONS: A NEW CLASS OF HIGH-EFFICIENCY LOW-COST PV

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, James [Princeton Univ., NJ (United States)

    2017-12-04

    This project is the first investigation of the use of thin titanium dioxide layers on silicon as a hole-blocking / electron-transparent selective contact to silicon. The work was motivated by the goal of a high-efficiency low-cost silicon-based solar cells that could be processed entirely at low temperature (300 Degree Celsius) or less, without requiring plasma-processing.

  20. Silicon solar cell performance deposited by diamond like carbon thin film ;Atomic oxygen effects;

    Science.gov (United States)

    Aghaei, Abbas Ail; Eshaghi, Akbar; Karami, Esmaeil

    2017-09-01

    In this research, a diamond-like carbon thin film was deposited on p-type polycrystalline silicon solar cell via plasma-enhanced chemical vapor deposition method by using methane and hydrogen gases. The effect of atomic oxygen on the functioning of silicon coated DLC thin film and silicon was investigated. Raman spectroscopy, field emission scanning electron microscopy, atomic force microscopy and attenuated total reflection-Fourier transform infrared spectroscopy were used to characterize the structure and morphology of the DLC thin film. Photocurrent-voltage characteristics of the silicon solar cell were carried out using a solar simulator. The results showed that atomic oxygen exposure induced the including oxidation, structural changes, cross-linking reactions and bond breaking of the DLC film; thus reducing the optical properties. The photocurrent-voltage characteristics showed that although the properties of the fabricated thin film were decreased after being exposed to destructive rays, when compared with solar cell without any coating, it could protect it in atomic oxygen condition enhancing solar cell efficiency up to 12%. Thus, it can be said that diamond-like carbon thin layer protect the solar cell against atomic oxygen exposure.

  1. Study on the fabrication of silicon nanoparticles in an amorphous silicon light absorbing layer for solar cell applications

    International Nuclear Information System (INIS)

    Park, Joo Hyung; Song, Jin Soo; Lee, Jae Hee; Lee, Jeong Chul

    2012-01-01

    Hydrogenated amorphous-silicon (a-Si:H) thin-film solar cells have advantages of relatively simple technology, less material consumption, higher absorption ratio compared to crystalline silicon, and low cost due to the use of cheaper substrates rather than silicon wafers. However, together with those advantages, amorphous-silicon thin-film solar cells face several issues such as a relatively lower efficiency, a relatively wider bandgap, and the Staebler-Wronski effect (SWE) compared to other competing materials (i.e., crystalline silicon, CdTe, Cu(In x Ga (1-x) )Se 2 (CIGS), etc.). As a remedy for those drawbacks and a way to enhance the cell conversion efficiency at the same time, the employment of crystalline silicon nanoparticles (Si-NPs) in the a-Si matrix is proposed to organize the quantum-dot (QD) structure as the light-absorbing layer. This structure of the light absorbing layer consists of single-crystal Si-NPs in an a-Si:H thin-film matrix. The single-crystal Si-NPs are synthesized by using SiH 4 gas decomposition with CO 2 laser pyrolysis, and the sizes of Si-NPs are calibrated to control their bandgaps. The synthesized size-controlled Si-NPs are directly transferred to another chamber to form a QD structure by using co-deposition of the Si-NPs and the a-Si:H matrix. Transmission electron microscopy (TEM) analyses are employed to verify the sizes and the crystalline properties of the Si-NPs alone and of the Si-NPs in the a-Si:H matrix. The TEM results show successful co-deposition of size-controlled Si-NPs in the a-Si:H matrix, which is meaningful because it suggests the possibility of further enhancement of the a-Si:H solar-cell structure and of tandem structure applications by using a single element.

  2. Studying the noise parameters of thin-film silicon resistors

    International Nuclear Information System (INIS)

    Belogurov, S.V.; Gostilo, V.V.; Yurov, A.S.

    1986-01-01

    The results of studies on spectral density and energy noise equivalent of thin-film resistors on the base of amorphous silicon and KIM and KVM commercial high-ohmic resistors are presented. Dependence of the active part of impedance on frequency is shown to be the main source of redundant noise in resistors. Dependence of spectral density of noise voltage of current noises of silicon resistors on applied voltage is described by the formula S T =B V 2 /f 1.6 with the values B=(1.4-1.7)x10 -12 Hz 0.6 . As to noise parameters the silicon resistor is superior to commercial resistors

  3. Al-Si alloy point contact formation and rear surface passivation for silicon solar cells using double layer porous silicon

    International Nuclear Information System (INIS)

    Moumni, Besma; Ben Jaballah, Abdelkader; Bessais, Brahim

    2012-01-01

    Lowering the rear surface recombination velocities by a dielectric layer has fascinating advantages compared with the standard fully covered Al back-contact silicon solar cells. In this work the passivation effect by double layer porous silicon (PS) (wide band gap) and the formation of Al-Si alloy in narrow p-type Si point contact areas for rear passivated solar cells are analysed. As revealed by Fourier transform infrared spectroscopy, we found that a thin passivating aluminum oxide (Al 2 O 3 ) layer is formed. Scanning electron microscopy analysis performed in cross sections shows that with bilayer PS, liquid Al penetrates into the openings, alloying with the Si substrate at depth and decreasing the contact resistivity. At the solar cell level, the reduction in the contact area and resistivity leads to a minimization of the fill factor losses.

  4. Thin layer activation: measuring wear and corrosion

    International Nuclear Information System (INIS)

    Delvigne, T.; Leyman, D.; Oxorn, K.

    1995-01-01

    The technique known as thin layer activation (TLA) is explained and assessed in this article. Widely used, in for example the automotive industry, TLA allows on-line monitoring of the loss of matter from a critical surface, by wear erosion and corrosion. The technique offers extremely high sensitivity thus leading to reduced test times. On-line wear phenomena can be assessed during operation of a mechanical process, even through thick engine walls. (UK)

  5. Amorphous silicon pixel radiation detectors and associated thin film transistor electronics readout

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Mireshghi, A.; Wildermuth, D.; Goodman, C.; Fujieda, I.

    1992-07-01

    We describe the characteristics of thin (1 μm) and thick (> 30 μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-ray, γ rays and thermal neutrons. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For thermal neutron detection we use thin (2∼5 μm) gadolinium converters on 30 μm thick a-Si:H diodes. For direct detection of minimum ionizing particles and others with high resistance to radiation damage, we use the thick p-i-n diode arrays. Diode and amorphous silicon readouts as well as polysilicon pixel amplifiers are described

  6. Methods To Determine the Silicone Oil Layer Thickness in Sprayed-On Siliconized Syringes.

    Science.gov (United States)

    Loosli, Viviane; Germershaus, Oliver; Steinberg, Henrik; Dreher, Sascha; Grauschopf, Ulla; Funke, Stefanie

    2018-01-01

    The silicone lubricant layer in prefilled syringes has been investigated with regards to siliconization process performance, prefilled syringe functionality, and drug product attributes, such as subvisible particle levels, in several studies in the past. However, adequate methods to characterize the silicone oil layer thickness and distribution are limited, and systematic evaluation is missing. In this study, white light interferometry was evaluated to close this gap in method understanding. White light interferometry demonstrated a good accuracy of 93-99% for MgF 2 coated, curved standards covering a thickness range of 115-473 nm. Thickness measurements for sprayed-on siliconized prefilled syringes with different representative silicone oil distribution patterns (homogeneous, pronounced siliconization at flange or needle side, respectively) showed high instrument (0.5%) and analyst precision (4.1%). Different white light interferometry instrument parameters (autofocus, protective shield, syringe barrel dimensions input, type of non-siliconized syringe used as base reference) had no significant impact on the measured average layer thickness. The obtained values from white light interferometry applying a fully developed method (12 radial lines, 50 mm measurement distance, 50 measurements points) were in agreement with orthogonal results from combined white and laser interferometry and 3D-laser scanning microscopy. The investigated syringe batches (lot A and B) exhibited comparable longitudinal silicone oil layer thicknesses ranging from 170-190 nm to 90-100 nm from flange to tip and homogeneously distributed silicone layers over the syringe barrel circumference (110- 135 nm). Empty break-loose (4-4.5 N) and gliding forces (2-2.5 N) were comparably low for both analyzed syringe lots. A silicone oil layer thickness of 100-200 nm was thus sufficient for adequate functionality in this particular study. Filling the syringe with a surrogate solution including short

  7. Polymorphous silicon thin films produced in dusty plasmas: application to solar cells

    International Nuclear Information System (INIS)

    Roca i Cabarrocas, Pere; Chaabane, N; Kharchenko, A V; Tchakarov, S

    2004-01-01

    We summarize our current understanding of the optimization of PIN solar cells produced by plasma enhanced chemical vapour deposition from silane-hydrogen mixtures. To increase the deposition rate, the discharge is operated under plasma conditions close to powder formation, where silicon nanocrystals contribute to the deposition of so-called polymorphous silicon thin films. We show that the increase in deposition rate can be achieved via an accurate control of the plasma parameters. However, this also results in a highly defective interface in the solar cells due to the bombardment of the P-layer by positively charged nanocrystals during the deposition of the I-layer. We show that decreasing the ion energy by increasing the total pressure or by using silane-helium mixtures allows us to increase both the deposition rate and the solar cells efficiency, as required for cost effective thin film photovoltaics

  8. Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

    International Nuclear Information System (INIS)

    Mouro, J.; Gualdino, A.; Chu, V.; Conde, J. P.

    2013-01-01

    Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n + -type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three different types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force

  9. Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

    Energy Technology Data Exchange (ETDEWEB)

    Mouro, J.; Gualdino, A.; Chu, V. [Instituto de Engenharia de Sistemas e Computadores – Microsistemas e Nanotecnologias (INESC-MN) and IN – Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Conde, J. P. [Instituto de Engenharia de Sistemas e Computadores – Microsistemas e Nanotecnologias (INESC-MN) and IN – Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Department of Bioengineering, Instituto Superior Técnico (IST), 1049-001 Lisbon (Portugal)

    2013-11-14

    Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n{sup +}-type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three different types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force.

  10. Micro-architecture embedding ultra-thin interlayer to bond diamond and silicon via direct fusion

    Science.gov (United States)

    Kim, Jong Cheol; Kim, Jongsik; Xin, Yan; Lee, Jinhyung; Kim, Young-Gyun; Subhash, Ghatu; Singh, Rajiv K.; Arjunan, Arul C.; Lee, Haigun

    2018-05-01

    The continuous demand on miniaturized electronic circuits bearing high power density illuminates the need to modify the silicon-on-insulator-based chip architecture. This is because of the low thermal conductivity of the few hundred nanometer-thick insulator present between the silicon substrate and active layers. The thick insulator is notorious for releasing the heat generated from the active layers during the operation of devices, leading to degradation in their performance and thus reducing their lifetime. To avoid the heat accumulation, we propose a method to fabricate the silicon-on-diamond (SOD) microstructure featured by an exceptionally thin silicon oxycarbide interlayer (˜3 nm). While exploiting the diamond as an insulator, we employ spark plasma sintering to render the silicon directly fused to the diamond. Notably, this process can manufacture the SOD microarchitecture via a simple/rapid way and incorporates the ultra-thin interlayer for minute thermal resistance. The method invented herein expects to minimize the thermal interfacial resistance of the devices and is thus deemed as a breakthrough appealing to the current chip industry.

  11. Critical Transitions in Thin Layer Turbulence

    Science.gov (United States)

    Benavides, Santiago; Alexakis, Alexandros

    2017-11-01

    We investigate a model of thin layer turbulence that follows the evolution of the two-dimensional motions u2 D (x , y) along the horizontal directions (x , y) coupled to a single Fourier mode along the vertical direction (z) of the form uq (x , y , z) = [vx (x , y) sin (qz) ,vy (x , y) sin (qz) ,vz (x , y) cos (qz) ] , reducing thus the system to two coupled, two-dimensional equations. Its reduced dimensionality allows a thorough investigation of the transition from a forward to an inverse cascade of energy as the thickness of the layer H = π / q is varied.Starting from a thick layer and reducing its thickness it is shown that two critical heights are met (i) one for which the forward unidirectional cascade (similar to three-dimensional turbulence) transitions to a bidirectional cascade transferring energy to both small and large scales and (ii) one for which the bidirectional cascade transitions to a unidirectional inverse cascade when the layer becomes very thin (similar to two-dimensional turbulence). The two critical heights are shown to have different properties close to criticality that we are able to analyze with numerical simulations for a wide range of Reynolds numbers and aspect ratios. This work was Granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01).

  12. Silicon nitride and intrinsic amorphous silicon double antireflection coatings for thin-film solar cells on foreign substrates

    International Nuclear Information System (INIS)

    Li, Da; Kunz, Thomas; Wolf, Nadine; Liebig, Jan Philipp; Wittmann, Stephan; Ahmad, Taimoor; Hessmann, Maik T.; Auer, Richard; Göken, Mathias; Brabec, Christoph J.

    2015-01-01

    Hydrogenated intrinsic amorphous silicon (a-Si:H) was investigated as a surface passivation method for crystalline silicon thin film solar cells on graphite substrates. The results of the experiments, including quantum efficiency and current density-voltage measurements, show improvements in cell performance. This improvement is due to surface passivation by an a-Si:H(i) layer, which increases the open circuit voltage and the fill factor. In comparison with our previous work, we have achieved an increase of 0.6% absolute cell efficiency for a 40 μm thick 4 cm 2 aperture area on the graphite substrate. The optical properties of the SiN x /a-Si:H(i) stack were studied using spectroscopic ellipsometer techniques. Scanning transmission electron microscopy inside a scanning electron microscope was applied to characterize the cross section of the SiN x /a-Si:H(i) stack using focus ion beam preparation. - Highlights: • We report a 10.8% efficiency for thin-film silicon solar cell on graphite. • Hydrogenated intrinsic amorphous silicon was applied for surface passivation. • SiN x /a-Si:H(i) stacks were characterized by spectroscopic ellipsometer techniques. • Cross-section micrograph was obtained by scanning transmission electron microscopy. • Quantum efficiency and J-V measurements show improvements in the cell performance

  13. Oxide layers for silicon detector protection against enviroment effects

    International Nuclear Information System (INIS)

    Bel'tsazh, E.; Brylovska, I.; Valerian, M.

    1986-01-01

    It is shown that for protection of silicon detectors of nuclear radiations oxide layers could be used. The layers are produced by electrochemical oxidation of silicon surface with the following low-temperature annealing. These layers have characteristics similar to those for oxide layers produced by treatment of silicon samples at elevated temperature in oxygen flow. To determine properties of oxide layers produced by electrochemical oxidation the α-particle back-scattering method and the method of volt-farad characteristics were used. Protection properties of such layers were checked on the surface-barrier detectors. It was shown that protection properties of such detectors were conserved during long storage at room temperature and during their storage under wet-bulb temperature. Detectors without protection layer have worsened their characteristics

  14. Thermoelectric characteristics of Pt-silicide/silicon multi-layer structured p-type silicon

    International Nuclear Information System (INIS)

    Choi, Wonchul; Jun, Dongseok; Kim, Soojung; Shin, Mincheol; Jang, Moongyu

    2015-01-01

    Electric and thermoelectric properties of silicide/silicon multi-layer structured devices were investigated with the variation of silicide/silicon heterojunction numbers from 3 to 12 layers. For the fabrication of silicide/silicon multi-layered structure, platinum and silicon layers are repeatedly sputtered on the (100) silicon bulk substrate and rapid thermal annealing is carried out for the silicidation. The manufactured devices show ohmic current–voltage (I–V) characteristics. The Seebeck coefficient of bulk Si is evaluated as 195.8 ± 15.3 μV/K at 300 K, whereas the 12 layered silicide/silicon multi-layer structured device is evaluated as 201.8 ± 9.1 μV/K. As the temperature increases to 400 K, the Seebeck coefficient increases to 237.2 ± 4.7 μV/K and 277.0 ± 1.1 μV/K for bulk and 12 layered devices, respectively. The increase of Seebeck coefficient in multi-layered structure is mainly attributed to the electron filtering effect due to the Schottky barrier at Pt-silicide/silicon interface. At 400 K, the thermal conductivity is reduced by about half of magnitude compared to bulk in multi-layered device which shows the efficient suppression of phonon propagation by using Pt-silicide/silicon hetero-junctions. - Highlights: • Silicide/silicon multi-layer structured is proposed for thermoelectric devices. • Electric and thermoelectric properties with the number of layer are investigated. • An increase of Seebeck coefficient is mainly attributed the Schottky barrier. • Phonon propagation is suppressed with the existence of Schottky barrier. • Thermal conductivity is reduced due to the suppression of phonon propagation

  15. Transparent conductive oxides for thin-film silicon solar cells

    NARCIS (Netherlands)

    Löffler, J.

    2005-01-01

    This thesis describes research on thin-film silicon solar cells with focus on the transparent conductive oxide (TCO) for such devices. In addition to the formation of a transparent and electrically conductive front electrode for the solar cell allowing photocurrent collection with low ohmic losses,

  16. Band engineering of amorphous silicon ruthenium thin film and its near-infrared absorption enhancement combined with nano-holes pattern on back surface of silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Anran; Zhong, Hao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Li, Wei, E-mail: wli@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Gu, Deen; Jiang, Xiangdong [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Jiang, Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-10-30

    Highlights: • The increase of Ru concentration leads to a narrower bandgap of a-Si{sub 1-x}Ru{sub x} thin film. • The absorption coefficient of a-Si{sub 1-x}Ru{sub x} is higher than that of SiGe. • A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} film and Si nano-holes layer is achieved. - Abstract: Silicon is widely used in semiconductor industry but has poor performance in near-infrared photoelectronic devices because of its bandgap limit. In this study, a narrow bandgap silicon rich semiconductor is achieved by introducing ruthenium (Ru) into amorphous silicon (a-Si) to form amorphous silicon ruthenium (a-Si{sub 1-x}Ru{sub x}) thin films through co-sputtering. The increase of Ru concentration leads to an enhancement of light absorption and a narrower bandgap. Meanwhile, a specific light trapping technique is employed to realize high absorption of a-Si{sub 1-x}Ru{sub x} thin film in a finite thickness to avoid unnecessary carrier recombination. A double-layer absorber comprising of a-Si{sub 1-x}Ru{sub x} thin film and silicon random nano-holes layer is formed on the back surface of silicon substrates, and significantly improves near-infrared absorption while the leaky light intensity is less than 5%. This novel absorber, combining narrow bandgap thin film with light trapping structure, may have a potential application in near-infrared photoelectronic devices.

  17. Effect of porous silicon layer on the performance of Si/oxide photovoltaic and photoelectrochemical cells

    International Nuclear Information System (INIS)

    Badawy, Waheed A.

    2008-01-01

    Photovoltaic and photoelectrochemical systems were prepared by the formation of a thin porous film on silicon. The porous silicon layer was formed on the top of a clean oxide free silicon wafer surface by anodic etching in HF/H 2 O/C 2 H 5 OH mixture (2:1:1). The silicon was then covered by an oxide film (tin oxide, ITO or titanium oxide). The oxide films were prepared by the spray/pyrolysis technique which enables doping of the oxide film by different atoms like In, Ru or Sb during the spray process. Doping of SnO 2 or TiO 2 films with Ru atoms improves the surface characteristics of the oxide film which improves the solar conversion efficiency. The prepared solar cells are stable against environmental attack due to the presence of the stable oxide film. It gives relatively high short circuit currents (I sc ), due to the presence of the porous silicon layer, which leads to the recorded high conversion efficiency. Although the open-circuit potential (V oc ) and fill factor (FF) were not affected by the thickness of the porous silicon film, the short circuit current was found to be sensitive to this thickness. An optimum thickness of the porous film and also the oxide layer is required to optimize the solar cell efficiency. The results represent a promising system for the application of porous silicon layers in solar energy converters. The use of porous silicon instead of silicon single crystals in solar cell fabrication and the optimization of the solar conversion efficiency will lead to the reduction of the cost as an important factor and also the increase of the solar cell efficiency making use of the large area of the porous structures

  18. Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

    International Nuclear Information System (INIS)

    Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

    2005-01-01

    Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

  19. Implant damage and redistribution of indium in indium-implanted thin silicon-on-insulator

    International Nuclear Information System (INIS)

    Chen Peng; An Zhenghua; Zhu Ming; Fu, Ricky K.Y.; Chu, Paul K.; Montgomery, Neil; Biswas, Sukanta

    2004-01-01

    The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 x 10 14 cm -2 ) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure

  20. Thin layer fibres are a knotty problem

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Concern that emergency core cooling system (ECCS) strainers can be blocked by insulation debris has been generated by an incident at the Swedish Barsebaeck-2 BWR in 1992 and two subsequent incidents at the Perry and Limerick BWR plants in the USA. Recent studies are reported which show that blockage of the small, passive suction type strainers common to these and many other BWRs can occur when only very small quantities of fibrous material present in the suppression pool combine with particulates such as corrosion products to form thin layers on the strainer surface. Layers only a few millimetres thick lead to extremely high head losses on the strainer surface and can cause cavitation in the ECCS pumps. It is concluded that the most practical reliable and cost effective solution is to replace the small strainers with larger ones. (UK)

  1. Hydrogenation of polycrystalline silicon thin films

    Czech Academy of Sciences Publication Activity Database

    Honda, Shinya; Mates, Tomáš; Knížek, Karel; Ledinský, Martin; Fejfar, Antonín; Kočka, Jan; Yamazaki, T.; Uraoka, Y.; Fuyuki, T.

    2006-01-01

    Roč. 501, - (2006), s. 144-148 ISSN 0040-6090 R&D Projects: GA MŠk ME 537; GA MŽP(CZ) SM/300/1/03; GA AV ČR(CZ) IAA1010316; GA AV ČR(CZ) IAA1010413; GA ČR(CZ) GA202/03/0789 Institutional research plan: CEZ:AV0Z1010914 Keywords : polycrystalline silicon * atmospheric pressure chemical vapour deposition * hydrogen passivation * photoluminescence * Raman spectroscopy * Si-H 2 bonding * hydrogen molecules Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.666, year: 2006

  2. Investigation of the interface region between a porous silicon layer and a silicon substrate

    International Nuclear Information System (INIS)

    Lee, Ki-Won; Park, Dae-Kyu; Kim, Young-You; Shin, Hyun-Joon

    2005-01-01

    Atomic force microscopy (AFM) measurement and X-ray diffraction (XRD) analysis were performed to investigate the physical and structural characteristics of the interface region between a porous silicon layer and a silicon substrate. We discovered that, when anodization time was increased under a constant current density, the Si crystallites in the interface region became larger and formed different lattice parameters than observed in the porous silicon layer. Secondary ion mass spectrometry (SIMS) analysis also revealed that the Si was more concentrated in the interface region than in the porous silicon layer. These results were interpreted by the deficiency of the HF solution in reaching to the interface through the pores during the porous silicon formation

  3. Measurement of mobility profile in ion-implanted silicon layers using electroreflection spectroscopy

    International Nuclear Information System (INIS)

    Galiev, G.B.; Kapaev, V.V.; Mokerov, V.G.

    1986-01-01

    The possibility is shown of the application of the low field linearized electroreflection spectroscopy for the measurement of profiles of carriers mobilities μ(x) simultaneously with the concentration profiles N(x) in thin ion-implanted silicon layers. The μ(χ) value is determined from the calibration curve of the dependence of the phenomenological broadening parameter γ on the mobility for uniformly doped samples. The results are presented for the measurements of the profiles μ(x) for boron- and arsenic-implanted silicon

  4. Silicon dioxide with a silicon interfacial layer as an insulating gate for highly stable indium phosphide metal-insulator-semiconductor field effect transistors

    Science.gov (United States)

    Kapoor, V. J.; Shokrani, M.

    1991-01-01

    A novel gate insulator consisting of silicon dioxide (SiO2) with a thin silicon (Si) interfacial layer has been investigated for high-power microwave indium phosphide (InP) metal-insulator-semiconductor field effect transistors (MISFETs). The role of the silicon interfacial layer on the chemical nature of the SiO2/Si/InP interface was studied by high-resolution X-ray photoelectron spectroscopy. The results indicated that the silicon interfacial layer reacted with the native oxide at the InP surface, thus producing silicon dioxide, while reducing the native oxide which has been shown to be responsible for the instabilities in InP MISFETs. While a 1.2-V hysteresis was present in the capacitance-voltage (C-V) curve of the MIS capacitors with silicon dioxide, less than 0.1 V hysteresis was observed in the C-V curve of the capacitors with the silicon interfacial layer incorporated in the insulator. InP MISFETs fabricated with the silicon dioxide in combination with the silicon interfacial layer exhibited excellent stability with drain current drift of less than 3 percent in 10,000 sec, as compared to 15-18 percent drift in 10,000 sec for devices without the silicon interfacial layer. High-power microwave InP MISFETs with Si/SiO2 gate insulators resulted in an output power density of 1.75 W/mm gate width at 9.7 GHz, with an associated power gain of 2.5 dB and 24 percent power added efficiency.

  5. Solid-phase crystallization of amorphous silicon on ZnO:Al for thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.; Conrad, E.; Dogan, P.; Fenske, F.; Gorka, B.; Haenel, T.; Lee, K.Y.; Rau, B.; Ruske, F.; Weber, T.; Gall, S.; Rech, B. [Helmholtz-Zentrum Berlin fuer Materialien und Energie (formerly Hahn-Meitner-Institut Berlin), Kekulestr. 5, D-12489 Berlin (Germany); Berginski, M.; Huepkes, J. [Institute of Photovoltaics, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany)

    2009-06-15

    The suitability of ZnO:Al thin films for polycrystalline silicon (poly-Si) thin-film solar cell fabrication was investigated. The electrical and optical properties of 700 -nm-thick ZnO:Al films on glass were analyzed after typical annealing steps occurring during poly-Si film preparation. If the ZnO:Al layer is covered by a 30 nm thin silicon film, the initial sheet resistance of ZnO:Al drops from 4.2 to 2.2 {omega} after 22 h annealing at 600 C and only slightly increases for a 200 s heat treatment at 900 C. A thin-film solar cell concept consisting of poly-Si films on ZnO:Al coated glass is introduced. First solar cell results will be presented using absorber layers either prepared by solid-phase crystallization (SPC) or by direct deposition at 600 C. (author)

  6. Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Martini, R., E-mail: roberto.martini@imec.be [Department of Electrical Engineering, KU Leuven, Kasteelpark 10, 3001 Leuven (Belgium); imec, Kapeldreef 75, 3001 Leuven (Belgium); Kepa, J.; Stesmans, A. [Department of Physics, KU Leuven, Celestijnenlaan 200 D, 3001 Leuven (Belgium); Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Poortmans, J. [Department of Electrical Engineering, KU Leuven, Kasteelpark 10, 3001 Leuven (Belgium); imec, Kapeldreef 75, 3001 Leuven (Belgium); Universiteit Hasselt, Martelarenlaan 42, B-3500 Hasselt (Belgium)

    2014-10-27

    We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process. A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.

  7. Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

    International Nuclear Information System (INIS)

    Martini, R.; Kepa, J.; Stesmans, A.; Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I.; Poortmans, J.

    2014-01-01

    We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process. A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.

  8. Diode behavior in ultra-thin low temperature ALD grown zinc-oxide on silicon

    Directory of Open Access Journals (Sweden)

    Nazek El-Atab

    2013-10-01

    Full Text Available A thin-film ZnO(n/Si(p+ heterojunction diode is demonstrated. The thin film ZnO layer is deposited by Atomic Layer Deposition (ALD at different temperatures on a p-type silicon substrate. Atomic force microscopy (AFM AC-in-Air method in addition to conductive AFM (CAFM were used for the characterization of ZnO layer and to measure the current-voltage characteristics. Forward and reverse bias n-p diode behavior with good rectification properties is achieved. The diode with ZnO grown at 80°C exhibited the highest on/off ratio with a turn-on voltage (VON ∼3.5 V. The measured breakdown voltage (VBR and electric field (EBR for this diode are 5.4 V and 3.86 MV/cm, respectively.

  9. Synchrotron-radiation XPS analysis of ultra-thin silane films: Specifying the organic silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Paul M., E-mail: paul.dietrich@yahoo.de [Bundesanstalt für Materialforschung und – prüfung (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Glamsch, Stephan [Bundesanstalt für Materialforschung und – prüfung (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Freie Universität Berlin, Institut für Chemie und Biochemie, Fabeckstr. 34/36, 14195 Berlin (Germany); Ehlert, Christopher [Bundesanstalt für Materialforschung und – prüfung (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam (Germany); Lippitz, Andreas [Bundesanstalt für Materialforschung und – prüfung (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Kulak, Nora [Freie Universität Berlin, Institut für Chemie und Biochemie, Fabeckstr. 34/36, 14195 Berlin (Germany); Unger, Wolfgang E.S. [Bundesanstalt für Materialforschung und – prüfung (BAM), Unter den Eichen 87, 12205 Berlin (Germany)

    2016-02-15

    Graphical abstract: - Highlights: • A synchrotron-based XPS method to analyze ultra-thin silane films is presented. • Specification and quantification of organic next to inorganic silicon is demonstrated. • Non-destructive chemical depth profiles of the silane monolayers were obtained. - Abstract: The analysis of chemical and elemental in-depth variations in ultra-thin organic layers with thicknesses below 5 nm is very challenging. Energy- and angle-resolved XPS (ER/AR-XPS) opens up the possibility for non-destructive chemical ultra-shallow depth profiling of the outermost surface layer of ultra-thin organic films due to its exceptional surface sensitivity. For common organic materials a reliable chemical in-depth analysis with a lower limit of the XPS information depth z{sub 95} of about 1 nm can be performed. As a proof-of-principle example with relevance for industrial applications the ER/AR-XPS analysis of different organic monolayers made of amino- or benzamidosilane molecules on silicon oxide surfaces is presented. It is demonstrated how to use the Si 2p core-level region to non-destructively depth-profile the organic (silane monolayer) – inorganic (SiO{sub 2}/Si) interface and how to quantify Si species, ranging from elemental silicon over native silicon oxide to the silane itself. The main advantage of the applied ER/AR-XPS method is the improved specification of organic from inorganic silicon components in Si 2p core-level spectra with exceptional low uncertainties compared to conventional laboratory XPS.

  10. Thin-film polycrystalline silicon solar cells

    Science.gov (United States)

    Funghnan, B. W.; Blanc, J.; Phillips, W.; Redfield, D.

    1980-08-01

    Thirty-four new solar cells were fabricated on Wacker Sislo substrates and the AM-1 parameters were measured. A detailed comparison was made between the measurement of minority carrier diffusion length by the OE method and the penetrating light laser scan grain boundary photoresponse linewidth method. The laser scan method has more experimental uncertainty and agrees within 10 to 50% with the QE method. It allows determination of L over a large area. Atomic hydrogen passivation studies continued on Wacker material by three techniques. A method of determining surface recombination velocity, s, from laser scan data was developed. No change in s in completed solar cells after H-plasma treatment was observed within experimental error. H-passivation of bare silicon cars as measured by the new laser scan photoconductivity technique showed very large effects.

  11. Mesoscopic layered structure in conducting polymer thin film fabricated by potential-programmed electropolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Fujitsuka, Mamoru (Div. of Molecular Engineering, Kyoto Univ. (Japan)); Nakahara, Reiko (Div. of Molecular Engineering, Kyoto Univ. (Japan)); Iyoda, Tomokazu (Div. of Molecular Engineering, Kyoto Univ. (Japan)); Shimidzu, Takeo (Div. of Molecular Engineering, Kyoto Univ. (Japan)); Tomita, Shigehisa (Toray Research Center Co., Ltd., Shiga (Japan)); Hatano, Yayoi (Toray Research Center Co., Ltd., Shiga (Japan)); Soeda, Fusami (Toray Research Center Co., Ltd., Shiga (Japan)); Ishitani, Akira (Toray Research Center Co., Ltd., Shiga (Japan)); Tsuchiya, Hajime (Nitto Technical Information Center Co., Ltd., Shimohozumi Ibaraki, Osaka (Japan)); Ohtani, Akira (Central Research Lab., Nitto Denko Co., Ltd., Shimohozumi Ibaraki, Osaka (Japan))

    1992-11-01

    Mesoscopic layered structures in conducting polymer thin films are fabricated by the potential-programmed electropolymerization method. High lateral quality in the layered structure is realized by the improvement of polymerization conditions, i.e., a mixture of pyrrole and bithiophene as monomers, a silicon single-crystal wafer as a working electrode and propylene carbonate as a solvent. SIMS depth profiling of the resulting layered films indicates a significant linear correlation between the electric charge passed and the thickness of the individual layers on a 100 A scale. (orig.)

  12. X-ray and scanning electron microscopic investigation of porous silicon and silicon epitaxial layers grown on porous silicon

    International Nuclear Information System (INIS)

    Wierzchowski, W.; Pawlowska, M.; Nossarzewska-Orlowska, E.; Brzozowski, A.; Wieteska, K.; Graeff, W.

    1998-01-01

    The 1 to 5 μm thick layers of porous silicon and epitaxial layers grown on porous silicon were studied by means of X-ray diffraction methods, realised with a wide use of synchrotron source and scanning microscopy. The results of x-ray investigation pointed the difference of lateral periodicity between the porous layer and the substrate. It was also found that the deposition of epitaxial layer considerably reduced the coherence of porous fragments. A number of interface phenomena was also observed in section and plane wave topographs. The scanning electron microscopic investigation of cleavage faces enabled direct evaluation of porous layer thickness and revealed some details of their morphology. The scanning observation of etched surfaces of epitaxial layers deposited on porous silicon revealed dislocations and other defects not reasonable in the X-ray topographs. (author)

  13. Increased carrier lifetimes in epitaxial silicon layers on buried silicon nitride produced by ion implantation

    International Nuclear Information System (INIS)

    Skorupa, W.; Kreissig, U.; Hensel, E.; Bartsch, H.

    1984-01-01

    Carrier lifetimes were measured in epitaxial silicon layers deposited on buried silicon nitride produced by high-dose nitrogen implantation at 330 keV. The values were in the range 20-200 μs. The results are remarkable taking into account the high density of crystal defects in the epitaxial layers. Comparing with other SOI technologies the measured lifetimes are higher by 1-2 orders of magnitude. (author)

  14. Morphological and optical properties of silicon thin films by PLD

    International Nuclear Information System (INIS)

    Ayouchi, R.; Schwarz, R.; Melo, L.V.; Ramalho, R.; Alves, E.; Marques, C.P.; Santos, L.; Almeida, R.; Conde, O.

    2009-01-01

    Silicon thin films have been prepared on sapphire substrates by pulsed laser deposition (PLD) technique. The films were deposited in vacuum from a silicon target at a base pressure of 10 -6 mbar in the temperature range from 400 to 800 deg. C. A Q-switched Nd:YAG laser (1064 nm, 5 ns duration, 10 Hz) at a constant energy density of 2 J x cm -2 has been used. The influence of the substrate temperature on the structural, morphological and optical properties of the Si thin films was investigated. Spectral ellipsometry and atomic force microscopy (AFM) were used to study the thickness and the surface roughness of the deposited films. Surface roughness values measured by AFM and ellipsometry show the same tendency of increasing roughness with increased deposition temperature

  15. Low cost thin film poly-silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report presents the results of a project to design and develop a high density plasma based thin-film poly-silicon (TFPS) deposition system based on PQL proprietary advanced plasma technology to produce semiconductor quality TFPS for fabricating a TFPS solar cell. Details are given of the TFPS deposition system, the material development programme, solar cell structure, and cell efficiencies. The reproducibility of the deposition process and prospects for commercial exploitation are discussed.

  16. Characterization of thin-film silicon materials and solar cells through numerical modeling

    NARCIS (Netherlands)

    Pieters, B.E.

    2008-01-01

    At present most commercially available solar cells are made of crystalline silicon (c-Si). The disadvantages of crystalline silicon solar cells are the high material cost and energy consumption during production. A cheaper alternative can be found in thin-film silicon solar cells. The thin-film

  17. Comparison of Light Trapping in Silicon Nanowire and Surface Textured Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Rion Parsons

    2017-04-01

    Full Text Available The optics of axial silicon nanowire solar cells is investigated and compared to silicon thin-film solar cells with textured contact layers. The quantum efficiency and short circuit current density are calculated taking a device geometry into account, which can be fabricated by using standard semiconductor processing. The solar cells with textured absorber and textured contact layers provide a gain of short circuit current density of 4.4 mA/cm2 and 6.1 mA/cm2 compared to a solar cell on a flat substrate, respectively. The influence of the device dimensions on the quantum efficiency and short circuit current density will be discussed.

  18. Galvanic corrosion of structural non-stoichiometric silicon nitride thin films and its implications on reliability of microelectromechanical devices

    Energy Technology Data Exchange (ETDEWEB)

    Broas, M., E-mail: mikael.broas@aalto.fi; Mattila, T. T.; Paulasto-Kröckel, M. [Department of Electrical Engineering and Automation, Aalto University, Espoo, P.O. Box 13500, FIN-00076 Aalto (Finland); Liu, X.; Ge, Y. [Department of Materials Science and Engineering, Aalto University, Espoo, P.O. Box 16200, FIN-00076 Aalto (Finland)

    2015-06-28

    This paper describes a reliability assessment and failure analysis of a poly-Si/non-stoichiometric silicon nitride thin film composite structure. A set of poly-Si/SiN{sub x} thin film structures were exposed to a mixed flowing gas (MFG) environment, which simulates outdoor environments, for 90 days, and an elevated temperature and humidity (85 °C/95% R.H.) test for 140 days. The mechanical integrity of the thin films was observed to degrade during exposure to the chemically reactive atmospheres. The degree of degradation was analyzed with nanoindentation tests. Statistical analysis of the forces required to initiate a fracture in the thin films indicated degradation due to the exposure to the MFG environment in the SiN{sub x} part of the films. Scanning electron microscopy revealed a porous-like reaction layer on top of SiN{sub x}. The morphology of the reaction layer resembled that of galvanically corroded poly-Si. Transmission electron microscopy further clarified the microstructure of the reaction layer which had a complex multi-phase structure extending to depths of ∼100 nm. Furthermore, the layer was oxidized two times deeper in a 90 days MFG-tested sample compared to an untested reference. The formation of the layer is proposed to be caused by galvanic corrosion of elemental silicon in non-stoichiometric silicon nitride during hydrofluoric acid etching. The degradation is proposed to be due uncontrolled oxidation of the films during the stress tests.

  19. Approximate reflection coefficients for a thin VTI layer

    KAUST Repository

    Hao, Qi; Stovas, Alexey

    2017-01-01

    We present an approximate method to derive simple expressions for the reflection coefficients of P- and SV-waves for a thin transversely isotropic layer with a vertical symmetry axis (VTI) embedded in a homogeneous VTI background. The layer

  20. Second-harmonic generation in substoichiometric silicon nitride layers

    Science.gov (United States)

    Pecora, Emanuele; Capretti, Antonio; Miano, Giovanni; Dal Negro, Luca

    2013-03-01

    Harmonic generation in optical circuits offers the possibility to integrate wavelength converters, light amplifiers, lasers, and multiple optical signal processing devices with electronic components. Bulk silicon has a negligible second-order nonlinear optical susceptibility owing to its crystal centrosymmetry. Silicon nitride has its place in the microelectronic industry as an insulator and chemical barrier. In this work, we propose to take advantage of silicon excess in silicon nitride to increase the Second Harmonic Generation (SHG) efficiency. Thin films have been grown by reactive magnetron sputtering and their nonlinear optical properties have been studied by femtosecond pumping over a wide range of excitation wavelengths, silicon nitride stoichiometry and thermal processes. We demonstrate SHG in the visible range (375 - 450 nm) using a tunable 150 fs Ti:sapphire laser, and we optimize the SH emission at a silicon excess of 46 at.% demonstrating a maximum SHG efficiency of 4x10-6 in optimized films. Polarization properties, generation efficiency, and the second order nonlinear optical susceptibility are measured for all the investigated samples and discussed in terms of an effective theoretical model. Our findings show that the large nonlinear optical response demonstrated in optimized Si-rich silicon nitride materials can be utilized for the engineering of nonlinear optical functions and devices on a Si chip.

  1. Passivation mechanism in silicon heterojunction solar cells with intrinsic hydrogenated amorphous silicon oxide layers

    Science.gov (United States)

    Deligiannis, Dimitrios; van Vliet, Jeroen; Vasudevan, Ravi; van Swaaij, René A. C. M. M.; Zeman, Miro

    2017-02-01

    In this work, we use intrinsic hydrogenated amorphous silicon oxide layers (a-SiOx:H) with varying oxygen content (cO) but similar hydrogen content to passivate the crystalline silicon wafers. Using our deposition conditions, we obtain an effective lifetime (τeff) above 5 ms for cO ≤ 6 at. % for passivation layers with a thickness of 36 ± 2 nm. We subsequently reduce the thickness of the layers using an accurate wet etching method to ˜7 nm and deposit p- and n-type doped layers fabricating a device structure. After the deposition of the doped layers, τeff appears to be predominantly determined by the doped layers themselves and is less dependent on the cO of the a-SiOx:H layers. The results suggest that τeff is determined by the field-effect rather than by chemical passivation.

  2. Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-04-24

    A flexible version of traditional thin lead zirconium titanate ((Pb1.1Zr0.48Ti0.52O3)-(PZT)) based ferroelectric random access memory (FeRAM) on silicon shows record performance in flexible arena. The thin PZT layer requires lower operational voltages to achieve coercive electric fields, reduces the sol-gel coating cycles required (i.e., more cost-effective), and, fabrication wise, is more suitable for further scaling of lateral dimensions to the nano-scale due to the larger feature size-to-depth aspect ratio (critical for ultra-high density non-volatile memory applications). Utilizing the inverse proportionality between substrate\\'s thickness and its flexibility, traditional PZT based FeRAM on silicon is transformed through a transfer-less manufacturable process into a flexible form that matches organic electronics\\' flexibility while preserving the superior performance of silicon CMOS electronics. Each memory cell in a FeRAM array consists of two main elements; a select/access transistor, and a storage ferroelectric capacitor. Flexible transistors on silicon have already been reported. In this work, we focus on the storage ferroelectric capacitors, and report, for the first time, its performance after transformation into a flexible version, and assess its key memory parameters while bent at 0.5 cm minimum bending radius.

  3. Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates.

    Science.gov (United States)

    Bhamla, M Saad; Balemans, Caroline; Fuller, Gerald G

    2015-07-01

    We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show that these surfactant layers extend the lifetime of the aqueous films. The films eventually "dewet" by the nucleation and growth of dry areas and the onset of this dewetting can be controlled by the surface rheology of the DPPC layer. We thus demonstrate that increasing the interfacial rheology of the DPPC layer leads to stable films that delay dewetting. We also show that dewetting can be exploited to controllably pattern the underlying curved SiHy substrates with DPPC layers. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Influence of metal induced crystallization parameters on the performance of polycrystalline silicon thin film transistors

    International Nuclear Information System (INIS)

    Pereira, L.; Barquinha, P.; Fortunato, E.; Martins, R.

    2005-01-01

    In this work, metal induced crystallization using nickel was employed to obtain polycrystalline silicon by crystallization of amorphous films for thin film transistor applications. The devices were produced through only one lithographic process with a bottom gate configuration using a new gate dielectric consisting of a multi-layer of aluminum oxide/titanium oxide produced by atomic layer deposition. The best results were obtained for TFTs with the active layer of poly-Si crystallized for 20 h at 500 deg. C using a nickel layer of 0.5 nm where the effective mobility is 45.5 cm 2 V -1 s -1 . The threshold voltage, the on/off current ratio and the sub-threshold voltage are, respectively, 11.9 V, 5.55x10 4 and 2.49 V/dec

  5. UV radiation hardness of silicon inversion layer solar cells

    International Nuclear Information System (INIS)

    Hezel, R.

    1990-01-01

    For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

  6. Size Control of Porous Silicon-Based Nanoparticles via Pore-Wall Thinning.

    Science.gov (United States)

    Secret, Emilie; Leonard, Camille; Kelly, Stefan J; Uhl, Amanda; Cozzan, Clayton; Andrew, Jennifer S

    2016-02-02

    Photoluminescent silicon nanocrystals are very attractive for biomedical and electronic applications. Here a new process is presented to synthesize photoluminescent silicon nanocrystals with diameters smaller than 6 nm from a porous silicon template. These nanoparticles are formed using a pore-wall thinning approach, where the as-etched porous silicon layer is partially oxidized to silica, which is dissolved by a hydrofluoric acid solution, decreasing the pore-wall thickness. This decrease in pore-wall thickness leads to a corresponding decrease in the size of the nanocrystals that make up the pore walls, resulting in the formation of smaller nanoparticles during sonication of the porous silicon. Particle diameters were measured using dynamic light scattering, and these values were compared with the nanocrystallite size within the pore wall as determined from X-ray diffraction. Additionally, an increase in the quantum confinement effect is observed for these particles through an increase in the photoluminescence intensity of the nanoparticles compared with the as-etched nanoparticles, without the need for a further activation step by oxidation after synthesis.

  7. Superior light trapping in thin film silicon solar cells through nano imprint lithography

    Energy Technology Data Exchange (ETDEWEB)

    Soppe, W.J.; Dorenkamper, M.S.; Schropp, R.E.I.; Pex, P.P.A.C.

    2013-10-15

    ECN and partners have developed a fabrication process based on nanoimprint lithography (NIL) of textures for light trapping in thin film solar cells such as thin-film silicon, OPV, CIGS and CdTe. The process can be applied in roll-to-roll mode when using a foil substrate or in roll-to-plate mode when using a glass substrate. The lacquer also serves as an electrically insulating layer for cells if steel foil is used as substrate, to enable monolithic series interconnection. In this paper we will show the superior light trapping in thin film silicon solar cells made on steel foil with nanotextured back contacts. We have made single junction a-Si and {mu}c-Si and a-Si/{mu}c-Si tandem cells, where we applied several types of nano-imprints with random and periodic structures. We will show that the nano-imprinted back contact enables more than 30% increase of current in comparison with non-textured back contacts and that optimized periodic textures outperform state-of-the-art random textures. For a-Si cells we obtained Jsc of 18 mA/cm{sup 2} and for {mu}c-Si cells more than 24 mA/cm{sup 2}. Tandem cells with a total Si absorber layer thickness of only 1350 nm have an initial efficiency of 11%.

  8. Improvement in IBC-silicon solar cell performance by insertion of highly doped crystalline layer at heterojunction interfaces

    International Nuclear Information System (INIS)

    Bashiri, Hadi; Azim Karami, Mohammad; Mohammadnejad, Shahramm

    2017-01-01

    By inserting a thin highly doped crystalline silicon layer between the base region and amorphous silicon layer in an interdigitated back-contact (IBC) silicon solar cell, a new passivation layer is investigated. The passivation layer performance is characterized by numerical simulations. Moreover, the dependence of the output parameters of the solar cell on the additional layer parameters (doping concentration and thickness) is studied. By optimizing the additional passivation layer in terms of doping concentration and thickness, the power conversion efficiency could be improved by a factor of 2.5%, open circuit voltage is increased by 30 mV and the fill factor of the solar cell by 7.4%. The performance enhancement is achieved due to the decrease of recombination rate, a decrease in solar cell resistivity and improvement of field effect passivation at heterojunction interface. The above-mentioned results are compared with reported results of the same conventional interdigitated back-contact silicon solar cell structure. Furthermore, the effect of a-Si:H/c-Si interface defect density on IBC silicon solar cell parameters with a new passivation layer is studied. The additional passivation layer also reduces the sensitivity of output parameter of solar cell to interface defect density. (paper)

  9. Electrical conductivity of free-standing mesoporous silicon thin films

    International Nuclear Information System (INIS)

    Khardani, M.; Bouaicha, M.; Dimassi, W.; Zribi, M.; Aouida, S.; Bessais, B.

    2006-01-01

    The effective electrical conductivity of free-standing p + -type porous silicon layers having porosities ranging from 30% to 80% was studied at both experimental and theoretical sides. An Effective Medium Approximation (EMA) model was used as a theoretical support. The porous silicon (PS) films were prepared by the electrochemical etching method for different values of the anodic current density. In order to model the PS electrical conductivity, the free-standing porous layer was assumed to be formed of three phases; vacuum, oxide and Si nanocrystallites. The analytical expression of the electrical conductivity of the Si nanocrystallites was established using the quantum confinement theory. This enables us to correlate the electrical conductivity of the mesoporous film to the value of the effective band gap energy estimated from the absorption coefficient. A perfect agreement between the theoretical and the experimental electrical conductivity values was obtained for all prospected PS porosities

  10. Development of thin pixel detectors on epitaxial silicon for HEP experiments

    International Nuclear Information System (INIS)

    Boscardin, Maurizio; Calvo, Daniela; Giacomini, Gabriele; Wheadon, Richard; Ronchin, Sabina; Zorzi, Nicola

    2013-01-01

    The foreseen luminosity of the new experiments in High Energy Physics will require that the innermost layer of vertex detectors will be able to sustain fluencies up to 10 16 n eq /cm 2 . Moreover, in many experiments there is a demand for the minimization of the material budget of the detectors. Therefore, thin pixel devices fabricated on n-type silicon are a natural choice to fulfill these requirements due to their rad-hard performances and low active volume. We present an R and D activity aimed at developing a new thin hybrid pixel device in the framework of PANDA experiments. The detector of this new device is a p-on-n pixel sensor realized starting from epitaxial silicon wafers and back thinned up to 50–100 μm after process completion. We present the main technological steps and some electrical characterization on the fabricated devices before and after back thinning and after bump bonding to the front-end electronics

  11. Development of thin pixel detectors on epitaxial silicon for HEP experiments

    Energy Technology Data Exchange (ETDEWEB)

    Boscardin, Maurizio, E-mail: boscardi@fbk.eu [FBK, CMM, Via Sommarive 18, I-38123 Povo, Trento (Italy); Calvo, Daniela [INFN and Dipartimento di Fisica, Università di Torino, Via Pietro Giuria, I-10125 Torino (Italy); Giacomini, Gabriele [FBK, CMM, Via Sommarive 18, I-38123 Povo, Trento (Italy); Wheadon, Richard [INFN and Dipartimento di Fisica, Università di Torino, Via Pietro Giuria, I-10125 Torino (Italy); Ronchin, Sabina; Zorzi, Nicola [FBK, CMM, Via Sommarive 18, I-38123 Povo, Trento (Italy)

    2013-08-01

    The foreseen luminosity of the new experiments in High Energy Physics will require that the innermost layer of vertex detectors will be able to sustain fluencies up to 10{sup 16} n{sub eq}/cm{sup 2}. Moreover, in many experiments there is a demand for the minimization of the material budget of the detectors. Therefore, thin pixel devices fabricated on n-type silicon are a natural choice to fulfill these requirements due to their rad-hard performances and low active volume. We present an R and D activity aimed at developing a new thin hybrid pixel device in the framework of PANDA experiments. The detector of this new device is a p-on-n pixel sensor realized starting from epitaxial silicon wafers and back thinned up to 50–100 μm after process completion. We present the main technological steps and some electrical characterization on the fabricated devices before and after back thinning and after bump bonding to the front-end electronics.

  12. Use of hexamethyldisiloxane for p-type microcrystalline silicon oxycarbide layers

    Directory of Open Access Journals (Sweden)

    Goyal Prabal

    2016-01-01

    Full Text Available The use of hexamethyldisiloxane (HMDSO as an oxygen source for the growth of p-type silicon-based layers deposited by Plasma Enhanced Chemical Vapor Deposition is evaluated. The use of this source led to the incorporation of almost equivalent amounts of oxygen and carbon, resulting in microcrystalline silicon oxycarbide thin films. The layers were examined with characterisation techniques including Spectroscopic Ellipsometry, Dark Conductivity, Fourier Transform Infrared Spectroscopy, Secondary Ion Mass Spectrometry and Transmission Electron Microscopy to check material composition and structure. Materials studies show that the refractive indices of the layers can be tuned over the range from 2.5 to 3.85 (measured at 600 nm and in-plane dark conductivities over the range from 10-8 S/cm to 1 S/cm, suggesting that these doped layers are suitable for solar cell applications. The p-type layers were tested in single junction amorphous silicon p-i-n type solar cells.

  13. Protective silicon coating for nanodiamonds using atomic layer deposition

    International Nuclear Information System (INIS)

    Lu, J.; Wang, Y.H.; Zang, J.B.; Li, Y.N.

    2007-01-01

    Ultrathin silicon coating was deposited on nanodiamonds using atomic layer deposition (ALD) from gaseous monosilane (SiH 4 ). The coating was performed by sequential reaction of SiH 4 saturated adsorption and in situ decomposition. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to investigate the structural and morphological properties of the coating. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal stability of nanodiamonds before and after silicon coating. The results confirmed that the deposited cubic phase silicon coating was even and continuous. The protective silicon coating could effectively improve the oxidation resistance of nanodiamonds in air flow, which facilitates the applications of nanodiamonds that are commonly hampered by their poor thermal stability

  14. Protective silicon coating for nanodiamonds using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Wang, Y.H. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China); Zang, J.B. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China) and College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)]. E-mail: diamondzjb@163.com; Li, Y.N. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao, Hebei 066004 (China)

    2007-01-30

    Ultrathin silicon coating was deposited on nanodiamonds using atomic layer deposition (ALD) from gaseous monosilane (SiH{sub 4}). The coating was performed by sequential reaction of SiH{sub 4} saturated adsorption and in situ decomposition. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to investigate the structural and morphological properties of the coating. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to compare the thermal stability of nanodiamonds before and after silicon coating. The results confirmed that the deposited cubic phase silicon coating was even and continuous. The protective silicon coating could effectively improve the oxidation resistance of nanodiamonds in air flow, which facilitates the applications of nanodiamonds that are commonly hampered by their poor thermal stability.

  15. Mobility of charge carriers in porous silicon layers

    International Nuclear Information System (INIS)

    Forsh, P. A.; Martyshov, M. N.; Latysheva, A. P.; Vorontsov, A. S.; Timoshenko, V. Yu.; Kashkarov, P. K.

    2008-01-01

    The (conduction) mobility of majority charge carriers in porous silicon layers of the n and p types is estimated by joint measurements of electrical conductivity and free charge carrier concentration, which is determined from IR absorption spectra. Adsorption of donor and acceptor molecules leading to a change in local electric fields in the structure is used to identify the processes controlling the mobility in porous silicon. It is found that adsorption of acceptor and donor molecules at porous silicon of the p and n types, respectively, leads to a strong increase in electrical conductivity, which is associated with an increase in the concentration of free carrier as well as in their mobility. The increase in the mobility of charge carriers as a result of adsorption indicates the key role of potential barriers at the boundaries of silicon nanocrystals and may be due to a decrease in the barrier height as a result of adsorption

  16. Plasma monitoring and PECVD process control in thin film silicon-based solar cell manufacturing

    Directory of Open Access Journals (Sweden)

    Gabriel Onno

    2014-02-01

    Full Text Available A key process in thin film silicon-based solar cell manufacturing is plasma enhanced chemical vapor deposition (PECVD of the active layers. The deposition process can be monitored in situ by plasma diagnostics. Three types of complementary diagnostics, namely optical emission spectroscopy, mass spectrometry and non-linear extended electron dynamics are applied to an industrial-type PECVD reactor. We investigated the influence of substrate and chamber wall temperature and chamber history on the PECVD process. The impact of chamber wall conditioning on the solar cell performance is demonstrated.

  17. The silicon-silicon oxide multilayers utilization as intrinsic layer on pin solar cells

    International Nuclear Information System (INIS)

    Colder, H.; Marie, P.; Gourbilleau, F.

    2008-01-01

    Silicon nanostructures are promising candidate for the intrinsic layer on pin solar cells. In this work we report on new material: silicon-rich silicon oxide (SRSO) deposited by reactive magnetron sputtering of a pure silica target and an interesting structure: multilayers consisting of a stack of SRSO and pure silicon oxide layers. Two thicknesses of the SRSO sublayer, t SRSO , are studied 3 nm and 5 nm whereas the thickness of silica sublayer is maintaining at 3 nm. The presence of nanocrystallites of silicon, evidenced by X-Ray diffraction (XRD), leads to photoluminescence (PL) emission at room temperature due to the quantum confinement of the carriers. The PL peak shifts from 1.3 eV to 1.5 eV is correlated to the decreasing of t SRSO from 5 nm down to 3 nm. In the purpose of their potential utilization for i-layer, the optical properties are studied by absorption spectroscopy. The achievement a such structures at promising absorption properties. Moreover by favouring the carriers injection by the tunnel effect between silicon nanograins and silica sublayers, the multilayers seem to be interesting for solar cells

  18. Thin-layer and paper chromatography

    International Nuclear Information System (INIS)

    Sherma, J.

    1986-01-01

    This selective review covers the literature of thin-layer chromatography (TLC) and paper chromatography (PC) cited in Chemical Abstracts from December 5, 1983, through November 25, 1985, and Analytical Abstracts from November 1983 to November 1985. Also researched directly were the following important journals publishing papers on TLC and PC: the Journal of Chromatography (including its bibliography issues), Journal of High Resolution Chromatography and Chromatography Communications, Journal of Chromatographic Science, Chromatographia, Analytical Chemistry, JAOAC, and the special TLC issues of the Journal of Liquid Chromatography. Many of the inherent advantages of TLC that are obvious to workers familiar with high performance, quantitative theory and practice still are not appreciated adequately by the majority of people using chromatography. These include unrestricted access to the separation process; introducing magnetic, thermal, electrical, and other physical forces to improve resolution; high sample throughput; truly multidimensional separations; and the use of controlled multiple gradients. Many advantages of TLC relative to column chromatography were discussed in the Introductions to our 1982 and 1984 reviews of TLC in this Journal. No complete commercial robotics system specifically for TLC has been developed, but all necessary modules are available for such a system. The combination of robotics, with the continued development of theory, practice, and instrumentation will lead eventually to TLC systems that are unrivaled for speed, versatility, accuracy, precision, and sensitivity. 573 references

  19. Development of laser-fired contacts for amorphous silicon layers obtained by Hot-Wire CVD

    International Nuclear Information System (INIS)

    Munoz, D.; Voz, C.; Blanque, S.; Ibarz, D.; Bertomeu, J.; Alcubilla, R.

    2009-01-01

    In this work we study aluminium laser-fired contacts for intrinsic amorphous silicon layers deposited by Hot-Wire CVD. This structure could be used as an alternative low temperature back contact for rear passivated heterojunction solar cells. An infrared Nd:YAG laser (1064 nm) has been used to locally fire the aluminium through the thin amorphous silicon layers. Under optimized laser firing parameters, very low specific contact resistances (ρ c ∼ 10 mΩ cm 2 ) have been obtained on 2.8 Ω cm p-type c-Si wafers. This investigation focuses on maintaining the passivation quality of the interface without an excessive increase in the series resistance of the device.

  20. Analysis of structure and defects in thin silicon films deposited from hydrogen diluted silane

    International Nuclear Information System (INIS)

    Elzakker, G. van; Nadazdy, V.; Tichelaar, F.D.; Metselaar, J.W.; Zeman, M.

    2006-01-01

    Thin silicon layers have been deposited from silane diluted with hydrogen. The dilution ratio R (R = [H 2 ]/[SiH 4 ]) has been varied between R = 0 and R = 40. The structural properties of Si:H films have been studied using transmission electron microscopy imaging and Raman spectroscopy. The phase evolution from the amorphous phase into the mixed and eventually microcrystalline phase strongly depends on the hydrogen dilution. The initiation of the microcrystalline growth occurs between R = 20 and R = 25. The phase transition becomes more abrupt with increasing hydrogen dilution. Optoelectronic properties of the layers have been determined. Increasing hydrogen dilution results in films with increasing effective defect density and Urbach energy, which is related to inhomogeneous growth. The charge deep-level transient spectroscopy technique (Q-DLTS) was applied for the first time on hydrogen diluted thin silicon films in order to investigate the energy distribution of the defect states in these layers as a function of the dilution ratio R. The Q-DLTS spectra indicate a difference in defect-state distribution when the films evolve from the amorphous phase into the microcrystalline phase

  1. Thin layer joining by gas adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Taga, Yasunori, E-mail: y-taga@isc.chubu.ac.jp; Fukumura, Toshio

    2014-10-01

    Highlights: • We report thin layer molecular joining between glass and COP by gas adsorption. Thickness of joining layer is 1–2 nm and joining process was carried out at low temperature at about 100 °C. • Adhesion strength measured by 180 degree peel test revealed to be 1–10 N/25 mm and the joined stack showed high durability for practical use. - Abstract: Attempt has been made to join borosilicate glass and cycloolefin (COP) polymer film by using gas adsorption method. After corona plasma treat, COP was exposed to (3-glycidoxypropyl) trimethoxysilane (GPS) and glass to (3-aminopropyl) triethoxysilane (APS) both in air atmosphere, resulting in co-adsorption of water vapor in the atmosphere and organosilane gases. Surface characterization of plasma treated and gas adsorbed surfaces was carried out by X-ray photoelectron spectroscopy (XPS) using Mg Kα X-ray source. Joining was carried out by a roll laminator after contact of both surfaces at room temperature, followed by annealing at 130 °C for 10 min. Adhesion strength was evaluated by 180 degree peel test based on ASTM D-903 and durability was examined under the conditions of 60 °C and 95% RH. It was found that after plasma treatment, complex functional groups such as C-H, C-O, C=O, O-C=O and CO{sub 3} were found on COP and O-H on glass. Thickness of GPS gas adsorption layer on COP was evaluated by the XPS to be at least 1.1 nm by taking inelastic mean free path of Si{sub 2p} photoelectron into consideration. Joining force was found to be more than 5 N/25 mm corresponding to almost equal to COP bulk tensile strength. In addition, durability of this adhesion strength remained unchanged over 2000 h even after exposure to the durability test conditions of 60 °C and 95% RH. The results can be explained in terms of formation of H-H hydrogen bonding and Si-O covalent bonding via silanols will be made at the interface as a result of lamination and annealing processes. In conclusion, ultrathin joining method

  2. On the timing performance of thin planar silicon sensors

    Science.gov (United States)

    Akchurin, N.; Ciriolo, V.; Currás, E.; Damgov, J.; Fernández, M.; Gallrapp, C.; Gray, L.; Junkes, A.; Mannelli, M.; Martin Kwok, K. H.; Meridiani, P.; Moll, M.; Nourbakhsh, S.; Pigazzini, S.; Scharf, C.; Silva, P.; Steinbrueck, G.; de Fatis, T. Tabarelli; Vila, I.

    2017-07-01

    We report on the signal timing capabilities of thin silicon sensors when traversed by multiple simultaneous minimum ionizing particles (MIP). Three different planar sensors, with depletion thicknesses 133, 211, and 285 μm, have been exposed to high energy muons and electrons at CERN. We describe signal shape and timing resolution measurements as well as the response of these devices as a function of the multiplicity of MIPs. We compare these measurements to simulations where possible. We achieve better than 20 ps timing resolution for signals larger than a few tens of MIPs.

  3. Methods for producing thin film charge selective transport layers

    Science.gov (United States)

    Hammond, Scott Ryan; Olson, Dana C.; van Hest, Marinus Franciscus Antonius Maria

    2018-01-02

    Methods for producing thin film charge selective transport layers are provided. In one embodiment, a method for forming a thin film charge selective transport layer comprises: providing a precursor solution comprising a metal containing reactive precursor material dissolved into a complexing solvent; depositing the precursor solution onto a surface of a substrate to form a film; and forming a charge selective transport layer on the substrate by annealing the film.

  4. Characterisation of irradiated thin silicon sensors for the CMS phase II pixel upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Bergauer, T.; Brondolin, E. [Institut fuer Hochenergiephysik, Vienna (Austria); and others

    2017-08-15

    The high luminosity upgrade of the Large Hadron Collider, foreseen for 2026, necessitates the replacement of the CMS experiment's silicon tracker. The innermost layer of the new pixel detector will be exposed to severe radiation, corresponding to a 1 MeV neutron equivalent fluence of up to Φ{sub eq} = 2 x 10{sup 16} cm{sup -2}, and an ionising dose of ∼5 MGy after an integrated luminosity of 3000 fb{sup -1}. Thin, planar silicon sensors are good candidates for this application, since the degradation of the signal produced by traversing particles is less severe than for thicker devices. In this paper, the results obtained from the characterisation of 100 and 200 μm thick p-bulk pad diodes and strip sensors irradiated up to fluences of Φ{sub eq} = 1.3 x 10{sup 16} cm{sup -2} are shown. (orig.)

  5. High-temperature laser annealing for thin film polycrystalline silicon solar cell on glass substrate

    Science.gov (United States)

    Chowdhury, A.; Schneider, J.; Dore, J.; Mermet, F.; Slaoui, A.

    2012-06-01

    Thin film polycrystalline silicon films grown on glass substrate were irradiated with an infrared continuous wave laser for defects annealing and/or dopants activation. The samples were uniformly scanned using an attachment with the laser system. Substrate temperature, scan speed and laser power were varied to find suitable laser annealing conditions. The Raman spectroscopy and Suns- V oc analysis were carried out to qualify the films quality after laser annealing. A maximum enhancement of the open circuit voltage V oc of about 100 mV is obtained after laser annealing of as-grown polysilicon structures. A strong correlation was found between the full width half maximum of the Si crystalline peak and V oc. It is interpreted as due to defects annealing as well as to dopants activation in the absorbing silicon layer. The maximum V oc reached is 485 mV after laser treatment and plasma hydrogenation, thanks to defects passivation.

  6. Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

    Science.gov (United States)

    Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

    2018-04-01

    In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

  7. Fabrication of metallic nanomasks by transfer of self-organized nanodot patterns from semiconductor material into thin metallic layers

    International Nuclear Information System (INIS)

    Bobek, T.; Kurz, H.

    2007-01-01

    The basic understanding of the formation of highly regular nanostructures during ion erosion of amorphous GaSb layers is revised. The essential physical parameters for the formation of the highly regular dot pattern are discussed. Numerical modelling based on the stabilized isotropic Kuramoto-Sivashinsky equation is presented and discussed. The experimental part of this contribution presents the successful pattern transfer into metallic buried thin layers as well as into Silicon underlayers. The critical conditions for this transfer technique are discussed. Application potential of using this self-organization scheme for the generation of highly regular patterns in ferromagnetic metal layers as well as in crystalline silicon is estimated

  8. Electrical behavior of free-standing porous silicon layers

    International Nuclear Information System (INIS)

    Bazrafkan, I.; Dariani, R.S.

    2009-01-01

    The electrical behavior of porous silicon (PS) layers has been investigated on one side of p-type silicon with various anodization currents and electrolytes. The two contact I-V characteristic is assigned by the metal/porous silicon rectifying interface, whereas, by using the van der Pauw technique, a nonlinear dependence of the current vs voltage was found. By using Dimethylformamide (DMF) in electrolyte, regular structures and columns were formed and porosity increased. Our results showed that by using DMF, surface resistivity of PS samples increased and became double for free-standing porous silicon (FPS). The reason could be due to increasing surface area and adsorbing some more gas molecules. Activation energy of PS samples was also increased from 0.31 to 0.34 eV and became 0.35 eV for FPS. The changes induced by storage are attributed to the oxidation process of the internal surface of free-standing porous silicon layers.

  9. Corrosion of pure magnesium under thin electrolyte layers

    International Nuclear Information System (INIS)

    Zhang Tao; Chen Chongmu; Shao Yawei; Meng Guozhe; Wang Fuhui; Li Xiaogang; Dong Chaofang

    2008-01-01

    The corrosion behavior of pure magnesium was investigated by means of cathodic polarization curve, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) under aerated and deaerated thin electrolyte layers (TEL) with various thicknesses. Based on shot noise theory and stochastic theory, the EN results were quantitatively analyzed by using the Weibull and Gumbel distribution function, respectively. The results show that the cathodic process of pure magnesium under thin electrolyte layer was dominated by hydrogen reduction. With the decreasing of thin electrolyte layer thickness, cathodic process was retarded slightly while the anodic process was inhibited significantly, which indicated that both the cathodic and anodic process were inhibited in the presence of oxygen. The absence of oxygen decreased the corrosion resistance of pure magnesium in case of thin electrolyte layer. The corrosion was more localized under thin electrolyte layer than that in bulk solution. The results also demonstrate that there exist two kinds of effects for thin electrolyte layer on the corrosion behavior of pure magnesium: (1) the rate of pit initiation was evidently retarded compared to that in bulk solution; (2) the probability of pit growth oppositely increased. The corrosion model of pure magnesium under thin electrolyte layer was suggested in the paper

  10. Investigation of silicon/silicon germanium multiple quantum well layers in silicon avalanche photodiodes

    International Nuclear Information System (INIS)

    Loudon, A.Y.

    2002-01-01

    Silicon single photon avalanche diodes (SPADs) are currently utilised in many single photon counting systems due to their high efficiency, fast response times, low voltage operation and potentially low cost. For fibre based applications however (at wavelengths 1.3 and 1.55μm) and eye-safe wavelength applications (>1.4μm), Si devices are not suitable due to their 1.1μm absorption edge and hence greatly reduced absorption above this wavelength. InGaAs/InP or Ge SPADs absorb at these longer wavelengths, but both require cryogenic cooling for low noise operation and III-V integration with conventional Si circuitry is difficult. Si/SiGe is currently attracting great interest for optoelectronic applications and attempts to combine Si avalanche photodiodes with Si/SiGe multiple quantum well absorbing layers have been successful. Here, an effort to utilise this material system has shown an improvement in photon counting efficiency above 1.1μm of more than 30 times compared to an all-Si control device. In addition to its longer wavelength response, this Si/SiGe device has room temperature operation, low cost fabrication and is compatible with conventional Si circuitry. (author)

  11. XPS studies of SiO2 surface layers formed by oxygen ion implantation into silicon

    International Nuclear Information System (INIS)

    Schulze, D.; Finster, J.

    1983-01-01

    SiO 2 surface layers of 160 nm thickness formed by 16 O + ion implantation into silicon are examined by X-ray photoelectron spectroscopy measurements into the depth after a step-by-step chemical etching. The chemical nature and the thickness of the transition layer were determined. The results of the XPS measurements show that the outer surface and the bulk of the layers formed by oxygen implantation and subsequent high temperature annealing consist of SiO 2 . There is no evidence for Si or SiO/sub x/ (0 2 and Si is similar to that of thin grown oxide layers. Only its thickness is somewhat larger than in thermal oxide

  12. Silicon carbide layer structure recovery after ion implantation

    International Nuclear Information System (INIS)

    Violin, Eh.E.; Demakov, K.D.; Kal'nin, A.A.; Nojbert, F.; Potapov, E.N.; Tairov, Yu.M.

    1984-01-01

    The process of recovery of polytype structure of SiC surface layers in the course of thermal annealing (TA) and laser annealing (LA) upon boron and aluminium implantation is studied. The 6H polytype silicon carbide C face (0001) has been exposed to ion radiation. The ion energies ranged from 80 to 100 keV, doses varied from 5x10 14 to 5x10 16 cm -2 . TA was performed in the 800-2000 K temperature range. It is shown that the recovery of the structure of silicon carbide layers after ion implantation takes place in several stages. Considerable effect on the structure of the annealed layers is exerted by the implantation dose and the type of implanted impurity. The recovery of polytype structure is possible only under the effect of laser pulses with duration not less than the time for the ordering of the polytype in question

  13. ZnO transparent conductive oxide for thin film silicon solar cells

    Science.gov (United States)

    Söderström, T.; Dominé, D.; Feltrin, A.; Despeisse, M.; Meillaud, F.; Bugnon, G.; Boccard, M.; Cuony, P.; Haug, F.-J.; Faÿ, S.; Nicolay, S.; Ballif, C.

    2010-03-01

    There is general agreement that the future production of electric energy has to be renewable and sustainable in the long term. Photovoltaic (PV) is booming with more than 7GW produced in 2008 and will therefore play an important role in the future electricity supply mix. Currently, crystalline silicon (c-Si) dominates the market with a share of about 90%. Reducing the cost per watt peak and energy pay back time of PV was the major concern of the last decade and remains the main challenge today. For that, thin film silicon solar cells has a strong potential because it allies the strength of c-Si (i.e. durability, abundancy, non toxicity) together with reduced material usage, lower temperature processes and monolithic interconnection. One of the technological key points is the transparent conductive oxide (TCO) used for front contact, barrier layer or intermediate reflector. In this paper, we report on the versatility of ZnO grown by low pressure chemical vapor deposition (ZnO LP-CVD) and its application in thin film silicon solar cells. In particular, we focus on the transparency, the morphology of the textured surface and its effects on the light in-coupling for micromorph tandem cells in both the substrate (n-i-p) and superstrate (p-i-n) configurations. The stabilized efficiencies achieved in Neuchâtel are 11.2% and 9.8% for p-i-n (without ARC) and n-i-p (plastic substrate), respectively.

  14. Experimental analysis of silicon oxycarbide thin films and waveguides

    Science.gov (United States)

    Memon, Faisal Ahmed; Morichetti, Francesco; Somaschini, Claudio; Iseni, Giosue; Melloni, Andrea

    2017-05-01

    Silicon oxycarbide (SiOC) thin films are produced with reactive rf magnetron sputtering of a silicon carbide (SiC) target on Si (100) and SiO2/Si substrates under varying deposition conditions. The optical properties of the deposited SiOC thin films are characterized with spectroscopic ellispometry at multiple angles of incidence over a wavelength range 300- 1600 nm. The derived optical constants of the SiOC films are modeled with Tauc-Lorentz model. The refractive index n of the SiOC films range from 1.45 to 1.85 @ 1550 nm and the extinction coefficient k is estimated to be less than 10-4 in the near-infrared region above 1000 nm. The topography of SiOC films is studied with SEM and AFM giving rms roughness of 0.9 nm. Channel waveguides with a SiOC core with a refractive index of 1.7 have been fabricated to demonstrate the potential of sputtered SiOC for integrated photonics applications. Propagation loss as low as 0.39 +/- 0.05 dB/mm for TE and 0.41 +/- 0.05 dB/mm for TM polarizations at telecommunication wavelength 1550 nm is demonstrated.

  15. Influence of oxygen on the ion-beam synthesis of silicon carbide buried layers in silicon

    International Nuclear Information System (INIS)

    Artamanov, V.V.; Valakh, M.Ya.; Klyui, N.I.; Mel'nik, V.P.; Romanyuk, A.B.; Romanyuk, B.N.; Yukhimchuk, V.A.

    1998-01-01

    The properties of silicon structures with silicon carbide (SiC) buried layers produced by high-dose carbon implantation followed by a high-temperature anneal are investigated by Raman and infrared spectroscopy. The influence of the coimplantation of oxygen on the features of SiC buried layer formation is also studied. It is shown that in identical implantation and post-implantation annealing regimes a SiC buried layer forms more efficiently in CZ Si wafers or in Si (CZ or FZ) subjected to the coimplantation of oxygen. Thus, oxygen promotes SiC layer formation as a result of the formation of SiO x precipitates and accommodation of the volume change in the region where the SiC phase forms. Carbon segregation and the formation of an amorphous carbon film on the SiC grain boundaries are also discovered

  16. Silicon nanowires in polymer nanocomposites for photovoltaic hybrid thin films

    International Nuclear Information System (INIS)

    Ben Dkhil, S.; Bourguiga, R.; Davenas, J.; Cornu, D.

    2012-01-01

    Highlights: ► Hybrid solar cells based on blends of poly(N-vinylcarbazole) and silicon nanowires have been fabricated. ► We have investigated the charge transfer between PVK and SiNWs by the way of the quenching of the PVK photoluminescence. ► The relation between the morphology of the composite thin films and the charge transfer between SiNWs and PVK has been examined. ► We have investigated the effects of SiNWs concentration on the photovoltaic characteristics leading to the optimization of a critical SiNWs concentration. - Abstract: Hybrid thin films combining the high optical absorption of a semiconducting polymer film and the electronic properties of silicon fillers have been investigated in the perspective of the development of low cost solar cells. Bulk heterojunction photovoltaic materials based on blends of a semiconductor polymer poly(N-vinylcarbazole) (PVK) as electron donor and silicon nanowires (SiNWs) as electron acceptor have been studied. Composite PVK/SiNWs films were cast from a common solvent mixture. UV–visible spectrometry and photoluminescence of the composites have been studied as a function of the SiNWs concentration. Photoluminescence spectroscopy (PL) shows the existence of a critical SiNWs concentration of about 10 wt % for PL quenching corresponding to the most efficient charge pair separation. The photovoltaic (PV) effect has been studied under illumination. The optimum open-circuit voltage V oc and short-circuit current density J sc are obtained for 10 wt % SiNWs whereas a degradation of these parameters is observed at higher SiNWs concentrations. These results are correlated to the formation of aggregates in the composite leading to recombination of the photogenerated charge pairs competing with the dissociation mechanism.

  17. Research and development of photovoltaic power system. Development of novel technologies for fabrication of high quality silicon thin films for solar cells; Taiyoko hatsuden system no kenkyu kaihatsu. Kohinshitsu silicon usumaku sakusei gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, T [Kanazawa University, Ishikawa (Japan). Faculty of Engineering

    1994-12-01

    Described herein are the results of the FY1994 research program for development of novel technologies for fabrication of high quality thin films of silicon for solar cells. The study on the mechanisms and effects of chemical annealing reveals that the film structure greatly varies depending on substrate temperature during the hydrotreatment process, based on the tests with substrate temperature, deposition of superthin film (T1) and hydrotreatment (T2) as the variable parameters. Chemical annealing at low temperature produces a high-quality a-Si:H film of low defect content. The study on fabrication of thin polycrystalline silicon films at low temperature observes on real time the process of deposition of the thin films on polycrystalline silicon substrates, where a natural oxide film is removed beforehand from the substrate. The results indicate that a thin polycrystalline silicon film of 100% crystallinity can be formed even on a polycrystalline silicon substrate by controlling starting gas composition and substrate temperature. The layer-by-layer method is used as the means for forming the seed crystals on a glass substrate, where deposition and hydrotreatment are repeated alternately, to produce the thin crystalline silicon films of high crystallinity. 3 figs.

  18. Wafer scale nano-membrane supported on a silicon microsieve using thin-film transfer technology

    NARCIS (Netherlands)

    Unnikrishnan, S.; Jansen, Henricus V.; Berenschot, Johan W.; Elwenspoek, Michael Curt

    A new micromachining method to fabricate wafer scale nano-membranes is described. The delicate thin-film nano-membrane is supported on a robust silicon microsieve fabricated by plasma etching. The silicon sieve is micromachined independently of the thin-film, which is later transferred onto it by

  19. Amorphous silicon pixel radiation detectors and associated thin film transistor electronics readout

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Drewery, J.; Hong, W.S.; Jing, T.; Kaplan, S.N.; Lee, H.; Mireshghi, A.

    1994-10-01

    We describe the characteristics of thin (1 μm) and thick (>30 μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and γ rays. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. Deposition techniques using helium dilution, which produce samples with low stress are described. Pixel arrays for flux exposures can be readout by transistor, single diode or two diode switches. Polysilicon charge sensitive pixel amplifiers for single event detection are described. Various applications in nuclear, particle physics, x-ray medical imaging, neutron crystallography, and radionuclide chromatography are discussed

  20. Local photoconductivity of microcrystalline silicon thin films measured by conductive atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ledinsky, Martin; Fejfar, Antonin; Vetushka, Aliaksei; Stuchlik, Jiri; Rezek, Bohuslav; Kocka, Jan [Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i. Cukrovarnicka 10, 162 00 Praha 6 (Czech Republic)

    2011-11-15

    Local currents measured under standard conductive atomic force microscopy (C-AFM) conditions on microcrystalline silicon ({mu}c-Si:H) thin films were studied. It was shown that the AFM detection diode illuminating the AFM cantilever (see the figure on the right side) 100 x enhanced the current flows through the photosensitive {mu}c-Si:H layer. The local current map and current-voltage characteristics were measured under dark conditions. This study enables mapping of both the dark current and photocurrent. C-AFM cantilever illuminated by the detection diode during measurement on {mu}c-Si:H thin film. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Reliability assessment of ultra-thin HfO2 films deposited on silicon wafer

    International Nuclear Information System (INIS)

    Fu, Wei-En; Chang, Chia-Wei; Chang, Yong-Qing; Yao, Chih-Kai; Liao, Jiunn-Der

    2012-01-01

    Highlights: ► Nano-mechanical properties on annealed ultra-thin HfO 2 film are studied. ► By AFM analysis, hardness of the crystallized HfO 2 film significantly increases. ► By nano-indention, the film hardness increases with less contact stiffness. ► Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO 2 ) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO 2 films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO 2 films deposited on silicon wafers (HfO 2 /SiO 2 /Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO 2 (nominal thickness ≈10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO 2 phases for the atomic layer deposited HfO 2 . The HfSi x O y complex formed at the interface between HfO 2 and SiO 2 /Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO 2 film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically sensitive nano-indentation. Quality assessments on as-deposited and annealed HfO 2 films can be thereafter used to estimate the mechanical properties and adhesion of ultra-thin HfO 2

  2. Reliability assessment of ultra-thin HfO{sub 2} films deposited on silicon wafer

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Wei-En [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Chang, Chia-Wei [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Chang, Yong-Qing [Center for Measurement Standards, Industrial Technology Research Institute, Room 216, Building 8, 321 Kuang Fu Road Sec. 2, Hsinchu, Taiwan (China); Yao, Chih-Kai [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Jiunn-Der, E-mail: jdliao@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Nano-mechanical properties on annealed ultra-thin HfO{sub 2} film are studied. Black-Right-Pointing-Pointer By AFM analysis, hardness of the crystallized HfO{sub 2} film significantly increases. Black-Right-Pointing-Pointer By nano-indention, the film hardness increases with less contact stiffness. Black-Right-Pointing-Pointer Quality assessment on the annealed ultra-thin films can thus be achieved. - Abstract: Ultra-thin hafnium dioxide (HfO{sub 2}) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO{sub 2} films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO{sub 2} films deposited on silicon wafers (HfO{sub 2}/SiO{sub 2}/Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO{sub 2} (nominal thickness Almost-Equal-To 10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO{sub 2} phases for the atomic layer deposited HfO{sub 2}. The HfSi{sub x}O{sub y} complex formed at the interface between HfO{sub 2} and SiO{sub 2}/Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO{sub 2} film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically

  3. Silver Nanoparticle Enhanced Freestanding Thin-Film Silicon Solar Cells

    Science.gov (United States)

    Winans, Joshua David

    As the supply of fossil fuels diminishes in quantity the demand for alternative energy sources will consistently increase. Solar cells are an environmentally friendly and proven technology that suffer in sales due to a large upfront cost. In order to help facilitate the transition from fossil fuels to photovoltaics, module costs must be reduced to prices well below $1/Watt. Thin-film solar cells are more affordable because of the reduced materials costs, but lower in efficiency because less light is absorbed before passing through the cell. Silver nanoparticles placed at the front surface of the solar cell absorb and reradiate the energy of the light in ways such that more of the light ends being captured by the silicon. Silver nanoparticles can do this because they have free electron clouds that can take on the energy of an incident photon through collective action. This bulk action of the electrons is called a plasmon. This work begins by discussing the economics driving the need for reduced material use, and the pros and cons of taking this step. Next, the fundamental theory of light-matter interaction is briefly described followed by an introduction to the study of plasmonics. Following that we discuss a traditional method of silver nanoparticle formation and the initial experimental studies of their effects on the ability of thin-film silicon to absorb light. Then, Finite-Difference Time-Domain simulation software is used to simulate the effects of nanoparticle morphology and size on the scattering of light at the surface of the thin-film.

  4. Amorphous silicon thin-film solar cells on glass fiber textiles

    Energy Technology Data Exchange (ETDEWEB)

    Plentz, Jonathan, E-mail: jonathan.plentz@leibniz-ipht.de; Andrä, Gudrun; Pliewischkies, Torsten; Brückner, Uwe; Eisenhawer, Björn; Falk, Fritz

    2016-02-15

    Graphical abstract: - Highlights: • Amorphous silicon solar cells on textile glass fiber fabrics are demonstrated. • Open circuit voltages of 883 mV show shunt-free contacting on non-planar fabrics. • Short-circuit current densities of 3.7 mA/cm{sup 2} are limited by transmission losses. • Fill factors of 43.1% and pseudo fill factors of 70.2% show high series resistance. • Efficiencies of 1.4% and pseudo efficiencies of 2.1% realized on textile fabrics. - Abstract: In this contribution, amorphous silicon thin-film solar cells on textile glass fiber fabrics for smart textiles are prepared and the photovoltaic performance is characterized. These solar cells on fabrics delivered open circuit voltages up to 883 mV. This shows that shunt-free contacting of the solar cells was successful, even in case of non-planar fabrics. The short-circuit current densities up to 3.7 mA/cm{sup 2} are limited by transmission losses in a 10 nm thin titanium layer, which was used as a semi-transparent contact. The low conductivity of this layer limits the fill factor to 43.1%. Pseudo fill factors, neglecting the series resistance, up to 70.2% were measured. Efficiencies up to 1.4% and pseudo efficiencies up to 2.1% were realized on textile fabrics. A transparent conductive oxide could further improve the efficiency to above 5%.

  5. Amorphous and microcrystalline silicon applied in very thin tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schicho, Sandra

    2011-07-28

    Thin-film solar cells are fabricated by low-cost production processes, and are therefore an alternative to conventionally used wafer solar cells based on crystalline silicon. Due to the different band gaps, tandem cells that consist of amorphous (a-Si:H) and microcrystalline ({mu}c-Si:H) single junction solar cells deposited on top of each other use the solar spectrum much more efficient than single junction solar cells. The silicon layers are usually deposited on TCO (Transparent Conductive Oxide)-coated glass and metal- or plastic foils. Compared to the CdTe and CIGS based thin-film technologies, silicon thin-film solar cells have the advantage that no limitation of raw material supply is expected and no toxic elements are used. Nevertheless, the production cost per Wattpeak is the decisive factor concerning competitiveness and can be reduced by, e.g., shorter deposition times or reduced material consumption. Both cost-reducing conceptions are simultaneously achieved by reducing the a-Si:H and {mu}c-Si:H absorber layer thicknesses in a tandem device. In the work on hand, the influence of an absorber layer thickness reduction up to 77% on the photovoltaic parameters of a-Si:H/{mu}c-Si:H tandem solar cells was investigated. An industry-oriented Radio Frequency Plasma-Enhanced Chemical Vapour Deposition (RF-PECVD) system was used to deposit the solar cells on glass substrates coated with randomly structured TCO layers. The thicknesses of top and bottom cell absorber layers were varied by adjusting the deposition time. Reduced layer thicknesses lead to lower absorption and, hence, to reduced short-circuit current densities which, however, are partially balanced by higher open-circuit voltages and fill factors. Furthermore, by using very thin amorphous top cells, the light-induced degradation decreases tremendously. Accordingly, a thickness reduction of 75% led to an efficiency loss of only 21 %. By adjusting the parameters for the deposition of a-Si:H top cells, a

  6. MOCVD ZnO/Screen Printed Ag Back Reflector for Flexible Thin Film Silicon Solar Cell Application

    Directory of Open Access Journals (Sweden)

    Amornrat Limmanee

    2014-01-01

    Full Text Available We have prepared Ag back electrode by screen printing technique and developed MOCVD ZnO/screen printed Ag back reflector for flexible thin film silicon solar cell application. A discontinuity and poor contact interface between the MOCVD ZnO and screen printed Ag layers caused poor open circuit voltage (Voc and low fill factor (FF; however, an insertion of a thin sputtered ZnO layer at the interface could solve this problem. The n type hydrogenated amorphous silicon (a-Si:H film is preferable for the deposition on the surface of MOCVD ZnO film rather than the microcrystalline film due to its less sensitivity to textured surface, and this allowed an improvement in the FF. The n-i-p flexible amorphous silicon solar cell using the MOCVD ZnO/screen printed Ag back reflector showed an initial efficiency of 6.2% with Voc=0.86 V, Jsc=12.4 mA/cm2, and FF = 0.58 (1 cm2. The identical quantum efficiency and comparable performance to the cells using conventional sputtered Ag back electrode have verified the potential of the MOCVD ZnO/screen printed Ag back reflector and possible opportunity to use the screen printed Ag thick film for flexible thin film silicon solar cells.

  7. Loading Effects on Resolution in Thin Layer Chromatography and ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. Loading Effects on Resolution in Thin Layer Chromatography and Paper Chromatography. K Girigowda V H Mulimani. Classroom Volume 10 Issue 11 November 2005 pp 79-84 ...

  8. Copper diffusion in TaN-based thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Nazon, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fraisse, B. [Laboratoire Structure, Proprietes et Modelisation des Solides (UMR 8580), Ecole Centrale de Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex (France); Sarradin, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fries, S.G. [SGF Scientific Consultancy, Arndt str.9, D-52064 Aachen (Germany); Tedenac, J.C. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Frety, N. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France)], E-mail: Nicole.Frety@univ-montp2.fr

    2008-07-15

    The diffusion of Cu through TaN-based thin layers into a Si substrate has been studied. The barrier efficiency of TaN/Ta/TaN multilayers of 150 nm in thickness has been investigated and is compared with that of TaN single layers. Thermal stabilities of these TaN-based thin layers against Cu diffusion were determined from in situ X-ray diffraction experiments, conducted in the temperature range of 773-973 K. The TaN/Ta/TaN barrier appeared to be more efficient in preventing Cu diffusion than the TaN single layer.

  9. The application of thick hydrogenated amorphous silicon layers to charged particle and x-ray detection

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Cho, G.; Fujieda, I.; Kaplan, S.N.; Qureshi, S.; Street, R.A.

    1989-04-01

    We outline the characteristics of thick hydrogenated amorphous silicon layers which are optimized for the detection of charged particles, x-rays and γ-rays. Signal amplitude as a function of the linear energy transfer of various particles are given. Noise sources generated by the detector material and by the thin film electronics - a-Si:H or polysilicon proposed for pixel position sensitive detectors readout are described, and their relative amplitudes are calculated. Temperature and neutron radiation effects on leakage currents and the corresponding noise changes are presented. 17 refs., 12 figs., 2 tabs

  10. Subattoampere current induced by single ions in silicon oxide layers of nonvolatile memory cells

    International Nuclear Information System (INIS)

    Cellere, G.; Paccagnella, A.; Larcher, L.; Visconti, A.; Bonanomi, M.

    2006-01-01

    A single ion impinging on a thin silicon dioxide layer generates a number of electron/hole pairs proportional to its linear energy transfer coefficient. Defects generated by recombination can act as a conductive path for electrons that cross the oxide barrier, thanks to a multitrap-assisted mechanism. We present data on the dependence of this phenomenon on the oxide thickness by using floating gate memory arrays. The tiny number of excess electrons stored in these devices allows for extremely high sensitivity, impossible with any direct measurement of oxide leakage current. Results are of particular interest for next generation devices

  11. Mass productions of thin film silicon PV modules

    International Nuclear Information System (INIS)

    Tawada, Y.; Yamagishi, H.; Yamamoto, K.

    2003-01-01

    Mass production technologies of a-Si single junction and a-Si/poly-Si hybrid modules with stable 8% and 10% efficiency were developed in the Shiga factory of Kaneka Corporation. Kaneka instituted Kaneka Solartech Corporation (KST) as a subsidiary company of 100% shareholder and invested 20 MW production plant in Toyooka City in 1999. There are fully automatic thin film fabrication equipments. KST started the manufacturing amorphous silicon PV modules in 1999 and those of hybrid type PV modules in 2001. The largest size glass substrates used for these modules are 95x98 cm and variable size of modules are being produced by cutting these large area base modules. Recent production yields are higher than 98%. Production technologies of a-Si, thin c-Si and solar cells, performances of modules, applications to the rooftop PV systems will be presented. We estimate the production cost of a-Si solar modules and a-Si/thin c-Si hybrid solar modules. The future business plan of our new type solar modules and our production lines will be discussed. (author)

  12. Ion beam analysis of thin films. Applications to porous silicon

    International Nuclear Information System (INIS)

    Ortega, C.; Grosman, A.; Morazzani, V.

    1995-01-01

    The aim of this paper is twofold: (1)- to present a summary of the fundamental interactions between ion beam (such as proton, deuteron or helium) of MeV energy and solids, interactions that are used in material analysis techniques such as Rutherford Backscattering Spectrometry (RBS), Elastic Recoil Detection Analysis (ERDA) and Nuclear Reaction Analysis (NRA), and (2)- to illustrate the use of these techniques to determine the composition of the surface and outer microns of material. Some examples will be given concerning porous silicon layers. (authors). 38 refs., 25 figs., 3 tabs

  13. Layer-by-Layer Assembly of a pH-Responsive and Electrochromic Thin Film

    Science.gov (United States)

    Schmidt, Daniel J.; Pridgen, Eric M.; Hammond, Paula T.; Love, J. Christopher

    2010-01-01

    This article summarizes an experiment on thin-film fabrication with layer-by-layer assembly that is appropriate for undergraduate laboratory courses. The purpose of this experiment is to teach students about self-assembly in the context of thin films and to expose students to the concepts of functional polymeric coatings. Students dip coat…

  14. Silicon-Light: a European FP7 Project Aiming at High Efficiency Thin Film Silicon Solar Cells on Foil

    DEFF Research Database (Denmark)

    Soppe, W.; Haug, F.-J.; Couty, P.

    2011-01-01

    Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: a) advanced light trapping by implementing nanotexturization through UV Nano...... calculations of ideal nanotextures for light trapping in thin film silicon solar cells; the fabrication of masters and the replication and roll-to-roll fabrication of these nanotextures. Further, results on ITO variants with improved work function are presented. Finally, the status of cell fabrication on foils...

  15. Layer-by-layer modification of thin-film metal-semiconductor multilayers with ultrashort laser pulses

    Science.gov (United States)

    Romashevskiy, S. A.; Tsygankov, P. A.; Ashitkov, S. I.; Agranat, M. B.

    2018-05-01

    The surface modifications in a multilayer thin-film structure (50-nm alternating layers of Si and Al) induced by a single Gaussian-shaped femtosecond laser pulse (350 fs, 1028 nm) in the air are investigated by means of atomic-force microscopy (AFM), scanning electron microscopy (SEM), and optical microscopy (OM). Depending on the laser fluence, various modifications of nanometer-scale metal and semiconductor layers, including localized formation of silicon/aluminum nanofoams and layer-by-layer removal, are found. While the nanofoams with cell sizes in the range of tens to hundreds of nanometers are produced only in the two top layers, layer-by-layer removal is observed for the four top layers under single pulse irradiation. The 50-nm films of the multilayer structure are found to be separated at their interfaces, resulting in a selective removal of several top layers (up to 4) in the form of step-like (concentric) craters. The observed phenomenon is associated with a thermo-mechanical ablation mechanism that results in splitting off at film-film interface, where the adhesion force is less than the bulk strength of the used materials, revealing linear dependence of threshold fluences on the film thickness.

  16. Light trapping with plasmonic back contacts in thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Paetzold, Ulrich Wilhelm

    2013-02-08

    Trapping light in silicon solar cells is essential as it allows an increase in the absorption of incident sunlight in optically thin silicon absorber layers. This way, the costs of the solar cells can be reduced by lowering the material consumption and decreasing the physical constraints on the material quality. In this work, plasmonic light trapping with Ag back contacts in thin-film silicon solar cells is studied. Solar cell prototypes with plasmonic back contacts are presented along with optical simulations of these devices and general design considerations of plasmonic back contacts. Based on three-dimensional electromagnetic simulations, the conceptual design of plasmonic nanostructures on Ag back contacts in thin-film silicon solar cells is studied in this work. Optimizations of the nanostructures regarding their ability to scatter incident light at low optical losses into large angles in the silicon absorber layers of the thin-film silicon solar cells are presented. Geometrical parameters as well as the embedding dielectric layer stack of the nanostructures on Ag layers are varied. Periodic as well as isolated hemispherical Ag nanostructures of dimensions above 200 nm are found to scatter incident light at high efficiencies and low optical losses. Hence, these nanostructures are of interest for light trapping in solar cells. In contrast, small Ag nanostructures of dimension below 100 nm are found to induce optical losses. At the surface of randomly textured Ag back contacts small Ag nanostructures exist which induce optical losses. In this work, the relevance of these localized plasmon induced optical losses as well as optical losses caused by propagating plasmons are investigated with regard to the reflectance of the textured back contacts. In state-of-the-art solar cells, the plasmon-induced optical losses are shifted out of the relevant wavelength range by incorporating a ZnO:Al interlayer of low refractive index at the back contact. The additional but

  17. Transparent conducting oxide contacts and textured metal back reflectors for thin film silicon solar cells

    Science.gov (United States)

    Franken, R. H.-J.

    2006-09-01

    With the growing population and the increasing environmental problems of the 'common' fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic (PV) systems, can play a major role in the urgently needed energy transition in electricity production. At the present time PV module production is dominated by the crystalline wafer technology. Thin film silicon technology is an alternative solar energy technology that operates at lower efficiencies, however, it has several significant advantages, such as the possibility of deposition on cheap (flexible) substrates and the much smaller silicon material consumption. Because of the small thickness of the solar cells, light trapping schemes are needed in order to obtain enough light absorption and current generation. This thesis describes the research on thin film silicon solar cells with the focus on the optimization of the transparent conducting oxide (TCO) layers and textured metal Ag substrate layers for the use as enhanced light scattering back reflectors in n-i-p type of solar cells. First we analyzed ZnO:Al (TCO) layers deposited in an radio frequent (rf) magnetron deposition system equipped with a 7 inch target. We have focused on the improvement of the electrical properties without sacrificing the optical properties by increasing the mobility and decreasing the grain boundary density. Furthermore, we described some of the effects on light trapping of ZnO:Al enhanced back reflectors. The described effects are able to explain the observed experimental data. Furthermore, we present a relation between the surface morphology of the Ag back contact and the current enhancement in microcrystalline (muc-Si:H) solar cells. We show the importance of the lateral feature sizes of the Ag surface on the light scattering and introduce a method to characterize the quality of the back reflector by combining the vertical and lateral feature sizes

  18. Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification.

    Science.gov (United States)

    Lassnig, R; Hollerer, M; Striedinger, B; Fian, A; Stadlober, B; Winkler, A

    2015-11-01

    In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p ++ -silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

  19. MultiLayer solid electrolyte for lithium thin film batteries

    Science.gov (United States)

    Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

    2015-07-28

    A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

  20. Low temperature plasma-enhanced atomic layer deposition of thin vanadium nitride layers for copper diffusion barriers

    Energy Technology Data Exchange (ETDEWEB)

    Rampelberg, Geert; Devloo-Casier, Kilian; Deduytsche, Davy; Detavernier, Christophe [Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, B-9000 Ghent (Belgium); Schaekers, Marc [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Blasco, Nicolas [Air Liquide Electronics US, L.P., 46401 Landing Parkway, Fremont, California 94538 (United States)

    2013-03-18

    Thin vanadium nitride (VN) layers were grown by atomic layer deposition using tetrakis(ethylmethylamino)vanadium and NH{sub 3} plasma at deposition temperatures between 70 Degree-Sign C and 150 Degree-Sign C on silicon substrates and polymer foil. X-ray photoelectron spectroscopy revealed a composition close to stoichiometric VN, while x-ray diffraction showed the {delta}-VN crystal structure. The resistivity was as low as 200 {mu}{Omega} cm for the as deposited films and further reduced to 143 {mu}{Omega} cm and 93 {mu}{Omega} cm by annealing in N{sub 2} and H{sub 2}/He/N{sub 2}, respectively. A 5 nm VN layer proved to be effective as a diffusion barrier for copper up to a temperature of 720 Degree-Sign C.

  1. ZnO buffer layer for metal films on silicon substrates

    Science.gov (United States)

    Ihlefeld, Jon

    2014-09-16

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

  2. Combined analyses of ion beam synthesized layers in porous silicon

    International Nuclear Information System (INIS)

    Ramos, A.R.; Silva, M.F. da; Silva, M.R. da; Soares, J.C.; Paszti, F.; Horvath, Z.E.; Vazsonyi, E.; Conde, O.

    2001-01-01

    High dose ion implantation was used to form polycrystalline silicide films on porous silicon with different native concentrations of light impurities (C and O). Porous silicon layers several μm thick were implanted with 170 KeV Cr + ions to fluences of 3x10'1 7 ions/cm 2 both at room temperature and 450 o C. Similar samples were implanted with 100 keV Co + ions to fluences of 2x10 17 ions/cm 2 at room temperature and 350 o C and 450 o C. The formed silicide compounds were studied by Rutherford backscattering spectrometry, elastic recoil detection, glancing incidence X-ray diffraction, and four point-probe sheet resistance measurements. Selected Co implanted samples were analysed by cross-section transmission electron microscopy. Results show that the light impurities were partially expelled from the forming silicide layer. Combining cross-section transmission electron microscopy with ion beam methods it was possible to show that, in the implanted region, the porous structure collapses and densities during implantation, but the underlying porous silicon remains intact. The layer structure as well as the quality and type of the formed silicide, were found to depend on the original impurity level, implantation temperature, and annealing. (author)

  3. Single-layer graphene on silicon nitride micromembrane resonators

    DEFF Research Database (Denmark)

    Schmid, Silvan; Bagci, Tolga; Zeuthen, Emil

    2014-01-01

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect...... for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling...

  4. Characterisation by optical spectroscopy of a plasma of depositions of thins layers

    International Nuclear Information System (INIS)

    Chouan, Yannick

    1984-01-01

    This research thesis reports a work which, by correlating emission and absorption spectroscopic measurements with properties of deposited thin layers, aimed at being a complement to works undertaken by a team in charge of the realisation of a flat screen. In a first part, the author reports the study of a cathodic pulverisation of a silicon target. He describes the experimental set-up, presents correlations obtained between plasma electric properties (target self-polarisation voltage), emission spectroscopic measurements (line profile and intensity) and absorption spectroscopic measurements (density of metastables), and the composition of deposited thin layers for two reactive pulverisation plasmas (Ar-H_2 and Ar-CH_4). The second part addresses the relationship between experimental conditions and spectroscopic characteristics (emission and absorption lines, excitation and rotation temperature) of a He-SiH_4 plasma. The author also determined the most adapted spectroscopic measurements to the 'control' of deposition, and which result in an optimisation of electronic properties and of the deposition rate for the hydrogenated amorphous silicon. The third part reports the characterisation of depositions. Electric and optic measurements are reported. Then, for both deposition techniques, the author relates the influence of experimental conditions to deposition properties and to spectroscopic diagnosis. The author finally presents static characteristics of a thin-layer-based transistor

  5. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    International Nuclear Information System (INIS)

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-01-01

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

  6. Piezoresistive silicon thin film sensor array for biomedical applications

    International Nuclear Information System (INIS)

    Alpuim, P.; Correia, V.; Marins, E.S.; Rocha, J.G.; Trindade, I.G.; Lanceros-Mendez, S.

    2011-01-01

    N-type hydrogenated nanocrystalline silicon thin film piezoresistors, with gauge factor - 28, were deposited on rugged and flexible polyimide foils by Hot-wire chemical vapor deposition using a tantalum filament heated to 1750 o C. The piezoresistive response under cyclic quasi-static and dynamical (up to 100 Hz) load conditions is reported. Test structures, consisting of microresistors having lateral dimensions in the range from 50 to 100 μm and thickness of 120 nm were defined in an array by reactive ion etching. Metallic pads, forming ohmic contacts to the sensing elements, were defined by a lift-off process. A readout circuit for the array consisting in a mutiplexer on each row and column of the matrix is proposed. The digital data will be processed, interpreted and stored internally by an ultra low-power micro controller, also responsible for the communication of two-way wireless data, e.g. from inside to outside the human body.

  7. Optically induced paramagnetism in amorphous hydrogenated silicon nitride thin films

    International Nuclear Information System (INIS)

    Warren, W.L.; Kanicki, J.; Buchwald, W.R.; Rong, F.C.; Harmatz, M.

    1992-01-01

    This paper reports that the creation mechanisms of Si and N dangling bond defect centers in amorphous hydrogenated silicon nitride thin films by ultra-violet (UV) illumination are investigated. The creation efficiency and density of Si centers in the N-rich films are independent of illumination temperature, strongly suggesting that the creation mechanism of the spins in electronic in nature, i.e., a charge transfer mechanism. However, our results suggest that the creation of the Si dangling bond in the Si-rich films are different. Last, we find that the creation of the N dangling-bond in N-rich films can be fit to a stretched exponential time dependence, which is characteristic of dispersive charge transport

  8. Ion beam analysis of PECVD silicon oxide thin films

    International Nuclear Information System (INIS)

    Fernandez-Lima, F.; Rodriguez, J.A.; Pedrero, E.; Fonseca Filho, H.D.; Llovera, A.; Riera, M.; Dominguez, C.; Behar, M.; Zawislak, F.C.

    2006-01-01

    A study of ion beam analysis techniques of plasma enhanced chemical vapor deposited (PECVD) silicon oxide thin films (1 μm thick) obtained from silane (SiH 4 ) and nitrous oxide (N 2 O) is reported. The film, elemental composition and surface morphology were determined as function of the reactant gas flow ratio, R = [N 2 O]/[SiH 4 ] in the 22-110 range using the Rutherford backscattering spectrometry, nuclear reaction analysis and atomic force microscopy techniques. The density of the films was determined by combining the RBS and thickness measurements. All the experiments were done at a deposition temperature of 300 deg. C. In all the cases almost stoichiometric oxides were obtained being the impurity content function of R. It was also observed that physical properties such as density, surface roughness and shape factor increase with R in the studied interval

  9. Influence of the Surface Layer on the Electrochemical Deposition of Metals and Semiconductors into Mesoporous Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chubenko, E. B., E-mail: eugene.chubenko@gmail.com; Redko, S. V.; Sherstnyov, A. I.; Petrovich, V. A.; Kotov, D. A.; Bondarenko, V. P. [Belarusian State University of Information and RadioElectronics (Belarus)

    2016-03-15

    The influence of the surface layer on the process of the electrochemical deposition of metals and semiconductors into porous silicon is studied. It is shown that the surface layer differs in structure and electrical characteristics from the host porous silicon bulk. It is established that a decrease in the conductivity of silicon crystallites that form the surface layer of porous silicon has a positive effect on the process of the filling of porous silicon with metals and semiconductors. This is demonstrated by the example of nickel and zinc oxide. The effect can be used for the formation of nanocomposite materials on the basis of porous silicon and nanostructures with a high aspect ratio.

  10. Influence of the Surface Layer on the Electrochemical Deposition of Metals and Semiconductors into Mesoporous Silicon

    International Nuclear Information System (INIS)

    Chubenko, E. B.; Redko, S. V.; Sherstnyov, A. I.; Petrovich, V. A.; Kotov, D. A.; Bondarenko, V. P.

    2016-01-01

    The influence of the surface layer on the process of the electrochemical deposition of metals and semiconductors into porous silicon is studied. It is shown that the surface layer differs in structure and electrical characteristics from the host porous silicon bulk. It is established that a decrease in the conductivity of silicon crystallites that form the surface layer of porous silicon has a positive effect on the process of the filling of porous silicon with metals and semiconductors. This is demonstrated by the example of nickel and zinc oxide. The effect can be used for the formation of nanocomposite materials on the basis of porous silicon and nanostructures with a high aspect ratio.

  11. Thin layer activation techniques in research and industry

    International Nuclear Information System (INIS)

    Conlon, T.W.

    1993-01-01

    The following key application of thin layer activation technique (TLA) are discussed: ion-erosion in fusion tokamaks, bio-engineering technology, automobile industry. Future developments of the techniques, such as fission fragment TLA, multi-layer TLA and recoil implantation are discussed as well. 7 refs, 6 figs, 1 tab

  12. Reflectance analysis of porosity gradient in nanostructured silicon layers

    Science.gov (United States)

    Jurečka, Stanislav; Imamura, Kentaro; Matsumoto, Taketoshi; Kobayashi, Hikaru

    2017-12-01

    In this work we study optical properties of nanostructured layers formed on silicon surface. Nanostructured layers on Si are formed in order to reach high suppression of the light reflectance. Low spectral reflectance is important for improvement of the conversion efficiency of solar cells and for other optoelectronic applications. Effective method of forming nanostructured layers with ultralow reflectance in a broad interval of wavelengths is in our approach based on metal assisted etching of Si. Si surface immersed in HF and H2O2 solution is etched in contact with the Pt mesh roller and the structure of the mesh is transferred on the etched surface. During this etching procedure the layer density evolves gradually and the spectral reflectance decreases exponentially with the depth in porous layer. We analyzed properties of the layer porosity by incorporating the porosity gradient into construction of the layer spectral reflectance theoretical model. Analyzed layer is splitted into 20 sublayers in our approach. Complex dielectric function in each sublayer is computed by using Bruggeman effective media theory and the theoretical spectral reflectance of modelled multilayer system is computed by using Abeles matrix formalism. Porosity gradient is extracted from the theoretical reflectance model optimized in comparison to the experimental values. Resulting values of the structure porosity development provide important information for optimization of the technological treatment operations.

  13. Large Area Thin Film Silicon: Synergy between Displays and Solar Cells

    NARCIS (Netherlands)

    Schropp, R.E.I.

    2012-01-01

    Thin-film silicon technology has changed our society, owing to the rapid advance of its two major application fields in communication (thin-film displays) and sustainable energy (thin-film solar cells). Throughout its development, advances in these application fields have always benefitted each

  14. Electronic structures of ultra-thin silicon carbides deposited on graphite

    International Nuclear Information System (INIS)

    Baba, Y.; Sekiguchi, T.; Shimoyama, I.; Nath, Krishna G.

    2004-01-01

    Electronic structures of ultra-thin silicon carbide films have been investigated by X-ray photoelectron spectroscopy (XPS) and Si K-edge X-ray absorption near edge structure (XANES) using linearly polarized synchrotron soft X-rays. Silicon carbide films were deposited on the surface of highly oriented pyrolytic graphite (HOPG) by ion beam deposition method. Tetramethylsilane (Si(CH 3 ) 4 ) was used as a discharge gas. The XPS and XANES features for the thick layers were similar to those for the bulk SiC. For sub-monolayered films, the Si 1s binding energy in XPS was higher by 2.5 eV than that for bulk SiC. This suggests the existence of low-dimensional SiC x where the silicon atoms are more positively charged than those in bulk SiC. After annealing the sub-monolayered film at 850 deg. C, a new peak appeared around 1840 eV in the XANES spectrum. The energy of this new peak was lower than those for any other silicon compounds. The low-energy feature of the XANES peak suggests the existence of π*-like orbitals around the silicon atom. On the basis of the polarization dependencies of the XANES spectra, it was revealed that the direction of the π*-like orbitals are nearly perpendicular to the surface. We conclude that sub-monolayered SiC x film exhibits flat-lying structure of which configuration is similar to a single sheet of graphite

  15. Templated Solid-State Dewetting of Thin Silicon Films.

    Science.gov (United States)

    Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Delobbe, Anne; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

    2016-11-01

    Thin film dewetting can be efficiently exploited for the implementation of functionalized surfaces over very large scales. Although the formation of sub-micrometer sized crystals via solid-state dewetting represents a viable method for the fabrication of quantum dots and optical meta-surfaces, there are several limitations related to the intrinsic features of dewetting in a crystalline medium. Disordered spatial organization, size, and shape fluctuations are relevant issues not properly addressed so far. This study reports on the deterministic nucleation and precise positioning of Si- and SiGe-based nanocrystals by templated solid-state dewetting of thin silicon films. The dewetting dynamics is guided by pattern size and shape taking full control over number, size, shape, and relative position of the particles (islands dimensions and relative distances are in the hundreds nm range and fluctuate ≈11% for the volumes and ≈5% for the positioning). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Hydrogenated amorphous silicon thin film anode for proton conducting batteries

    Science.gov (United States)

    Meng, Tiejun; Young, Kwo; Beglau, David; Yan, Shuli; Zeng, Peng; Cheng, Mark Ming-Cheng

    2016-01-01

    Hydrogenated amorphous Si (a-Si:H) thin films deposited by chemical vapor deposition were used as anode in a non-conventional nickel metal hydride battery using a proton-conducting ionic liquid based non-aqueous electrolyte instead of alkaline solution for the first time, which showed a high specific discharge capacity of 1418 mAh g-1 for the 38th cycle and retained 707 mAh g-1 after 500 cycles. A maximum discharge capacity of 3635 mAh g-1 was obtained at a lower discharge rate, 510 mA g-1. This electrochemical discharge capacity is equivalent to about 3.8 hydrogen atoms stored in each silicon atom. Cyclic voltammogram showed an improved stability 300 mV below the hydrogen evolution potential. Both Raman spectroscopy and Fourier transform infrared spectroscopy studies showed no difference to the pre-existing covalent Si-H bond after electrochemical cycling and charging, indicating a non-covalent nature of the Si-H bonding contributing to the reversible hydrogen storage of the current material. Another a-Si:H thin film was prepared by an rf-sputtering deposition followed by an ex-situ hydrogenation, which showed a discharge capacity of 2377 mAh g-1.

  17. Crystallization of Electrodeposited Germanium Thin Film on Silicon (100).

    Science.gov (United States)

    Abidin, Mastura Shafinaz Zainal; Matsumura, Ryo; Anisuzzaman, Mohammad; Park, Jong-Hyeok; Muta, Shunpei; Mahmood, Mohamad Rusop; Sadoh, Taizoh; Hashim, Abdul Manaf

    2013-11-06

    We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm -1 corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm -1 corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

  18. Crystallization of Electrodeposited Germanium Thin Film on Silicon (100

    Directory of Open Access Journals (Sweden)

    Abdul Manaf Hashim

    2013-11-01

    Full Text Available We report the crystallization of electrodeposited germanium (Ge thin films on n-silicon (Si (100 by rapid melting process. The electrodeposition was carried out in germanium (IV chloride: propylene glycol (GeCl4:C3H8O2 electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm−1 corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm−1 corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

  19. Laser generated guided waves and finite element modeling for the thickness gauging of thin layers.

    Science.gov (United States)

    Lefevre, F; Jenot, F; Ouaftouh, M; Duquennoy, M; Ourak, M

    2010-03-01

    In this paper, nondestructive testing has been performed on a thin gold layer deposited on a 2 in. silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup and a two-dimensional fast Fourier transform technique was employed to obtain the dispersion curves. A gold layer thickness of 1.33 microm has been determined with a +/-5% margin of error using the shape of the two first propagating modes, assuming for the substrate and the layer an uncertainty on the elastic parameters of +/-2.5%. A finite element model has been implemented to validate the data post-treatment and the experimental results. A good agreement between the numerical simulation, the analytical modeling and the experimentations has been observed. This method was considered suitable for thickness layer higher than 0.7 microm.

  20. On the structural and optical properties of sputtered hydrogenated amorphous silicon thin films

    International Nuclear Information System (INIS)

    Barhdadi, A.; Chafik El ldrissi, M.

    2002-08-01

    The present work is essentially focused on the study of optical and structural properties of hydrogenated amorphous silicon thin films (a-Si:H) prepared by radio-frequency cathodic sputtering. We examine separately the influence of hydrogen partial pressure during film deposition, and the effect of post-deposition thermal annealings on the main optical characteristics of the layers such as refraction index, optical gap and Urbach energy. Using the grazing X-rays reflectometry technique, thin film structural properties are examined immediately after films deposition as well as after surface oxidation or annealing. We show that low hydrogen pressures allow a saturation of dangling bonds in the layers, while high doses lead to the creation of new defects. We show also that thermal annealing under moderate temperatures improves the structural quality of the deposited layers. For the films examined just after deposition, the role of hydrogen appears in the increase of their density. For those analysed after a short stay in the ambient, hydrogen plays a protective role against the oxidation of their surfaces. This role disappears for a long time stay in the ambient. (author)

  1. Carrier collection losses in interface passivated amorphous silicon thin-film solar cells

    International Nuclear Information System (INIS)

    Neumüller, A.; Sergeev, O.; Vehse, M.; Agert, C.; Bereznev, S.; Volobujeva, O.; Ewert, M.; Falta, J.

    2016-01-01

    In silicon thin-film solar cells the interface between the i- and p-layer is the most critical. In the case of back diffusion of photogenerated minority carriers to the i/p-interface, recombination occurs mainly on the defect states at the interface. To suppress this effect and to reduce recombination losses, hydrogen plasma treatment (HPT) is usually applied. As an alternative to using state of the art HPT we apply an argon plasma treatment (APT) before the p-layer deposition in n-i-p solar cells. To study the effect of APT, several investigations were applied to compare the results with HPT and no plasma treatment at the interface. Carrier collection losses in resulting solar cells were examined with spectral response measurements with and without bias voltage. To investigate single layers, surface photovoltage and X-ray photoelectron spectroscopy (XPS) measurements were conducted. The results with APT at the i/p-interface show a beneficial contribution to the carrier collection compared with HPT and no plasma treatment. Therefore, it can be concluded that APT reduces the recombination centers at the interface. Further, we demonstrate that carrier collection losses of thin-film solar cells are significantly lower with APT.

  2. Carrier collection losses in interface passivated amorphous silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Neumüller, A., E-mail: alex.neumueller@next-energy.de; Sergeev, O.; Vehse, M.; Agert, C. [NEXT ENERGY EWE Research Centre for Energy Technology at the University of Oldenburg, Carl-von-Ossietzky-Straße 15, 26129 Oldenburg (Germany); Bereznev, S.; Volobujeva, O. [Department of Materials Science, Tallinn University of Technology, Ehitajate Tee 5, Tallinn 19086 (Estonia); Ewert, M.; Falta, J. [Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen (Germany); MAPEX Center for Materials and Processes, University of Bremen, 28359 Bremen (Germany)

    2016-07-25

    In silicon thin-film solar cells the interface between the i- and p-layer is the most critical. In the case of back diffusion of photogenerated minority carriers to the i/p-interface, recombination occurs mainly on the defect states at the interface. To suppress this effect and to reduce recombination losses, hydrogen plasma treatment (HPT) is usually applied. As an alternative to using state of the art HPT we apply an argon plasma treatment (APT) before the p-layer deposition in n-i-p solar cells. To study the effect of APT, several investigations were applied to compare the results with HPT and no plasma treatment at the interface. Carrier collection losses in resulting solar cells were examined with spectral response measurements with and without bias voltage. To investigate single layers, surface photovoltage and X-ray photoelectron spectroscopy (XPS) measurements were conducted. The results with APT at the i/p-interface show a beneficial contribution to the carrier collection compared with HPT and no plasma treatment. Therefore, it can be concluded that APT reduces the recombination centers at the interface. Further, we demonstrate that carrier collection losses of thin-film solar cells are significantly lower with APT.

  3. Ultra-thin distributed Bragg reflectors via stacked single-crystal silicon nanomembranes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Minkyu; Seo, Jung-Hun; Lee, Jaeseong; Mi, Hongyi; Kim, Munho; Ma, Zhenqiang, E-mail: mazq@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Zhao, Deyin; Zhou, Weidong [Nanophotonics Lab, Department of Electrical Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States); Yin, Xin; Wang, Xudong [Department of Material Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2015-05-04

    In this paper, we report ultra-thin distributed Bragg reflectors (DBRs) via stacked single-crystal silicon (Si) nanomembranes (NMs). Mesh hole-free single-crystal Si NMs were released from a Si-on-insulator substrate and transferred to quartz and Si substrates. Thermal oxidation was applied to the transferred Si NM to form high-quality SiO{sub 2} and thus a Si/SiO{sub 2} pair with uniform and precisely controlled thicknesses. The Si/SiO{sub 2} layers, as smooth as epitaxial grown layers, minimize scattering loss at the interface and in between the layers. As a result, a reflection of 99.8% at the wavelength range from 1350 nm to 1650 nm can be measured from a 2.5-pair DBR on a quartz substrate and 3-pair DBR on a Si substrate with thickness of 0.87 μm and 1.14 μm, respectively. The high reflection, ultra-thin DBRs developed here, which can be applied to almost any devices and materials, holds potential for application in high performance optoelectronic devices and photonics applications.

  4. Broadband wavelength conversion in hydrogenated amorphous silicon waveguide with silicon nitride layer

    Science.gov (United States)

    Wang, Jiang; Li, Yongfang; Wang, Zhaolu; Han, Jing; Huang, Nan; Liu, Hongjun

    2018-01-01

    Broadband wavelength conversion based on degenerate four-wave mixing is theoretically investigated in a hydrogenated amorphous silicon (a-Si:H) waveguide with silicon nitride inter-cladding layer (a-Si:HN). We have found that enhancement of the non-linear effect of a-Si:H waveguide nitride intermediate layer facilitates broadband wavelength conversion. Conversion bandwidth of 490 nm and conversion efficiency of 11.4 dB were achieved in a numerical simulation of a 4 mm-long a-Si:HN waveguide under 1.55 μm continuous wave pumping. This broadband continuous-wave wavelength converter has potential applications in photonic networks, a type of readily manufactured low-cost highly integrated optical circuits.

  5. Growth of (100)-highly textured BaBiO{sub 3} thin films on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ferreyra, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); Departamento de Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 1, Ciudad Universitaria, Buenos Aires (Argentina); Marchini, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, Buenos Aires (Argentina); Granell, P. [INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Golmar, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); INTI, CMNB, Av. Gral Paz 5445, B1650KNA San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología, UNSAM, Campus Miguelete, 1650 San Martín, Buenos Aires (Argentina); Albornoz, C. [GIyA and INN, CNEA, Av. Gral Paz 1499, 1650 San Martín, Buenos Aires (Argentina); and others

    2016-08-01

    We report on the growth and characterization of non-epitaxial but (100)-highly textured BaBiO{sub 3} thin films on silicon substrates. We have found the deposition conditions that optimize the texture, and show that the textured growth is favoured by the formation of a BaO layer at the first growth stages. X-ray diffraction Φ-scans, together with the observation that the same textured growth is found on films grown on Pt and SiO{sub 2} buffered Si, demonstrate the absence of epitaxy. Finally, we have shown that our (100)-oriented BaBiO{sub 3} films can be used as suitable buffers for the growth of textured heterostructures on silicon, which could facilitate the integration of potential devices with standard electronics. - Highlights: • BaBiO{sub 3} thin films were grown on Si substrates and characterized. • Films prepared using optimized conditions are highly textured in the (100) direction. • The absence of in-plane texture was demonstrated by X-ray diffraction. • Our films are suitable buffers for the growth of (100)-textured oxide heterostructures.

  6. Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

    International Nuclear Information System (INIS)

    Gao, Feng; Arpiainen, Sanna; Puurunen, Riikka L.

    2015-01-01

    Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000 μm) and cavity height (e.g., 200–1000 nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25 000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al 2 O 3 and TiO 2 processes from Me 3 Al/H 2 O and TiCl 4 /H 2 O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes

  7. Layered structure in core–shell silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Van Tuan, Pham [Advanced Institute for Science and Technology (AIST) and International Training Institute for Materials Science Hanoi University of Science and Technology, 01 Dai Co Viet Street,Hanoi 10000,Vietnam (Viet Nam); Anh Tuan, Chu; Thanh Thuy, Tran; Binh Nam, Vu [Institute of Materials Science (IMS), Vietnamese Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Hanoi 10000 (Viet Nam); Toan Thang, Pham [Advanced Institute for Science and Technology (AIST) and International Training Institute for Materials Science Hanoi University of Science and Technology, 01 Dai Co Viet Street,Hanoi 10000,Vietnam (Viet Nam); Hong Duong, Pham, E-mail: duongphamhong@yahoo.com [Institute of Materials Science (IMS), Vietnamese Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Hanoi 10000 (Viet Nam); Thanh Huy, Pham, E-mail: huy.phamthanh@hust.edu.vn [Advanced Institute for Science and Technology (AIST) and International Training Institute for Materials Science Hanoi University of Science and Technology, 01 Dai Co Viet Street,Hanoi 10000,Vietnam (Viet Nam)

    2014-10-15

    Silicon nanowires (NWs) with core–shell structures were prepared using the Vapor–Liquid–Solid (VLS) method. The wires have lengths of several hundreds of nanometers and diameters in the range of 30–50 nm. Generally, these wires are too large to exhibit the quantum confinement effect of excitons in Si nanocrystals. However, the photoluminescence (PL) and Raman spectra are similar to those of nanocrystalline silicon embedded in a SiO{sub 2} matrix, in which the recombination of quantum-confined excitons plays an important role. This effect occurs only when the average size of the silicon nanocrystals is smaller than 5 nm. To understand this discrepancy, TEM images of nanowires were obtained and analyzed. The results revealed that the cores of wires have a layered Si/SiO{sub 2} structure, in which the thickness of each layer is much smaller than its diameter. The temperature dependence of the PL intensity was recorded from 11 to 300 K; the result is in good agreement with a model that takes into account the energy splitting between the excitonic singlet and triplet levels. - Highlights: • The cores of the Si NWs have a layered Si/SiO{sub 2} structure. • The Si NWs were formed due to the phase separation of Si and SiO{sub 2} and the partial oxidization by residual oxygen. • Two processes, the reaction of Si and oxygen atoms and the combination between Si atoms, occur simultaneously. • The formation of the layered structures is associated with the self-limiting oxidation phenomenon in Si nanostructures.

  8. Fatigue characteristics of polycrystalline silicon thin-film membrane and its dependence on humidity

    International Nuclear Information System (INIS)

    Tanemura, Tomoki; Yamashita, Shuichi; Wado, Hiroyuki; Takeuchi, Yukihiro; Tsuchiya, Toshiyuki; Tabata, Osamu

    2013-01-01

    This paper describes fatigue characteristics of a polycrystalline silicon thin-film membrane under different humidity evaluated by out-of-plane resonant vibration. The membrane, without the surface of sidewalls by patterning of photolithography and etching process, was applied to evaluate fatigue characteristics precisely against the changes in the surrounding humidity owing to narrower deviation in the fatigue lifetime. The membrane has 16 mm square-shaped multilayered films consisting of a 250 or 500 nm thick polysilicon film on silicon dioxide and silicon nitride underlying layers. A circular weight of 12 mm in diameter was placed at the center of the membrane to control the resonant frequency. Stress on the polysilicon film was generated by deforming the membrane oscillating the weight in the out-of-plane direction. The polysilicon film was fractured by fatigue damage accumulation under cyclic stress. The lifetime of the polysilicon membrane extended with lower relative humidity, especially at 5%RH. The results of the fatigue tests were well formulated with Weibull's statistics and Paris’ law. The dependence of fatigue characteristics on humidity has been quantitatively revealed for the first time. The crack growth rate indicated by the fatigue index decreased with the reduction in humidity, whereas the deviation of strength represented by the Weibull modulus was nearly constant against humidity. (paper)

  9. Dual-side and three-dimensional microelectrode arrays fabricated from ultra-thin silicon substrates

    International Nuclear Information System (INIS)

    Du, Jiangang; Masmanidis, Sotiris C; Roukes, Michael L

    2009-01-01

    A method for fabricating planar implantable microelectrode arrays was demonstrated using a process that relied on ultra-thin silicon substrates, which ranged in thickness from 25 to 50 µm. The challenge of handling these fragile materials was met via a temporary substrate support mechanism. In order to compensate for putative electrical shielding of extracellular neuronal fields, separately addressable electrode arrays were defined on each side of the silicon device. Deep reactive ion etching was employed to create sharp implantable shafts with lengths of up to 5 mm. The devices were flip-chip bonded onto printed circuit boards (PCBs) by means of an anisotropic conductive adhesive film. This scalable assembly technique enabled three-dimensional (3D) integration through formation of stacks of multiple silicon and PCB layers. Simulations and measurements of microelectrode noise appear to suggest that low impedance surfaces, which could be formed by electrodeposition of gold or other materials, are required to ensure an optimal signal-to-noise ratio as well a low level of interchannel crosstalk

  10. Polycrystalline silicon thin-film solar cells on glass

    Energy Technology Data Exchange (ETDEWEB)

    Gall, S.; Becker, C.; Conrad, E.; Dogan, P.; Fenske, F.; Gorka, B.; Lee, K.Y.; Rau, B.; Ruske, F.; Rech, B. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH (formerly Hahn-Meitner-Institut Berlin GmbH), Department Silicon Photovoltaics (SE1), Kekulestr. 5, D-12489 Berlin (Germany)

    2009-06-15

    Poly-Si thin-film solar cells on glass feature the potential to reach single-junction efficiencies of 15% or even higher at low costs. In this paper innovative approaches are discussed, which could lead to substantial efficiency improvements and significant cost reductions: (i) preparation of large-grained poly-Si films using the 'seed layer concept' targeting at high material quality, (ii) utilization of ZnO:Al-coated glass enabling simple contacting and light-trapping schemes, (iii) utilization of high-rate electron-beam evaporation for the absorber deposition offering a high potential for cost reduction. (author)

  11. Rapid Thermal annealing of silicon layers amorphized by ion implantation

    International Nuclear Information System (INIS)

    Hasenack, C.M.

    1986-01-01

    The recrystallization behavior and the supression mechanisms of the residual defects of silicon layers amorphized by ion implantation, were investigated. The samples were annealed with the aid of a rapid thermal annealing (RTA) system at temperature range from 850 to 1200 0 C, and annealing time up to 120 s. Random and aligned Rutherford backscattering spectroscopy were used to analyse the samples. Similarities in the recrystallization behavior for layers implanted with ions of the same chemical groups such as As or Sb; Ge, Sn or Pb, In or Ga, are observed. The results show that the effective supression of resisual defects of the recrystallired layers is vinculated to the redistribution of impurities via thermal diffusion. (author) [pt

  12. Front buried metallic contacts and thin porous silicon combination for efficient polycrystalline silicon solar cells

    International Nuclear Information System (INIS)

    Ben Rabha, M.; Boujmil, M.F.; Meddeb, N.; Saadoun, M.; Bessais, B.

    2006-01-01

    We investigate the impacts of achieving buried grid metallic contacts (BGMC), with and without application of a front porous silicon (PS) layer, on the photovoltaic properties of polycrystalline silicon (pc-Si) solar cells. A grooving method based on Chemical Vapor Etching (CVE) was used to perform buried grid contacts on the emitter of pc-Si solar cells. After realizing the n + /p junction using a phosphorus diffusion source, BGMCs were realized using the screen printing technique. We found that the buried metallic contacts improve the short circuit current from 16 mA/cm 2 (for reference cell without buried contacts) to about 19 mA/cm 2 . After application of a front PS layer on the n + emitter, we observe an enhancement of the short circuit current from 19 to 24 mA/cm 2 with a decrease of the reflectivity by about 40% of its initial value. The dark I-V characteristics of the pc-Si cells with PS-based emitter show an important reduction of the reverse current together with an improvement of the rectifying behaviour. Spectral response measurements performed at a wavelength range of 400-1100 nm showed a significant increase in the quantum efficiency, particularly at shorter wavelength (400-650 nm). These results indicate that the BGMCs improve the carrier collection and that the PS layer acts as an antireflective coating that reduces reflection losses and passivates the front surface. This low cost and simple technology based on the CVE technique could enable preparing efficient polycrystalline silicon solar cells

  13. Characterization of Lateral Structure of the p-i-n Diode for Thin-Film Silicon Solar Cell.

    Science.gov (United States)

    Kiaee, Zohreh; Joo, Seung Ki

    2018-03-01

    The lateral structure of the p-i-n diode was characterized for thin-film silicon solar cell application. The structure can benefit from a wide intrinsic layer, which can improve efficiency without increasing cell thickness. Compared with conventional thin-film p-i-n cells, the p-i-n diode lateral structure exploited direct light irradiation on the absorber layer, one-side contact, and bifacial irradiation. Considering the effect of different carrier lifetimes and recombinations, we calculated efficiency parameters by using a commercially available simulation program as a function of intrinsic layer width, as well as the distance between p/i or n/i junctions to contacts. We then obtained excellent parameter values of 706.52 mV open-circuit voltage, 24.16 mA/Cm2 short-circuit current, 82.66% fill factor, and 14.11% efficiency from a lateral cell (thickness = 3 μm; intrinsic layer width = 53 μm) in monofacial irradiation mode (i.e., only sunlight from the front side was considered). Simulation results of the cell without using rear-side reflector in bifacial irradiation mode showed 11.26% front and 9.72% rear efficiencies. Our findings confirmed that the laterally structured p-i-n cell can be a potentially powerful means for producing highly efficient, thin-film silicon solar cells.

  14. Thin film photovoltaic devices with a minimally conductive buffer layer

    Science.gov (United States)

    Barnes, Teresa M.; Burst, James

    2016-11-15

    A thin film photovoltaic device (100) with a tunable, minimally conductive buffer (128) layer is provided. The photovoltaic device (100) may include a back contact (150), a transparent front contact stack (120), and an absorber (140) positioned between the front contact stack (120) and the back contact (150). The front contact stack (120) may include a low resistivity transparent conductive oxide (TCO) layer (124) and a buffer layer (128) that is proximate to the absorber layer (140). The photovoltaic device (100) may also include a window layer (130) between the buffer layer (128) and the absorber (140). In some cases, the buffer layer (128) is minimally conductive, with its resistivity being tunable, and the buffer layer (128) may be formed as an alloy from a host oxide and a high-permittivity oxide. The high-permittivity oxide may further be chosen to have a bandgap greater than the host oxide.

  15. Ion beam analysis of aluminium in thin layers

    International Nuclear Information System (INIS)

    Healy, M.J.F.; Pidduck, A.J.; Dollinger, G.; Gorgens, L.; Bergmaier, A.

    2002-01-01

    This work quantifies aluminium in thin surface and near surface layers. In one example, the layer overlies a thin gallium nitride layer on an aluminium oxide substrate and in a second example the aluminium exists just below the surface of an indium arsenide substrate. The technique of non-Rutherford elastic backscattering of protons was used for the samples where aluminum in the layer of interest needed to be resolved from aluminium in the sapphire substrate and the results were corroborated at the Technische Universitaet Muenchen using heavy ion elastic recoil detection analysis. In the second example, where it was unnecessary to isolate the signal of aluminium in the layer of interest (as the substrate contained no aluminium), then the 27 Al(d,p 01 ) 28 Al nuclear reaction was used. The elastic proton scattering cross section of aluminum was found to vary very rapidly over the energy range of interest

  16. Optical characteristics of silicon nanowires grown from tin catalyst layers on silicon coated glass

    KAUST Repository

    Ball, Jeremy

    2012-08-20

    The optical characteristics of silicon nanowires grown on Si layers on glass have been modeled using the FDTD (Finite Difference Time Domain) technique and compared with experimental results. The wires were grown by the VLS (vapour-liquid-solid) method using Sn catalyst layers and exhibit a conical shape. The resulting measured and modeled absorption, reflectance and transmittance spectra have been investigated as a function of the thickness of the underlying Si layer and the initial catalyst layer, the latter having a strong influence on wire density. High levels of absorption (>90% in the visible wavelength range) and good agreement between the modeling and experiment have been observed when the nanowires have a relatively high density of ∼4 wires/μ m2. The experimental and modeled results diverge for samples with a lower density of wire growth. The results are discussed along with some implications for solar cell fabrication. © 2012 Optical Society of America.

  17. Optical characteristics of silicon nanowires grown from tin catalyst layers on silicon coated glass

    KAUST Repository

    Ball, Jeremy; Centeno, Anthony; Mendis, Budhika G.; Reehal, H. S.; Alford, Neil

    2012-01-01

    The optical characteristics of silicon nanowires grown on Si layers on glass have been modeled using the FDTD (Finite Difference Time Domain) technique and compared with experimental results. The wires were grown by the VLS (vapour-liquid-solid) method using Sn catalyst layers and exhibit a conical shape. The resulting measured and modeled absorption, reflectance and transmittance spectra have been investigated as a function of the thickness of the underlying Si layer and the initial catalyst layer, the latter having a strong influence on wire density. High levels of absorption (>90% in the visible wavelength range) and good agreement between the modeling and experiment have been observed when the nanowires have a relatively high density of ∼4 wires/μ m2. The experimental and modeled results diverge for samples with a lower density of wire growth. The results are discussed along with some implications for solar cell fabrication. © 2012 Optical Society of America.

  18. Formation and properties of the buried isolating silicon-dioxide layer in double-layer “porous silicon-on-insulator” structures

    Energy Technology Data Exchange (ETDEWEB)

    Bolotov, V. V.; Knyazev, E. V.; Ponomareva, I. V.; Kan, V. E., E-mail: kan@obisp.oscsbras.ru; Davletkildeev, N. A.; Ivlev, K. E.; Roslikov, V. E. [Russian Academy of Sciences, Omsk Scientific Center, Siberian Branch (Russian Federation)

    2017-01-15

    The oxidation of mesoporous silicon in a double-layer “macroporous silicon–mesoporous silicon” structure is studied. The morphology and dielectric properties of the buried insulating layer are investigated using electron microscopy, ellipsometry, and electrical measurements. Specific defects (so-called spikes) are revealed between the oxidized macropore walls in macroporous silicon and the oxidation crossing fronts in mesoporous silicon. It is found that, at an initial porosity of mesoporous silicon of 60%, three-stage thermal oxidation leads to the formation of buried silicon-dioxide layers with an electric-field breakdown strength of E{sub br} ~ 10{sup 4}–10{sup 5} V/cm. Multilayered “porous silicon-on-insulator” structures are shown to be promising for integrated chemical micro- and nanosensors.

  19. Advanced methods for light trapping in optically thin silicon solar cells

    Science.gov (United States)

    Nagel, James Richard

    2011-12-01

    The field of light trapping is the study of how best to absorb light in a thin film of material when most light either reflects away at the surface or transmits straight through to the other side. This has tremendous application to the field of photovoltaics where thin silicon films can be manufactured cheaply, but also fail to capture all of the available photons in the solar spectrum. Advancements in light trapping therefore bring us closer to the day when photovoltaic devices may reach grid parity with traditional fossil fuels on the electrical energy market. This dissertation advances our understanding of light trapping by first modeling the effects of loss in planar dielectric waveguides. The mathematical framework developed here can be used to model any arbitrary three-layer structure with mixed gain or loss and then extract the total field solution for the guided modes. It is found that lossy waveguides possess a greater number of eigenmodes than their lossless counterparts, and that these "loss guided" modes attenuate much more rapidly than conventional modes. Another contribution from this dissertation is the exploration of light trapping through the use of dielectric nanospheres embedded directly within the active layer of a thin silicon film. The primary benefit to this approach is that the device can utilize a surface nitride layer serving as an antireflective coating while still retaining the benefits of light trapping within the film. The end result is that light trapping and light injection are effectively decoupled from each other and may be independently optimized within a single photovoltaic device. The final contribution from this work is a direct numerical comparison between multiple light trapping schemes. This allows us to quantify the relative performances of various design techniques against one another and objectively determine which ideas tend to capture the most light. Using numerical simulation, this work directly compares the absorption

  20. Modulated surface textures for enhanced scattering in thin-film silicon solar cells

    NARCIS (Netherlands)

    Isabella, O.; Battaglia, C.; Ballif, C.; Zeman, M.

    2012-01-01

    Nano-scale randomly textured front transparent oxides are superposed on micro-scale etched glass substrates to form modulated surface textures. The resulting enhanced light scattering is implemented in single and double junction thin-film silicon solar cells.

  1. Analysis of influence of buffer layers on microwave propagation through high-temperature superconducting thin films

    International Nuclear Information System (INIS)

    Ceremuga, J.; Barton, M.; Miranda, F.

    1994-01-01

    Methods of analysis of microwave propagation through superconducting thin films with buffer layers on dielectric substrates have been discussed. Expressions describing the transmission coefficient S 21 through the structure and the complex conductivity sigma of a superconductor in an analytical form have been derived. The derived equations are valid for microwave propagation in waveguides as well as in free space with relevant definition of impedances. Using the obtained solutions, the influences of buffer layers' parameters (thickness, relative permittivity and loss tangent) on the transmission coefficient has been investigated using MATLAB. Simulations have been performed for 10 GHz transmission through YBa 2 Cu 3 O 7 films on sapphire with SrTiO 3 and CeO 2 buffer layers and on silicon with CaF 2 and YSZ buffer layers. To illustrate the simulations, measurements of the transmission through YBCO film on sapphire with SrTiO 3 buffer layer have been performed. It has been shown that even lossy buffer layers have very little impact (smaller than 1% in magnitude and 0.3% in phase) on the transmission coefficient through superconducting thin films, providing their thickness is below 10 mu m. (author)

  2. Grazing incidence X-ray fluorescence analysis of buried interfaces in periodically structured crystalline silicon thin-film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Eisenhauer, David; Preidel, Veit; Becker, Christiane [Young Investigator Group Nanostructured Silicon for Photovoltaic and Photonic Implementations (Nano-SIPPE), Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Pollakowski, Beatrix; Beckhoff, Burkhard [Physikalisch-Technische Bundesanstalt, Berlin (Germany); Baumann, Jonas; Kanngiesser, Birgit [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin (Germany); Amkreutz, Daniel; Rech, Bernd [Institut Silizium Photovoltaik, Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Back, Franziska; Rudigier-Voigt, Eveline [SCHOTT AG, Mainz (Germany)

    2015-03-01

    We present grazing incidence X-ray fluorescence (GIXRF) experiments on 3D periodically textured interfaces of liquid phase crystallized silicon thin-film solar cells on glass. The influence of functional layers (SiO{sub x} or SiO{sub x}/SiC{sub x}) - placed between glass substrate and silicon during crystallization - on the final carbon and oxygen contaminations inside the silicon was analyzed. Baring of the buried structured silicon surface prior to GIXRF measurement was achieved by removal of the original nano-imprinted glass substrate by wet-chemical etching. A broad angle of incidence distribution was determined for the X-ray radiation impinging on this textured surface. Optical simulations were performed in order to estimate the incident radiation intensity on the structured surface profile considering total reflection and attenuation effects. The results indicate a much lower contamination level for SiO{sub x} compared to the SiO{sub x}/SiC{sub x} interlayers, and about 25% increased contamination when comparing structured with planar silicon layers, both correlating with the corresponding solar cell performances. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Ultra-thin Metal and Dielectric Layers for Nanophotonic Applications

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Leandro, Lorenzo; Malureanu, Radu

    2015-01-01

    In our talk we first give an overview of the various thin films used in the field of nanophotonics. Then we describe our own activity in fabrication and characterization of ultra-thin films of high quality. We particularly focus on uniform gold layers having thicknesses down to 6 nm fabricated by......-beam deposition on dielectric substrates and Al-oxides/Ti-oxides multilayers prepared by atomic layer deposition in high aspect ratio trenches. In the latter case we show more than 1:20 aspect ratio structures can be achieved....

  4. Formation of hydrated layers in PMMA thin films in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Akers, Peter W. [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); Nelson, Andrew R.J. [The Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia); Williams, David E. [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington (New Zealand); McGillivray, Duncan J., E-mail: d.mcgillivray@auckland.ac.nz [School of Chemical Sciences, University of Auckland, Auckland (New Zealand); MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington (New Zealand)

    2015-10-30

    Graphical abstract: - Highlights: • Homogeneous thin PMMA films prepared on Si/SiOx substrates and measured in air and water. • Reproducible formation of highly hydrated layer containing 50% water at the PMMA/SiOx interface. • When heated the films swell at 50 °C without loss of material. • Upon re-cooling to 25 °C the surface roughens and material is lost. - Abstract: Neutron reflectometry (NR) measurements have been made on thin (70–150 Å) poly(methylmethacrylate) (PMMA) films on Si/SiOx substrates in aqueous conditions, and compared with parameters measured using ellipsometry and X-Ray reflectometry (XRR) on dry films. All techniques show that the thin films prepared using spin-coating techniques were uniform and had low roughness at both the silicon and subphase interfaces, and similar surface energetics to thicker PMMA films. In aqueous solution, NR measurements at 25 °C showed that PMMA forms a partially hydrated layer at the SiOx interface 10 Å under the film, while the bulk film remains intact and contains around 4% water. Both the PMMA film layer and the sublayer showed minimal swelling over a period of 24 h. At 50 °C, PMMA films in aqueous solution roughen and swell, without loss of PMMA material at the surface. After cooling back to 25 °C, swelling and roughening increases further, with loss of material from the PMMA layer.

  5. Formation of hydrated layers in PMMA thin films in aqueous solution

    International Nuclear Information System (INIS)

    Akers, Peter W.; Nelson, Andrew R.J.; Williams, David E.; McGillivray, Duncan J.

    2015-01-01

    Graphical abstract: - Highlights: • Homogeneous thin PMMA films prepared on Si/SiOx substrates and measured in air and water. • Reproducible formation of highly hydrated layer containing 50% water at the PMMA/SiOx interface. • When heated the films swell at 50 °C without loss of material. • Upon re-cooling to 25 °C the surface roughens and material is lost. - Abstract: Neutron reflectometry (NR) measurements have been made on thin (70–150 Å) poly(methylmethacrylate) (PMMA) films on Si/SiOx substrates in aqueous conditions, and compared with parameters measured using ellipsometry and X-Ray reflectometry (XRR) on dry films. All techniques show that the thin films prepared using spin-coating techniques were uniform and had low roughness at both the silicon and subphase interfaces, and similar surface energetics to thicker PMMA films. In aqueous solution, NR measurements at 25 °C showed that PMMA forms a partially hydrated layer at the SiOx interface 10 Å under the film, while the bulk film remains intact and contains around 4% water. Both the PMMA film layer and the sublayer showed minimal swelling over a period of 24 h. At 50 °C, PMMA films in aqueous solution roughen and swell, without loss of PMMA material at the surface. After cooling back to 25 °C, swelling and roughening increases further, with loss of material from the PMMA layer.

  6. Oxygen recoil implant from SiO2 layers into single-crystalline silicon

    International Nuclear Information System (INIS)

    Wang, G.; Chen, Y.; Li, D.; Oak, S.; Srivastav, G.; Banerjee, S.; Tasch, A.; Merrill, P.; Bleiler, R.

    2001-01-01

    It is important to understand the distribution of recoil-implanted atoms and the impact on device performance when ion implantation is performed at a high dose through surface materials into single crystalline silicon. For example, in ultralarge scale integration impurity ions are often implanted through a thin layer of screen oxide and some of the oxygen atoms are inevitably recoil implanted into single-crystalline silicon. Theoretical and experimental studies have been performed to investigate this phenomenon. We have modified the Monte Carlo ion implant simulator, UT-Marlowe (B. Obradovic, G. Wang, Y. Chen, D. Li, C. Snell, and A. F. Tasch, UT-MARLOWE Manual, 1999), which is based on the binary collision approximation, to follow the full cascade and to dynamically modify the stoichiometry of the Si layer as oxygen atoms are knocked into it. CPU reduction techniques are used to relieve the demand on computational power when such a full cascade simulation is involved. Secondary ion mass spectrometry (SIMS) profiles of oxygen have been carefully obtained for high dose As and BF 2 implants at different energies through oxide layers of various thicknesses, and the simulated oxygen profiles are found to agree very well with the SIMS data. [copyright] 2001 American Institute of Physics

  7. Crystalline Silicon Solar Cells with Thin Silicon Passivation Film Deposited prior to Phosphorous Diffusion

    Directory of Open Access Journals (Sweden)

    Ching-Tao Li

    2014-01-01

    Full Text Available We demonstrate the performance improvement of p-type single-crystalline silicon (sc-Si solar cells resulting from front surface passivation by a thin amorphous silicon (a-Si film deposited prior to phosphorus diffusion. The conversion efficiency was improved for the sample with an a-Si film of ~5 nm thickness deposited on the front surface prior to high-temperature phosphorus diffusion, with respect to the samples with an a-Si film deposited on the front surface after phosphorus diffusion. The improvement in conversion efficiency is 0.4% absolute with respect to a-Si film passivated cells, that is, the cells with an a-Si film deposited on the front surface after phosphorus diffusion. The new technique provided a 0.5% improvement in conversion efficiency compared to the cells without a-Si passivation. Such performance improvements result from reduced surface recombination as well as lowered contact resistance, the latter of which induces a high fill factor of the solar cell.

  8. Thin film silicon solar cells: advanced processing and characterization - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ballif, Ch.

    2008-04-15

    This final report elaborated for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a project carried out at the photovoltaics laboratory at the University of Neuchatel in Switzerland. The project aimed to demonstrate the production of high-efficiency thin-film silicon devices on flexible substrates using low cost processes. New ways of improving processing and characterisation are examined. The process and manufacturing know-how necessary to provide support for industrial partners within the framework of further projects is discussed. The authors state that the efficiency of most devices was significantly improved, both on glass substrates and on flexible plastic foils. The process reproducibility was also improved and the interactions between the different layers in the device are now said to be better understood. The report presents the results obtained and discusses substrate materials, transparent conductors, defect analyses and new characterisation tools. Finally, the laboratory infrastructure is described.

  9. Highly conducting p-type nanocrystalline silicon thin films preparation without additional hydrogen dilution

    Science.gov (United States)

    Patra, Chandralina; Das, Debajyoti

    2018-04-01

    Boron doped nanocrystalline silicon thin film has been successfully prepared at a low substrate temperature (250 °C) in planar inductively coupled RF (13.56 MHz) plasma CVD, without any additional hydrogen dilution. The effect of B2H6 flow rate on structural and electrical properties of the films has been studied. The p-type nc-Si:H films prepared at 5 ≤ B2H6 (sccm) ≤ 20 retains considerable amount of nanocrystallites (˜80 %) with high conductivity ˜101 S cm-1 and dominant crystallographic orientation which has been correlated with the associated increased ultra- nanocrystalline component in the network. Such properties together make the material significantly effective for utilization as p-type emitter layer in heterojunction nc-Si solar cells.

  10. Frequency dependence of the active impedance component of silicon thin-film resistors

    International Nuclear Information System (INIS)

    Belogurov, S.V.; Gostilo, V.V.; Yurov, A.S.

    1987-01-01

    A high-resistant resistor on the silicon thin-film substrate considerably superior in noise and frequency performance than commercial resistors is described. The frequency dependence of the active impedance component is tested for determining noise and frequency dependences of silicon thin-film resistors. The obtained results permit to calculate the energy equivalent of resistor noise in nuclear radiation detection units at any temperature according to its frequency characteristic at room temperature

  11. Plasma deposition of thin film silicon at low substrate temperature and at high growth rate

    NARCIS (Netherlands)

    Verkerk, A.D.|info:eu-repo/dai/nl/304831719

    2009-01-01

    To expand the range of applications for thin film solar cells incorporating hydrogenated amorphous silicon (a-Si:H) and hydrogenated nanocrystalline silicon (nc-Si:H), the growth rate has to be increased 0.5 or less to several nm/s and the substrate temperature should be lowered to around 100 C. In

  12. Single-layer graphene on silicon nitride micromembrane resonators

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Silvan; Guillermo Villanueva, Luis; Amato, Bartolo; Boisen, Anja [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, 2800 Kongens Lyngby (Denmark); Bagci, Tolga; Zeuthen, Emil; Sørensen, Anders S.; Usami, Koji; Polzik, Eugene S. [QUANTOP, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Taylor, Jacob M. [Joint Quantum Institute/NIST, College Park, Maryland 20899 (United States); Herring, Patrick K.; Cassidy, Maja C. [School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Charles M. [Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Cheol Shin, Yong; Kong, Jing [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-02-07

    Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling of graphene covered membranes is found to be equal to a perfectly conductive membrane, without significantly adding mass, decreasing the superior mechanical quality factor or affecting the optical properties of pure SiN micromembranes. The concept of graphene-SiN resonators allows a broad range of new experiments both in applied physics and fundamental basic research, e.g., for the mechanical, electrical, or optical characterization of graphene.

  13. Development of practical application technology for photovoltaic power generation systems in fiscal 1997. Development of technologies to manufacture application type thin film solar cells with new structure (development of technologies to manufacture amorphous silicon and thin film poly-crystal silicon hybrid thin film solar cells); 1997 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu. Usumaku taiyo denchi no seizo gijutsu kaihatsu, oyogata shinkozo usumaku taiyo denchi no seizo gijutsu kaihatsu (amorphous silicon/usumaku takessho silicon hybrid usumaku taiyo denchi no seizo gijutsu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Research and development was performed with an objective to manufacture amorphous silicon and thin film poly-crystal silicon hybrid solar cells with large area and at low cost, being a high-efficiency next generation solar cell. The research was performed based on a principle that low-cost substrates shall be used, that a manufacturing process capable of forming amorphous silicon films with large area shall be based on, and that silicon film with as thin as possible thickness shall be used. Fiscal 1997 has started research and development on making the cells hybrid with amorphous silicon cells. As a result of the research and development, such achievements have been attained as using texture structure on the rear layer in thin poly-crystal silicon film solar cells with a thickness of two microns, and having achieved conversion efficiency of 10.1% by optimizing the junction interface forming conditions. A photo-deterioration test was carried out on hybrid cells which combine the thin poly-crystal silicon film cells having STAR structure with the amorphous silicon cells. Stabilization efficiency of 11.5% was attained after light has been irradiated for 500 hours or longer. (NEDO)

  14. High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, H.

    2011-03-01

    Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

  15. Fracture properties of hydrogenated amorphous silicon carbide thin films

    International Nuclear Information System (INIS)

    Matsuda, Y.; King, S.W.; Bielefeld, J.; Xu, J.; Dauskardt, R.H.

    2012-01-01

    The cohesive fracture properties of hydrogenated amorphous silicon carbide (a-SiC:H) thin films in moist environments are reported. Films with stoichiometric compositions (C/Si ≈ 1) exhibited a decreasing cohesive fracture energy with decreasing film density similar to other silica-based hybrid organic–inorganic films. However, lower density a-SiC:H films with non-stoichiometric compositions (C/Si ≈ 5) exhibited much higher cohesive fracture energy than the films with higher density stoichiometric compositions. One of the non-stoichiometric films exhibited fracture energy (∼9.5 J m −2 ) greater than that of dense silica glasses. The increased fracture energy was due to crack-tip plasticity, as demonstrated by significant pileup formation during nanoindentation and a fracture energy dependence on film thickness. The a-SiC:H films also exhibited a very low sensitivity to moisture-assisted cracking compared with other silica-based hybrid films. A new atomistic fracture model is presented to describe the observed moisture-assisted cracking in terms of the limited Si-O-Si suboxide bond formation that occurs in the films.

  16. Axial ion channeling patterns from ultra-thin silicon membranes

    International Nuclear Information System (INIS)

    Motapothula, M.; Dang, Z.Y.; Venkatesan, T.; Breese, M.B.H.; Rana, M.A.; Osman, A.

    2012-01-01

    We present channeling patterns produced by MeV protons transmitted through 55 nm thick [0 0 1] silicon membranes showing the early evolution of the axially channeled beam angular distribution for small tilts away from the [0 0 1], [0 1 1] and [1 1 1] axes. Instead of a ring-like “doughnut” distribution previously observed at small tilts to major axes in thicker membranes, geometric shapes such as squares and hexagons are observed along different axes in ultra-thin membranes. The different shapes arise because of the highly non-equilibrium transverse momentum distribution of the channeled beam during its initial propagation in the crystal and the reduced multiple scattering which allows the fine angular structure to be resolved. We describe a simple geometric construction of the intersecting planar channels at an axis to gain insight into the origin of the geometric shapes observed in such patterns and how they evolve into the ‘doughnut’ distributions in thicker crystals.

  17. Realization of dual-heterojunction solar cells on ultra-thin ∼25 μm, flexible silicon substrates

    KAUST Repository

    Onyegam, Emmanuel U.; Sarkar, Dabraj; Hilali, Mohamed M.; Saha, Sayan; Mathew, Leo; Rao, Rajesh A.; Smith, Ryan S.; Xu, Dewei; Jawarani, Dharmesh; Garcia, Ricardo; Ainom, Moses; Banerjee, Sanjay K.

    2014-01-01

    Silicon heterojunction (HJ) solar cells with different rear passivation and contact designs were fabricated on ∼ 25 μ m semiconductor-on-metal (SOM) exfoliated substrates. It was found that the performance of these cells is limited by recombination at the rear-surface. Employing the dual-HJ architecture resulted in the improvement of open-circuit voltage (Voc) from 605 mV (single-HJ) to 645 mV with no front side intrinsic amorphous silicon (i-layer) passivation. Addition of un-optimized front side i-layer passivation resulted in further enhancement in Voc to 662 mV. Pathways to achieving further improvement in the performance of HJ solar cells on ultra-thin SOM substrates are discussed. © 2014 AIP Publishing LLC.

  18. Realization of dual-heterojunction solar cells on ultra-thin ∼25 μm, flexible silicon substrates

    KAUST Repository

    Onyegam, Emmanuel U.

    2014-04-14

    Silicon heterojunction (HJ) solar cells with different rear passivation and contact designs were fabricated on ∼ 25 μ m semiconductor-on-metal (SOM) exfoliated substrates. It was found that the performance of these cells is limited by recombination at the rear-surface. Employing the dual-HJ architecture resulted in the improvement of open-circuit voltage (Voc) from 605 mV (single-HJ) to 645 mV with no front side intrinsic amorphous silicon (i-layer) passivation. Addition of un-optimized front side i-layer passivation resulted in further enhancement in Voc to 662 mV. Pathways to achieving further improvement in the performance of HJ solar cells on ultra-thin SOM substrates are discussed. © 2014 AIP Publishing LLC.

  19. Defects and defect generation in oxide layer of ion implanted silicon-silicon dioxide structures

    CERN Document Server

    Baraban, A P

    2002-01-01

    One studies mechanism of generation of defects in Si-SiO sub 2 structure oxide layer as a result of implantation of argon ions with 130 keV energy and 10 sup 1 sup 3 - 3.2 x 10 sup 1 sup 7 cm sup - sup 2 doses. Si-SiO sub 2 structures are produced by thermal oxidation of silicon under 950 deg C temperature. Investigations were based on electroluminescence technique and on measuring of high-frequency volt-farad characteristics. Increase of implantation dose was determined to result in spreading of luminosity centres and in its maximum shifting closer to boundary with silicon. Ion implantation was shown, as well, to result in increase of density of surface states at Si-SiO sub 2 interface. One proposed model of defect generation resulting from Ar ion implantation into Si-SiO sub 2

  20. Alveolar Thin Layer Flows and Surfactant Dynamics

    Science.gov (United States)

    Roumie, Ahmad; Jbaily, Abdulrahman; Szeri, Andrew J.

    2017-11-01

    Pulmonary surfactants play a vital role in everyday respiration. They regulate surface tension in the lungs by diffusing through the hypophase, a liquid layer that lines the interior surface of the alveoli, and adsorbing to the existing air-fluid interface. This decreases the equilibrium surface tension value by as much as a factor of 3, minimizing breathing effort and preventing lung collapse at the end of exhalation. Given that the hypophase thickness h lies within the range 0.1 μm < h <0.5 μm , and that the average alveolar radius R is 100 μm , for some purposes the hypophase may usefully be modeled as a fluid layer on a flat sheet representing the alveolar wall. Moreover, because of the large aspect ratio, the lubrication approximation can be applied. The aim of the present work is to study the interaction between the straining of the alveolar wall and the fluid flow in the hypophase. The analysis is governed by the relative magnitudes of the time scales of surfactant diffusion, adsorption, desorption, viscous dissipation and sheet straining. Cases of particular interest include non-uniform surfactant concentration at the interface, leading to Marangoni flows and a non-uniform hypophase thickness profile. The analytical formulation and numerical simulations are presented. This work is motivated by a need to understand alveolar deformation during breathing, and to do so in a way that derives from improved understanding of the fluid mechanics of the problem.

  1. Enhancing crystalline silicon solar cell efficiency with SixGe1-x layers

    Science.gov (United States)

    Ali, Adnan; Cheow, S. L.; Azhari, A. W.; Sopian, K.; Zaidi, Saleem H.

    Crystalline silicon (c-Si) solar cell represents a cost effective, environment-friendly, and proven renewable energy resource. Industrially manufacturing of c-Si solar has now matured in terms of efficiency and cost. Continuing cost-effective efficiency enhancement requires transition towards thinner wafers in near term and thin-films in the long term. Successful implementation of either of these alternatives must address intrinsic optical absorption limitation of Si. Bandgap engineering through integration with SixGe1-x layers offers an attractive, inexpensive option. With the help of PC1D software, role of SixGe1-x layers in conventional c-Si solar cells has been intensively investigated in both wafer and thin film configurations by varying Ge concentration, thickness, and placement. In wafer configuration, increase in Ge concentration leads to enhanced absorption through bandgap broadening with an efficiency enhancement of 8% for Ge concentrations of less than 20%. At higher Ge concentrations, despite enhanced optical absorption, efficiency is reduced due to substantial lowering of open-circuit voltage. In 5-25-μm thickness, thin-film solar cell configurations, efficiency gain in excess of 30% is achievable. Therefore, SixGe1-x based thin-film solar cells with an order of magnitude reduction in costly Si material are ideally-suited both in terms of high efficiency and cost. Recent research has demonstrated significant improvement in epitaxially grown SixGe1-x layers on nanostructured Si substrates, thereby enhancing potential of this approach for next generation of c-Si based photovoltaics.

  2. XPS study of palladium sensitized nano porous silicon thin film

    Indian Academy of Sciences (India)

    Keywords. Porous silicon; passivation; palladium; oxidation; XPS. Abstract. Nano porous silicon (PS) was formed on -type monocrystalline silicon of 2–5 cm resistivity and (100) orientation by electrochemical anodization method using HF and ethanol as the electrolytes. High density of surface states, arising due to its ...

  3. ANTIREFLECTION MULTILAYER COATINGS WITH THIN METAL LAYERS

    Directory of Open Access Journals (Sweden)

    L. A. Gubanova

    2016-03-01

    Full Text Available The design of anti-reflective coatings for metal surfaces of Al, Ti, N,i Cr is proposed. The coatings have the form of alternating layers of dielectric/metal/dielectric with the number of cells up to15. The method of calculation of such coatings is proposed. We have calculated the coatings of the type [HfO2/Cr/HfO2]15, [ZrO2/Ti/Al2O3]15, [ZrO2/Cr/ZrO2]15. It is shown that the proposed interference coatings provide reduction of the residual reflectance of the metal several times (from 3.5 to 6.0 in a wide spectral range (300-1000 nm. The proposed coatings can be recommended as anti-reflective coatings for energy saving solar systems and batteries, and photovoltaic cells.

  4. Pre-staining thin layer chromatography method for amino acid ...

    African Journals Online (AJOL)

    Jane

    2010-12-13

    Dec 13, 2010 ... inexpensive and the results obtained were clean and reproducible. However, it is suitable for the high throughput screening of amino acid-producing strains. Key words: Thin layer chromatography, pre-staining, amino acid detection. INTRODUCTION. Several analytical techniques have been often used for.

  5. Determination of ferulic acid and related compounds by thin layer ...

    African Journals Online (AJOL)

    The analysis of certain phenolic compounds from plants, and their chemical transformation with microorganisms or isolated enzymes, has application in the food and pharmaceutical industry. The rapid quantitative estimation of ferulic acid by thin layer chromatography is described by measurement of the area of the ...

  6. Evaluation of a thin-layer chromatographic technique for ...

    African Journals Online (AJOL)

    Methanol extracts of both fistula and bush samples were prepared and analysed by thin-layer chromatography. Chromatoplates, when visualised under ultraviolet light, revealed a number of fluorescent compounds, some of which were common in both the fistula and bush sample extracts. By comparing the presence of ...

  7. Outdoor open thin-layer microalgal photobioreactor: potential productivity

    Czech Academy of Sciences Publication Activity Database

    Doucha, Jiří; Lívanský, Karel

    2009-01-01

    Roč. 21, č. 1 (2009), s. 111-117 ISSN 0921-8971 Institutional research plan: CEZ:AV0Z50200510 Keywords : productivity * photobioreactor * thin layer Subject RIV: EE - Microbiology, Virology Impact factor: 1.018, year: 2009

  8. Modeling of thin layer drying of tarragon (Artemisia dracunculus L.)

    NARCIS (Netherlands)

    ArabHosseini, A.; Huisman, W.; Boxtel, van A.J.B.; Mueller, J.

    2009-01-01

    The drying behavior of tarragon leaves as well as chopped plants were evaluated at air temperatures ranging from 40 to 90 °C, at various air relative humidities and a constant air velocity of 0.6 m/s. The experimental data was fitted to a number of thin layer drying equations. The equations were

  9. Comparison of two detection methods in thin layer chromatographic ...

    African Journals Online (AJOL)

    o-tolidine plus potassium iodide and photosynthesis inhibition detection methods were investigated for the analysis of three triazine herbicides (atrazine, ametryne, simazine) and two urea herbicides (diuron, metobromuron) in a coastal savanna soil using thin layer chromatography to compare the suitability of the two ...

  10. Physicochemical, thin layer and gas-liquid chromatographic ...

    African Journals Online (AJOL)

    DELL

    2012-05-22

    May 22, 2012 ... PEG (3 m × 3 mm I. D.) was used for gas chromatography. Physicochemical analysis ... subjected to thin layer chromatography on plates (20 × 20 cm) having 0.25 mm thick silica gel ..... Headspace solid- phase microextraction ...

  11. (AJST) THIN- LAYER DRYING OF DICED CASSAVA ROOTS

    African Journals Online (AJOL)

    opiyo

    effect of drying temperature on thin-layer drying was high, followed by initial moisture .... The moisture content was converted to moisture ratio (MR) using the non-exponential part .... The Potential of Cassava As a Cash. Crop For Small Holder ...

  12. Thin Cell Layer technology in ornamental plant micropropagation ...

    African Journals Online (AJOL)

    Thin cell layer (TCL) technology originated almost 30 years ago with the controlled development of flowers, roots, shoots and somatic embryos on tobacco pedicel longitudinal TCLs. Since then TCLs have been successfully used in the micropropagation of many ornamental plant species whose previous in vitro ...

  13. Thin Layer Drying Kinetics of Pineapple: Effect of Blanching ...

    African Journals Online (AJOL)

    Four thin-layer drying models were fitted to the experimental drying data. The .... MATLAB software package (version 6.5). The correlation ... to evaluate the goodness of fit of the simulation ... during the oven-drying process of pineapple slices.

  14. Thin-layer electrochemistry of ferrocenylbenzene derivatives: Intramolecular electronic communication

    International Nuclear Information System (INIS)

    Wang, Michael C.P.; Li Yunchao; Merbouh, Nabyl; Yu, Hua-Zhong

    2008-01-01

    Three arylferrocene derivatives, ferrocenylbenzene (MFcB), 1,3-diferrocenylbenzene (DFcB), and 1,3,5-triferrocenylbenzene (TFcB), were prepared and their redox properties systematically explored by thin-layer cyclic voltammetry (CV) and differential-pulse voltammetry (DPV). In contrast to conventional CV measurements that produced only a single pair of redox waves for all three compounds, the thin-layer technique discriminated between the multistep electron-transfer processes of DFcB and TFcB. In particular, two and three pairs of symmetric peaks were observed, respectively, when CV curves were recorded at a graphite electrode coated with a DFcB-containing and a TFcB-containing thin film of nitrobenzene and immersed in aqueous sodium perchlorate solution. These results demonstrate that the ferrocenyl moieties attached to the meta-positions of a benzene ring communicate electronically with each other, as a result of their distinct face-to-face orientations

  15. Investigation of epitaxial silicon layers as a material for radiation hardened silicon detectors

    International Nuclear Information System (INIS)

    Li, Z.; Eremin, V.; Ilyashenko, I.; Ivanov, A.; Verbitskaya, E.

    1997-12-01

    Epitaxial grown thick layers (≥ 100 micrometers) of high resistivity silicon (Epi-Si) have been investigated as a possible candidate of radiation hardened material for detectors for high-energy physics. As grown Epi-Si layers contain high concentration (up to 2 x 10 12 cm -3 ) of deep levels compared with that in standard high resistivity bulk Si. After irradiation of test diodes by protons (E p = 24 GeV) with a fluence of 1.5 x 10 11 cm -2 , no additional radiation induced deep traps have been detected. A reasonable explanation is that there is a sink of primary radiation induced defects (interstitial and vacancies), possibly by as-grown defects, in epitaxial layers. The ''sinking'' process, however, becomes non-effective at high radiation fluences (10 14 cm -2 ) due to saturation of epitaxial defects by high concentration of radiation induced ones. As a result, at neutron fluence of 1 x 10 14 cm -2 the deep level spectrum corresponds to well-known spectrum of radiation induced defects in high resistivity bulk Si. The net effective concentration in the space charge region equals to 3 x 10 12 cm -3 after 3 months of room temperature storage and reveals similar annealing behavior for epitaxial as compared to bulk silicon

  16. Role of atomic layer deposited aluminum oxide as oxidation barrier for silicon based materials

    Energy Technology Data Exchange (ETDEWEB)

    Fiorentino, Giuseppe, E-mail: g.fiorentino@tudelft.nl; Morana, Bruno [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT Delft (Netherlands); Forte, Salvatore [Department of Electronic, University of Naples Federico II, Piazzale Tecchio, 80125 Napoli (Italy); Sarro, Pasqualina Maria [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT, Delft (Netherlands)

    2015-01-15

    In this paper, the authors study the protective effect against oxidation of a thin layer of atomic layer deposited (ALD) aluminum oxide (Al{sub 2}O{sub 3}). Nitrogen doped silicon carbide (poly-SiC:N) based microheaters coated with ALD Al{sub 2}O{sub 3} are used as test structure to investigate the barrier effect of the alumina layers to oxygen and water vapor at very high temperature (up to 1000 °C). Different device sets have been fabricated changing the doping levels, to evaluate possible interaction between the dopants and the alumina layer. The as-deposited alumina layer morphology has been evaluated by means of AFM analysis and compared to an annealed sample (8 h at 1000 °C) to estimate the change in the grain structure and the film density. The coated microheaters are subjected to very long oxidation time in dry and wet environment (up to 8 h at 900 and 1000 °C). By evaluating the electrical resistance variation between uncoated reference devices and the ALD coated devices, the oxide growth on the SiC is estimated. The results show that the ALD alumina coating completely prevents the oxidation of the SiC up to 900 °C in wet environment, while an oxide thickness reduction of 50% is observed at 1000 °C compared to uncoated devices.

  17. Segregation and Clustering Effects on Complex Boron Redistribution in Strongly Doped Polycrystalline-Silicon Layers

    International Nuclear Information System (INIS)

    Abadli, S.; Mansour, F.

    2011-01-01

    This work deals with the investigation of the complex phenomenon of boron (B) transient enhanced diffusion (TED) in strongly implanted silicon (Si) layers. It concerns the instantaneous influences of the strong B concentrations, the Si layers crystallization, the clustering and the B trapping/segregation during thermal post-implantation annealing. We have used Si thin layers obtained from disilane (Si2H6) by low pressure chemical vapor deposition (LPCVD) and then B implanted with a dose of 4 x 1015 atoms/cm2 at an energy of 15 keV. To avoid long redistributions, thermal annealing was carried out at relatively low-temperatures (700, 750 and 800 'deg'C) for various short-times ranging between 1 and 30 minutes. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of Si-LPCVD layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the TED process in strongly doped Si-LPCVD layers. It was found that boron TED is strongly affected by the simultaneous complex kinetics of clustering, crystallization, trapping and segregation during annealing. The fast formation of small Si-B clusters enhances the B diffusivity whereas the evolution of the clusters and segregation reduce this enhancement. (author)

  18. A thin-film silicon/silicon hetero-junction hybrid solar cell for photoelectrochemical water-reduction applications

    NARCIS (Netherlands)

    Vasudevan, R.A.; Thanawala, Z; Han, L.; Buijs, Thom; Tan, H.; Deligiannis, D.; Perez Rodriguez, P.; Digdaya, I.A.; Smith, W.A.; Zeman, M.; Smets, A.H.M.

    2016-01-01

    A hybrid tandem solar cell consisting of a thin-film, nanocrystalline silicon top junction and a siliconheterojunction bottom junction is proposed as a supporting solar cell for photoelectrochemical applications.Tunneling recombination junction engineering is shown to be an important consideration

  19. Low-Dimensional Nanomaterials as Active Layer Components in Thin-Film Photovoltaics

    Science.gov (United States)

    Shastry, Tejas Attreya

    Thin-film photovoltaics offer the promise of cost-effective and scalable solar energy conversion, particularly for applications of semi-transparent solar cells where the poor absorption of commercially-available silicon is inadequate. Applications ranging from roof coatings that capture solar energy to semi-transparent windows that harvest the immense amount of incident sunlight on buildings could be realized with efficient and stable thin-film solar cells. However, the lifetime and efficiency of thin-film solar cells continue to trail their inorganic silicon counterparts. Low-dimensional nanomaterials, such as carbon nanotubes and two-dimensional metal dichalcogenides, have recently been explored as materials in thin-film solar cells due to their exceptional optoelectronic properties, solution-processability, and chemical inertness. Thus far, issues with the processing of these materials has held back their implementation in efficient photovoltaics. This dissertation reports processing advances that enable demonstrations of low-dimensional nanomaterials in thin-film solar cells. These low-dimensional photovoltaics show enhanced photovoltaic efficiency and environmental stability in comparison to previous devices, with a focus on semiconducting single-walled carbon nanotubes as an active layer component. The introduction summarizes recent advances in the processing of carbon nanotubes and their implementation through the thin-film photovoltaic architecture, as well as the use of two-dimensional metal dichalcogenides in photovoltaic applications and potential future directions for all-nanomaterial solar cells. The following chapter reports a study of the interaction between carbon nanotubes and surfactants that enables them to be sorted by electronic type via density gradient ultracentrifugation. These insights are utilized to construct of a broad distribution of carbon nanotubes that absorb throughout the solar spectrum. This polychiral distribution is then shown

  20. The thin layer technique and its application to electron microscopy

    International Nuclear Information System (INIS)

    Ranc, G.

    1957-10-01

    This work deals with the technique of thin layers obtained by evaporation under vacuum, in the thickness range extending from a few monoatomic layers to several hundred angstroms. The great theoretical and practical interest of these layers has, it is well known, given rise to many investigations from Faraday onwards. Within the necessarily restricted limits of this study, we shall approach the problem more particularly from the point of view of: - their production; - their use in electron microscopy. A critical appraisal is made, in the light of present-day knowledge, based on our personal experience and on an extensive bibliography which we have collected on the subject. (author) [fr

  1. 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.

  2. 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

  3. Effect of atmospheric-pressure plasma treatment on the adhesion properties of a thin adhesive layer in a selective transfer process

    Science.gov (United States)

    Yoon, Min-Ah; Kim, Chan; Hur, Min; Kang, Woo Seok; Kim, Jaegu; Kim, Jae-Hyun; Lee, Hak-Joo; Kim, Kwang-Seop

    2018-01-01

    The adhesion between a stamp and thin film devices is crucial for their transfer on a flexible substrate. In this paper, a thin adhesive silicone layer on the stamp was treated by atmospheric pressure plasma to locally control the adhesion strength for the selective transfer. The adhesion strength of the silicone layer was significantly reduced after the plasma treatment, while its surface energy was increased. To understand the inconsistency between the adhesion strength and surface energy changes, the surface properties of the silicone layer were characterized using nanoindentation and X-ray photoelectron spectroscopy. These techniques revealed that a thin, hard, silica-like layer had formed on the surface from plasma-enhanced oxidation. This layer played an important role in decreasing the contact area and increasing the interfacial slippage, resulting in decreased adhesion. As a practical application, the transfer process was demonstrated on GaN LEDs that had been previously delaminated by a laser lift-off (LLO) process. Although the LEDs were not transferred onto the treated adhesive layer due to the reduced adhesion, the untreated adhesive layer could readily pick up the LEDs. It is expected that this simple method of controlling the adhesion of a stamp with a thin adhesive layer would enable a continuous, selective and large-scale roll-to-roll selective transfer process and thereby advance the development of flexible, stretchable and wearable electronics.

  4. Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass.

    Science.gov (United States)

    Calnan, Sonya; Gabriel, Onno; Rothert, Inga; Werth, Matteo; Ring, Sven; Stannowski, Bernd; Schlatmann, Rutger

    2015-09-02

    In this study, various silicon dielectric films, namely, a-SiOx:H, a-SiNx:H, and a-SiOxNy:H, grown by plasma enhanced chemical vapor deposition (PECVD) were evaluated for use as interlayers (ILs) between crystalline silicon and glass. Chemical bonding analysis using Fourier transform infrared spectroscopy showed that high values of oxidant gases (CO2 and/or N2), added to SiH4 during PECVD, reduced the Si-H and N-H bond density in the silicon dielectrics. Various three layer stacks combining the silicon dielectric materials were designed to minimize optical losses between silicon and glass in rear side contacted heterojunction pn test cells. The PECVD grown silicon dielectrics retained their functionality despite being subjected to harsh subsequent processing such as crystallization of the silicon at 1414 °C or above. High values of short circuit current density (Jsc; without additional hydrogen passivation) required a high density of Si-H bonds and for the nitrogen containing films, additionally, a high N-H bond density. Concurrently high values of both Jsc and open circuit voltage Voc were only observed when [Si-H] was equal to or exceeded [N-H]. Generally, Voc correlated with a high density of [Si-H] bonds in the silicon dielectric; otherwise, additional hydrogen passivation using an active plasma process was required. The highest Voc ∼ 560 mV, for a silicon acceptor concentration of about 10(16) cm(-3), was observed for stacks where an a-SiOxNy:H film was adjacent to the silicon. Regardless of the cell absorber thickness, field effect passivation of the buried silicon surface by the silicon dielectric was mandatory for efficient collection of carriers generated from short wavelength light (in the vicinity of the glass-Si interface). However, additional hydrogen passivation was obligatory for an increased diffusion length of the photogenerated carriers and thus Jsc in solar cells with thicker absorbers.

  5. Silicon-integrated thin-film structure for electro-optic applications

    Science.gov (United States)

    McKee, Rodney A.; Walker, Frederick Joseph

    2000-01-01

    A crystalline thin-film structure suited for use in any of an number of electro-optic applications, such as a phase modulator or a component of an interferometer, includes a semiconductor substrate of silicon and a ferroelectric, optically-clear thin film of the perovskite BaTiO.sub.3 overlying the surface of the silicon substrate. The BaTiO.sub.3 thin film is characterized in that substantially all of the dipole moments associated with the ferroelectric film are arranged substantially parallel to the surface of the substrate to enhance the electro-optic qualities of the film.

  6. Enhanced photoluminescence from ring resonators in hydrogenated amorphous silicon thin films at telecommunications wavelengths.

    Science.gov (United States)

    Patton, Ryan J; Wood, Michael G; Reano, Ronald M

    2017-11-01

    We report enhanced photoluminescence in the telecommunications wavelength range in ring resonators patterned in hydrogenated amorphous silicon thin films deposited via low-temperature plasma enhanced chemical vapor deposition. The thin films exhibit broadband photoluminescence that is enhanced by up to 5 dB by the resonant modes of the ring resonators due to the Purcell effect. Ellipsometry measurements of the thin films show a refractive index comparable to crystalline silicon and an extinction coefficient on the order of 0.001 from 1300 nm to 1600 nm wavelengths. The results are promising for chip-scale integrated optical light sources.

  7. Effects of excitation intensity on the photocurrent response of thin film silicon solar modules

    Science.gov (United States)

    Kim, Q.; Shumka, A.; Trask, J.

    1986-01-01

    Photocurrent responses of amorphous thin film silicon solar modules at room temperature were studied at different excitation intensities using various monochromatic light sources. Photocurrent imaging techniques have been effectively used to locate rapidly, and non-destructively, failure and defect sites in the multilayer thin film device. Differences observed in the photocurrent response characteristics for two different cells in the same amorphous thin film silicon solar module suggest the possibility of the formation of dissimilarly active devices, even though the module is processed in the same fabrication process. Possible mechanisms are discussed.

  8. Silicon-based thin films as bottom electrodes in chalcogenide nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Yun [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)], E-mail: seungyun@etri.re.kr; Yoon, Sung-Min; Choi, Kyu-Jeong; Lee, Nam-Yeal; Park, Young-Sam; Ryu, Sang-Ouk; Yu, Byoung-Gon; Kim, Sang-Hoon; Lee, Sang-Heung [IT Convergence and Components Laboratory, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon 305-350 (Korea, Republic of)

    2007-10-31

    The effect of the electrical resistivity of a silicon-germanium (SiGe) thin film on the phase transition in a GeSbTe (GST) chalcogenide alloy and the manufacturing aspect of the fabrication process of a chalcogenide memory device employing the SiGe film as bottom electrodes were investigated. While p-type SiGe bottom electrodes were formed using in situ doping techniques, n-type ones could be made in a different manner where phosphorus atoms diffused from highly doped silicon underlayers to undoped SiGe films. The p-n heterojunction did not form between the p-type GST and n-type SiGe layers, and the semiconduction type of the SiGe alloys did not influence the memory device switching. It was confirmed that an optimum resistivity value existed for memory operation in spite of proportionality of Joule heating to electrical resistivity. The very high resistivity of the SiGe film had no effect on the reduction of reset current, which might result from the resistance decrease of the SiGe alloy at high temperatures.

  9. Characterization of irradiated thin silicon sensors for the CMS phase II pixel upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Centis Vignali, Matteo; Garutti, Erika; Junkes, Alexandra; Steinbrueck, Georg [Institut fuer Experimentalphysik, Universitaet Hamburg (Germany); Eckstein, Doris; Eichhorn, Thomas [Deutsches Elektronen Synchrotron (DESY) (Germany)

    2016-07-01

    The high-luminosity upgrade of the Large Hadron Collider, foreseen for 2025, necessitates the replacement of the tracker of the CMS experiment. The innermost layer of the new pixel detector will be exposed to severe radiation corresponding to a 1 MeV neutron equivalent fluence up to Φ{sub eq} = 2 . 10{sup 16} cm{sup -2} and an ionizing dose of ∼ 10 MGy after an integrated luminosity of 3000 fb{sup -1}. Silicon crystals grown with different methods and sensor designs are under investigation in order to optimize the sensors for such high fluences. Thin planar silicon sensors are good candidates to achieve this goal, since the degradation of the signal produced by traversing particles is less severe than for thicker devices. Epitaxial pad diodes and strip sensors irradiated up to fluences of Φ{sub eq} = 1.3 . 10{sup 16} cm{sup -2} have been characterized in laboratory measurements and beam tests at the DESY II facility. The active thickness of the strip sensors and pad diodes is 100 μm. In addition, strip sensors produced using other growth techniques with a thickness of 200 μm have been studied. In this talk, the results obtained for p-bulk sensors are shown.

  10. Solid phase crystallized polycrystalline thin-films on glass from evaporated silicon for photovoltaic applications

    International Nuclear Information System (INIS)

    Song Dengyuan; Inns, Daniel; Straub, Axel; Terry, Mason L.; Campbell, Patrick; Aberle, Armin G.

    2006-01-01

    Polycrystalline silicon (poly-Si) thin-films are made on planar and textured glass substrates by solid phase crystallization (SPC) of in situ doped amorphous silicon (a-Si) deposited by electron-beam evaporation. These materials are referred to by us as EVA materials (SPC of evaporated a-Si). The properties of EVA poly-Si films are characterised by Raman microscopy, transmission electron microscopy, and X-ray diffraction. A narrow and symmetrical Raman peak at a wave number of about 520 cm -1 is observed for all samples, showing that the films are fully crystallized. X-ray diffraction (XRD) reveals that the films are preferentially (111)-oriented. Furthermore, the full width at half maximum of the dominant (111) XRD peaks indicates that the structural quality of the films is affected by the a-Si deposition temperature and the surface morphology of the glass substrates. A-Si deposition at 200 instead of 400 deg. C leads to an enhanced poly-Si grain size. On textured glass, the addition of a SiN barrier layer between the glass and the Si improves the poly-Si material quality. No such effect occurs on planar glass. Mesa-type solar cells are made from these EVA films on planar and textured glass. A strong correlation between the cells' current-voltage characteristics and their crystalline material quality is observed

  11. Selective deposition contact patterning using atomic layer deposition for the fabrication of crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Cho, Young Joon; Shin, Woong-Chul; Chang, Hyo Sik

    2014-01-01

    Selective deposition contact (SDC) patterning was applied to fabricate the rear side passivation of crystalline silicon (Si) solar cells. By this method, using screen printing for contact patterning and atomic layer deposition for the passivation of Si solar cells with Al 2 O 3 , we produced local contacts without photolithography or any laser-based processes. Passivated emitter and rear-contact solar cells passivated with ozone-based Al 2 O 3 showed, for the SDC process, an up-to-0.7% absolute conversion-efficiency improvement. The results of this experiment indicate that the proposed method is feasible for conversion-efficiency improvement of industrial crystalline Si solar cells. - Highlights: • We propose a local contact formation process. • Local contact forms a screen print and an atomic layer deposited-Al 2 O 3 film. • Ozone-based Al 2 O 3 thin film was selectively deposited onto patterned silicon. • Selective deposition contact patterning method can increase cell-efficiency by 0.7%

  12. Low-stress silicon nitride layers for MEMS applications

    Science.gov (United States)

    Iliescu, Ciprian; Wei, Jiashen; Chen, Bangtao; Ong, Poh Lam; Tay, Francis E. H.

    2006-12-01

    The paper presents two deposition methods for generation of SiN x layers with "zero" residual stress in PECVD reactors: mixed frequency and high power in high frequency mode (13.56 MHz). Traditionally, mix frequency mode is commonly used to produce low stress SiN x layers, which alternatively applies the HF and LF mode. However, due to the low deposition rate of LF mode, the combined deposition rate of mix frequency is quite small in order to produce homogenous SiN x layers. In the second method, a high power which was up to 600 W has been used, may also produce low residual stress (0-20 MPa), with higher deposition rate (250 to 350 nm/min). The higher power not only leads to higher dissociation rates of gases which results in higher deposition rates, but also brings higher N bonding in the SiN x films and higher compressive stress from higher volume expansion of SiN x films, which compensates the tensile stress and produces low residual stress. In addition, the paper investigates the influence of other important parameters which have great impact to the residual stress and deposition rates, such as reactant gases flow rate and pressure. By using the final optimized recipe, masking layer for anisotropic wet etching in KOH and silicon nitride cantilever have been successfully fabricated based on the low stress SiN x layers. Moreover, nanoporous membrane with 400nm pores has also been fabricated and tested for cell culture. By cultivating the mouse D1 mesenchymal stem cells on top of the nanoporous membrane, the results showed that mouse D1 mesenchymal stem cells were able to grow well. This shows that the nanoporous membrane can be used as the platform for interfacing with living cells to become biocapsules for biomolecular separation.

  13. Polyenergy ion beam synthesis of buried oxynitride layer in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Barabanenkov, M.Yu. E-mail: barab@ipmt-hpm.ac.ru; Agafonov, Yu.A.; Mordkovich, V.N.; Pustovit, A.N.; Vyatkin, A.F.; Zinenko, V.I

    2000-11-01

    The efficiency of silicon oxynitride synthesis in silicon crystals implanted with substoichiometric doses of oxygen and nitrogen ions is investigated both experimentally and theoretically. Si crystals are implanted with oxygen and nitrogen ions with doses of 1.5 and 4.5x10{sup 17} cm{sup -2}, respectively, at fixed oxygen ion energy of 150 keV and nitrogen ion energies varied from 80 to 180 keV. The samples annealed at 1200 deg C for 2 h were analysed by secondary ion mass spectroscopy (SIMS). Theoretically, a `diffusion-alternative sinks' model is applied to the annealing stage of ion beam synthesis of a buried layer of a new phase in solids. It is shown that the maximum of the ternary phase production is attained when nitrogen ions are implanted deeper than oxygen ions. An explanation of this fact is given in terms of that (i) the segregation of oxygen and nitrogen species on the surface of oxide nuclei removes the kinetic restriction of nuclei growth, characteristic of oxide growth, at the expense of only oxygen atoms, and (ii) the higher the implantation energy the smoother the shape of ion range distribution in the target, which, in its turn, causes the predominance of the impurity sink over the impurity diffusion.

  14. Polyenergy ion beam synthesis of buried oxynitride layer in silicon

    International Nuclear Information System (INIS)

    Barabanenkov, M.Yu.; Agafonov, Yu.A.; Mordkovich, V.N.; Pustovit, A.N.; Vyatkin, A.F.; Zinenko, V.I.

    2000-01-01

    The efficiency of silicon oxynitride synthesis in silicon crystals implanted with substoichiometric doses of oxygen and nitrogen ions is investigated both experimentally and theoretically. Si crystals are implanted with oxygen and nitrogen ions with doses of 1.5 and 4.5x10 17 cm -2 , respectively, at fixed oxygen ion energy of 150 keV and nitrogen ion energies varied from 80 to 180 keV. The samples annealed at 1200 deg C for 2 h were analysed by secondary ion mass spectroscopy (SIMS). Theoretically, a `diffusion-alternative sinks' model is applied to the annealing stage of ion beam synthesis of a buried layer of a new phase in solids. It is shown that the maximum of the ternary phase production is attained when nitrogen ions are implanted deeper than oxygen ions. An explanation of this fact is given in terms of that (i) the segregation of oxygen and nitrogen species on the surface of oxide nuclei removes the kinetic restriction of nuclei growth, characteristic of oxide growth, at the expense of only oxygen atoms, and (ii) the higher the implantation energy the smoother the shape of ion range distribution in the target, which, in its turn, causes the predominance of the impurity sink over the impurity diffusion

  15. Bovine serum albumin adsorption on passivated porous silicon layers

    Science.gov (United States)

    Lockwood, David; Boukherroub, Rabah

    2005-03-01

    Hydrogen-terminated porous silicon (pSi) films were fabricated through electrochemical anodization of crystalline Si in HF-based solutions. The pSi-H surface was chemically functionalized by thermal reaction with undecylenic acid to produce an organic monolayer covalently attached to the silicon surface through Si-C bonds and bearing an acid terminal group. Bovine serum albumin (BSA) was then adsorbed onto the modified surface. SEM showed that the porous films were damaged and partially lifted off the Si substrate after a prolonged BSA adsorption. Ellipsometry revealed that the BSA had penetrated ˜ 1.3 micrometers into the porous structure. The film damage results from BSA anchoring itself tightly through strong electrostatic interactions to the acid-covered Si sidewalls. A change in surface tension during BSA film formation then causes the pSi layer to buckle and lift-off the underlying Si substrate. FTIR results from the modified pSi surfaces showed the presence of strong characteristic Amide I, II and III vibrational bands after BSA adsorption.

  16. Development in fiscal 1999 of technologies to put photovoltaic power generation systems into practical use. Development of thin film solar cell manufacturing technologies (Development of low-cost large-area module manufacturing technologies, and development of technologies to manufacture amorphous silicon/thin film poly-crystalline silicon hybrid thin film solar cells); 1999 nendo taiyoko hatsuden system jitsuyoka gijutsu kaihatsu seika hokokusho. Usumaku taiyo denchi no seizo gijutsu kaihatsu (tei cost daimenseki module seizo kaihatsu (oyogata shinkozo usumaku taiyo denchi no seizo gijutsu kaihatsu (amorphous silicon / usumaku takessho silicon hybrid usumaku taiyo denchi no seizo gijutsu kaihatsu))

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Developmental research has been performed on large-area low-cost manufacturing technologies on hybrid thin film solar cells of amorphous silicon and poly-crystalline silicon. This paper summarizes the achievements in fiscal 1999. The research has been performed on a texture construction formed naturally on silicon surface, and thin film poly-crystalline silicon cells with STAR structure having a rear side reflection layer to increase light absorption. The research achievements during the current fiscal year may be summarized as follows: the laser scribing technology for thin film poly-crystalline silicon was established, which is important for modularization, making fabrication of low-cost and large-area modules possible; a stabilization efficiency of 11.3% was achieved in a hybrid mini module comprising of ten-stage series integrated amorphous silicon and thin film poly-crystalline silicon; structures different hybrid modules were discussed, whereas an initial efficiency of 10.3% (38.78W) was achieved in a sub-module having a substrate size of 910 mm times 455 mm; and feasibility of forming large-area hybrid modules was demonstrated. (NEDO)

  17. Thin hybrid pixel assembly fabrication development with backside compensation layer

    Energy Technology Data Exchange (ETDEWEB)

    Bates, R., E-mail: richard.bates@glasgow.ac.uk [Experimental Particle Physics Group, SUPA School of Physics and Astronomy, The University of Glasgow, Glasgow G12 8QQ (United Kingdom); Buttar, C.; McMullen, T.; Cunningham, L.; Ashby, J.; Doherty, F. [Experimental Particle Physics Group, SUPA School of Physics and Astronomy, The University of Glasgow, Glasgow G12 8QQ (United Kingdom); Pares, G.; Vignoud, L.; Kholti, B. [CEA Leti, MINATEC, 17 rue des Martyrs, F38054, Grenoble (France); Vahanen, S. [Advacam Oy, Tietotie 3, 02150 Espoo (Finland)

    2017-02-11

    The ATLAS and CMS experiments will both replace their entire tracking systems for operation at the HL-LHC in 2026. This will include a significantly larger pixel systems, for example, for ATLAS approximately 15 m{sup 2}. To keep the tracker material budget low it is crucial to minimize the mass of the pixel modules via thinning both the sensor and readout chip to about 150 μm each. The bump yield of thin module assemblies using solder based bump bonding can be problematic due to wafer bowing during solder reflow at high temperature. A new bump-bonding process using backside compensation on the readout chip to address the issue of low yield will be presented. The objective is to compensate dynamically the stress of the front side stack by adding a compensating layer to the backside of the wafer. A SiN and Al:Si stack has been chosen for the backside layer. The bow reducing effect of applying a backside compensation layer will be demonstrated using the FE-I4 wafer. The world's first results from assemblies produced from readout wafers thinned to 100 μm with a stress compensation layer are presented with bond yields close to 100% measured using the FE-I4 readout chip.

  18. Polycrystalline ZnO: B grown by LPCVD as TCO for thin film silicon solar cells

    International Nuclear Information System (INIS)

    Fay, Sylvie; Steinhauser, Jerome; Nicolay, Sylvain; Ballif, Christophe

    2010-01-01

    Conductive zinc oxide (ZnO) grown by low pressure chemical vapor deposition (LPCVD) technique possesses a rough surface that induces an efficient light scattering in thin film silicon (TF Si) solar cells, which makes this TCO an ideal candidate for contacting such devices. IMT-EPFL has developed an in-house LPCVD process for the deposition of nanotextured boron doped ZnO films used as rough TCO for TF Si solar cells. This paper is a general review and synthesis of the study of the electrical, optical and structural properties of the ZnO:B that has been performed at IMT-EPFL. The influence of the free carrier absorption and the grain size on the electrical and optical properties of LPCVD ZnO:B is discussed. Transport mechanisms at grain boundaries are studied. It is seen that high doping of the ZnO grains facilitates the tunnelling of the electrons through potential barriers that are located at the grain boundaries. Therefore, even if these potential barriers increase after an exposition of the film to a humid atmosphere, the heavily doped LPCVD ZnO:B layers show a remarkable stable conductivity. However, the introduction of diborane in the CVD reaction induces also a degradation of the intra-grain mobility and increases over-proportionally the optical absorption of the ZnO:B films. Hence, the necessity to finely tune the doping level of LPCVD ZnO:B films is highlighted. Finally, the next challenges to push further the optimization of LPCVD ZnO:B films for thin film silicon solar cells are discussed, as well as some remarkable record cell results achieved with LPCVD ZnO:B as front electrode.

  19. Comparative study on electrical properties of atomic layer deposited high-permittivity materials on silicon substrates

    International Nuclear Information System (INIS)

    Duenas, S.; Castan, H.; Garcia, H.; Barbolla, J.; Kukli, K.; Ritala, M.; Leskelae, M.

    2005-01-01

    Deep level transient spectroscopy, capacitance-voltage and conductance transient measurement techniques have been applied in order to evaluate the electrical quality of thin high-permittivity oxide layers on silicon. The oxides studied included HfO 2 film grown from two different oxygen-free metal precursors and Ta 2 O 5 and Nb 2 O 5 nanolaminates. The interface trap densities correlated to the oxide growth chemistry and semiconductor substrate treatment. No gap state densities induced by structural disorder were measured in the films grown on chemical SiO 2 . Trap densities were also clearly lower in HfO 2 films compared to Ta 2 O 5 -Nb 2 O 5

  20. Eddy current imaging for electrical characterization of silicon solar cells and TCO layers

    Science.gov (United States)

    Hwang, Byungguk; Hillmann, Susanne; Schulze, Martin; Klein, Marcus; Heuer, Henning

    2015-03-01

    Eddy Current Testing has been mainly used to determine defects of conductive materials and wall thicknesses in heavy industries such as construction or aerospace. Recently, high frequency Eddy Current imaging technology was developed. This enables the acquirement of information of different depth level in conductive thin-film structures by realizing proper standard penetration depth. In this paper, we summarize the state of the art applications focusing on PV industry and extend the analysis implementing achievements by applying spatially resolved Eddy Current Testing. The specific state of frequency and complex phase angle rotation demonstrates diverse defects from front to back side of silicon solar cells and characterizes homogeneity of sheet resistance in Transparent Conductive Oxide (TCO) layers. In order to verify technical feasibility, measurement results from the Multi Parameter Eddy Current Scanner, MPECS are compared to the results from Electroluminescence.

  1. Lanthanide-Assisted Deposition of Strongly Electro-optic PZT Thin Films on Silicon: Toward Integrated Active Nanophotonic Devices.

    Science.gov (United States)

    George, J P; Smet, P F; Botterman, J; Bliznuk, V; Woestenborghs, W; Van Thourhout, D; Neyts, K; Beeckman, J

    2015-06-24

    The electro-optical properties of lead zirconate titanate (PZT) thin films depend strongly on the quality and crystallographic orientation of the thin films. We demonstrate a novel method to grow highly textured PZT thin films on silicon using the chemical solution deposition (CSD) process. We report the use of ultrathin (5-15 nm) lanthanide (La, Pr, Nd, Sm) based intermediate layers for obtaining preferentially (100) oriented PZT thin films. X-ray diffraction measurements indicate preferentially oriented intermediate Ln2O2CO3 layers providing an excellent lattice match with the PZT thin films grown on top. The XRD and scanning electron microscopy measurements reveal that the annealed layers are dense, uniform, crack-free and highly oriented (>99.8%) without apparent defects or secondary phases. The EDX and HRTEM characterization confirm that the template layers act as an efficient diffusion barrier and form a sharp interface between the substrate and the PZT. The electrical measurements indicate a dielectric constant of ∼650, low dielectric loss of ∼0.02, coercive field of 70 kV/cm, remnant polarization of 25 μC/cm(2), and large breakdown electric field of 1000 kV/cm. Finally, the effective electro-optic coefficients of the films are estimated with a spectroscopic ellipsometer measurement, considering the electric field induced variations in the phase reflectance ratio. The electro-optic measurements reveal excellent linear effective pockels coefficients of 110 to 240 pm/V, which makes the CSD deposited PZT thin film an ideal candidate for Si-based active integrated nanophotonic devices.

  2. Effect of annealing temperature on optical and electrical properties of metallophthalocyanine thin films deposited on silicon substrate

    Directory of Open Access Journals (Sweden)

    Skonieczny R.

    2016-09-01

    Full Text Available The cobalt phthalocyanine (CoPc thin films (300 nm thick deposited on n-type silicon substrate have been studied using micro-Raman spectroscopy, atomic force spectroscopy (AFM and I-V measurement. The CoPc thin layers have been deposited at room temperature by the quasi-molecular beam evaporation technique. The micro-Raman spectra of CoPc thin films have been recorded in the spectral range of 1000 cm-1 to 1900 cm-1 using 488 nm excitation wavelength. Moreover, using surface Raman mapping it was possible to obtain information about polymorphic forms distribution (before and after annealing of metallophthalocyanine (α and β form from polarized Raman spectra. The I-V characteristics of the Au/CoPc/n-Si/Al Schottky barrier were also investigated. The obtained results showed that influence of the annealing process plays a crucial role in the ordering and electrical conductivity of the molecular structure of CoPc thin films deposited on n-type silicon substrate.

  3. Coating of carbon short fibers with thin ceramic layers by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hackl, Gerrit; Gerhard, Helmut; Popovska, Nadejda

    2006-01-01

    Carbon short fiber bundles with a length of 6 mm were uniformly coated using specially designed, continuous chemical vapor deposition (CVD) equipment. Thin layers of titanium nitride, silicon nitride (SiC) and pyrolytic carbon (pyC) were deposited onto several kilograms of short fibers in this large scale CVD reactor. Thermo-gravimetric analyses and scanning electron microscopy investigations revealed layer thicknesses between 20 and 100 nm on the fibers. Raman spectra of pyC coated fibers show a change of structural order depending on the CVD process parameters. For the fibers coated with SiC, Raman investigations showed a deposition of amorphous SiC. The coated carbon short fibers will be applied as reinforcing material in composites with ceramic and metallic matrices

  4. Apparatus and method of manufacture for depositing a composite anti-reflection layer on a silicon surface

    Science.gov (United States)

    Pain, Bedabrata (Inventor)

    2012-01-01

    An apparatus and associated method are provided. A first silicon layer having at least one of an associated passivation layer and barrier is included. Also included is a composite anti-reflection layer including a stack of layers each with a different thickness and refractive index. Such composite anti-reflection layer is disposed adjacent to the first silicon layer.

  5. Liquid phase epitaxial growth of silicon on porous silicon for photovoltaic applications

    International Nuclear Information System (INIS)

    Berger, S.; Quoizola, S.; Fave, A.; Kaminski, A.; Perichon, S.; Barbier, D.; Laugier, A.

    2001-01-01

    The aim of this experiment is to grow a thin silicon layer ( 2 atmosphere, and finally LPE silicon growth with different temperature profiles in order to obtain a silicon layer on the sacrificial porous silicon (p-Si). We observed a pyramidal growth on the surface of the (100) porous silicon but the coalescence was difficult to obtain. However, on a p-Si (111) oriented wafer, homogeneous layers were obtained. (orig.)

  6. Growth of a delta-doped silicon layer by molecular beam epitaxy on a charge-coupled device for reflection-limited ultraviolet quantum efficiency

    Science.gov (United States)

    Hoenk, Michael E.; Grunthaner, Paula J.; Grunthaner, Frank J.; Terhune, R. W.; Fattahi, Masoud; Tseng, Hsin-Fu

    1992-01-01

    Low-temperature silicon molecular beam epitaxy is used to grow a delta-doped silicon layer on a fully processed charge-coupled device (CCD). The measured quantum efficiency of the delta-doped backside-thinned CCD is in agreement with the reflection limit for light incident on the back surface in the spectral range of 260-600 nm. The 2.5 nm silicon layer, grown at 450 C, contained a boron delta-layer with surface density of about 2 x 10 exp 14/sq cm. Passivation of the surface was done by steam oxidation of a nominally undoped 1.5 nm Si cap layer. The UV quantum efficiency was found to be uniform and stable with respect to thermal cycling and illumination conditions.

  7. Direct bonding of ALD Al2O3 to silicon nitride thin films

    DEFF Research Database (Denmark)

    Laganà, Simone; Mikkelsen, E. K.; Marie, Rodolphe

    2017-01-01

    microscopy (TEM) by improving low temperature annealing bonding strength when using atomic layer deposition of aluminum oxide. We have investigated and characterized bonding of Al2O3-SixNy (low stress silicon rich nitride) and Al2O3-Si3N4 (stoichiometric nitride) thin films annealed from room temperature up......O3 can be bonded to. Preliminary tests demonstrating a well-defined nanochannel system with-100 nm high channels successfully bonded and tests against leaks using optical fluorescence technique and transmission electron microscopy (TEM) characterization of liquid samples are also reported. Moreover...

  8. Electron and ion beam degradation effects in AES analysis of silicon nitride thin films

    International Nuclear Information System (INIS)

    Fransen, F.; Vanden Berghe, R.; Vlaeminck, R.; Hinoul, M.; Remmerie, J.; Maes, H.E.

    1985-01-01

    Silicon nitride films are currently investigated by AES combined with ion profiling techniques for their stoichiometry and oxygen content. During this analysis, ion beam and primary electron effects were observed. The effect of argon ion bombardment is the preferential sputtering of nitrogen, forming 'covalent' silicon at the surface layer (AES peak at 91 eV). The electron beam irradiation results in a decrease of the covalent silicon peak, either by an electron beam annealing effect in the bulk of the silicon nitride film, or by an ionization enhanced surface diffusion process of the silicon (electromigration). By the electron beam annealing, nitrogen species are liberated in the bulk of the silicon nitride film and migrate towards the surface where they react with the covalent silicon. The ionization enhanced diffusion originates from local charging of the surface, induced by the electron beam. (author)

  9. Analysis of photonic band gaps in two-dimensional photonic crystals with rods covered by a thin interfacial layer

    International Nuclear Information System (INIS)

    Trifonov, T.; Marsal, L.F.; Pallares, J.; Rodriguez, A.; Alcubilla, R.

    2004-01-01

    We investigate different aspects of the absolute photonic band gap (PBG) formation in two-dimensional photonic structures consisting of rods covered with a thin dielectric film. Specifically, triangular and honeycomb lattices in both complementary arrangements, i.e., air rods drilled in silicon matrix and silicon rods in air, are studied. We consider that the rods are formed of a dielectric core (silicon or air) surrounded by a cladding layer of silicon dioxide (SiO 2 ), silicon nitride (Si 3 N 4 ), or germanium (Ge). Such photonic lattices present absolute photonic band gaps, and we study the evolution of these gaps as functions of the cladding material and thickness. Our results show that in the case of air rods in dielectric media the existence of dielectric cladding reduces the absolute gap width and may cause complete closure of the gap if thick layers are considered. For the case of dielectric rods in air, however, the existence of a cladding layer can be advantageous and larger absolute PBG's can be achieved

  10. DEPTH MEASUREMENT OF DISRUPTED LAYER ON SILICON WAFER SURFACE USING AUGER SPECTROSCOPY METHOD

    Directory of Open Access Journals (Sweden)

    V. A. Solodukha

    2016-01-01

    Full Text Available The paper proposes a method for depth measurement of a disrupted layer on silicon wafer surface which is based on application of Auger spectroscopy with the precision sputtering of surface silicon layers and registration of the Auger electron yield intensity. In order to measure the disrupted layer with the help of Auger spectroscopy it is necessary to determine dependence of the released Auger electron amount on sputtering time (profile and then the dependence is analyzed. Silicon amount in the disrupted layer is less than in the volume. While going deeper the disruptive layer is decreasing that corresponds to an increase of atom density in a single layer. The essence of the method lies in the fact the disruptive layer is removed by ion beam sputtering and detection of interface region is carried out with the help of registration of the Auger electron yield intensity from the sputtered surface up to the moment when it reaches the value which is equal to the Auger electron yield intensity for single-crystal silicon. While removing surface silicon layers the registration of the Auger electron yield intensity from silicon surface makes it possible to control efficiently a presence of the disrupted layer on the silicon wafer surface. In this case depth control locality is about 1.0 nm due to some peculiarities of Auger spectroscopy method. The Auger electron yield intensity is determined automatically while using Auger spectrometer and while removing the disrupted layer the intensity is gradually increasing. Depth of the disrupted layer is determined by measuring height of the step which has been formed as a result of removal of the disrupted layer from the silicon wafer surface. Auger spectroscopy methods ensures an efficient depth control surface disruptions at the manufacturing stages of silicon wafers and integrated circuits. The depth measurement range of disruptions constitutes 0.001–1.000 um.

  11. Accretion disc boundary layers - geometrically and optically thin case

    International Nuclear Information System (INIS)

    Regev, Oded; Hougerat, A.A.

    1988-01-01

    The method of matched asymptotic expansions is applied to an optically and geometrically thin boundary layer between an accretion disc and the accreting star. Analytical solutions are presented for a particular viscosity prescription in the boundary layer. For a typical example we find that the disc closely resembles standard steady-disc theory. It is identical to it everywhere save a narrow boundary layer, where the temperature increases rapidly inward (by an order of magnitude), the angular velocity achieves maximum and decreases to its surface value and other variables also undergo rapid changes. This and previous work can now be used to calculate the emission from accretion discs including the boundary layers for a wide range of parameters. (author)

  12. Band gap determination of thin praseodymium oxide layers on aluminium oxynitride films

    Energy Technology Data Exchange (ETDEWEB)

    Bergholz, Matthias; Schmeisser, Dieter [Brandenburgische Technische Universitaet, Cottbus (Germany). Angewandte Physik - Sensorik

    2008-07-01

    High-k dielectrics are important as never before in semiconductor industry. We investigate Pr{sub 2}O{sub 3} as one representative of this group on silicon and silicon-aluminium oxynitride substrates. In earlier work we observed the positive influence of this AlO{sub x}N{sub y} intermediate layer on the electrical properties of the Pr{sub 2}O{sub 3} layer. Now we present in-situ EELS, XPS and UPS measurements of gradually grown thin Pr{sub 2}O{sub 3} on AlO{sub x}N{sub y}. From these measurements we determine the band structure and find a very fast change of the band gap for the first few A, coupled with n-type behaviour for the Pr{sub 2}O{sub 3} film. These results are compared with RIXS measurements of a 5 nm Pr{sub 2}O{sub 3} on a 1 nm thick AlO{sub x}N{sub y} layer.

  13. Application of thin-layer chromatography in radiochemistry

    International Nuclear Information System (INIS)

    Maki, Yasuyuki; Murakami, Yukio.

    1976-01-01

    In relation to the experimental procedures of thin-layer chromatography (TLC) in radiochemistry, the authors explained the preparation and development of radioactive test solutions, the methods of detection by autoradiography of isolated spots and by the calculation of measuring apparatus, and the identification of isolated spots. Next they outlined the carrier-free isolation and purification of nuclides, the quantification in combination with γ-ray spectrum, confirmation of the purity of RI-labeled medical supplies, their application to RI generator, thin-layer electrophoresis, in which electrophoresis and TLC were combined, and the application of this electrophoresis to isolation in recoil chemistry and to analysis and identification in carrier-free chemistry. (Kanao, K.)

  14. Rosenzweig instability in a thin layer of a magnetic fluid

    Science.gov (United States)

    Korovin, V. M.

    2013-12-01

    A simple mathematical model of the initial stage of nonlinear evolution of the Rosenzweig instability in a thin layer of a nonlinearly magnetized viscous ferrofluid coating a horizontal nonmagnetizable plate is constructed on the basis of the system of equations and boundary conditions of ferrofluid dynamics. A dispersion relation is derived and analyzed using the linearized equations of this model. The critical magnetization of the initial layer with a flat free surface, the threshold wavenumber, and the characteristic time of evolution of the most rapidly growing mode are determined. The equation for the neutral stability curve, which is applicable for any physically admissible law of magnetization of a ferrofluid, is derived analytically.

  15. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    International Nuclear Information System (INIS)

    Zhang, Yijun; Liu, Ming; Ren, Wei; Zhang, Yuepeng; Chen, Xing; Ye, Zuo-Guang

    2015-01-01

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe 3 O 4 thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe 3 O 4 thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H 2 /Ar at 400 °C, the as-grown α−Fe 2 O 3 sample is reduced to Fe 3 O 4 phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications

  16. Targets with thin ferromagnetic layers for transient field experiments

    International Nuclear Information System (INIS)

    Gallant, J.L.; Dmytrenko, P.

    1982-01-01

    Multilayer targets containing a central layer sufficiently thin so that all recoil nuclei can traverse it and subsequently stop in a suitable cubic environment have been prepared. Such targets are required in experiments making use of a magnetic field acting on an ion moving through a ferromagnetic material. The preparation and annealing of the ferromagnetic foils (iron and gadolinium) and the fabrication of the multilayer targets are described. (orig.)

  17. XPS studies of SiO/sub 2/ surface layers formed by oxygen ion implantation into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, D.; Finster, J. (Karl-Marx-Universitaet, Leipzig (German Democratic Republic). Sektion Chemie); Hensel, E.; Skorupa, W.; Kreissig, U. (Zentralinstitut fuer Kernforschung, Rossendorf bei Dresden (German Democratic Republic))

    1983-03-16

    SiO/sub 2/ surface layers of 160 nm thickness formed by /sup 16/O/sup +/ ion implantation into silicon are examined by X-ray photoelectron spectroscopy measurements into the depth after a step-by-step chemical etching. The chemical nature and the thickness of the transition layer were determined. The results of the XPS measurements show that the outer surface and the bulk of the layers formed by oxygen implantation and subsequent high temperature annealing consist of SiO/sub 2/. There is no evidence for Si or SiO/sub x/ (0thin grown oxide layers. Only its thickness is somewhat larger than in thermal oxide.

  18. Inverted amorphous silicon solar cell utilizing cermet layers

    Science.gov (United States)

    Hanak, Joseph J.

    1979-01-01

    An amorphous silicon solar cell incorporating a transparent high work function metal cermet incident to solar radiation and a thick film cermet contacting the amorphous silicon opposite to said incident surface.

  19. Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

    International Nuclear Information System (INIS)

    Mazzillo, M.; Renna, L.; Costa, N.; Badalà, P.; Sciuto, A.; Mannino, G.

    2016-01-01

    Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320–400 nm) and UV-B (290–320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni 2 Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm 2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

  20. Improved ITO thin films for photovoltaic applications with a thin ZnO layer by sputtering

    International Nuclear Information System (INIS)

    Herrero, J.; Guillen, C.

    2004-01-01

    The improvement of the optical and electrical characteristics of indium tin oxide (ITO) layers is pursued to achieve a higher efficiency in its application as frontal electrical contacts in thin film photovoltaic devices. In order to take advantage of the polycrystalline structure of ZnO films as growth support, the properties of ITO layers prepared at room temperature by sputtering onto bare and ZnO-coated substrates have been analyzed using X-ray diffraction, optical and electrical measurements. It has been found that by inserting a thin ZnO layer, the ITO film resistivity can be reduced as compared to that of a single ITO film with similar optical transmittance. The electrical quality improvement is related to ITO grain growth enhancement onto the polycrystalline ZnO underlayer

  1. On the photon annealing of silicon-implanted gallium-nitride layers

    International Nuclear Information System (INIS)

    Seleznev, B. I.; Moskalev, G. Ya.; Fedorov, D. G.

    2016-01-01

    The conditions for the formation of ion-doped layers in gallium nitride upon the incorporation of silicon ions followed by photon annealing in the presence of silicon dioxide and nitride coatings are analyzed. The conditions of the formation of ion-doped layers with a high degree of impurity activation are established. The temperature dependences of the surface concentration and mobility of charge carriers in ion-doped GaN layers annealed at different temperatures are studied.

  2. Growth of YBCO superconducting thin films on CaF sub 2 buffered silicon

    CERN Document Server

    Bhagwat, S S; Patil, J M; Shirodkar, V S

    2000-01-01

    CaF sub 2 films were grown on silicon using the neutral cluster beam deposition technique. These films were highly crystalline and c-axis oriented. Superconducting YBCO thin films were grown on the Ca F sub 2 buffered silicon using the laser ablation technique. These films showed T sub c (onset) at 90 K and Tc(zero) at 86 K. X-ray diffraction analysis showed that the YBCO films were also oriented along the c-axis.

  3. Annealing of polycrystalline thin film silicon solar cells in water vapour at sub-atmospheric pressures

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Píč, Vlastimil; Benda, V.; Fejfar, Antonín

    2014-01-01

    Roč. 54, č. 5 (2014), s. 341-347 ISSN 1210-2709 R&D Projects: GA MŠk 7E10061 EU Projects: European Commission(XE) 240826 - PolySiMode Grant - others:AVČR(CZ) M100101216 Institutional support: RVO:68378271 Keywords : passivation * water vapour * thin film solar cell * polycrystalline silicon (poly-Si) * multicrys- talline silicon (m-Si) * Suns-VOC Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use

  4. Sunlight-thin nanophotonic monocrystalline silicon solar cells

    Science.gov (United States)

    Depauw, Valérie; Trompoukis, Christos; Massiot, Inès; Chen, Wanghua; Dmitriev, Alexandre; Cabarrocas, Pere Roca i.; Gordon, Ivan; Poortmans, Jef

    2017-09-01

    Introducing nanophotonics into photovoltaics sets the path for scaling down the surface texture of crystalline-silicon solar cells from the micro- to the nanoscale, allowing to further boost the photon absorption while reducing silicon material loss. However, keeping excellent electrical performance has proven to be very challenging, as the absorber is damaged by the nanotexturing and the sensitivity to the surface recombination is dramatically increased. Here we realize a light-wavelength-scale nanotextured monocrystalline silicon cell with the confirmed efficiency of 8.6% and an effective thickness of only 830 nm. For this we adopt a self-assembled large-area and industry-compatible amorphous ordered nanopatterning, combined with an advanced surface passivation, earning strongly enhanced solar light absorption while retaining efficient electron collection. This prompts the development of highly efficient flexible and semitransparent photovoltaics, based on the industrially mature monocrystalline silicon technology.

  5. Investigation of thin oxide layer removal from Si substrates using an SiO2 atomic layer etching approach: the importance of the reactivity of the substrate

    International Nuclear Information System (INIS)

    Metzler, Dominik; Oehrlein, Gottlieb S; Li, Chen; Lai, C Steven; Hudson, Eric A

    2017-01-01

    The evaluation of a plasma-based atomic layer etching (ALE) approach for native oxide surface removal from Si substrates is described. Objectives include removal of the native oxide while minimizing substrate damage, surface residues and substrate loss. Oxide thicknesses were measured using in situ ellipsometry and surface chemistry was analyzed by x-ray photoelectron spectroscopy. The cyclic ALE approach when used for removal of native oxide SiO 2 from a Si substrate did not remove native oxide to the extent required. This is due to the high reactivity of the silicon substrate during the low-energy (<40 eV) ion bombardment phase of the cyclic ALE approach which leads to reoxidation of the silicon surface. A modified process, which used continuously biased Ar plasma with periodic CF 4 injection, achieved significant oxygen removal from the Si surface, with some residual carbon and fluorine. A subsequent H 2 /Ar plasma exposure successfully removed residual carbon and fluorine while passivating the silicon surface. The combined treatment reduced oxygen and carbon levels to about half compared to as received silicon surfaces. The downside of this process sequence is a net loss of about 40 Å of Si. A generic insight of this work is the importance of the substrate and final surface chemistry in addition to precise etch control of the target film for ALE processes. By a fluorocarbon-based ALE technique, thin SiO 2 layer removal at the Ångstrom level can be precisely performed from an inert substrate, e.g. a thick SiO 2 layer. However, from a reactive substrate, like Si, complete removal of the thin SiO 2 layer is prevented by the high reactivity of low energy Ar + ion bombarded Si. The Si surfaces are reoxidized during the ALE ion bombardment etch step, even for very clean and ultra-low O 2 process conditions. (paper)

  6. Layer-by-layer thinning of MoSe_2 by soft and reactive plasma etching

    International Nuclear Information System (INIS)

    Sha, Yunfei; Xiao, Shaoqing; Zhang, Xiumei; Qin, Fang; Gu, Xiaofeng

    2017-01-01

    Highlights: • Soft plasma etching technique using SF_6 + N_2 as precursors for layer-by-layer thinning of MoSe_2 was adopted in this work. • Optical microscopy, Raman, photoluminescence and atomic force microscopy measurements were used to confirm the thickness change. • Layer-dependent vibrational and photoluminescence spectra of the etched MoSe_2 were also demonstrated. • Equal numbers of MoSe_2 layers can be removed uniformly without affecting the underlying SiO_2 substrate and the remaining MoSe_2 layers. - Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs) like molybdenum diselenide (MoSe_2) have recently gained considerable interest since their properties are complementary to those of graphene. Unlike gapless graphene, the band structure of MoSe_2 can be changed from the indirect band gap to the direct band gap when MoSe_2 changed from bulk material to monolayer. This transition from multilayer to monolayer requires atomic-layer-precision thining of thick MoSe_2 layers without damaging the remaining layers. Here, we present atomic-layer-precision thinning of MoSe_2 nanaosheets down to monolayer by using SF_6 + N_2 plasmas, which has been demonstrated to be soft, selective and high-throughput. Optical microscopy, atomic force microscopy, Raman and photoluminescence spectra suggest that equal numbers of MoSe_2 layers can be removed uniformly regardless of their initial thickness, without affecting the underlying SiO_2 substrate and the remaining MoSe_2 layers. By adjusting the etching rates we can achieve complete MoSe_2 removal and any disired number of MoSe_2 layers including monolayer. This soft plasma etching method is highly reliable and compatible with the semiconductor manufacturing processes, thereby holding great promise for various 2D materials and TMD-based devices.

  7. Dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating

    DEFF Research Database (Denmark)

    Guo, Kai; Christensen, Jesper B.; Christensen, Erik N.

    2017-01-01

    We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also numerica......We numerically demonstrate dispersion tailoring of a silicon strip waveguide employing Titania-Alumina thin-film coating using a finite-difference mode solver. The proposed structure exhibits spectrally-flattened near-zero anomalous dispersion within the telecom wavelength range. We also...

  8. Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

    Science.gov (United States)

    Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

    2018-03-01

    Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

  9. Nanopatterned Silicon Substrate Use in Heterojunction Thin Film Solar Cells Made by Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Shao-Ze Tseng

    2014-01-01

    Full Text Available This paper describes a method for fabricating silicon heterojunction thin film solar cells with an ITO/p-type a-Si : H/n-type c-Si structure by radiofrequency magnetron sputtering. A short-circuit current density and efficiency of 28.80 mA/cm2 and 8.67% were achieved. Novel nanopatterned silicon wafers for use in cells are presented. Improved heterojunction cells are formed on a nanopatterned silicon substrate that is prepared with a self-assembled monolayer of SiO2 nanospheres with a diameter of 550 nm used as an etching mask. The efficiency of the nanopattern silicon substrate heterojunction cells was 31.49% greater than that of heterojunction cells on a flat silicon wafer.

  10. Crystalline silicon thin film growth by ECR plasma CVD for solar cells

    International Nuclear Information System (INIS)

    Licai Wang

    1999-07-01

    This thesis describes the background, motivation and work carried out towards this PhD programme entitled 'Crystalline Silicon Thin Film Growth by ECR Plasma CVD for Solar Cells'. The fundamental principles of silicon solar cells are introduced with a review of silicon thin film and bulk solar cells. The development and prospects for thin film silicon solar cells are described. Some results of a modelling study on thin film single crystalline solar cells are given which has been carried out using a commercially available solar cell simulation package (PC-1D). This is followed by a description of thin film deposition techniques. These include Chemical Vapour Deposition (CVD) and Plasma-Assisted CVD (PACVD). The basic theory and technology of the emerging technique of Electron Cyclotron Resonance (ECR) PACVD, which was used in this research, are introduced and the potential advantages summarised. Some of the basic methods of material and cell characterisation are briefly described, together with the work carried out in this research. The growth by ECR PACVD at temperatures 2 illumination. The best efficiency in the ECR grown structures was 13.76% using an epitaxial emitter. Cell performance was analysed in detail and the factors controlling performance identified by fitting self-consistently the fight and dark current-voltage and spectral response data using PC-1D. Finally, the conclusions for this research and suggestions for further work are outlined. (author)

  11. Layer-by-layer deposition of nanostructured CsPbBr3 perovskite thin films

    Science.gov (United States)

    Reshetnikova, A. A.; Matyushkin, L. B.; Andronov, A. A.; Sokolov, V. S.; Aleksandrova, O. A.; Moshnikov, V. A.

    2017-11-01

    Layer-by-layer deposition of nanostructured perovskites cesium lead halide thin films is described. The method of deposition is based on alternate immersion of the substrate in the precursor solutions or colloidal solution of nanocrystals and methyl acetate/lead nitrate solution using the device for deposition of films by SILAR and dip-coating techniques. An example of obtaining a photosensitive structure based on nanostructures of ZnO nanowires and layers of CsBbBr3 nanocrystals is also shown.

  12. Nanoimprint lithography of light trapping patterns in sol-gel coatings for thin film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Heijna, M.; Loffler, J.; Van Aken, B.B.; Soppe, W.J. [ECN Solar Energy, Petten (Netherlands); Borg, H.; Peeters, P. [OM and T, Eindhoven (Netherlands)

    2008-04-15

    For thin-film silicon solar cells, light trapping schemes are of uppermost importance to harvest all available sunlight. Typically, randomly textured TCO front layers are used to scatter the light diffusively in p-i-n cells on glass. Here, we investigate methods to texture the back contact with both random and periodic textures, for use in n-i-p cells on opaque foil. We applied an electrically insulating SiOx-polymer coating on a stainless steel substrate, and textured this barrier layer by nanoimprint. On this barrier layer the back contact is deposited for further use in the solar cell stack. Replication of masters with various random and periodic patterns was tested, and, using scanning electron microscopy, replicas were found to compare well with the originals. Masters with U-grooves of various sub micrometer widths have been used to investigate the optimal dimensions of regular patterns for light trapping in the silicon layers. Angular reflection distributions were measured to evaluate the light scattering properties of both periodic and random patterns. Diffraction gratings show promising results in scattering the light to specific angles, enhancing the total internal reflection in the solar cell.

  13. Development of Thin Film Amorphous Silicon Tandem Junction Based Photocathodes Providing High Open-Circuit Voltages for Hydrogen Production

    Directory of Open Access Journals (Sweden)

    F. Urbain

    2014-01-01

    Full Text Available Hydrogenated amorphous silicon thin film tandem solar cells (a-Si:H/a-Si:H have been developed with focus on high open-circuit voltages for the direct application as photocathodes in photoelectrochemical water splitting devices. By temperature variation during deposition of the intrinsic a-Si:H absorber layers the band gap energy of a-Si:H absorber layers, correlating with the hydrogen content of the material, can be adjusted and combined in a way that a-Si:H/a-Si:H tandem solar cells provide open-circuit voltages up to 1.87 V. The applicability of the tandem solar cells as photocathodes was investigated in a photoelectrochemical cell (PEC measurement set-up. With platinum as a catalyst, the a-Si:H/a-Si:H based photocathodes exhibit a high photocurrent onset potential of 1.76 V versus the reversible hydrogen electrode (RHE and a photocurrent of 5.3 mA/cm2 at 0 V versus RHE (under halogen lamp illumination. Our results provide evidence that a direct application of thin film silicon based photocathodes fulfills the main thermodynamic requirements to generate hydrogen. Furthermore, the presented approach may provide an efficient and low-cost route to solar hydrogen production.

  14. Contribution to implanted silicon layers and their annealing

    International Nuclear Information System (INIS)

    Combasson, J.-L.

    1976-01-01

    Defects created by boron implantation in silicon have been characterized by measuring the diffusion coefficient during annealing. Implanted impurity distributions were calculated after analyzing the hypotheses relating to charged particle slowing down through matter. Profiles are predicted with a good accuracy, by replacing occasionally the electronic stopping law by an empirical law. The asymmetries predicted are generally observed but deviations may occur for crystalline targets, or when the ion is heavy with regard to the substrate (in the event the Thomas-Fermi potential is not yet valid due to the high impact parameters). When deviations are neglected, the displacement cascade from implantation is represented by a damage profile proportional to the distribution of the Frenkel pairs. The annealing of the implanted layers is characterized by three annealing stages. The first one (400 deg C-600 deg C) is imputed to divacancy annealing associated to the formation and migration of boron-vacancy complexes. The second one (500 deg C-650 deg C) is characterized by the Watkins replacement mechanism. At high temperatures, when the annealing duration is longer than that of precipitation, interstitial loops are dissolved, and the thermal diffusion of boron atoms involves the vacancy mechanism of thermal diffusion [fr

  15. Research of morphology and structure of 3C–SiC thin films on silicon by electron microscopy and X-ray diffractometry

    Directory of Open Access Journals (Sweden)

    Alexander S. Gusev

    2015-12-01

    Full Text Available Thin films of silicon carbide possessing unique properties attract increasing attention of researchers both in the field of semiconductor physics and in the technology of new semiconductor devices for high power, RF and optoelectronics. The growth of the production of silicon carbide based devices promotes the search for more resource saving and safe SiC layer synthesis technologies. Potential method is pulse laser deposition (PLD in vacuum. This technology does not require the use of chemically aggressive and explosive gases and allows forming thin and continuous coatings with thicknesses of from several nanometers at relatively low substrate temperatures. Submicron thickness silicon carbide films have been grown on single crystal silicon by vacuum laser ablation of a ceramic target. The physical and technological parameters of silicon carbide thin film low temperature synthesis by PLD have been studied and, in particular, the effect of temperature and substrate crystalline orientation on the composition, structural properties and morphology of the surface of the experimental specimens has been analyzed. At above 500 °C the crystalline β-SiC phase forms on Si (100 and (111. At a substrate temperature of 950 °C the formation of textured heteroepitaxial 3C–SiC films was observed.

  16. Diblock Copolymer/Layered Silicate Nanocomposite Thin Film Stability

    Science.gov (United States)

    Limary, Ratchana; Green, Peter

    2000-03-01

    The stability of thin film symmetric diblock copolymers blended with layered silicate nanocomposites were examined using a combination of optical microscopy, atomic force microscopy (AFM), and X-ray diffraction (XRD). Two cases were examined PS-b-PMMA (polystyrene-b-polymethylacrylate) blended with montmorillonite stoichiometrically loaded with alkyl ammonium ions, OLS(S), and PS-b-PMMA blended with montmorillonite loaded with excess alkyl ammonium ions, OLS(E). XRD spectra show an increase in the gallery spacing of the OLSs, indicating that the copolymer chains have intercalated the layered silicates. AFM images reveal a distinct difference between the two nanocomposite thin films: regions in the vicinity of OLS(S) aggregates were depleted of material, while in the vicinity of OLS(E) aggregates, dewetting of the substrate occurred. We show that the stability of the copolymer/OLS nanocomposite films is determined by the enthalpic driving force associated with intercalation of the copolymer chains into the galleries of the modified OLS layers and by the substrate/organic modifier interactions.

  17. Thermal conductivity of silicon nanocrystals and polystyrene nanocomposite thin films

    International Nuclear Information System (INIS)

    Juangsa, Firman Bagja; Muroya, Yoshiki; Nozaki, Tomohiro; Ryu, Meguya; Morikawa, Junko

    2016-01-01

    Silicon nanocrystals (SiNCs) are well known for their size-dependent optical and electronic properties; they also have the potential for low yet controllable thermal properties. As a silicon-based low-thermal conductivity material is required in microdevice applications, SiNCs can be utilized for thermal insulation. In this paper, SiNCs and polymer nanocomposites were produced, and their thermal conductivity, including the density and specific heat, was measured. Measurement results were compared with thermal conductivity models for composite materials, and the comparison shows a decreasing value of the thermal conductivity, indicating the effect of the size and presence of the nanostructure on the thermal conductivity. Moreover, employing silicon inks at room temperature during the fabrication process enables a low cost of fabrication and preserves the unique properties of SiNCs. (paper)

  18. Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

    International Nuclear Information System (INIS)

    Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

    1988-01-01

    Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

  19. Effect of additive gases and injection methods on chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F2 remote plasmas

    International Nuclear Information System (INIS)

    Yun, Y. B.; Park, S. M.; Kim, D. J.; Lee, N.-E.; Kim, K. S.; Bae, G. H.

    2007-01-01

    The authors investigated the effects of various additive gases and different injection methods on the chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F 2 remote plasmas. N 2 and N 2 +O 2 gases in the F 2 /Ar/N 2 and F 2 /Ar/N 2 /O 2 remote plasmas effectively increased the etch rate of the layers. The addition of direct-injected NO gas increased the etch rates most significantly. NO radicals generated by the addition of N 2 and N 2 +O 2 or direct-injected NO molecules contributed to the effective removal of nitrogen and oxygen in the silicon nitride and oxide layers, by forming N 2 O and NO 2 by-products, respectively, and thereby enhancing SiF 4 formation. As a result of the effective removal of the oxygen, nitrogen, and silicon atoms in the layers, the chemical dry etch rates were enhanced significantly. The process regime for the etch rate enhancement of the layers was extended at elevated temperature

  20. Mathematical modelling of thin layer drying of pear

    Directory of Open Access Journals (Sweden)

    Lutovska Monika

    2016-01-01

    Full Text Available In this study, a thin - layer drying of pear slices as a function of drying conditions were examined. The experimental data set of thin - layer drying kinetics at five drying air temperatures 30, 40, 50, 60 and 70°C, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate industrial convective dryer. Five well known thin - layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, numerical experiments were made. For each model and data set, the statistical performance index, (φ, and chi-squared, (χ2, value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Midilli gives the best statistical results. Because the effect of drying air temperature and drying air velocity on the empirical parameters was not included in the base Midilli model, in this study the generalized form of this model was developed. With this model, the drying kinetic data of pear slices can be approximated with high accuracy. The effective moisture diffusivity was determined by using Fick’s second laws. The obtained values of the effective moisture diffusivity, (Deff, during drying ranged between 6.49 x 10-9 and 3.29 x 10-8 m2 s-1, while the values of activation energy (E0 varied between 28.15 to 30.51 kJ mol-1.

  1. Thin-Layer Solutions of the Helmholtz and Related Equations

    KAUST Repository

    Ockendon, J. R.

    2012-01-01

    This paper concerns a certain class of two-dimensional solutions to four generic partial differential equations-the Helmholtz, modified Helmholtz, and convection-diffusion equations, and the heat conduction equation in the frequency domain-and the connections between these equations for this particular class of solutions.S pecifically, we consider thin-layer solutions, valid in narrow regions across which there is rapid variation, in the singularly perturbed limit as the coefficient of the Laplacian tends to zero.F or the wellstudied Helmholtz equation, this is the high-frequency limit and the solutions in question underpin the conventional ray theory/WKB approach in that they provide descriptions valid in some of the regions where these classical techniques fail.E xamples are caustics, shadow boundaries, whispering gallery, and creeping waves and focusing and bouncing ball modes.It transpires that virtually all such thin-layer models reduce to a class of generalized parabolic wave equations, of which the heat conduction equation is a special case. Moreover, in most situations, we will find that the appropriate parabolic wave equation solutions can be derived as limits of exact solutions of the Helmholtz equation.W e also show how reasonably well-understood thin-layer phenomena associated with any one of the four generic equations may translate into less well-known effects associated with the others.In addition, our considerations also shed some light on the relationship between the methods of matched asymptotic, WKB, and multiple-scales expansions. © 2012 Society for Industrial and Applied Mathematics.

  2. Thin layer activation and ultra thin layer activation: two complementary techniques for wear and corrosion studies in various fields

    International Nuclear Information System (INIS)

    Sauvage, T.; Vincent, L.; Blondiaux, G.

    2002-01-01

    Thin layer activation (TLA) is widely used since more than 25 years to study surface wear or corrosion. This well known technique uses most of the time charged particles activation, which gives sensitivity in the range of the micrometer, except when the fluid mode of detection is utilized. In this case application of the method is limited to phenomena where we have transport of radioactive fragments to detection point. The main disadvantage of this procedure is the error due to trapping phenomena between the wear or corrosion point and detection setup. So the ultra thin layer activation (UTLA) has been developed to get nanometric sensitivity without using any fluid for radioactivity transportation, which is the main source of error of the TLA technique. In this paper we shall briefly describe the TLA technique and the most important fields of application. Then we shall emphasise on UTLA with a presentation of the principle of the method and actual running of application. The main problem concerning UTLA is calibration which requires the use of thin films (usually 10 to 100 nanometers) deposited on substrate. This process is time consuming and we shall demonstrate how running software developed in the lab can solve it. We shall finish the presentation by giving some potential application of the technique in various fields. (authors)

  3. Investigation of thin ZnO layers in view of laser desorption-ionization

    Energy Technology Data Exchange (ETDEWEB)

    Grechnikov, A A; Borodkov, A S [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 19 Kosygin Str., 119991 Moscow (Russian Federation); Georgieva, V B [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Alimpiev, S S; Nikiforov, S M; Simanovsky, Ya O [General Physics Institute, Russian Academy of Sciences, 38 Vavilov Str., 119991 Moscow (Russian Federation); Dimova-Malinovska, D; Angelov, O I, E-mail: lazarova@issp.bas.b [Laboratory for Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria)

    2010-04-01

    Thin zinc oxide films (ZnO) were developed as a matrix-free platform for surface assisted laser desorption-ionization (SALDI) time-of-flight mass spectrometry. The ZnO films were deposited by RF magnetron sputtering of ZnO ceramic targets in Ar atmospheres on monocrystalline silicon. The generation under UV (355 nm) laser irradiation of positive ions of atenolol, reserpine and gramicidin S from the ZnO layers deposited was studied. All analytes tested were detected as protonated molecules with no or very structure-specific fragmentation. The mass spectra obtained showed low levels of chemical background noise. All ZnO films studied exhibited high stability and good reproducibility. The detection limits for test analytes are in the 10 femtomol range.

  4. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Science.gov (United States)

    Reyes, R.; Cremona, M.; Achete, C. A.

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq3) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq3/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  5. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R [Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, Av. Tupac Amaru SN, Lima (Peru); Cremona, M [Departamento de Fisica, PontifIcia Universidade Catolica de Rio de Janeiro, PUC-Rio, Cx. Postal 38071, Rio de Janeiro, RJ, CEP 22453-970 (Brazil); Achete, C A, E-mail: rreyes@uni.edu.pe [Departamento de Engenheria Metalurgica e de Materiais, Universidade Federal do Rio de Janeiro, Cx. Postal 68505, Rio de Janeiro, RJ, CEP 21945-970 (Brazil)

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq{sub 3}) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq{sub 3}/Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  6. Light emission in forward and reverse bias operation in OLED with amorphous silicon carbon nitride thin films

    International Nuclear Information System (INIS)

    Reyes, R; Cremona, M; Achete, C A

    2011-01-01

    Amorphous silicon carbon nitride (a-SiC:N) thin films deposited by magnetron sputtering were used in the structure of an organic light emitting diode (OLED), obtaining an OLED operating in forward and reverse bias mode. The device consist of the heterojunction structure ITO/a-SiC:N/Hole Transport Layer (HTL)/ Electron Transport Layer (ETL)/a-SiC:N/Al. As hole transporting layer was used a thin film of 1-(3-methylphenyl)-1,2,3,4 tetrahydroquinoline - 6 - carboxyaldehyde - 1,1'- diphenylhydrazone (MTCD), while the tris(8-hydroxyquinoline aluminum) (Alq 3 ) is used as electron transport and emitting layer. A significant increase in the voltage operation compared to the conventional ITO/MTCD/Alq 3 /Al structure was observed, so the onset of electroluminescence occurs at about 22 V in the forward and reverse bias mode of operation. The electroluminescence spectra is similar in both cases, only slightly shifted 0.14 eV to lower energies in relation to the conventional device.

  7. Ultra-thin, single-layer polarization rotator

    Directory of Open Access Journals (Sweden)

    T. V. Son

    2016-08-01

    Full Text Available We demonstrate light polarization control over a broad spectral range by a uniform layer of vanadium dioxide as it undergoes a phase transition from insulator to metal. Changes in refractive indices create unequal phase shifts on s- and p-polarization components of incident light, and rotation of linear polarization shows intensity modulation by a factor of 103 when transmitted through polarizers. This makes possible polarization rotation devices as thin as 50 nm that would be activated thermally, optically or electrically.

  8. Induced nano-scale self-formed metal-oxide interlayer in amorphous silicon tin oxide thin film transistors.

    Science.gov (United States)

    Liu, Xianzhe; Xu, Hua; Ning, Honglong; Lu, Kuankuan; Zhang, Hongke; Zhang, Xiaochen; Yao, Rihui; Fang, Zhiqiang; Lu, Xubing; Peng, Junbiao

    2018-03-07

    Amorphous Silicon-Tin-Oxide thin film transistors (a-STO TFTs) with Mo source/drain electrodes were fabricated. The introduction of a ~8 nm MoO x interlayer between Mo electrodes and a-STO improved the electron injection in a-STO TFT. Mo adjacent to the a-STO semiconductor mainly gets oxygen atoms from the oxygen-rich surface of a-STO film to form MoO x interlayer. The self-formed MoO x interlayer acting as an efficient interface modification layer could conduce to the stepwise internal transport barrier formation while blocking Mo atoms diffuse into a-STO layer, which would contribute to the formation of ohmic contact between Mo and a-STO film. It can effectively improve device performance, reduce cost and save energy for the realization of large-area display with high resolution in future.

  9. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes/polymer composite thin film.

    Science.gov (United States)

    Rajanna, Pramod Mulbagal; Gilshteyn, Evgenia; Yagafarov, Timur; Alekseeva, Alena; Anisimov, Anton; Sergeev, Oleg; Neumueller, Alex; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert

    2018-01-09

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and a thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high quality SWCNTs with an enhanced conductivity by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with different SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit Jsc, open-circuit Voc, and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and efficiency of 3.4% under simulated one-sun AM 1.5G direct illumination. © 2018 IOP Publishing Ltd.

  10. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film

    Science.gov (United States)

    Rajanna, Pramod M.; Gilshteyn, Evgenia P.; Yagafarov, Timur; Aleekseeva, Alena K.; Anisimov, Anton S.; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G.

    2018-03-01

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

  11. An RBS study of thin PLD and MOCVD strontium copper oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Kantor, Z. [Institute of Physics, University of Pannonia, H-8200 Veszprem (Hungary); Papadopoulou, E.L.; Aperathitis, E. [Inst. Electronic Struture and Laser, Foundation for Research and Technology - Hellas, P.O. Box 1527, Heraklion 71110 (Greece); Deschanvres, J.-L. [LMPG INP Grenoble-Minatec, BP 257, 38016 Grenoble Cedex 1 (France); Somogyi, K. [MicroVacuum Ltd., Kerekgyarto u.: 10, H-1147 Budapest (Hungary)], E-mail: karoly.somogyi@microvacuum.com; Szendro, I. [MicroVacuum Ltd., Kerekgyarto u.: 10, H-1147 Budapest (Hungary)

    2008-09-30

    Strontium copper oxide (SCO) has been studied as p-type transparent (VIS) conductive oxide material. Also theoretical studies suggested p-type conductivity of the SrCu{sub 2}O{sub 2} composition. SCO thin layers, with thicknesses of 30-2000 nm, were deposited on glass and silicon substrates both by pulsed laser deposition (PLD) and by MOCVD method. The as-grown layers showed high electrical resistance. Due to an annealing process, the resistivity significantly decreased and the layers showed p-type conductivity. Optical transparency measured on samples grown on glass substrates was found about or above 80%, including also thickness dependence. RBS measurements were applied for the determination of the chemical composition profile of the layers. A comparison revealed some specific differences between as-grown and annealed PLD samples. Due to the annealing, the ratio of oxide phases was changed and a vertical inhomogeneity in chemical composition was observed. Our measurements revealed also the influence of the deposition technique and of the substrate.

  12. Quadruple-Junction Thin-Film Silicon-Based Solar Cells

    NARCIS (Netherlands)

    Si, F.T.

    2017-01-01

    The direct utilization of sunlight is a critical energy source in a sustainable future. One of the options is to convert the solar energy into electricity using thin-film silicon-based solar cells (TFSSCs). Solar cells in a triple-junction configuration have exhibited the highest energy conversion

  13. Light management in large area thin-film silicon solar modules

    Czech Academy of Sciences Publication Activity Database

    Losio, P.A.; Caglar, O.; Cashmore, J.S.; Hötzel, J.E.; Ristau, S.; Holovský, Jakub; Remeš, Zdeněk; Sinicco, I.

    2015-01-01

    Roč. 143, Dec (2015), s. 375-385 ISSN 0927-0248 R&D Projects: GA ČR(CZ) GA14-05053S Institutional support: RVO:68378271 Keywords : micromorph * thin-film silicon solar cells * light management * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.732, year: 2015

  14. Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates

    NARCIS (Netherlands)

    Bhamla, M.S.; Balemans, C.; Fuller, G.G.

    2015-01-01

    We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show

  15. On the oxidation mechanism of microcrystalline silicon thin films studied by Fourier transform infrared spectroscopy

    NARCIS (Netherlands)

    Bronneberg, A. C.; Smets, A. H. M.; Creatore, M.; M. C. M. van de Sanden,

    2011-01-01

    Insight into the oxidation mechanism of microcrystalline silicon thin films has been obtained by means of Fourier transform infrared spectroscopy. The films were deposited by using the expanding thermal plasma and their oxidation upon air exposure was followed in time. Transmission spectra were

  16. Light Trapping in Thin Film Silicon Solar Cells on Plastic Substrates

    NARCIS (Netherlands)

    de Jong, M.M.

    2013-01-01

    In the search for sustainable energy sources, solar energy can fulfil a large part of the growing demand. The biggest threshold for large-scale solar energy harvesting is the solar panel price. For drastic cost reductions, roll-to-roll fabrication of thin film silicon solar cells using plastic

  17. Experimentally validated dispersion tailoring in a silicon strip waveguide with alumina thin-film coating

    DEFF Research Database (Denmark)

    Guo, Kai; Christensen, Jesper Bjerge; Shi, Xiaodong

    2018-01-01

    We propose a silicon strip waveguide structure with alumina thin-film coating in-between the core and the cladding for group-velocity dispersion tailoring. By carefully designing the core dimension and the coating thickness, a spectrally-flattened near-zero anomalous group-velocity dispersion...

  18. Carrier transport in polycrystalline silicon thin films solar cells grown on a highly textured structure

    Czech Academy of Sciences Publication Activity Database

    Honda, Shinya; Takakura, H.; Hamakawa, Y.; Muhida, R.; Kawamura, T.; Harano, T.; Toyama, T.; Okamoto, H.

    2004-01-01

    Roč. 43, 9A (2004), s. 5955-5959 ISSN 0021-4922 Institutional research plan: CEZ:AV0Z1010914 Keywords : polycrystalline silicon thin film * solar cells * substrate texture Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.142, year: 2004

  19. Materials and Light Management for High-Efficiency Thin-Film Silicon Solar Cells

    NARCIS (Netherlands)

    Tan, H.

    2015-01-01

    Direct conversion of sunlight into electricity is one of the most promising approaches to provide sufficient renewable energy for humankind. Solar cells are such devices which can efficiently generate electricity from sunlight through the photovoltaic effect. Thin-film silicon solar cells, a type of

  20. Chemical resistance of thin film materials based on metal oxides grown by atomic layer deposition

    International Nuclear Information System (INIS)

    Sammelselg, Väino; Netšipailo, Ivan; Aidla, Aleks; Tarre, Aivar; Aarik, Lauri; Asari, Jelena; Ritslaid, Peeter; Aarik, Jaan

    2013-01-01

    Etching rate of technologically important metal oxide thin films in hot sulphuric acid was investigated. The films of Al-, Ti-, Cr-, and Ta-oxides studied were grown by atomic layer deposition (ALD) method on silicon substrates from different precursors in large ranges of growth temperatures (80–900 °C) in order to reveal process parameters that allow deposition of coatings with higher chemical resistance. The results obtained demonstrate that application of processes that yield films with lower concentration of residual impurities as well as crystallization of films in thermal ALD processes leads to significant decrease of etching rate. Crystalline films of materials studied showed etching rates down to values of < 5 pm/s. - Highlights: • Etching of atomic layer deposited thin metal oxide films in hot H 2 SO 4 was studied. • Smallest etching rates of < 5 pm/s for TiO 2 , Al 2 O 3 , and Cr 2 O 3 were reached. • Highest etching rate of 2.8 nm/s for Al 2 O 3 was occurred. • Remarkable differences in etching of non- and crystalline films were observed

  1. Light scattering of thin azobenzene side-chain polyester layers

    DEFF Research Database (Denmark)

    Kerekes, Á.; Lörincz, E.; Ramanujam, P.S.

    2002-01-01

    Light scattering properties of liquid crystalline and amorphous azobenzene side-chain polyester layers used for optical data storage were examined by means of transmissive scatterometry. Comparative experiments show that the amorphous polyester has significantly lower light scattering...... characteristics than the liquid crystalline polyester. The amorphous samples have negligible polarization part orthogonal to the incident beam. the liquid crystalline samples have relative high orthogonal polarization part in light scattering, The light scattering results can be used to give a lower limit...... for the domain size in thin liquid crystalline polyester layers being responsible for the dominant light scattering. The characteristic domain Sizes obtained from the Fourier transformation of polarization microscopic Pictures confirm these values....

  2. Influence of Magnetron Effect on Barium Hexaferrite Thin Layers

    International Nuclear Information System (INIS)

    Hassane, H.; Chatelon, J.P.; Rousseau, J.J; Siblini, A.; Kriga, A.

    2011-01-01

    In this paper, we study the effects of a magnet, located in the cathode, on barium hexaferrite thin films deposited by RF magnetron sputtering technique. During the process, these effects can modify thickness, roughness and stress of coatings. The characteristics of the deposited layers depend on the substrate position that is located opposite of magnetron cathode. In the m agnetron area , one can observe that the high stress can produce cracks or detachment of layers and the increasing of both depositing rate and surface roughness. After sputtering elaboration, barium hexaferrite films are in a compressive stress mode. But, after the post-deposition heat treatment these films are in a tensile stress mode. To improve the quality of BaM films, the subsrtate has to be set outside the magnetron area. (author)

  3. Ultra-thin silicon/electro-optic polymer hybrid waveguide modulators

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Feng; Spring, Andrew M. [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Sato, Hiromu [Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Maeda, Daisuke; Ozawa, Masa-aki; Odoi, Keisuke [Nissan Chemical Industries, Ltd., 2-10-1 Tuboi Nishi, Funabashi, Chiba 274-8507 (Japan); Aoki, Isao; Otomo, Akira [National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe 651-2492 (Japan); Yokoyama, Shiyoshi, E-mail: s-yokoyama@cm.kyushu-u.ac.jp [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan)

    2015-09-21

    Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed and fabricated. The waveguide consists of a silicon core with a thickness of 30 nm and a width of 2 μm. The cladding is an EO polymer. Optical mode calculation reveals that 55% of the optical field around the silicon extends into the EO polymer in the TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. The measured half-wave voltage of the MZI with 7 μm spacing and 1.3 cm long electrodes is 4.6 V at 1550 nm. The evaluated EO coefficient is 70 pm/V, which is comparable to that of the bulk EO polymer film. Using ultra-thin silicon is beneficial in order to reduce the side-wall scattering loss, yielding a propagation loss of 4.0 dB/cm. We also investigated a mode converter which couples light from the hybrid EO waveguide into a strip silicon waveguide. The calculation indicates that the coupling loss between these two devices is small enough to exploit the potential fusion of a hybrid EO polymer modulator together with a silicon micro-photonics device.

  4. Growth and Etch Rate Study of Low Temperature Anodic Silicon Dioxide Thin Films

    Directory of Open Access Journals (Sweden)

    Akarapu Ashok

    2014-01-01

    Full Text Available Silicon dioxide (SiO2 thin films are most commonly used insulating films in the fabrication of silicon-based integrated circuits (ICs and microelectromechanical systems (MEMS. Several techniques with different processing environments have been investigated to deposit silicon dioxide films at temperatures down to room temperature. Anodic oxidation of silicon is one of the low temperature processes to grow oxide films even below room temperature. In the present work, uniform silicon dioxide thin films are grown at room temperature by using anodic oxidation technique. Oxide films are synthesized in potentiostatic and potentiodynamic regimes at large applied voltages in order to investigate the effect of voltage, mechanical stirring of electrolyte, current density and the water percentage on growth rate, and the different properties of as-grown oxide films. Ellipsometry, FTIR, and SEM are employed to investigate various properties of the oxide films. A 5.25 Å/V growth rate is achieved in potentiostatic mode. In the case of potentiodynamic mode, 160 nm thickness is attained at 300 V. The oxide films developed in both modes are slightly silicon rich, uniform, and less porous. The present study is intended to inspect various properties which are considered for applications in MEMS and Microelectronics.

  5. Thin-film piezoelectric-on-silicon resonators for high-frequency reference oscillator applications.

    Science.gov (United States)

    Abdolvand, Reza; Lavasani, Hossein M; Ho, Gavin K; Ayazi, Farrokh

    2008-12-01

    This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators. Low-motional-impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble reference oscillators and the performance characteristics of the oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is approximately 350 microW for an oscillator operating at approximately 106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/ degrees C) temperature coefficient of frequency is obtained for an 82-MHz oscillator.

  6. Thin pixel development for the SuperB silicon vertex tracker

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, G., E-mail: giuliana.rizzo@pi.infn.it [INFN-Pisa and Universita di Pisa (Italy); Avanzini, C.; Batignani, G.; Bettarini, S.; Bosi, F.; Ceccanti, M.; Cenci, R.; Cervelli, A.; Crescioli, F.; Dell' Orso, M.; Forti, F.; Giannetti, P.; Giorgi, M.A. [INFN-Pisa and Universita di Pisa (Italy); Lusiani, A. [Scuola Normale Superiore and INFN-Pisa (Italy); Gregucci, S.; Mammini, P.; Marchiori, G.; Massa, M.; Morsani, F.; Neri, N. [INFN-Pisa and Universita di Pisa (Italy); and others

    2011-09-11

    The high luminosity SuperB asymmetric e{sup +}e{sup -} collider, to be built near the INFN National Frascati Laboratory in Italy, has been designed to deliver a luminosity greater than 10{sup 36} cm{sup -2} s{sup -1} with moderate beam currents and a reduced center of mass boost with respect to earlier B-Factories. An improved vertex resolution is required for precise time-dependent measurements and the SuperB Silicon Vertex Tracker will be equipped with an innermost layer of small radius (about 1.5 cm), resolution of 10-15{mu}m in both coordinates, low material budget (<1% X0), and able to withstand a background rate of several tens of MHz/cm{sup 2}. The ambitious goal of designing a thin pixel device with these stringent requirements is being pursued with specific R and D programs on different technologies: hybrid pixels, CMOS MAPS and pixel sensors developed with vertical integration technology. The latest results on the various pixel options for the SuperB SVT will be presented.

  7. The investigation of ZnO:Al2O3/metal composite back reflectors in amorphous silicon germanium thin film solar cells

    Institute of Scientific and Technical Information of China (English)

    Wang Guang-Hong; Zhao Lei; Yan Bao-Jun; Chen Jing-Wei; Wang Ge; Diao Hong-Wei; Wang Wen-Jing

    2013-01-01

    Different aluminum-doped ZnO (AZO)/metal composite thin films,including AZO/Ag/Al,AZO/Ag/nickelchromium alloy (NiCr),and AZO/Ag/NiCr/Al,are utilized as the back reflectors of p-i-n amorphous silicon germanium thin film solar cells.NiCr is used as diffusion barrier layer between Ag and Al to prevent mutual diffusion,which increases the short circuit current density of solar cell.NiCr and NiCr/Al layers are used as protective layers of Ag layer against oxidation and sulfurization,the higher efficiency of solar cell is achieved.The experimental results show that the performance of a-SiGe solar cell with AZO/Ag/NiCr/Al back reflector is best.The initial conversion efficiency is achieved to be 8.05%.

  8. Deposition of yttrium oxysulfide thin films by atomic layer epitaxy

    International Nuclear Information System (INIS)

    Kukli, K.; University of Tartu, Tartu,; Johansson, L-S.; Nykaenen, E.; Peussa, M.; Ninistoe, L.

    1998-01-01

    Full text: Yttrium oxysulfide is a highly interesting material for optoelectronic applications. It is industrially exploited in the form of doped powder in catholuminescent phosphors, e.g. Y 2 O 2 S: Eu 3+ for colour TV. Attempts to grow thin films of Y 2 O 2 S have not been frequent and only partially successful due to the difficulties in obtaining crystalline films at a reasonable temperature. Furthermore, sputtering easily leads to a sulphur deficiency. Evaporation of the elements from a multi-source offers a better control of the stoichiometry resulting in hexagonal (0002) oriented films at 580 deg C. In this paper we present the first successful thin film growth experiments using a chemical process with molecular precursors. Atomic layer epitaxy (ALE) allows the use of a relatively low deposition temperature and thus compatibility with other technologies. Already at 425 deg C the reaction between H 2 S and Y(thd) 3 (thd = 2,2,6,6 - tetramethyl-heptane-3,5- dione) yields a crystalline Y 2 O 2 S thin film which was characterized by XRD, XRF and XPS

  9. Photonic Structures for Light Trapping in Thin Film Silicon Solar Cells: Design and Experiment

    Directory of Open Access Journals (Sweden)

    Yi Ding

    2017-12-01

    Full Text Available One of the foremost challenges in designing thin-film silicon solar cells (TFSC is devising efficient light-trapping schemes due to the short optical path length imposed by the thin absorber thickness. The strategy relies on a combination of a high-performance back reflector and an optimized texture surface, which are commonly used to reflect and scatter light effectively within the absorption layer, respectively. In this paper, highly promising light-trapping structures based on a photonic crystal (PC for TFSCs were investigated via simulation and experiment. Firstly, a highly-reflective one-dimensional photonic crystal (1D-PC was designed and fabricated. Then, two types of 1D-PC-based back reflectors (BRs were proposed: Flat 1D-PC with random-textured aluminum-doped zinc oxide (AZO or random-textured 1D-PC with AZO. These two newly-designed BRs demonstrated not only high reflectivity and sufficient conductivity, but also a strong light scattering property, which made them efficient candidates as the electrical contact and back reflector since the intrinsic losses due to the surface plasmon modes of the rough metal BRs can be avoided. Secondly, conical two-dimensional photonic crystal (2D-PC-based BRs were investigated and optimized for amorphous a-SiGe:H solar cells. The maximal absorption value can be obtained with an aspect ratio of 1/2 and a period of 0.75 µm. To improve the full-spectral optical properties of solar cells, a periodically-modulated PC back reflector was proposed and experimentally demonstrated in the a-SiGe:H solar cell. This periodically-modulated PC back reflector, also called the quasi-crystal structure (QCS, consists of a large periodic conical PC and a randomly-textured Ag layer with a feature size of 500–1000 nm. The large periodic conical PC enables conformal growth of the layer, while the small feature size of Ag can further enhance the light scattering. In summary, a comprehensive study of the design, simulation

  10. Modification of thin-layer systems by swift heavy ions

    International Nuclear Information System (INIS)

    Bolse, W.; Schattat, B.; Feyh, A.

    2003-01-01

    The electronic energy loss of swift heavy ions (MeV/amu) within a solid results in a highly excited cylindrical zone of some nm in diameter, within which all atoms may be in motion for some tens of ps (transient local melting). After cooling down, a defect-rich or even amorphous latent track is left in many cases, especially in insulating materials. The resulting property alterations (density, micro-structure, morphology, phase composition, etc.) have been investigated for many bulk materials, while only very few experiments have been carried out with thin-film systems. In the present paper, a summary will be given of our studies on the transport of matter in thin-film packages induced by irradiation with high-energy ions. These is, on the one hand, atomic mixing at the interfaces, which is especially pronounced in ceramic systems and which seems to occur by interdiffusion in the molten ion track. On the other hand, we have discovered a self-organisation phenomenon in swift-heavy-ion-irradiated NiO layers, which at low fluences first showed periodic cracking perpendicular to the projected beam direction. After application of high fluences, the NiO layer was reorganised in 100-nm-thick and 1-μm-high NiO lamellae of the same separation distance (1-3 μm) and orientation as found for the cracks. Both effects can be attributed to transient melting of the material surrounding the ion trajectory. (orig.)

  11. Titanium dioxide thin films by atomic layer deposition: a review

    Science.gov (United States)

    Niemelä, Janne-Petteri; Marin, Giovanni; Karppinen, Maarit

    2017-09-01

    Within its rich phase diagram titanium dioxide is a truly multifunctional material with a property palette that has been shown to span from dielectric to transparent-conducting characteristics, in addition to the well-known catalytic properties. At the same time down-scaling of microelectronic devices has led to an explosive growth in research on atomic layer deposition (ALD) of a wide variety of frontier thin-film materials, among which TiO2 is one of the most popular ones. In this topical review we summarize the advances in research of ALD of titanium dioxide starting from the chemistries of the over 50 different deposition routes developed for TiO2 and the resultant structural characteristics of the films. We then continue with the doped ALD-TiO2 thin films from the perspective of dielectric, transparent-conductor and photocatalytic applications. Moreover, in order to cover the latest trends in the research field, both the variously constructed TiO2 nanostructures enabled by ALD and the Ti-based hybrid inorganic-organic films grown by the emerging ALD/MLD (combined atomic/molecular layer deposition) technique are discussed.

  12. Investigation of thin polymer layers for biosensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Saftics, András; Agócs, Emil [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Fodor, Bálint [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Physics, Faculty of Science, University of Pécs, 7624 Pécs, Ifjúság útja 6 (Hungary); Patkó, Dániel; Petrik, Péter [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary); Kolari, Kai; Aalto, Timo [VTT Technical Research Centre of Finland, PL 1000, Tietotie 3, 02044 Espoo (Finland); Fürjes, Péter [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Horvath, Robert [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary); Kurunczi, Sándor, E-mail: kurunczi.sandor@ttk.mta.hu [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary)

    2013-09-15

    Novel biosensors made of polymers may offer advantages over conventional technology such as possibility of mass production and tunability of the material properties. With the ongoing work on the polymer photonic chip fabrication in our project, simple model samples were tested parallel for future immobilization and accessing conditions for applications in typical aqueous buffers. The model samples consist of a thin, high refractive index polyimide film on top of TEOS on Si wafer. These model samples were measured by in situ spectroscopic ellipsometry using different aqueous buffers. The experiments revealed a high drift in aqueous solutions; the drift in the ellipsometric parameters (delta, psi) can be evaluated and presented as changes in thickness and refractive index of the polyimide layer. The first molecular layer of immobilization is based on polyethyleneimine (PEI). The signal for the PEI adsorption was detected on a stable baseline, only after a long conditioning. The stability of polyimide films in aqueous buffer solutions should be improved toward the real biosensor application. Preliminary results are shown on the possibilities to protect the polyimide. Optical Waveguide Lightmode Spectroscopy (OWLS) has been used to demonstrate the shielding effect of the thin TiO{sub 2} adlayer in biosensor applications.

  13. Thin film silicon on silicon nitride for radiation hardened dielectrically isolated MISFET's

    International Nuclear Information System (INIS)

    Neamen, D.; Shedd, W.; Buchanan, B.

    1975-01-01

    The permanent ionizing radiation effects resulting from charge trapping in a silicon nitride isolation dielectric have been determined for a total ionizing dose up to 10 7 rads (Si). Junction FET's, whose active channel region is directly adjacent to the silicon-silicon nitride interface, were used to measure the effects of the radiation induced charge trapping in the Si 3 N 4 isolation dielectric. The JFET saturation current and channel conductance versus junction gate voltage and substrate voltage were characterized as a function of the total ionizing radiation dose. The experimental results on the Si 3 N 4 are compared to results on similar devices with SiO 2 dielectric isolation. The ramifications of using the silicon nitride for fabricating radiation hardened dielectrically isolated MIS devices are discussed

  14. SIMULATED 8 MeV NEUTRON RESPONSE FUNCTIONS OF A THIN SILICON NEUTRON SENSOR.

    Science.gov (United States)

    Takada, Masashi; Matsumoto, Tetsuro; Masuda, Akihiko; Nunomiya, Tomoya; Aoyama, Kei; Nakamura, Takashi

    2017-12-22

    Neutron response functions of a thin silicon neutron sensor are simulated using PHITS2 and MCNP6 codes for an 8 MeV neutron beam at angles of incidence of 0°, 30° and 60°. The contributions of alpha particles created from the 28Si(n,α)25Mg reaction and the silicon nuclei scattered elastically by neutrons in the silicon sensor have not been well reproduced using the MCNP6 code. The 8 MeV neutron response functions simulated using the PHITS2 code with an accurate event generator mode are in good agreement with experimental results and include the contributions of the alpha particles and silicon nuclei. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Studies on layer growth and interfaces on Ta-base thin layers by means of XPS

    International Nuclear Information System (INIS)

    Zier, M.

    2007-01-01

    In this thesis studies on the growth and on the formation of the interfaces of Ta and TaN layers on Si and SiO 2 were performed. In the system TaN on SiO 2 no reaction on the interface could be found. As the system with the mostly disturbed interface Ta on SiO 2 was proved. Here a reduction of the SiO 2 at simultaneous oxidation of the Ta was to be observed. Additionally tantalum silicide was formed to be considered concerning the bonding state as Ta 5 Si 3 , from which a double layer of a tantalum silicide and a tantalum suboxide resulted. A whole thickness of the double layer of above 1 nm resulted. In the system Ta on Si at the deposition of the film on the interface a tantalum silicide was formed to be characterized concerning the bonding state as TaSi 2 . The thickness of the interlayer growed thereby up to 0.8 nm in form of islands. Finally in the system TaN on Si a silicon nitride formation during the deposition was observed, which was attributed to the insertion of adsorbed nitrogen from the sputtering atmosphere by recoil implantation of the sputtered Ta atoms. The silicon nitride interlayer growed thereby up to a thickness of 0.8 nm

  16. Structural, Electrical and Optical Properties of TiO2 Thin Film Deposited on the Nano Porous Silicon Template

    Science.gov (United States)

    Bahar, Mahmood; Dermani, Ensieh Khalili

    The porous silicon (PSi), which is produced by the electrochemical etching, has been used as a substrate for the growth of the titanium oxide (TiO2) thin films. By using the EBPVD method, TiO2 thin films have been deposited on the surface of the PSi substrate. TiO2/PSi layers were annealed at the temperature of 400∘C, 500∘C and 600∘C for different tests. The morphology and structures of layers were investigated by the scanning electron microscopy (SEM) and X-ray diffraction (XRD). The current-voltage characteristic curves of samples and the ideality factor of heterojunction were studied. The results showed that the electrical properties of the samples change with increase in the annealing temperature. The optical properties of the prepared samples were investigated by using UV-Vis and photoluminescence (PL) spectroscopy. Green light emission of the PSi combined with the blue light and violet-blue emission obtained from the TiO2/PSi PL spectra. The results showed that the optical band gap energy of the PSi has increased from 1.86eV to 2.93eV due to the deposition of TiO2 thin film.

  17. Thermal recrystallization of physical vapor deposition based germanium thin films on bulk silicon (100)

    KAUST Repository

    Hussain, Aftab M.

    2013-08-16

    We demonstrate a simple, low-cost, and scalable process for obtaining uniform, smooth surfaced, high quality mono-crystalline germanium (100) thin films on silicon (100). The germanium thin films were deposited on a silicon substrate using plasma-assisted sputtering based physical vapor deposition. They were crystallized by annealing at various temperatures ranging from 700 °C to 1100 °C. We report that the best quality germanium thin films are obtained above the melting point of germanium (937 °C), thus offering a method for in-situ Czochralski process. We show well-behaved high-κ /metal gate metal-oxide-semiconductor capacitors (MOSCAPs) using this film. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of multi-layered bottom electrodes on the orientation of strontium-doped lead zirconate titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskaran, M. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)], E-mail: madhu.bhaskaran@gmail.com; Sriram, S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia); Mitchell, D.R.G.; Short, K.T. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, New South Wales 2234 (Australia); Holland, A.S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)

    2008-09-30

    This article discusses the results from X-ray diffraction (XRD) analysis of piezoelectric strontium-doped lead zirconate titanate (PSZT) thin films deposited on multi-layer coatings on silicon. The films were deposited by RF magnetron sputtering on a metal coated substrate. The aim was to exploit the pronounced piezoelectric effect that is theoretically expected normal to the substrate. This work highlighted the influence that the bottom electrode architecture exerts on the final crystalline orientation of the deposited thin films. A number of bottom electrode architectures were used, with the uppermost metal layer on which PSZT was deposited being gold or platinum. The XRD analysis revealed that the unit cell of the PSZT thin films deposited on gold and on platinum were deformed, relative to expected unit cell dimensions. Experimental results have been used to estimate the unit cell parameters. The XRD results were then indexed based on these unit cell parameters. The choice and the thickness of the intermediate adhesion layers influenced the relative intensity, and in some cases, the presence of perovskite peaks. In some cases, undesirable reactions between the bottom electrode layers were observed, and layer architectures to overcome these reactions are also discussed.

  19. Ion induced segregation in gold nanostructured thin films on silicon

    International Nuclear Information System (INIS)

    Ghatak, J.; Satyam, P.V.

    2008-01-01

    We report a direct observation of segregation of gold atoms to the near surface regime due to 1.5 MeV Au 2+ ion impact on isolated gold nanostructures deposited on silicon. Irradiation at fluences of 6 x 10 13 , 1 x 10 14 and 5 x 10 14 ions cm -2 at a high beam flux of 6.3 x 10 12 ions cm -2 s -1 show a maximum transported distance of gold atoms into the silicon substrate to be 60, 45 and 23 nm, respectively. At a lower fluence (6 x 10 13 ions cm -2 ) transport has been found to be associated with the formation of gold silicide (Au 5 Si 2 ). At a high fluence value of 5 x 10 14 ions cm -2 , disassociation of gold silicide and out-diffusion lead to the segregation of gold to defect - rich surface and interface regions.

  20. Silicon Dioxide Thin Film Mediated Single Cell Nucleic Acid Isolation

    Science.gov (United States)

    Bogdanov, Evgeny; Dominova, Irina; Shusharina, Natalia; Botman, Stepan; Kasymov, Vitaliy; Patrushev, Maksim

    2013-01-01

    A limited amount of DNA extracted from single cells, and the development of single cell diagnostics make it necessary to create a new highly effective method for the single cells nucleic acids isolation. In this paper, we propose the DNA isolation method from biomaterials with limited DNA quantity in sample, and from samples with degradable DNA based on the use of solid-phase adsorbent silicon dioxide nanofilm deposited on the inner surface of PCR tube. PMID:23874571

  1. Effect of hydrogen passivation on polycrystalline silicon thin films

    Czech Academy of Sciences Publication Activity Database

    Honda, Shinya; Mates, Tomáš; Ledinský, Martin; Oswald, Jiří; Fejfar, Antonín; Kočka, Jan; Yamazaki, T.; Uraoka, Y.; Fuyuki, T.

    2005-01-01

    Roč. 487, - (2005), s. 152-156 ISSN 0040-6090 R&D Projects: GA AV ČR(CZ) IAA1010316; GA AV ČR(CZ) IAA1010413; GA ČR(CZ) GD202/05/H003 Institutional research plan: CEZ:AV0Z10100521 Keywords : hydrogen passivation * polycrystalline silicon * photoluminescence * Raman spectroscopy * Si-H 2 * hydrogen molecules Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.569, year: 2005

  2. Optical properties of uniformly sized silicon nanocrystals within a single silicon oxide layer

    Energy Technology Data Exchange (ETDEWEB)

    En Naciri, A., E-mail: aotmane.en-naciri@univ-lorraine.fr [Universite de Lorraine, LCP-A2MC, Institut Jean Barriol (France); Miska, P. [Universite de Lorraine, Institut Jean Lamour CNRS UMR 7198 (France); Keita, A.-S. [Max Planck Institute for Intelligent Systems (Germany); Battie, Y. [Universite de Lorraine, LCP-A2MC, Institut Jean Barriol (France); Rinnert, H.; Vergnat, M. [Universite de Lorraine, Institut Jean Lamour CNRS UMR 7198 (France)

    2013-04-15

    Silicon nanocrystals (Si-NC) with different sizes (2-6 nm) are synthesized by evaporation. The system is composed of a single Si-NC layer that is well controlled in size. The numerical modeling of such system, without a large size distribution, is suitable to perform easily the optical calculations. The nanocrystal size and confinement effects on the optical properties are determined by photoluminescence (PL) measurements, absorption in the UV visible range, and spectroscopic ellipsometry (SE). The optical constants and the bandgap energies are then extracted and analyzed. The dependence of the optical responses with the decrease of the size of the Si-NC occurs not only with a drastic reduction of the amplitudes of dielectric function but also by a significant expansion of the optical gap. This study supports the idea of a presence of a critical size of Si-NC for which the confinement effect becomes weak. The evolution of those bandgap energies are discussed in comparison with values reported in literature.

  3. Effect of layer thickness on device response of silicon heavily supersaturated with sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, David [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy NY 12180 (United States); Department of Physics and Nuclear Engineering, United States Military Academy, West Point NY 10996 (United States); Mathews, Jay [US Army ARDEC – Benét Laboratories, Watervliet NY 12189 (United States); Department of Physics, University of Dayton, Dayton, OH 45469 (United States); Sullivan, Joseph T.; Buonassisi, Tonio [School of Engineering, Massachusetts Institute of Technology, Cambridge MA 02139 (United States); Akey, Austin [School of Engineering, Massachusetts Institute of Technology, Cambridge MA 02139 (United States); Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge MA 02138 (United States); Aziz, Michael J. [Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge MA 02138 (United States); Persans, Peter [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy NY 12180 (United States); Warrender, Jeffrey M., E-mail: jwarrend@post.harvard.edu [US Army ARDEC – Benét Laboratories, Watervliet NY 12189 (United States)

    2016-05-15

    We report on a simple experiment in which the thickness of a hyperdoped silicon layer, supersaturated with sulfur by ion implantation followed by pulsed laser melting and rapid solidification, is systematically varied at constant average sulfur concentration, by varying the implantation energy, dose, and laser fluence. Contacts are deposited and the external quantum efficiency (EQE) is measured for visible wavelengths. We posit that the sulfur layer primarily absorbs light but contributes negligible photocurrent, and we seek to support this by analyzing the EQE data for the different layer thicknesses in two interlocking ways. In the first, we use the measured concentration depth profiles to obtain the approximate layer thicknesses, and, for each wavelength, fit the EQE vs. layer thickness curve to obtain the absorption coefficient of hyperdoped silicon for that wavelength. Comparison to literature values for the hyperdoped silicon absorption coefficients [S.H. Pan et al. Applied Physics Letters 98, 121913 (2011)] shows good agreement. Next, we essentially run this process in reverse; we fit with Beer’s law the curves of EQE vs. hyperdoped silicon absorption coefficient for those wavelengths that are primarily absorbed in the hyperdoped silicon layer, and find that the layer thicknesses obtained from the fit are in good agreement with the original values obtained from the depth profiles. We conclude that the data support our interpretation of the hyperdoped silicon layer as providing negligible photocurrent at high S concentrations. This work validates the absorption data of Pan et al. [Applied Physics Letters 98, 121913 (2011)], and is consistent with reports of short mobility-lifetime products in hyperdoped layers. It suggests that for optoelectronic devices containing hyperdoped layers, the most important contribution to the above band gap photoresponse may be due to photons absorbed below the hyperdoped layer.

  4. Effect of layer thickness on device response of silicon heavily supersaturated with sulfur

    Directory of Open Access Journals (Sweden)

    David Hutchinson

    2016-05-01

    Full Text Available We report on a simple experiment in which the thickness of a hyperdoped silicon layer, supersaturated with sulfur by ion implantation followed by pulsed laser melting and rapid solidification, is systematically varied at constant average sulfur concentration, by varying the implantation energy, dose, and laser fluence. Contacts are deposited and the external quantum efficiency (EQE is measured for visible wavelengths. We posit that the sulfur layer primarily absorbs light but contributes negligible photocurrent, and we seek to support this by analyzing the EQE data for the different layer thicknesses in two interlocking ways. In the first, we use the measured concentration depth profiles to obtain the approximate layer thicknesses, and, for each wavelength, fit the EQE vs. layer thickness curve to obtain the absorption coefficient of hyperdoped silicon for that wavelength. Comparison to literature values for the hyperdoped silicon absorption coefficients [S.H. Pan et al. Applied Physics Letters 98, 121913 (2011] shows good agreement. Next, we essentially run this process in reverse; we fit with Beer’s law the curves of EQE vs. hyperdoped silicon absorption coefficient for those wavelengths that are primarily absorbed in the hyperdoped silicon layer, and find that the layer thicknesses obtained from the fit are in good agreement with the original values obtained from the depth profiles. We conclude that the data support our interpretation of the hyperdoped silicon layer as providing negligible photocurrent at high S concentrations. This work validates the absorption data of Pan et al. [Applied Physics Letters 98, 121913 (2011], and is consistent with reports of short mobility-lifetime products in hyperdoped layers. It suggests that for optoelectronic devices containing hyperdoped layers, the most important contribution to the above band gap photoresponse may be due to photons absorbed below the hyperdoped layer.

  5. GigaTracker, a Thin and Fast Silicon Pixels Tracker

    CERN Document Server

    Velghe, Bob; Bonacini, Sandro; Ceccucci, Augusto; Kaplon, Jan; Kluge, Alexander; Mapelli, Alessandro; Morel, Michel; Noël, Jérôme; Noy, Matthew; Perktold, Lukas; Petagna, Paolo; Poltorak, Karolina; Riedler, Petra; Romagnoli, Giulia; Chiozzi, Stefano; Cotta Ramusino, Angelo; Fiorini, Massimiliano; Gianoli, Alberto; Petrucci, Ferruccio; Wahl, Heinrich; Arcidiacono, Roberta; Jarron, Pierre; Marchetto, Flavio; Gil, Eduardo Cortina; Nuessle, Georg; Szilasi, Nicolas

    2014-01-01

    GigaTracker, the NA62’s upstream spectrometer, plays a key role in the kinematically constrained background suppression for the study of the K + ! p + n ̄ n decay. It is made of three independent stations, each of which is a six by three cm 2 hybrid silicon pixels detector. To meet the NA62 physics goals, GigaTracker has to address challenging requirements. The hit time resolution must be better than 200 ps while keeping the total thickness of the sensor to less than 0.5 mm silicon equivalent. The 200 μm thick sensor is divided into 18000 300 μm 300 μm pixels bump-bounded to ten independent read-out chips. The chips use an end-of-column architecture and rely on time-over- threshold discriminators. A station can handle a crossing rate of 750 MHz. Microchannel cooling technology will be used to cool the assembly. It allows us to keep the sensor close to 0 C with 130 μm of silicon in the beam area. The sensor and read-out chip performance were validated using a 45 pixel demonstrator with a laser test setu...

  6. Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

    International Nuclear Information System (INIS)

    Gusain, Rashi; Kokufu, Sho; Bakshi, Paramjeet S.; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki; Khatri, Om P.

    2016-01-01

    Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF_6) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF_6 thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF_6 thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF_6 thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF_6 thin film, the covalent interaction between ImPF_6 ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

  7. Retinal Layers Measurements following Silicone Oil Tamponade for Retinal Detachment Surgery.

    Science.gov (United States)

    Jurišić, Darija; Geber, Mia Zorić; Ćavar, Ivan; Utrobičić, Dobrila Karlica

    2017-12-19

    This study aimed to investigate the influence of silicone oil on the retinal nerve fiber layer (RNFL) thickness in patients with primary rhegmatogenous retinal detachment who underwent vitreoretinal surgery. The study included 47 patients (eyes), who underwent a pars plana vitrectomy with the silicone oil tamponade. The control group included unoperated eye of all participants. Spectral-domain optical coherence tomography (SD-OCT) was used for the measurements of peripapilar and macular RNFL thickness. The average peripapillary RNFL thickness was significantly higher in the silicone oil filled eyes during endotamponade and after its removal. The eyes with elevated IOP had less thickening of the RNFL in comparison to the eyes with normal IOP. Central macular thickness and macular volume were decreased in the silicone oil filled eyes in comparison to the control eyes. In conclusion, silicone oil caused peripapilar RNFL thickening in the vitrectomized eyes during endotamponade and after silicone oil removal.

  8. Substrate and p-layer effects on polymorphous silicon solar cells

    Directory of Open Access Journals (Sweden)

    Abolmasov S.N.

    2014-07-01

    Full Text Available The influence of textured transparent conducting oxide (TCO substrate and p-layer on the performance of single-junction hydrogenated polymorphous silicon (pm-Si:H solar cells has been addressed. Comparative studies were performed using p-i-n devices with identical i/n-layers and back reflectors fabricated on textured Asahi U-type fluorine-doped SnO2, low-pressure chemical vapor deposited (LPCVD boron-doped ZnO and sputtered/etched aluminum-doped ZnO substrates. The p-layers were hydrogenated amorphous silicon carbon and microcrystalline silicon oxide. As expected, the type of TCO and p-layer both have a great influence on the initial conversion efficiency of the solar cells. However they have no effect on the defect density of the pm-Si:H absorber layer.

  9. Hadron-therapy beam monitoring: Towards a new generation of ultra-thin p-type silicon strip detectors

    International Nuclear Information System (INIS)

    Bouterfa, M.; Aouadi, K.; Bertrand, D.; Olbrechts, B.; Delamare, R.; Raskin, J. P.; Gil, E. C.; Flandre, D.

    2011-01-01

    Hadron-therapy has gained increasing interest for cancer treatment especially within the last decade. System commissioning and quality assurance procedures impose to monitor the particle beam using 2D dose measurements. Nowadays, several monitoring systems exist for hadron-therapy but all show a relatively high influence on the beam properties: indeed, most devices consist of several layers of materials that degrade the beam through scattering and energy losses. For precise treatment purposes, ultra-thin silicon strip detectors are investigated in order to reduce this beam scattering. We assess the beam size increase provoked by the Multiple Coulomb Scattering when passing through Si, to derive a target thickness. Monte-Carlo based simulations show a characteristic scattering opening angle lower than 1 mrad for thicknesses below 20 μm. We then evaluated the fabrication process feasibility. We successfully thinned down silicon wafers to thicknesses lower than 10 μm over areas of several cm 2 . Strip detectors are presently being processed and they will tentatively be thinned down to 20 μm. Moreover, two-dimensional TCAD simulations were carried out to investigate the beam detector performances on p-type Si substrates. Additionally, thick and thin substrates have been compared thanks to electrical simulations. Reducing the pitch between the strips increases breakdown voltage, whereas leakage current is quite insensitive to strips geometrical configuration. The samples are to be characterized as soon as possible in one of the IBA hadron-therapy facilities. For hadron-therapy, this would represent a considerable step forward in terms of treatment precision. (authors)

  10. Characterization of Nanocrystalline SiGe Thin Film Solar Cell with Double Graded-Dead Absorption Layer

    Directory of Open Access Journals (Sweden)

    Chao-Chun Wang

    2012-01-01

    Full Text Available The nanocrystalline silicon-germanium (nc-SiGe thin films were deposited by high-frequency (27.12 MHz plasma-enhanced chemical vapor deposition (HF-PECVD. The films were used in a silicon-based thin film solar cell with graded-dead absorption layer. The characterization of the nc-SiGe films are analyzed by scanning electron microscopy, UV-visible spectroscopy, and Fourier transform infrared absorption spectroscopy. The band gap of SiGe alloy can be adjusted between 0.8 and 1.7 eV by varying the gas ratio. For thin film solar cell application, using double graded-dead i-SiGe layers mainly leads to an increase in short-circuit current and therefore cell conversion efficiency. An initial conversion efficiency of 5.06% and the stabilized efficiency of 4.63% for an nc-SiGe solar cell were achieved.

  11. Surface plasmons based terahertz modulator consisting of silicon-air-metal-dielectric-metal layers

    Science.gov (United States)

    Wang, Wei; Yang, Dongxiao; Qian, Zhenhai

    2018-05-01

    An optically controlled modulator of the terahertz wave, which is composed of a metal-dielectric-metal structure etched with circular loop arrays on both the metal layers and a photoexcited silicon wafer separated by an air layer, is proposed. Simulation results based on experimentally measured complex permittivities predict that modification of complex permittivity of the silicon wafer through excitation laser leads to a significant tuning of transmission characteristics of the modulator, forming the modulation depths of 59.62% and 96.64% based on localized surface plasmon peak and propagating surface plasmon peak, respectively. The influences of the complex permittivity of the silicon wafer and the thicknesses of both the air layer and the silicon wafer are numerically studied for better understanding the modulation mechanism. This study proposes a feasible methodology to design an optically controlled terahertz modulator with large modulation depth, high speed and suitable insertion loss, which is useful for terahertz applications in the future.

  12. A novel diagnostic approach for studying silicon thin film growth

    NARCIS (Netherlands)

    Hoefnagels, J.P.M.

    2005-01-01

    In the deposition of thin films, the material properties are formed through the interaction of gas phase species with the growing surface. The resulting surface kinetics and chemistry is determined by the reactivity of the different gas phase species as well as by the surface chemical nature and may

  13. Development of A Thin Film Crystalline Silicon Solar Cell

    International Nuclear Information System (INIS)

    Sopori, B.; Chen, W.; Zhang, Y.

    1998-01-01

    A new design for a single junction, thin film Si solar cell is presented. The cell design is compatible with low-temperature processing required for the use of a low-cost glass substrate, and includes effective light trapping and impurity gettering. Elements of essential process steps are discussed

  14. Progress in thin-film silicon solar cells based on photonic-crystal structures

    Science.gov (United States)

    Ishizaki, Kenji; De Zoysa, Menaka; Tanaka, Yoshinori; Jeon, Seung-Woo; Noda, Susumu

    2018-06-01

    We review the recent progress in thin-film silicon solar cells with photonic crystals, where absorption enhancement is achieved by using large-area resonant effects in photonic crystals. First, a definitive guideline for enhancing light absorption in a wide wavelength range (600–1100 nm) is introduced, showing that the formation of multiple band edges utilizing higher-order modes confined in the thickness direction and the introduction of photonic superlattice structures enable significant absorption enhancement, exceeding that observed for conventional random scatterers. Subsequently, experimental evidence of this enhancement is demonstrated for a variety of thin-film Si solar cells: ∼500-nm-thick ultrathin microcrystalline silicon cells, few-µm-thick microcrystalline silicon cells, and ∼20-µm-thick thin single-crystalline silicon cells. The high short-circuit current densities and/or efficiencies observed for each cell structure confirm the effectiveness of using multiple band-edge resonant modes of photonic crystals for enhancing broadband absorption in actual solar cells.

  15. Crystallinity Improvement of Zn O Thin Film on Different Buffer Layers Grown by MBE

    International Nuclear Information System (INIS)

    Shao-Ying, T.; Che-Hao, L.; Wen-Ming, Ch.; Yang, C.C.; Po-Ju, Ch.; Hsiang-Chen, W.; Ya-Ping, H.

    2012-01-01

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

  16. Recrystallization of implanted amorphous silicon layers. I. Electrical properties of silicon implanted with BF+2 or Si++B+

    International Nuclear Information System (INIS)

    Tsai, M.Y.; Streetman, B.G.

    1979-01-01

    Electrical properties of recrystallized amorphous silicon layers, formed by BF + 2 implants or Si + +B + implants, have been studied by differential resistivity and Hall-effect measurements. Electrical carrier distribution profiles show that boron atoms inside the amorphized Si layers can be fully activated during recrystallization at 550 0 C. The mobility is also recovered. However, the tail of the B distribution, located inside a damaged region near the original amorphous-crystalline interface, remains inactive. This inactive tail has been observed for all samples implanted with BF + 2 . Only in a thicker amorphous layer, formed for example by Si + predamage implants, can the entire B profile be activated. The etch rate of amorphous silicon in HF and the effect of fluorine on the recrystallization rate are also reported

  17. Sol–gel derived scattering layers as substrates for thin-film photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Hegmann, Jan [Lehrstuhl für Chemische Technologie der Materialsynthese, Universität Würzburg, Röntgenring 11, 97070 Würzburg (Germany); Mandl, Magdalena [Fraunhofer-Institut für Silicatforschung, Neunerplatz 2, 97082 Würzburg (Germany); Löbmann, Peer, E-mail: peer.loebmann@isc.fraunhofer.de [Fraunhofer-Institut für Silicatforschung, Neunerplatz 2, 97082 Würzburg (Germany)

    2014-08-01

    Agglomerated silica particles were coated on glass by dip-coating; the resulting films exhibited optical scattering. With constant optical transmittances > 80% their haze could be modified by the withdrawal rate applied for the respective deposition procedure. Film thickness, surface topography and coverage of the substrate were characterized by Scanning Electron Microscopy and Atomic Force Microscopy. For the use in radiation management in thin-film silicon solar cells in a first step the scattering layers were coated with aluminum-doped zinc oxide by sputtering; the optical performance of the resulting bilayer was characterized by haze measurements and angle resolved scattering spectroscopy. Quantum efficiencies of complete solar cells could be determined after the deposition of a hydrogenated amorphous Si/hydrogenated microcrystalline Si tandem absorber and application of metallic back contacts. It turned out that the external quantum efficiency of the resulting cells is not directly related to the light scattering performance of the scattering layer used. - Highlights: • Characterization of sol–gel scattering layers • Combination of different coating-technologies to prepare stacks with optical functionality • Comprehensive material preparation and characterization for complex multilayer.

  18. Surface and interface characterization of thin-film silicon solar cell structures

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, Dominic

    2013-02-21

    our Si L{sub 2,3} XES analysis. Spatially resolved x-ray photoelectron spectroscopy data support this and even suggest the formation of sub-oxides or zinc silicate as an interface species. The electronic structure of the buried a-SiO{sub x}:H(B)/ZnO:Al and {mu}c-Si:H(B)/ZnO:Al interfaces are unraveled with ''depth resolved'' hard x-ray photoelectron spectroscopy. A surface band bending limited to the very surface of the silicon layers is found. The valence band maxima for the Si cover layers and the ZnO:Al TCO are determined and interface induced band bending for both interfaces are derived. At the a-SiO{sub x}:H(B)/ZnO:Al interface a tunnel barrier of (0.22 {+-} 0.31) eV and at {mu}c-Si:H(B)/ZnO:Al interface a tunnel barrier of (-0.08 {+-} 0.31) eV is determined. This explains a previously empirically found solar cell efficiency increase produced by introducing a {mu}c-Si:H(B) buffer layer between an a-Si p-i-n cell and the ZnO:Al/glass substrate.

  19. Approximate reflection coefficients for a thin VTI layer

    KAUST Repository

    Hao, Qi

    2017-09-18

    We present an approximate method to derive simple expressions for the reflection coefficients of P- and SV-waves for a thin transversely isotropic layer with a vertical symmetry axis (VTI) embedded in a homogeneous VTI background. The layer thickness is assumed to be much smaller than the wavelengths of P- and SV-waves inside. The exact reflection and transmission coefficients are derived by the propagator matrix method. In the case of normal incidence, the exact reflection and transmission coefficients are expressed in terms of the impedances of vertically propagating P- and S-waves. For subcritical incidence, the approximate reflection coefficients are expressed in terms of the contrast in the VTI parameters between the layer and the background. Numerical examples are designed to analyze the reflection coefficients at normal and oblique incidence, and investigate the influence of transverse isotropy on the reflection coefficients. Despite giving numerical errors, the approximate formulae are sufficiently simple to qualitatively analyze the variation of the reflection coefficients with the angle of incidence.

  20. Thin layer activation technique applied to the measurement of wear

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, P [UKAEA Research Group, Harwell. Atomic Energy Research Establishment

    1978-01-01

    A thin layer of radioactive atoms is produced in the material by bombardment with charged particles, and as the material is worn away the total activity level is monitored. If the activity to depth relationship is then known the amount of material worn away can be determined. By a selective choice of the charged particle species and energy the depth of the active layer, its natural decay rate, and the energy of the emitted radiation can be pre-determined. The Harwell Tandem Electrostatic Generator has been found very suitable for the work. The total activity level can be made as little or as large as required, but a level around 5 to 10 microcuries is usually found to be adequate, and the active layer usually has a depth of 50 to 300 ..mu..m. The activated area can be from < 1 mm/sup 2/ to 4 cm/sup 2/. Particular reference is made to the production of /sup 56/Co in Fe. Experimental arrangements for the irradiation of components are described. Some practical applications undertaken by Harwell for industry are briefly mentioned, including wear of diesel engine valve seatings and fuel injection equipment, engine testing of lubricants, surface loss of rails and railway wheels, wear of gears, wear of graphite bearing materials, and corrosion and erosion of materials. 4 references.

  1. Silicon wafer wettability and aging behaviors: Impact on gold thin-film morphology

    KAUST Repository

    Yang, Xiaoming; Zhong, Zhaowei; Diallo, Elhadj; Wang, Zhihong; Yue, Weisheng

    2014-01-01

    This paper reports on the wettability and aging behaviors of the silicon wafers that had been cleaned using a piranha (3:1 mixture of sulfuric acid (H2SO4, 96%) and hydrogen peroxide (H2O 2, 30%), 120 °C), SC1 (1:1:5 mixture of NH4OH, H 2O2 and H2O, at 80°C) or HF solution (6 parts of 40% NH4F and 1 part of 49% HF, at room temperature) solution, and treated with gaseous plasma. The silicon wafers cleaned using the piranha or SC1 solution were hydrophilic, and the water contact angles on the surfaces would increase along with aging time, until they reached the saturated points of around 70°. The contact angle increase rate of these wafers in a vacuum was much faster than that in the open air, because of loss of water, which was physically adsorbed on the wafer surfaces. The silicon wafers cleaned with the HF solution were hydrophobic. Their contact angle decreased in the atmosphere, while it increased in the vacuum up to 95°. Gold thin films deposited on the hydrophilic wafers were smoother than that deposited on the hydrophobic wafers, because the numerous oxygen groups formed on the hydrophilic surfaces would react with gold adatoms in the sputtering process to form a continuous thin film at the nucleation stage. The argon, nitrogen, oxygen gas plasma treatments could change the silicon wafer surfaces from hydrophobic to hydrophilic by creating a thin (around 2.5 nm) silicon dioxide film, which could be utilized to improve the roughness and adhesion of the gold thin film. © 2014 Elsevier Ltd. All rights reserved.

  2. Silicon wafer wettability and aging behaviors: Impact on gold thin-film morphology

    KAUST Repository

    Yang, Xiaoming

    2014-10-01

    This paper reports on the wettability and aging behaviors of the silicon wafers that had been cleaned using a piranha (3:1 mixture of sulfuric acid (H2SO4, 96%) and hydrogen peroxide (H2O 2, 30%), 120 °C), SC1 (1:1:5 mixture of NH4OH, H 2O2 and H2O, at 80°C) or HF solution (6 parts of 40% NH4F and 1 part of 49% HF, at room temperature) solution, and treated with gaseous plasma. The silicon wafers cleaned using the piranha or SC1 solution were hydrophilic, and the water contact angles on the surfaces would increase along with aging time, until they reached the saturated points of around 70°. The contact angle increase rate of these wafers in a vacuum was much faster than that in the open air, because of loss of water, which was physically adsorbed on the wafer surfaces. The silicon wafers cleaned with the HF solution were hydrophobic. Their contact angle decreased in the atmosphere, while it increased in the vacuum up to 95°. Gold thin films deposited on the hydrophilic wafers were smoother than that deposited on the hydrophobic wafers, because the numerous oxygen groups formed on the hydrophilic surfaces would react with gold adatoms in the sputtering process to form a continuous thin film at the nucleation stage. The argon, nitrogen, oxygen gas plasma treatments could change the silicon wafer surfaces from hydrophobic to hydrophilic by creating a thin (around 2.5 nm) silicon dioxide film, which could be utilized to improve the roughness and adhesion of the gold thin film. © 2014 Elsevier Ltd. All rights reserved.

  3. Characteristics of thin-film transistors based on silicon nitride passivation by excimer laser direct patterning

    International Nuclear Information System (INIS)

    Chen, Chao-Nan; Huang, Jung-Jie

    2013-01-01

    This study explored the removal of silicon nitride using KrF laser ablation technology with a high threshold fluence of 990 mJ/cm 2 . This technology was used for contact hole patterning to fabricate SiN x -passivation-based amorphous-silicon thin films in a transistor device. Compared to the photolithography process, laser direct patterning using KrF laser ablation technology can reduce the number of process steps by at least three. Experimental results showed that the mobility and threshold voltages of thin film transistors patterned using the laser process were 0.16 cm 2 /V-sec and 0.2 V, respectively. The device performance and the test results of gate voltage stress reliability demonstrated that laser direct patterning is a promising alternative to photolithography in the panel manufacturing of thin-film transistors for liquid crystal displays. - Highlights: ► KrF laser ablation technology is used to remove silicon nitride. ► A simple method for direct patterning contact-hole in thin-film-transistor device. ► Laser technology reduced processing by at least three steps

  4. Underpotential deposition-mediated layer-by-layer growth of thin films

    Science.gov (United States)

    Wang, Jia Xu; Adzic, Radoslav R.

    2015-05-19

    A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves the use of underpotential deposition of a first element to mediate the growth of a second material by overpotential deposition. Deposition occurs between a potential positive to the bulk deposition potential for the mediating element where a full monolayer of mediating element forms, and a potential which is less than, or only slightly greater than, the bulk deposition potential of the material to be deposited. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis. This process is especially suitable for the formation of a catalytically active layer on core-shell particles for use in energy conversion devices such as fuel cells.

  5. Local photoconductivity of microcrystalline silicon thin films measured by conductive atomic force microscopy

    Czech Academy of Sciences Publication Activity Database

    Ledinský, Martin; Fejfar, Antonín; Vetushka, Aliaksi; Stuchlík, Jiří; Rezek, Bohuslav; Kočka, Jan

    2011-01-01

    Roč. 5, 10-11 (2011), s. 373-375 ISSN 1862-6254 R&D Projects: GA MŠk(CZ) LC06040; GA MŠk(CZ) MEB061012; GA AV ČR KAN400100701; GA MŠk LC510 EU Projects: European Commission(XE) 240826 - PolySiMode Institutional research plan: CEZ:AV0Z10100521 Keywords : amorphous silicon * nanocrystalline silicon * thin films * atomic force microscopy * photoconductivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.218, year: 2011

  6. Mass transfer in silicon at deposition of Ti thin films assisted by self ion irradiation

    International Nuclear Information System (INIS)

    Mikhalkovich, O.M.; Tashlykov, I.S.; Gusakov, V.E.

    2011-01-01

    In this paper a composite structure, processes of diffusion in Si, modified by means of ion-assisted deposition of coatings in conditions of a self-irradiation are discussed. Rutherford backscattering in combination with a channelling (RBS/Ch) of He + ions and computer program RUMP were applied to investigate an element composition. It is established, that coatings include atoms of metal, hydrogen, carbon, oxygen, silicon. The interstitial Si atoms, generated by radiation effect, diffuse during deposition of thin coating, both in a depth of a wafers, and in coatings. The influence of irradiation of ions Xe+ on diffusion processes in silicon are revealed. (authors)

  7. Laser annealed HWCVD and PECVD thin silicon films. Electron field emission

    International Nuclear Information System (INIS)

    O'Neill, K.A.; Shaikh, M.Z.; Lyttle, G.; Anthony, S.; Fan, Y.C.; Persheyev, S.K.; Rose, M.J.

    2006-01-01

    Electron Field Emission (FE) properties of various laser annealed thin silicon films on different substrates were investigated. HWCVD microcrystalline and PECVD amorphous silicon films were irradiated with Nd : YAG and XeCl Excimer lasers at varying energy densities. Encouraging FE results were mainly from XeCl Excimer laser processed PECVD and HWCVD films on metal backplanes. FE measurements were complemented by the study of film surface morphology. Geometric field enhancement factors from surface measurements and Fowler-Nordheim Theory (FNT) were compared. FE properties of the films were also found to be particularly influenced by the backplane material

  8. Geometric photovoltaics applied to amorphous silicon thin film solar cells

    Science.gov (United States)

    Kirkpatrick, Timothy

    Geometrically generalized analytical expressions for device transport are derived from first principles for a photovoltaic junction. Subsequently, conventional planar and unconventional coaxial and hemispherical photovoltaic architectures are applied to detail the device physics of the junction based on their respective geometry. For the conventional planar cell, the one-dimensional transport equations governing carrier dynamics are recovered. For the unconventional coaxial and hemispherical junction designs, new multi-dimensional transport equations are revealed. Physical effects such as carrier generation and recombination are compared for each cell architecture, providing insight as to how non-planar junctions may potentially enable greater energy conversion efficiencies. Numerical simulations are performed for arrays of vertically aligned, nanostructured coaxial and hemispherical amorphous silicon solar cells and results are compared to those from simulations performed for the standard planar junction. Results indicate that fundamental physical changes in the spatial dependence of the energy band profile across the intrinsic region of an amorphous silicon p-i-n junction manifest as an increase in recombination current for non-planar photovoltaic architectures. Despite an increase in recombination current, however, the coaxial architecture still appears to be able to surpass the efficiency predicted for the planar geometry, due to the geometry of the junction leading to a decoupling of optics and electronics.

  9. Passivating electron contact based on highly crystalline nanostructured silicon oxide layers for silicon solar cells

    Czech Academy of Sciences Publication Activity Database

    Stuckelberger, J.; Nogay, G.; Wyss, P.; Jeangros, Q.; Allebe, Ch.; Debrot, F.; Niquille, X.; Ledinský, Martin; Fejfar, Antonín; Despeisse, M.; Haug, F.J.; Löper, P.; Ballif, C.

    2016-01-01

    Roč. 158, Dec (2016), s. 2-10 ISSN 0927-0248 R&D Projects: GA MŠk LM2015087 Institutional support: RVO:68378271 Keywords : surface passivation * passivating contact * nanostructure * silicon oxide * nanocrystalline * microcrystalline * poly-silicon * crystallization * Raman * transmission line measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.784, year: 2016

  10. Investigation of Processes and Factors Regulating the Generation, Maintenance and Breakdown of Bioluminescent Thin Layers

    National Research Council Canada - National Science Library

    Widder, Edith

    2001-01-01

    .... Katz's submersible holographic camera mounted on the upper work platform. Thin layers were located using real-time sensor feedback from intensified video recordings of stimulated bioluminescence...

  11. Surface PIXE analysis of phosphorus in a thin SiO2 (P, B) CVD layer deposited onto Si substrate

    International Nuclear Information System (INIS)

    Roumie, M.; Nsouli, B.

    2001-01-01

    Phosphorus determination, at level of percent, in Si matrix is not an easy analytical task. The analyzed materials arc Borophosphosilicate glass which are an important component of silicon based semiconductor technology. It's a thin SiO2 layer (400 nm) doped with boron and phosphorus using, in general, CVD (Chemical Vapor Deposition) process, in order to improve its plasticity, and deposited onto Si substrate. Therefore, the mechanical behaviour of the CVD SiO2 (P, B) layer is very sensitive to the phosphorus concentration. In this work we explore the capability of FIXE (Particle Induced X-ray Emission) to monitor a rapid and accurate quantification of P which is usually very low in such materials (few percent of the thin CVD layer deposited onto a silicon substrate). A systematic study is undertaken using Proton (0.5-3 MeV energy) and helium (1-3 MeV energy) beams, different thickness of X-ray absorber (131 and 146 μm of Kapton filter) and different tilting angles (0,45,60 and 80 deg.). The optimized measurement conditions should improve the P signal detection comparing to the Si and Background ones

  12. The thin layer activation method and its applications in industry

    International Nuclear Information System (INIS)

    1997-01-01

    The thin layer activation (TLA) method is one of the most effective and precise methods for the measurement and monitoring of corrosion (erosion) and wear in industry and is used for on-line remote measurement of wear and corrosion rate of central parts in machines or processing vessels under real operating conditions. This document is a comprehensive manual on TLA method in its applications for monitoring wear and corrosion in industry. It describes the theory and presents case studies on TLA method applications in industry. In addition, in annexes are given tables of nuclear data relating to TLA (decay characteristics, depth distribution of reaction products, activation data for charged-particle nuclear reactions), references from INIS database on TLA and a detailed production of the application of TLA for wear measurement of superhard turning tools

  13. Thin layer modelling of Gelidium sesquipedale solar drying process

    International Nuclear Information System (INIS)

    Ait Mohamed, L.; Ethmane Kane, C.S.; Kouhila, M.; Jamali, A.; Mahrouz, M.; Kechaou, N.

    2008-01-01

    The effect of air temperature and air flow rate on the drying kinetics of Gelidium sesquipedale was investigated in convective solar drying. Drying was conducted at 40, 50 and 60 deg. C. The relative humidity was varied from 50% to 57%, and the drying air flow rate was varied from 0.0277 to 0.0833 m 3 /s. The expression for the drying rate equation is determined empirically from the characteristic drying curve. Thirteen mathematical models of thin layer drying are selected in order to estimate the suitable model for describing the drying curves. The two term model gives the best prediction of the drying curves and satisfactorily describes the drying characteristics of G. sesquipedale with a correlation coefficient R of 0.9999 and chi-square (χ 2 ) of 3.381 x 10 -6

  14. Thin layer modelling of Gelidium sesquipedale solar drying process

    Energy Technology Data Exchange (ETDEWEB)

    Ait Mohamed, L. [Laboratoire d' Energie Solaire et des Plantes Aromatiques et Medicinales, Ecole Normale Superieure, BP 2400, Marrakech (Morocco); Faculte des Sciences Semlalia, BP 2390, Marrakech (Morocco); Ethmane Kane, C.S. [Faculte des Sciences de Tetouan, BP 2121, Tetouan (Morocco); Kouhila, M.; Jamali, A. [Laboratoire d' Energie Solaire et des Plantes Aromatiques et Medicinales, Ecole Normale Superieure, BP 2400, Marrakech (Morocco); Mahrouz, M. [Faculte des Sciences Semlalia, BP 2390, Marrakech (Morocco); Kechaou, N. [Ecole Nationale d' Ingenieurs de Sfax, BPW 3038 (Tunisia)

    2008-05-15

    The effect of air temperature and air flow rate on the drying kinetics of Gelidium sesquipedale was investigated in convective solar drying. Drying was conducted at 40, 50 and 60 C. The relative humidity was varied from 50% to 57%, and the drying air flow rate was varied from 0.0277 to 0.0833 m{sup 3}/s. The expression for the drying rate equation is determined empirically from the characteristic drying curve. Thirteen mathematical models of thin layer drying are selected in order to estimate the suitable model for describing the drying curves. The two term model gives the best prediction of the drying curves and satisfactorily describes the drying characteristics of G. sesquipedale with a correlation coefficient R of 0.9999 and chi-square ({chi}{sup 2}) of 3.381 x 10{sup -6}. (author)

  15. Robotic thin layer chromatography instrument for synthetic chemistry

    International Nuclear Information System (INIS)

    Corkan, L.A.; Haynes, E.; Kline, S.; Lindsey, J.S.

    1991-01-01

    We have constructed a second generation instrument for performing automated thin layer chromatography (TLC), The TLC instrument Consists of four dedicated stations for (1) plate dispensing, (2) sample application, (3) plate development, and (4) densitometry. A robot is used to move TLC plates among stations. The TLC instrument functions either as a stand-alone unit or as one analytical module in a robotic workstation for synthetic chemistry. An integrated hardware and software architecture enables automatic TLC analysis of samples produced concurrently from synthetic reactions in progress on the workstation. The combination of fixed automation and robotics gives a throughput of 12 TLC samples per hour. From these results a blueprint has emerged for an advanced automated TLC instrument with far greater throughput and analytical capabilities

  16. The thin layer activation method and its applications in industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    The thin layer activation (TLA) method is one of the most effective and precise methods for the measurement and monitoring of corrosion (erosion) and wear in industry and is used for on-line remote measurement of wear and corrosion rate of central parts in machines or processing vessels under real operating conditions. This document is a comprehensive manual on TLA method in its applications for monitoring wear and corrosion in industry. It describes the theory and presents case studies on TLA method applications in industry. In addition, in annexes are given tables of nuclear data relating to TLA (decay characteristics, depth distribution of reaction products, activation data for charged-particle nuclear reactions), references from INIS database on TLA and a detailed production of the application of TLA for wear measurement of superhard turning tools.

  17. Plasma enhanced atomic layer deposited MoOx emitters for silicon heterojunction solar cells

    OpenAIRE

    Ziegler, J.; Mews, M.; Kaufmann, K.; Schneider, T.; Sprafke, A.N.; Korte, L.; Wehrsporn, R.B

    2015-01-01

    A method for the deposition of molybdenum oxide MoOx with high growth rates at temperatures below 200 C based on plasma enhanced atomic layer deposition is presented. The stoichiometry of the overstoichiometric MoOx films can be adjusted by the plasma parameters. First results of these layers acting as hole selective contacts in silicon heterojunction solar cells are presented and discussed

  18. Ultra thin buried oxide layers formed by low dose Simox process

    Energy Technology Data Exchange (ETDEWEB)

    Aspar, B.; Pudda, C.; Papon, A.M. [CEA Centre d`Etudes de Grenoble, 38 (France). Lab. d`Electronique et d`Instrumentation; Auberton Herve, A.J.; Lamure, J.M. [SOITEC, 38 - Grenoble (France)

    1994-12-31

    Oxygen low dose implantation is studied for two implantation energies. For 190 keV, a continuous buried oxide layer is obtained with a high dislocation density in the top silicon layer due to SiO{sub 2} precipitates. For 120 keV, this silicon layer is free of SiO{sub 2} precipitate and has a low dislocation density. Low density of pin-holes is observed in the buried oxide. The influence of silicon islands in the buried oxide on the breakdown electric fields is discussed. (authors). 6 refs., 5 figs.

  19. Ultra thin buried oxide layers formed by low dose Simox process

    International Nuclear Information System (INIS)

    Aspar, B.; Pudda, C.; Papon, A.M.

    1994-01-01

    Oxygen low dose implantation is studied for two implantation energies. For 190 keV, a continuous buried oxide layer is obtained with a high dislocation density in the top silicon layer due to SiO 2 precipitates. For 120 keV, this silicon layer is free of SiO 2 precipitate and has a low dislocation density. Low density of pin-holes is observed in the buried oxide. The influence of silicon islands in the buried oxide on the breakdown electric fields is discussed. (authors). 6 refs., 5 figs

  20. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  1. In-situ determination of the effective absorbance of thin μc-Si:H layers growing on rough ZnO:Al

    Directory of Open Access Journals (Sweden)

    Meier Matthias

    2013-10-01

    Full Text Available In this study optical transmission measurements were performed in-situ during the growth of microcrystalline silicon (μc-Si:H layers by plasma enhanced chemical vapor deposition (PECVD. The stable plasma emission was used as light source. The effective absorption coefficient of the thin μc-Si:H layers which were deposited on rough transparent conductive oxide (TCO surfaces was calculated from the transient transmission signal. It was observed that by increasing the surface roughness of the TCO, the effective absorption coefficient increases which can be correlated to the increased light scattering effect and thus the enhanced light paths inside the silicon. A correlation between the in-situ determined effective absorbance of the μc-Si:H absorber layer and the short-circuit current density of μc-Si:H thin-film silicon solar cells was found. Hence, an attractive technique is demonstrated to study, on the one hand, the absorbance and the light trapping in thin films depending on the roughness of the substrate and, on the other hand, to estimate the short-circuit current density of thin-film solar cells in-situ, which makes the method interesting as a process control tool.

  2. High performance thin layer chromatography profile of Cassytha filiformis

    Institute of Scientific and Technical Information of China (English)

    Mythili Sathiavelu; Sathiavelu Arunachalam

    2012-01-01

    Objective: To study the phenols, flavonoids, saponin profile of the medicinal plant Cassytha filiformis (C. filiformis) using high performance thin layer chromatography (HPTLC). Methods:The extracts were tested to determine the presence of various phytochmeicals like alkaloids, phenolic compounds, flavonoids, carbohydrates, glycosides, saponins, terpenoids, tannins, fixed oils, fats and protein and aminoacids (Harborne and Harborne, 1998). HPTLC studies were carried out by Harborne and Wagner et al method. Different compositions of the mobile phase for HPTLC analysis were tested in order to obtain high resolution and reproducible peaks. Results: The results of the preliminary phytochemical studies confirm the presence of phenols, alkaloids, carbohydrates, saponins, flavanoids, terpenoids and tannins in the methanolic extracts of C. filiformis. The methanolic extracts of C. filiformis displayed the presence of 13 types of phenolic substances with 13 different Rf values ranging from 0.01 to 0.96. The results illustrated the presence of 9 different types of flavonoides with 9 different Rf values ranging from 0.01 to 0.97. The results of HPTLC analysis of saponins demonstrated the presence of 11 different types of saponins with 11 different Rf values ranging from 0.04 to 0.92. Conclusions: In the present study we observed the phenols, flavonoids, saponin profile of the medicinal plant C. filiformis using high performance thin layer chromatography (HPTLC). Hence it was concluded that the phenolic compounds present in the methonolic extract could be responsible for antioxidant activities. Plant derived antioxidants, especially phenols and flavonoids, have been described to have various properties like anticancer, antiaging and prevention of cardiovascular diseases. Furthur, separation and characterization of the bioactive compound from the plant is to be evaluated and reported in near future.

  3. Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Kirill O. Bugaev

    2012-01-01

    Full Text Available Vibrational properties of hydrogenated silicon-rich nitride (SiN:H of various stoichiometry (0.6≤≤1.3 and hydrogenated amorphous silicon (a-Si:H films were studied using Raman spectroscopy and Fourier transform infrared spectroscopy. Furnace annealing during 5 hours in Ar ambient at 1130∘C and pulse laser annealing were applied to modify the structure of films. Surprisingly, after annealing with such high-thermal budget, according to the FTIR data, the nearly stoichiometric silicon nitride film contains hydrogen in the form of Si–H bonds. From analysis of the FTIR data of the Si–N bond vibrations, one can conclude that silicon nitride is partly crystallized. According to the Raman data a-Si:H films with hydrogen concentration 15% and lower contain mainly Si–H chemical species, and films with hydrogen concentration 30–35% contain mainly Si–H2 chemical species. Nanosecond pulse laser treatments lead to crystallization of the films and its dehydrogenization.

  4. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Directory of Open Access Journals (Sweden)

    Moulin Etienne

    2015-01-01

    Full Text Available The optical and electrical properties of transparent conductive oxides (TCOs, traditionally used in thin-film silicon (TF-Si solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-μm-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  5. Pulsed Laser Deposition of Zinc Sulfide Thin Films on Silicon: The influence of substrate orientation and preparation on thin film morphology and texture

    OpenAIRE

    Heimdal, Carl Philip J

    2014-01-01

    The effect of orientation and preparation of silicon substrates on the growth morphology and crystalline structure of ZnS thin films deposited by pulsed laser deposition (PLD) has been investigated through scanning electron microscopy (SEM) and grazing incidence x-ray diffraction (GIXRD). ZnS thin films were grown on silicon (100) and (111), on HF-treated and untreated silicon (100) as well as substrates coated with Al, Ge and Au. The ZnS films showed entirely different morphologies for ZnS f...

  6. Structure and field emission of graphene layers on top of silicon nanowire arrays

    International Nuclear Information System (INIS)

    Huang, Bohr-Ran; Chan, Hui-Wen; Jou, Shyankay; Chen, Guan-Yu; Kuo, Hsiu-An; Song, Wan-Jhen

    2016-01-01

    Graphical abstract: - Highlights: • We prepared graphene on top of silicon nanowires by transfer-print technique. • Graphene changed from discrete flakes to a continuous by repeated transfer-print. • The triple-layer graphene had high electron field emission due to large edge ratio. - Abstract: Monolayer graphene was grown on copper foils and then transferred on planar silicon substrates and on top of silicon nanowire (SiNW) arrays to form single- to quadruple-layer graphene films. The morphology, structure, and electron field emission (FE) of these graphene films were investigated. The graphene films on the planar silicon substrates were continuous. The single- to triple-layer graphene films on the SiNW arrays were discontinuous and while the quadruple-layer graphene film featured a mostly continuous area. The Raman spectra of the graphene films on the SiNW arrays showed G and G′ bands with a singular-Lorentzian shape together with a weak D band. The D band intensity decreased as the number of graphene layers increased. The FE efficiency of the graphene films on the planar silicon substrates and the SiNW arrays varied with the number of graphene layers. The turn-on field for the single- to quadruple-layer graphene films on planar silicon substrates were 4.3, 3.7, 3.5 and 3.4 V/μm, respectively. The turn-on field for the single- to quadruple-layer graphene films on SiNW arrays decreased to 3.9, 3.3, 3.0 and 3.3 V/μm, respectively. Correlation of the FE with structure and morphology of the graphene films is discussed.

  7. Structure and field emission of graphene layers on top of silicon nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Bohr-Ran; Chan, Hui-Wen [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Jou, Shyankay, E-mail: sjou@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Chen, Guan-Yu [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Kuo, Hsiu-An; Song, Wan-Jhen [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China)

    2016-01-30

    Graphical abstract: - Highlights: • We prepared graphene on top of silicon nanowires by transfer-print technique. • Graphene changed from discrete flakes to a continuous by repeated transfer-print. • The triple-layer graphene had high electron field emission due to large edge ratio. - Abstract: Monolayer graphene was grown on copper foils and then transferred on planar silicon substrates and on top of silicon nanowire (SiNW) arrays to form single- to quadruple-layer graphene films. The morphology, structure, and electron field emission (FE) of these graphene films were investigated. The graphene films on the planar silicon substrates were continuous. The single- to triple-layer graphene films on the SiNW arrays were discontinuous and while the quadruple-layer graphene film featured a mostly continuous area. The Raman spectra of the graphene films on the SiNW arrays showed G and G′ bands with a singular-Lorentzian shape together with a weak D band. The D band intensity decreased as the number of graphene layers increased. The FE efficiency of the graphene films on the planar silicon substrates and the SiNW arrays varied with the number of graphene layers. The turn-on field for the single- to quadruple-layer graphene films on planar silicon substrates were 4.3, 3.7, 3.5 and 3.4 V/μm, respectively. The turn-on field for the single- to quadruple-layer graphene films on SiNW arrays decreased to 3.9, 3.3, 3.0 and 3.3 V/μm, respectively. Correlation of the FE with structure and morphology of the graphene films is discussed.

  8. Conformity and structure of titanium oxide films grown by atomic layer deposition on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jogi, Indrek [University of Tartu, Institute of Experimental Physics and Technology, Taehe 4, 51010, Tartu (Estonia)], E-mail: indrek.jogi@ut.ee; Paers, Martti; Aarik, Jaan; Aidla, Aleks [University of Tartu, Institute of Physics, Riia 142, 51014, Tartu (Estonia); Laan, Matti [University of Tartu, Institute of Experimental Physics and Technology, Taehe 4, 51010, Tartu (Estonia); Sundqvist, Jonas; Oberbeck, Lars; Heitmann, Johannes [Qimonda Dresden GmbH and Co. OHG, Koenigsbruecker Strasse 180, 01099, Dresden (Germany); Kukli, Kaupo [University of Tartu, Institute of Experimental Physics and Technology, Taehe 4, 51010, Tartu (Estonia)

    2008-06-02

    Conformity and phase structure of atomic layer deposited TiO{sub 2} thin films grown on silicon substrates were studied. The films were grown using TiCl{sub 4} and Ti(OC{sub 2}H{sub 5}){sub 4} as titanium precursors in the temperature range from 125 to 500 {sup o}C. In all cases perfect conformal growth was achieved on patterned substrates with elliptical holes of 7.5 {mu}m depth and aspect ratio of about 1:40. Conformal growth was achieved with process parameters similar to those optimized for the growth on planar wafers. The dominant crystalline phase in the as-grown films was anatase, with some contribution from rutile at relatively higher temperatures. Annealing in the oxygen ambient resulted in (re)crystallization whereas the effect of annealing depended markedly on the precursors used in the deposition process. Compared to films grown from TiCl{sub 4}, the films grown from Ti(OC{sub 2}H{sub 5}){sub 4} were transformed into rutile in somewhat greater extent, whereas in terms of step coverage the films grown from Ti(OC{sub 2}H{sub 5}){sub 4} remained somewhat inferior compared to the films grown from TiCl{sub 4}.

  9. Synthesis of Si epitaxial layers from technical silicon by liquid-phase epitaxy method

    International Nuclear Information System (INIS)

    Ibragimov, Sh.I.; Saidov, A.S.; Sapaev, B.; Horvat, M.A.

    2004-01-01

    Full text: For today silicon is one of the most suitable materials because it is investigated, cheap and several its parameters are even just as good as those of connections A III B V . Disintegration of the USSR has led to the must difficult position of the industry of silicon instrument manufacture because of all industry of semiconductor silicon manufacture had generally concentrated in Ukraine. The importance of semiconductor silicon is rather great, because of, in opinion of expects, the nearest decade this material will dominate over not only on microelectronics but also in the majority of basic researches. Research of obtain of semiconductor silicon, power electronics and solar conversion, is topical interest of the science. In the work research of technological conditions of obtain and measurement of parameters of epitaxial layers obtained from technical silicon + stannum is resulted. Growth of silicon epitaxial layer with suitable parameters on thickness, cleanliness uniformity and structural perfection depends on the correct choice of condition of the growth and temperature. It is shown that in this case the growth occurring without preliminary clearing of materials (mix materials and substrates) at crystallization of epitaxial layer from technical silicon is accompanied by clearing of silicon film from majority of impurities order-of-magnitude. As starting raw material technical silicon of mark Kr.3 has been taken. By means of X-ray microanalyzer 'Jeol' JSM 5910 LV - Japan the quantitative analysis from the different points has been and from the different sides and from different points has been carried out. After corresponding chemical and mechanical processing the quantitative analysis of layer on chip has been carried out. Results of the quantitative analysis are shown. More effective clearing occurs that of the impurity atoms such as Al, P, Ca, Ti and Fe. The obtained material (epitaxial layer) has the parameters: specific resistance ρ∼0.1-4.0

  10. The Acoustical Durability of Thin Noise Reducing Asphalt Layers

    Directory of Open Access Journals (Sweden)

    Cedric Vuye

    2016-05-01

    Full Text Available Within the context of the European Noise Directive, traffic noise action plans have been established. One of those actions is to deepen the knowledge about low noise roads, as they are considered the most cost-efficient measure for traffic noise abatement. Therefore, ten test sections were installed in May 2012 in Belgium, with the objective of integrating Thin noise-reducing Asphalt Layers (TAL in the Flemish road surface policy in a later stage. Eight test sections are paved with TAL with a thickness of a maximum of 30 mm and a maximum content of accessible voids of 18%. The other two sections consist of a Double-layer Porous Asphalt Concrete (DPAC and a Stone Mastic Asphalt (SMA-10 as a reference section. The acoustical quality of the asphalt surfaces has been monitored in time using Statistical Pass-By (SPB and Close-ProXimity (CPX measurements up to 34 months after construction. Texture measurements performed with a laser profilometer are linked to the noise measurement results. Very promising initial noise reductions were found, up to 6 dB(A, but higher than expected acoustic deterioration rates and the presence of raveling led to noise reductions of a max. of 1 dB(A after almost three years. It is shown that the construction process itself has a large influence on the acoustical quality over time.

  11. Thin Layer Sensory Cues Affect Antarctic Krill Swimming Kinematics

    Science.gov (United States)

    True, A. C.; Webster, D. R.; Weissburg, M. J.; Yen, J.

    2013-11-01

    A Bickley jet (laminar, planar free jet) is employed in a recirculating flume system to replicate thin shear and phytoplankton layers for krill behavioral assays. Planar laser-induced fluorescence (LIF) and particle image velocimetry (PIV) measurements quantify the spatiotemporal structure of the chemical and free shear layers, respectively, ensuring a close match to in situ hydrodynamic and biochemical conditions. Path kinematics from digitized trajectories of free-swimming Euphausia superba examine the effects of hydrodynamic sensory cues (deformation rate) and bloom level phytoplankton patches (~1000 cells/mL, Tetraselamis spp.) on krill behavior (body orientation, swimming modes and kinematics, path fracticality). Krill morphology is finely tuned for receiving and deciphering both hydrodynamic and chemical information that is vital for basic life processes such as schooling behaviors, predator/prey, and mate interactions. Changes in individual krill behavior in response to ecologically-relevant sensory cues have the potential to produce population-scale phenomena with significant ecological implications. Krill are a vital trophic link between primary producers (phytoplankton) and larger animals (seabirds, whales, fish, penguins, seals) as well as the subjects of a valuable commercial fishery in the Southern Ocean; thus quantifying krill behavioral responses to relevant sensory cues is an important step towards accurately modeling Antarctic ecosystems.

  12. Fabricating 40 µm-thin silicon solar cells with different orientations by using SLiM-cut method

    Science.gov (United States)

    Wang, Teng-Yu; Chen, Chien-Hsun; Shiao, Jui-Chung; Chen, Sung-Yu; Du, Chen-Hsun

    2017-10-01

    Thin silicon foils with different crystal orientations were fabricated using the stress induced lift-off (SLiM-cut) method. The thickness of the silicon foils was approximately 40 µm. The ≤ft foil had a smoother surface than the ≤ft foil. With surface passivation, the minority carrier lifetimes of the ≤ft and ≤ft silicon foil were 1.0 µs and 1.6 µs, respectively. In this study, 4 cm2-thin silicon solar cells with heterojunction structures were fabricated. The energy conversion efficiencies were determined to be 10.74% and 14.74% for the ≤ft and ≤ft solar cells, respectively. The surface quality of the silicon foils was determined to affect the solar cell character. This study demonstrated that fabricating the solar cell by using silicon foil obtained from the SLiM-cut method is feasible.

  13. Nanostructured thin films for multibandgap silicon triple junction solar cells

    NARCIS (Netherlands)

    Schropp, R.E.I.; Li, H. B. T.; Franken, R.H.; Rath, J.K.; van der Werf, C.H.M.; Schuttauf, J.A.; Stolk, R.L.

    2009-01-01

    A considerable improvement in performance has been achieved for multibandgap proto-Si/proto-SiGe/nc-Si:H triple junction n–i–p solar cells in which hot-wire chemical vapor deposition (HWCVD) is used to obtain the absorber layers of the bottom and the top cell. To achieve this, optimized Ag/ZnO

  14. Graphene Quantum Dot Layers with Energy-Down-Shift Effect on Crystalline-Silicon Solar Cells.

    Science.gov (United States)

    Lee, Kyung D; Park, Myung J; Kim, Do-Yeon; Kim, Soo M; Kang, Byungjun; Kim, Seongtak; Kim, Hyunho; Lee, Hae-Seok; Kang, Yoonmook; Yoon, Sam S; Hong, Byung H; Kim, Donghwan

    2015-09-02

    Graphene quantum dot (GQD) layers were deposited as an energy-down-shift layer on crystalline-silicon solar cell surfaces by kinetic spraying of GQD suspensions. A supersonic air jet was used to accelerate the GQDs onto the surfaces. Here, we report the coating results on a silicon substrate and the GQDs' application as an energy-down-shift layer in crystalline-silicon solar cells, which enhanced the power conversion efficiency (PCE). GQD layers deposited at nozzle scan speeds of 40, 30, 20, and 10 mm/s were evaluated after they were used to fabricate crystalline-silicon solar cells; the results indicate that GQDs play an important role in increasing the optical absorptivity of the cells. The short-circuit current density was enhanced by about 2.94% (0.9 mA/cm(2)) at 30 mm/s. Compared to a reference device without a GQD energy-down-shift layer, the PCE of p-type silicon solar cells was improved by 2.7% (0.4 percentage points).

  15. Modeling the influence of the seeding layer on the transition behavior of a ferroelectric thin film

    International Nuclear Information System (INIS)

    Oubelkacem, A.; Essaoudi, I.; Ainane, A.; Saber, M.; Dujardin, F.

    2011-01-01

    The transition properties of a ferroelectric thin film with seeding layers were studied using the effective field theory with a probability distribution technique that accounts for the self-spin correlation functions. The effect of interaction parameters for the seeding layer on the phase diagram was also examined. We calculated the critical temperature and the polarization of the ferroelectric thin film for different seeding layer structures. We found that the seeding layer can greatly increase the Curie temperature and the polarization.

  16. Properties of non-stoichiometric nitrogen doped LPCVD silicon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, F.; Mahamdi, R. [Departement d' Electronique, Universite Mentouri, Constantine (Algeria); Beghoul, M.R. [Departement d' Electronique, Universite de Jijel (Algeria); Temple-Boyer, P. [CNRS, LAAS, Toulouse (France); Universite de Toulouse, UPS, INSA, INP, ISAE, LAAS, Toulouse (France); Bouridah, H.

    2010-02-15

    The influence of nitrogen on the internal structure and so on the electrical properties of silicon thin films obtained by low-pressure chemical vapor deposition (LPCVD) was studied using several investigation methods. We found by using Raman spectroscopy and SEM observations that a strong relationship exists between the structural order of the silicon matrix and the nitrogen ratio in film before and after thermal treatment. As a result of the high disorder caused by nitrogen on silicon network during the deposit phase of films, the crystallization phenomena in term of nucleation and crystalline growth were found to depend upon the nitrogen content. Resistivity measurements results show that electrical properties of NIDOS films depend significantly on structural properties. It was appeared that for high nitrogen content, the films tend to acquire an insulator behavior. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Formation of a Polycrystalline Silicon Thin Film by Using Blue Laser Diode Annealing

    Science.gov (United States)

    Choi, Young-Hwan; Ryu, Han-Youl

    2018-04-01

    We report the crystallization of an amorphous silicon thin film deposited on a SiO2/Si wafer using an annealing process with a high-power blue laser diode (LD). The laser annealing process was performed using a continuous-wave blue LD of 450 nm in wavelength with varying laser output power in a nitrogen atmosphere. The crystallinity of the annealed poly-silicon films was investigated using ellipsometry, electron microscope observation, X-ray diffraction, and Raman spectroscopy. Polysilicon grains with > 100-nm diameter were observed to be formed after the blue LD annealing. The crystal quality was found to be improved as the laser power was increased up to 4 W. The demonstrated blue LD annealing is expected to provide a low-cost and versatile solution for lowtemperature poly-silicon processes.

  18. Pyroelectricity of silicon-doped hafnium oxide thin films

    Science.gov (United States)

    Jachalke, Sven; Schenk, Tony; Park, Min Hyuk; Schroeder, Uwe; Mikolajick, Thomas; Stöcker, Hartmut; Mehner, Erik; Meyer, Dirk C.

    2018-04-01

    Ferroelectricity in hafnium oxide thin films is known to be induced by various doping elements and in solid-solution with zirconia. While a wealth of studies is focused on their basic ferroelectric properties and memory applications, thorough studies of the related pyroelectric properties and their application potential are only rarely found. This work investigates the impact of Si doping on the phase composition and ferro- as well as pyroelectric properties of thin film capacitors. Dynamic hysteresis measurements and the field-free Sharp-Garn method were used to correlate the reported orthorhombic phase fractions with the remanent polarization and pyroelectric coefficient. Maximum values of 8.21 µC cm-2 and -46.2 µC K-1 m-2 for remanent polarization and pyroelectric coefficient were found for a Si content of 2.0 at%, respectively. Moreover, temperature-dependent measurements reveal nearly constant values for the pyroelectric coefficient and remanent polarization over the temperature range of 0 ° C to 170 ° C , which make the material a promising candidate for IR sensor and energy conversion applications beyond the commonly discussed use in memory applications.

  19. Production and characterization of SLID interconnected n-in-p pixel modules with 75 micron thin silicon sensors

    CERN Document Server

    Andricek, L; Macchiolo, A; Moser, H.G; Nisius, R; Richter, R.H; Terzo, S; Weigell, P

    2014-01-01

    The performance of pixel modules built from 75 micrometer thin silicon sensors and ATLAS read-out chips employing the Solid Liquid InterDiffusion (SLID) interconnection technology is presented. This technology, developed by the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. It allows for stacking of different interconnected chip and sensor layers without destroying the already formed bonds. In combination with Inter-Chip-Vias (ICVs) this paves the way for vertical integration. Both technologies are combined in a pixel module concept which is the basis for the modules discussed in this paper. Mechanical and electrical parameters of pixel modules employing both SLID interconnections and sensors of 75 micrometer thickness are covered. The mechanical features discussed include the interconnection efficiency, alignment precision and mechanical strength. The electrical properties comprise the leakage currents, tuning characteristics, charge collection, cluster sizes and hit efficiencies. T...

  20. Production and Characterisation of SLID Interconnected n-in-p Pixel Modules with 75 Micrometer Thin Silicon Sensors

    CERN Document Server

    Andricek, L; Macchiolo, A.; Moser, H.-G.; Nisius, R.; Richter, R.H.; Terzo, S.; Weigell, P.

    2014-01-01

    The performance of pixel modules built from 75 micrometer thin silicon sensors and ATLAS read-out chips employing the Solid Liquid InterDiffusion (SLID) interconnection technology is presented. This technology, developed by the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. It allows for stacking of different interconnected chip and sensor layers without destroying the already formed bonds. In combination with Inter-Chip-Vias (ICVs) this paves the way for vertical integration. Both technologies are combined in a pixel module concept which is the basis for the modules discussed in this paper. Mechanical and electrical parameters of pixel modules employing both SLID interconnections and sensors of 75 micrometer thickness are covered. The mechanical features discussed include the interconnection efficiency, alignment precision and mechanical strength. The electrical properties comprise the leakage currents, tunability, charge collection, cluster sizes and hit efficiencies. Targeting at ...

  1. Detection of charged particles in amorphous silicon layers

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Morel, J.; Kaplan, S.N.; Street, R.A.

    1986-02-01

    The successful development of radiation detectors made from amorphous silicon could offer the possibility for relatively easy construction of large area position-sensitive detectors. We have conducted a series of measurements with prototype detectors, on signals derived from alpha particles. The measurement results are compared with simple model calculations, and projections are made of potential applications in high-energy and nuclear physics

  2. Plated copper front side metallization on printed seed-layers for silicon solar cells

    OpenAIRE

    Kraft, Achim

    2015-01-01

    A novel copper front side metallization architecture for silicon solar cells based on a fine printed silver seed-layer, plated with nickel, copper and silver, is investigated. The work focuses on the printing of fine seed-layers with low silver consumption, the corrosion of the printed seed-layers by the interaction with electrolyte solutions and the encapsulation material on module level and on the long term stability of the cells due to copper migration. The investigation of the correlation...

  3. Research, development and pilot production of high output thin silicon solar cells

    Science.gov (United States)

    Iles, P. A.

    1976-01-01

    Work was performed to define and apply processes which could lead to high output from thin (2-8 mils) silicon solar cells. The overall problems are outlined, and two satisfactory process sequences were developed. These sequences led to good output cells in the thickness range to just below 4 mils; although the initial contract scope was reduced, one of these sequences proved capable of operating beyond a pilot line level, to yield good quality 4-6 mil cells of high output.

  4. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    Science.gov (United States)

    Ang, P. C.; Ibrahim, K.; Pakhuruddin, M. Z.

    2015-04-01

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 µm electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.57×1016 atoms/cm3) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate.

  5. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Ang, P. C.; Ibrahim, K.; Pakhuruddin, M. Z. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, Minden 11800 Penang (Malaysia)

    2015-04-24

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 µm electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.57×10{sup 16} atoms/cm{sup 3}) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate.

  6. Plasma processing of microcrystalline silicon films : filling in the gaps

    NARCIS (Netherlands)

    Bronneberg, A.C.

    2012-01-01

    Hydrogenated microcrystalline silicon (µc-Si:H) is a mixed-phase material consisting of crystalline silicon grains, hydrogenated amorphous silicon (a-Si:H) tissue, and voids. Microcrystalline silicon is extensively used as absorber layer in thin-film tandem solar cells, combining the advantages of a

  7. CHARACTERIZATION OF A THIN SILICON SENSOR FOR ACTIVE NEUTRON PERSONAL DOSEMETERS.

    Science.gov (United States)

    Takada, M; Nunomiya, T; Nakamura, T; Matsumoto, T; Masuda, A

    2016-09-01

    A thin silicon sensor has been developed for active neutron personal dosemeters for use by aircrews and first responders. This thin silicon sensor is not affected by the funneling effect, which causes detection of cosmic protons and over-response to cosmic neutrons. There are several advantages to the thin silicon sensor: a decrease in sensitivity to gamma rays, an improvement of the energy detection limit for neutrons down to 0.8 MeV and an increase in the sensitivity to fast neutrons. Neutron response functions were experimentally obtained using 2.5 and 5 MeV monoenergy neutron beams and a (252)Cf neutron source. Simulation results using the Monte Carlo N-Particle transport code agree quite well with the experimental ones when an energy deposition region shaped like a circular truncated cone is used in place of a cylindrical region. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Activity and lifetime of urease immobilized using layer-by-layer nano self-assembly on silicon microchannels.

    Science.gov (United States)

    Forrest, Scott R; Elmore, Bill B; Palmer, James D

    2005-01-01

    Urease has been immobilized and layered onto the walls of manufactured silicon microchannels. Enzyme immobilization was performed using layer-by-layer nano self-assembly. Alternating layers of oppositely charged polyelectrolytes, with enzyme layers "encased" between them, were deposited onto the walls of the silicon microchannels. The polycations used were polyethylenimine (PEI), polydiallyldimethylammonium (PDDA), and polyallylamine (PAH). The polyanions used were polystyrenesulfonate (PSS) and polyvinylsulfate (PVS). The activity of the immobilized enzyme was tested by pumping a 1 g/L urea solution through the microchannels at various flow rates. Effluent concentration was measured using an ultraviolet/visible spectrometer by monitoring the absorbance of a pH sensitive dye. The architecture of PEI/PSS/PEI/urease/PEI with single and multiple layers of enzyme demonstrated superior performance over the PDDA and PAH architectures. The precursor layer of PEI/PSS demonstrably improved the performance of the reactor. Conversion rates of 70% were achieved at a residence time of 26 s, on d 1 of operation, and >50% at 51 s, on d 15 with a six-layer PEI/urease architecture.

  9. Effect of Mg doping in ZnO buffer layer on ZnO thin film devices for electronic applications

    Science.gov (United States)

    Giri, Pushpa; Chakrabarti, P.

    2016-05-01

    Zinc Oxide (ZnO) thin films have been grown on p-silicon (Si) substrate using magnesium doped ZnO (Mg: ZnO) buffer layer by radio-frequency (RF) sputtering method. In this paper, we have optimized the concentration of Mg (0-5 atomic percent (at. %)) ZnO buffer layer to examine its effect on ZnO thin film based devices for electronic and optoelectronic applications. The crystalline nature, morphology and topography of the surface of the thin film have been characterized. The optical as well as electrical properties of the active ZnO film can be tailored by varying the concentration of Mg in the buffer layer. The crystallite size in the active ZnO thin film was found to increase with the Mg concentration in the buffer layer in the range of 0-3 at. % and subsequently decrease with increasing Mg atom concentration in the ZnO. The same was verified by the surface morphology and topography studies carried out with scanning electron microscope (SEM) and atomic electron microscopy (AFM) respectively. The reflectance in the visible region was measured to be less than 80% and found to decrease with increase in Mg concentration from 0 to 3 at. % in the buffer region. The optical bandgap was initially found to increase from 3.02 eV to 3.74 eV by increasing the Mg content from 0 to 3 at. % but subsequently decreases and drops down to 3.43 eV for a concentration of 5 at. %. The study of an Au:Pd/ZnO Schottky diode reveals that for optimum doping of the buffer layer the device exhibits superior rectifying behavior. The barrier height, ideality factor, rectification ratio, reverse saturation current and series resistance of the Schottky diode were extracted from the measured current voltage (I-V) characteristics.

  10. Observing the morphology of single-layered embedded silicon nanocrystals by using temperature-stable TEM membranes

    Directory of Open Access Journals (Sweden)

    Sebastian Gutsch

    2015-04-01

    Full Text Available We use high-temperature-stable silicon nitride membranes to investigate single layers of silicon nanocrystal ensembles by energy filtered transmission electron microscopy. The silicon nanocrystals are prepared from the precipitation of a silicon-rich oxynitride layer sandwiched between two SiO2 diffusion barriers and subjected to a high-temperature annealing. We find that such single layers are very sensitive to the annealing parameters and may lead to a significant loss of excess silicon. In addition, these ultrathin layers suffer from significant electron beam damage that needs to be minimized in order to image the pristine sample morphology. Finally we demonstrate how the silicon nanocrystal size distribution develops from a broad to a narrow log-normal distribution, when the initial precipitation layer thickness and stoichiometry are below a critical value.

  11. Electroresistance Effect in Gold Thin Film Induced by Ionic-Liquid-Gated Electric Double Layer

    NARCIS (Netherlands)

    Nakayama, Hiroyasu; Ye, Jianting; Ohtani, Takashi; Fujikawa, Yasunori; Ando, Kazuya; Iwasa, Yoshihiro; Saitoh, Eiji

    Electroresistance effect was detected in a metallic thin film using ionic-liquid-gated electric-double-layer transistors (EDLTs). We observed reversible modulation of the electric resistance of a Au thin film. In this system, we found that an electric double layer works as a nanogap capacitor with

  12. Use of a wedge cuvette in thin layer photometry and its application to oximetry

    NARCIS (Netherlands)

    Spaan, J. A.; Garred, L. J.; van de Borne, P.

    1977-01-01

    A wedge cuvette was constructed by fixing 2 glass plates at a known angle with a spacer at one end. This resulted in a thin layer with thickness varying from 0 to 250 micrometer. By measuring the intensity of a beam of light through the thin layer as a function of distance along the wedge (and thus

  13. Using thin metal layers on composite structures for shielding the electromagnetic pulse caused by nearby lightning

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, Frederik Johannes Karel; Damstra, G.C.; Leferink, Frank Bernardus Johannes

    2011-01-01

    Electronic systems in composite structures could be vulnerable to the (dominant magnetic) field caused by a lightning strike, because only thin layers of metal can be used on composite structures. Thin layers result in a very low shielding effectiveness against magnetic fields. Many experiments

  14. Proteins at fluid interfaces: adsorption layers and thin liquid films.

    Science.gov (United States)

    Yampolskaya, Galina; Platikanov, Dimo

    2006-12-21

    A review in which many original published results of the authors as well as many other papers are discussed. The structure and some properties of the globular proteins are shortly presented, special accent being put on the alpha-chymotrypsin (alpha-ChT), lysozyme (LZ), human serum albumin (HSA), and bovine serum albumin (BSA) which have been used in the experiments with thin liquid films. The behaviour of protein adsorption layers (PAL) is extensively discussed. The dynamics of PAL formation, including the kinetics of adsorption as well as the time evolution of the surface tension of protein aqueous solutions, are considered. A considerable place is devoted to the surface tension and adsorption isotherms of the globular protein solutions, the simulation of PAL by interacting hard spheres, the experimental surface tension isotherms of the above mentioned proteins, and the interfacial tension isotherms for the protein aqueous solution/oil interface. The rheological properties of PAL at fluid interfaces are shortly reviewed. After a brief information about the experimental methods for investigation of protein thin liquid (foam or emulsion) films, the properties of the protein black foam films are extensively discussed: the conditions for their formation, the influence of the electrolytes and pH on the film type and stability, the thermodynamic properties of the black foam films, the contact angles film/bulk and their dynamic hysteresis. The next center of attention concerns some properties of the protein emulsion films: the conditions for formation of emulsion black films, the formation and development of a dimpling in microscopic, circular films. The protein-phospholipid mixed foam films are also briefly considered.

  15. Use of B{sub 2}O{sub 3} films grown by plasma-assisted atomic layer deposition for shallow boron doping in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kalkofen, Bodo, E-mail: bodo.kalkofen@ovgu.de; Amusan, Akinwumi A.; Bukhari, Muhammad S. K.; Burte, Edmund P. [Institute of Micro and Sensor Systems, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg (Germany); Garke, Bernd [Institute for Experimental Physics, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg (Germany); Lisker, Marco [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Gargouri, Hassan [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany)

    2015-05-15

    Plasma-assisted atomic layer deposition (PALD) was carried for growing thin boron oxide films onto silicon aiming at the formation of dopant sources for shallow boron doping of silicon by rapid thermal annealing (RTA). A remote capacitively coupled plasma source powered by GaN microwave oscillators was used for generating oxygen plasma in the PALD process with tris(dimethylamido)borane as boron containing precursor. ALD type growth was obtained; growth per cycle was highest with 0.13 nm at room temperature and decreased with higher temperature. The as-deposited films were highly unstable in ambient air and could be protected by capping with in-situ PALD grown antimony oxide films. After 16 weeks of storage in air, degradation of the film stack was observed in an electron microscope. The instability of the boron oxide, caused by moisture uptake, suggests the application of this film for testing moisture barrier properties of capping materials particularly for those grown by ALD. Boron doping of silicon was demonstrated using the uncapped PALD B{sub 2}O{sub 3} films for RTA processes without exposing them to air. The boron concentration in the silicon could be varied depending on the source layer thickness for very thin films, which favors the application of ALD for semiconductor doping processes.

  16. Use of Monocrystalline Silicon as Tool Material for Highly Accurate Blanking of Thin Metal Foils

    International Nuclear Information System (INIS)

    Hildering, Sven; Engel, Ulf; Merklein, Marion

    2011-01-01

    The trend towards miniaturisation of metallic mass production components combined with increased component functionality is still unbroken. Manufacturing these components by forming and blanking offers economical and ecological advantages combined with the needed accuracy. The complexity of producing tools with geometries below 50 μm by conventional manufacturing methods becomes disproportional higher. Expensive serial finishing operations are required to achieve an adequate surface roughness combined with accurate geometry details. A novel approach for producing such tools is the use of advanced etching technologies for monocrystalline silicon that are well-established in the microsystems technology. High-precision vertical geometries with a width down to 5 μm are possible. The present study shows a novel concept using this potential for the blanking of thin copper foils with monocrystallline silicon as a tool material. A self-contained machine-tool with compact outer dimensions was designed to avoid tensile stresses in the brittle silicon punch by an accurate, careful alignment of the punch, die and metal foil. A microscopic analysis of the monocrystalline silicon punch shows appropriate properties regarding flank angle, edge geometry and surface quality for the blanking process. Using a monocrystalline silicon punch with a width of 70 μm blanking experiments on as-rolled copper foils with a thickness of 20 μm demonstrate the general applicability of this material for micro production processes.

  17. Adhesion between coating layers based on epoxy and silicone

    DEFF Research Database (Denmark)

    Svendsen, Jacob R.; Kontogeorgis, Georgios; Kiil, Søren

    2007-01-01

    The adhesion between a silicon tie-coat and epoxy primers, used in marine coating systems, has been studied in this work. Six epoxy coatings (with varying chain lengths of the epoxy resins), some of which have shown problems with adhesion to the tie-coat during service life, have been considered....... The experimental investigation includes measurements of the surface tension of the tie-coat and the critical surface tensions of the epoxies, topographic investigation of the surfaces of cured epoxy coatings via atomic force microscopy (AFM), and pull-off tests for investigating the strength of adhesion...... to the silicon/epoxy systems. Calculations for determining the roughness factor of the six epoxy coatings (based on the AFM topographies) and the theoretical work of adhesion have been carried out. The coating surfaces are also characterized based on the van Oss-Good theory. Previous studies on the modulus...

  18. Effects of silicon:carbon P+ layer interfaces on solar cells

    International Nuclear Information System (INIS)

    Jeffrey, F.R.; Vernstrom, G.D.; Weber, M.F.; Gilbert, J.R.

    1987-01-01

    Results are presented showing the effects on amorphous silicon (a-Si) photovoltaic performance of the interfaces associated with a silicon carbide (a-Si:C) p+ layer. Carbon grading into the intrinsic layer from the p+ layer increases open circuit voltage (Voc) from 0.7V to 0.88V. This effect is very similar to the boron profile effect reported earlier and supports the contention that Voc is being limited by an electron current at the p-i interface. The interface between the p+ a-Si:C layer and the transparent conductive oxide (TCO) is shown to be a potential source of high series resistance, with an abrupt interface showing the most serious problem. The effect is explained by electron injection from the TCO into the p+ layer being inhibited as a result of band mismatch

  19. Detection of charged particles in amorphous silicon layers

    International Nuclear Information System (INIS)

    Kaplan, S.N.; Morel, J.R.; Mulera, T.A.; Perez-Mendez, V.; Schnurmacher, G.; Street, R.A.

    1985-10-01

    The successful development of radiation detectors made from amorphous silicon could offer the possibility for relatively easy construction of large area position-sensitive detectors. We have conducted a series of measurements with prototype detectors, on signals derived from alpha particles. The measurement results are compared with simple model calculations, and projections are made of potential applications in high-energy and nuclear physics. 4 refs., 7 figs

  20. Fatigue crack layer propagation in silicon-iron

    Science.gov (United States)

    Birol, Y.; Welsch, G.; Chudnovsky, A.

    1986-01-01

    Fatigue crack propagation in metal is almost always accompanied by plastic deformation unless conditions strongly favor brittle fracture. The analysis of the plastic zone is crucial to the understanding of crack propagation behavior as it governs the crack growth kinetics. This research was undertaken to study the fatigue crack propagation in a silicon iron alloy. Kinetic and plasticity aspects of fatigue crack propagation in the alloy were obtained, including the characterization of damage evolution.