An Effective Approach on Attaining Enhanced Silicon Solar Cell Performance Through Sputter Deposited Perovskite Thin Films

Silicon - Antireflection coatings (ARCs) have become one of the key techniques for mass production of Si solar cells. They are generally performed by vacuum processes such as thermal evaporation,...     

CoFeZrRE非晶薄膜的各向异性研究

研究了磁性稀土元素 (RE)的种类和含量 (0≤x≤ 3) ,对非晶态 (Co73 Fe2 0 Zr7) 10 0 -x (RE) x 薄膜各向异性的影响 ,并着重探讨该类薄膜中出现的平面单轴各向异性 (Ku)和垂直各向异性 (Kp)的起源问题。薄膜是在外加磁场中溅射而成。当掺入的稀土元素为Nd ,Pr,Dy和Tb时 ,获得了显著的平面单轴各向异性Ku ,且Ku与稀土元素的单离子各向异性密切相关。当稀土元素为Gd和Sm时 ,则会出现双轴各向异性 (Ku和Kp) ,这主要是成膜温度高于临界温度时 ,同时形成了 2种局域性的异质的磁结构。     

Annealing Temperature Effect on Bismuth Induced Crystallization of Hydrogenated Amorphous Silicon Thin Films

Silicon - In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50 nm of bismuth thin films are deposited by vapor...     

Study of Optical Properties of Single and Double Layered Amorphous Silicon Nitride Films for Photovoltaics Applications

Silicon - This work focuses on the optical properties of single- and double-layer amorphous silicon nitride (a-SiNx:H) thin films of different stoichiometry relevant for photovoltaic applications...     

Boron Induced Crystallization of Silicon on Glass: an Alternate Way to Crystallize Amorphous Silicon Films for Solar Cells

Silicon - Demand for efficient window layer in thin film solar cells with high crystallinity is ever increasing that finds important application in multi-junction/tandem silicon solar cells. Doping...     

Elaboration and Characterization of Amorphous Silicon Carbide Thin Films (a-SiC) by Sputerring Magnetron Technique for Photoelectrochemical CO2 Conversion

Silicon - Semiconductors as photoelectric catalysis is recognized as a promising strategy for simultaneous face energy crisis and environmental pollution. In this study, amorphous silicon carbide...     

Comparative Study of WS2 and Co(Ni)/WS2 HDS Catalysts Prepared by ex situ/in situ Activation of Ammonium Thiotungstate

A comparative study of the syntheses of unsupported WS₂ and M/WS₂ (M = Co, Ni) catalysts by ex situ/in situ decomposition of ammonium thiotungstate (ATT) is herein reported. Ex situ activation was performed under a H₂S (15% volume)/H₂ flow, whereas in situ activation consists in the direct decomposition of ATT or Co(Ni)/ATT precursors in the presence of a hydrocarbon solvent during the hydrodesulfurization (HDS) of dibenzothiophene (DBT). Precursors were characterized by thermogravimetric analysis and final catalysts by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). Catalysts activated using the in situ mode of activation present higher specific surface areas with the noticeable exception of the Ni/ATT precursor. Activity measurements showed that the in situ activated WS₂ and Ni/WS₂ catalysts exhibit higher activity than the ex situ activated catalysts.     

Thickness Alteration of Grain-Boundary Amorphous Films during Creep of a Multiphase Silicon Nitride Ceramic

Experimental observations of the creep response of a commercial sintered silicon nitride ceramic are presented. The stable microstructure of this material at high temperature contains secondary crystalline phases which result from partial devitrification of the intergranular phase. The widths of amorphous films along grain boundaries (between silicon nitride grains) and phase boundaries (between silicon nitride and secondary phase grains) are characterized by transmission electron microscopy. The thickness distributions of grain-boundary films before and after creep are analyzed by a statistical method. While the film widths are highly uniform before creep, a bimodal distribution is observed after creep. The results suggest that viscous flow of the boundary amorphous films occurs during creep deformation.     

NiCuB非晶态催化剂催化性能研究

采用化学还原法制备了NiCuB非晶态催化剂,研究了NiCuB非晶态催化剂对异丙醇和仲丁醇常压液相脱氢反应的催化性能.结果表明,NiCuB对异丙醇和仲丁醇常压液相脱氢反应具有较好的催化活性.NiCuB比NiB具有更好的催化性能,NiCuB对异丙醇常压液相脱氢反应的催化效果高于对仲丁醇的催化效果.Cu含量增加,NiCuB非晶态催化剂的催化性能增强.适当增加NiCuB催化剂的用量可以提高异丙醇的转化率.NiCuB非晶态催化剂随着催化反应的进行逐渐失活,晶化和氧化是失活的主要原因.     

Properties and Network Constitution of rf-Sputtered Amorphous Films in the System Silicon Dioxide–Aluminum Orthophosphate

Amorphous films in the system SiO₂–AlPO₄ were prepared by means of the rf-sputtering method, and their physical properties, such as density, refractive index, and temperature coefficient of Young's modulus, and infrared spectra were measured. Also, the K α X-ray emission spectra of silicon and aluminum were measured in order to investigate the coordination state of these cations in the amorphous films. The density and the refractive index were close to those of amorphous SiO₂ and AlPO₄ and the compositional dependence showed a small deviation from linearity. The temperature coefficients of Young's modulus were positive for all of the samples. The infrared absorption spectra of all of the samples were similar to those of SiO₂ glass and amorphous AlPO₄ film, and there was no evidence of the presence of P═O bonds. The coordination states of silicon and aluminum ions in the present amorphous films were the same as those in fused silica and AlPO₄ crystal, respectively. The results of the properties, infrared absorption spectra, and X-ray emission spectra suggest that SiO₄ tetrahedrons and AlO₄–PO₄ connecting tetrahedral dimers constitute the network of the present amorphous films. A small deviation of the physical properties from an additive rule was thought to result from the difference in the bond character between the newly formed Si–O–Al and Si–O–P bonds and the bonds in the end members, Si–O–Si and Al–O–P.     

Growth of Mixed-Phase Amorphous and Ultra Nanocrystalline Silicon Thin Films in the Low Pressure Regime by a VHF PECVD Process

A mixed-phase of amorphous (a-Si:H) and ultra nanocrystalline silicon thin films (ultra nc-Si:H) were grown in a low deposition pressure regime (0.10–0.62 Torr) using a very high frequency (60 MHz) plasma enhanced chemical vapor deposition (VHF PECVD) technique. The deposition rate, stress, hydrogen configuration and morphology varying with the deposition pressure were systematically studied. The maximum deposition rate was found to be 8.3 Å/s at a pressure of 0.47 Torr. The stress of these films decreases from 669.7 MPa to 285 MPa with the increase of deposition pressure from 0.10 to 0.62 Torr. The change in deposition pressure showed the variation of the microstructure and hydrogen bonding configuration of the nc-Si:H films. The ultra small crystallites (size?~?2 nm) were formed in the films which were confirmed by the X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) measurements. An attempt was made to understand their growth by analysis of the bonding environment.     

电沉积TiO2纳米晶薄膜及其光电性能研究

采用阴极电沉积法在导电玻璃基体上制备了TiO2薄膜.运用扫描电子显微镜、X-射线能量散射分析仪和X-射线衍射仪对TiO2薄膜的形貌和结构进行了分析.以N719染料敏化的TiO2薄膜为阳极,0.5 mol/L KI和0.05 mol/L I2的乙氰和乙烯碳酸酯的混合溶液为电解液,碳电极为阴极,组成太阳能电池,通过电流-电压曲线研究了太阳能电池的性能.结果表明:TiO2薄膜的晶型为锐钛矿,其晶粒d平均为28.8 nm.太阳能电池的U开路为0.513 V,J短路为22.8 A/m2,填充因子为0.392,光电转换效率为0.466%.     

Characteristic Study of Silicon Nitride Films Deposited by LPCVD and PECVD

This paper analyzes and compares the characteristics of silicon nitride films deposited by low pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD), with special attention to the hydrogenation and chemical composition of silicon nitride films. Three different LPCVD processes at various DCS and NH₃ gas flow rates and deposition temperatures, together with PECVD using SiH₄ and NH₃ and ICP CVD using SiH₄ and N₂, were compared. The silicon nitride film deposition rate decreases with an increasing NH₃/DCS ratio in LPCVD, which also leads to an increase in the refractive index and a decrease in the residual stress in the film. There is nearly no hydrogen incorporated in the LPCVD films, which differs from PECVD and ICP CVD that show significant Si-H and N-H bonds. The chemical composition of silicon nitride films is mostly Si-rich, except for the LPCVD process at high NH₃/DCS ratio with near stoichiometric chemistry.     

聚合物/层状纳米填料阻隔复合薄膜研究进展

综述了层状纳米复合材料的制备方法,以蒙脱土(MMT)、层状双氢氧化物(LDHs)和石墨烯(GNSs)为典型例子,系统阐述了层状纳米填料改善聚合物薄膜阻透性能的机理,最后讨论了高阻透、多功能化的纳米复合薄膜在制备及应用中所面临的挑战。     

Characterization of Doped Amorphous Silicon Thin Films through the Investigation of Dopant Elements by Glow Discharge Spectrometry. A Correlation of Conductivity and Bandgap Energy Measurements

The determination of optical parameters, such as absorption and extinction coefficients, refractive index and the bandgap energy, is crucial to understand the behavior and final efficiency of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The influence of small variations of the gas flow rates used for the preparation of the p-a-SiC:H layer on the bandgap energy, as well as on the dopant elements concentration, thickness and conductivity of the p-layer, is investigated in this work using several complementary techniques. UV-NIR spectrophotometry and ellipsometry were used for the determination of bandgap energies of four p-a-SiC:H thin films, prepared by using different B(2)H(6) and SiH(4) fluxes (B(2)H(6) from 12 sccm to 20 sccm and SiH(4) from 6 sccm to 10 sccm). Moreover, radiofrequency glow discharge optical emission spectrometry technique was used for depth profiling characterization of p-a-SiC:H thin films and valuable information about dopant elements concentration and distribution throughout the coating was found. Finally, a direct relationship between the conductivity of p-a-SiC:H thin films and the dopant elements concentration, particularly boron and carbon, was observed for the four selected samples.     

缓蚀剂WS对20A的缓蚀行为研究

用失重法、极化曲线法研究了缓蚀剂 WS 在5％盐酸溶液中对20A 的缓蚀行为,结果表明,缓蚀剂 WS 是混合型缓蚀剂,缓蚀效果良好。通过对 WS 加入浓度与缓蚀效率的研究,找到了 WS 在20A 上的吸附等温式。     

用微波ECR等离子体增强磁控溅射沉积法在玻璃上镀膜

利用微波ECR等离子体增强磁控溅射沉积技术在玻璃表面制备了硅膜.研究了所得硅膜的表面形貌、附着力和化学稳定性及其红外-可见光谱特性.结果表明此法制备的硅膜均匀性好,附着力及化学稳定性高,对近红外波段有较低的透过率和较高的反射率.     

快中子辐照直拉硅中非晶区的FTIR研究

利用Fourier变换红外光谱技术研究了高剂量快中子辐照直拉单晶硅中的辐照缺陷.研究表明,当中子剂量超过1018n·cm-2,在硅晶体会引入大量的非晶区和少量的非晶层(由连续的非晶区组成),分别在FTIR光谱中引入485和529.2 cm-1两个吸收带.退火实验表明,非晶区(485 cm-1)经150℃热处理后开始再结晶,有效的退火温度约为300℃;非晶层(529.2 cm-1)经300℃热处理后开始再结晶,有效的退火温度为500℃左右.     

Silicon Carbide Films by Laser Pyrolysis of Polycarbosilane

Thin films of polycarbosilane were deposited on Si and SiO₂ substrates. Instead of conventional oven annealing (high temperatures, inert atmosphere), laser pyrolysis was used to achieve the polymer-to-ceramic conversion. In some conditions, especially when laser radiation absorption was enhanced by depositing a carbon layer on the surface of as-deposited films or by embedding graphite particles, this processing method yielded SiC ceramic coatings, without damaging the substrate. Processing in air or low vacuum did not result in oxidized coatings, contrary to what happens for oven pyrolysis. Laser-converted films were similar to oven-heated films processed at 1000° to 1200°C.     

Tensile Strength of Silicon Nitride Whiskers Synthesized by Reacting Amorphous Silicon Nitride and Titanium Dioxide

The tensile strength of α-Si₃N₄ whiskers synthesized by reacting amorphous Si₃N₄ and TiO₂ at 1490°C under a N₂ pressure of 700 torr was measured using a microbalance, and the diameter dependence of the strength was investigated. The Si₃N₄ whiskers had diameters of 0.04 and 0.8 μm and dominant [1011] and [1010] growth directions. Chemical analysis showed that they contained Ti and O impurities. The tensile strength of six Si₃N₄ whiskers increased from 17 to 59 GPa with decreasing whisker diameter.