Nanocolumnar Preferentially Oriented PSZT Thin Films Deposited on Thermally Grown Silicon Dioxide

We report the first instance of deposition of preferentially oriented, nanocrystalline, and nanocolumnar strontium-doped lead zirconate titanate (PSZT) ferroelectric thin films directly on thermal silicon dioxide. No intermediate seed or activation layers were used between PSZT and silicon dioxide. The deposited thin films have been characterised using a combination of diffraction and microscopy techniques.     

Intrinsic Sub-Nanocrystalline Silicon Thin Films: Active Layer for Solar Cells

Silicon - The study presents the typical aspects of silicon thin films in terms of growth under variation of applied power using Radio frequency Plasma Enhanced Chemical Vapor Deposition technique...     

超声喷雾热分解法制备硅薄膜太阳电池用ZnO：In透明导电膜

采用超声喷雾热分解法,在Eagle2000衬底上制备ZnO薄膜。通过Hall测试、X射线衍射、扫描电子显微镜和透过率测试研究不同In掺量对ZnO薄膜电学、结构、表面形貌和光学特性的影响。结果表明：当In摩尔掺量（In与ZnO的摩尔比）为1.5%时,获得的薄膜具有较低的电阻率（2.48×10–3cm）;所有In掺杂ZnO...     

Properties of Aluminium Thin Films on Polyethylene Terephthalate Substrates as Back Contacts in Thin Film Silicon Solar Cells

Aluminium thin films on polyethylene terephthalate substrates prepared via thermal evaporation method and annealed under different temperatures have been investigated. High peak belonging to aluminium atoms is evident from energy dispersive X-ray spectra. From X-ray diffraction pattern, the polycrystalline nature of aluminium thin film is observed with (200) dominant peak at 2θ = 44.52°. With increased annealing temperatures, the atomic force microscope shows increased surface roughness root-mean-square but sheet resistance and surface reflectance show reducing values. The effects of each characterization towards performance of thin film silicon solar cells are subsequently discussed.     

电阻率对N型单晶硅电池电性能影响的研究

近年来,P型太阳电池商业化生产效率已趋于稳定,N型太阳电池逐渐走向产业化.基于N+ Np+型铝背结单晶硅太阳电池,研究了电阻率为1 ～5.5 Ω·cm的N型硅衬底材料经过相同工艺后电池性能的差别,可以有效的节省成本.通过选用不同电阻率的N型硅片,经过相同的工艺制备N型单晶硅太阳电池,采用QSSPC、四探针、ECV、恒光源Ⅰ-Ⅴ测试系统对电池的少子寿命、方块电阻、磷元素分布、电性能进行测量.实验结果表明:虽然电池的少子寿命随电阻率的升高而升高,但是在方块电阻、磷元素分布、开路电压Voc、短路电流Isc、填充因子FF、转换效率Eff等方面不同电阻率的电池并无明显差异.     

氮化硅薄膜的热丝化学气相沉积法制备及微结构研究

采用热丝化学气相沉积法,以Sill4、NH3、N2为反应气源,通过改变氮气流量沉积氮化硅薄膜.通过紫外-可见(UV-VIS)光吸收谱、傅里叶红外透射光谱(FTIR)、X射线衍射谱(XRD)等测试手段对薄膜的光学带隙、键合特性及晶相进行表征与分析.结果表明:薄膜主要表现为Si-N键合结构,当N2流量从20 sccm变化到40 sccm时,热丝能够充分的分解N2,薄膜中N原子过量,其周围的Si和H能充分的与N结合.但由于N2的解离能较高,当N2流量高于40 sccm时,氮气在反应过程中对薄膜内的氮原子反而起到了稀释作用,薄膜的有序程度增大,光学带隙减小,致密性降低.当氮气流量达到150 sccm时,在2θ为69.5°处出现了晶化β-Si3 N4的尖锐衍射峰,其择优取向沿(322)晶向,且Si3 N4晶粒显著增大.因此,氮气流量对薄膜中的氮含量有显著影响,适当的增加氮气流量有利于制备出优质含有小晶粒β-Si3 N4薄膜.     

Effect of Substrate Orientation on Interfacial and Bulk Character of Chemically Vapor Deposited Monocrystalline Silicon Carbide Thin Films

The high breakdown electric field, saturated electron drift velocity, and melting (decomposition) point of SiC have given continual impetus to research concerned with the development of thin films having minimum concentrations of line and planar defects and electronic devices for severe environments. To this end, epitaxial growth via chemical vapor deposition of monocrystalline films of β-SiC on Si (100) and 6 H -SiC {0001} substrates and 6 H -SiC on vicinal 6 H -SiC {0001} substrates have been conducted. High concentrations of stacking faults, microtwins, and inversion domain boundaries were produced in films grown directly on Si (100) as a result of a lattice parameter difference of ∼ 20% and the presence of single (or odd number) atomic steps on the substrate surface. Growth on Si (100) oriented 3° to 4° toward [011] completely eliminated the IDBs (but not the other defects) due to the preferential formation of double steps with dimerization axes on the upper terraces parallel to the step edges. Growth of β-SiC films on 6 H {0001} lowered the density of all defects but resulted in the formation of a new defect, namely, double positioning boundaries. The latter were eliminated by using 6 H {0001} oriented 3° toward [1120]. The defect density in these last films, relative to those grown on on-axis Si (100), was reduced substantially (to ∼10⁵ cm/cm³). However, the resulting film was 6 H -SiC. Significant improvements in electrical properties of simple devices were obtained as the defect density was progressively decreased.     

Impact of Stoichiometry on Structural and Optical Properties of Sputter Deposited Multicomponent Tellurite Glass Films

Multicomponent TeO₂–Bi₂O₃–ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. We observed that thin films sputtered in an oxygen‐rich environment are optically transparent while those sputtered in an oxygen‐deficient environment exhibit broadband absorption. The structural origin of the optical property variation was studied using X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy which revealed that the presence of under‐coordinated Te leads to the observed optical absorption in oxygen‐deficient films.     

不同衬底上ZnO:Al透明导电薄膜的性能

室温下,采用射频磁控溅射法在玻璃和聚对苯二甲酸乙二醇酯（polyethylene terephthalate,PET）上沉积了掺铝的氧化锌（ZnO：Al,AZO）透明导电薄膜。通过X射线衍射仪分析不同衬底上AZO薄膜的结构,采用四探针测试仪及紫外可见光分光光度计测试薄膜的光电性能。结果表明：沉积在两种衬底上的AZO薄膜都具有六方纤锌矿结构,最佳取向均为[002]方向;玻璃衬底和PET衬底上制备的AZO薄膜的方阻分别为19/sq和45/sq,薄膜透光率均高于90%。实验表明,柔性衬底透明导电氧化物薄膜可以代替硬质衬底透明导电薄膜使电子器件向小型化、轻便化方向发展。     

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.     

Spectral and Morphological Studies of Nanocrystalline Silicon Thin Films Synthesized by PECVD for Solar Cells

In this work, a series of nanocrystalline silicon films were studied with different microstructural tools to elucidate the film microstructure at different stages of growth. Thin Si films, with a series of multilayers, were deposited by radio frequency glow discharge using Plasma Enhanced Chemical Vapour Deposition (PECVD) in silane gas (SiH₄) highly diluted by hydrogen. Different nanostructured films were prepared by systematically varying gas flow ratios (R = 1/1, 1/5, 1/7.5, 1/10, 1/15, 1/20) for films having different thicknesses. By changing the structure of the material, going from pure amorphous to nanocrystalline silicon, it is possible to obtain a variation in optical gap using the same material. In these structures, layers with different individual optical gaps are stacked together in order to cover as much of the solar spectrum as possible. The nanostructures of the silicon thin films were studied using FTIR, RS, PL, XRD, AFM, SEM, TEM and HRTEM. The results were correlated for conglomerate surface, grain surface. Some theoretical calculations were used for designing the overall stack geometry and for interpretation of characterization. These agree well with experimental observation.     

Investigation on Molybdenum Thin Films Deposited by DC-Sputtering on Polyethylene Terephthalate Substrate

Molybdenum (Mo) films were prepared by DC sputtering on a polyethylene terephthalate (PET) substrate with different thicknesses. The molybdenum finds use in a very broad spectrum of applications in widely different forms. The obtained results of thin films of molybdenum deposited on PET are characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD) and (EDX). It was found that the thickness increases with the time of deposition and reduces the resistivity and sheet resistance. The lowest resistivity value we found for the Mo films was 1.3 × 10^?5 Ω · cm at thickness (210 nm).     

A Comparative Study on the Anti-Friction Performance of Amorphous Silicon Films Enhanced by WS2 Nanoflakes

Silicon - Silicon has been irreplaceable for a long time due to its well-estiblished design and fabrication in the field of Micro-Electro-Mechanical System (MEMS). However, it has poor tribological...     

Influence of Electrosprayed MoSe2 Antireflective Surface Coatings on Performance of Multicrystalline Silicon Solar Cell

Silicon - The present scenario indefinitely needs certain developments in the field of renewable energy as an effective replacement of conventional energy sources. Reflection loss in solar cell is...     

An Investigation on a Crystalline-Silicon Solar Cell with Black Silicon Layer at the Rear

Crystalline-Si (c-Si) solar cell with black Si (b-Si) layer at the rear was studied in order to develop c-Si solar cell with sub-band gap photovoltaic response. The b-Si was made by chemical etching. The c-Si solar cell with b-Si at the rear was found to perform far better than that of similar structure but with no b-Si at the rear, with the efficiency being increased relatively by 27.7%. This finding was interesting as b-Si had a large specific surface area, which could cause high surface recombination and degradation of solar cell performance. A graded band gap was found to form at the rear of the c-Si solar cell with b-Si layer at the rear. This graded band gap tended to expel free electrons away from the rear, thus reducing the probability of electron-hole recombination at b-Si and improving the performance of c-Si solar cell.     

Enhanced Solar Cell Conversion Efficiency Using Birefringent Liquid Crystal Polymer Homeotropic Films from Reactive Mesogens

Novel birefringent liquid crystal polymer homeotropic films have been coated on semiconductor solar cells to improve the effective incident sunlight angles. The liquid crystal polymer precursor, based on reactive mesogens, is fluidic and flows like liquid. It would distribute uniformly on the solar cell sample surface by any traditional coating technique. The birefringence for light, due to the liquid crystal retardation properties, manipulated the optical length and the deflection of incident light, thus allowed an increase in the energy conversion efficiency. The expensive sunlight tracking systems could be avoided. The processing parameters can be tuned such as different mesogen concentrations and plate speeds of spin-coating. The results showed that the solar cell conversion efficiency was improved from 14.56% to 14.85% at an incident sunlight angle of 15°. It was further improved from 13.40% to 13.81% when the angle was 30°. The interesting angular dependency on solar cell efficiency enhancement has been evaluated.