模拟非硅衬底上转换效率10%的多晶硅薄膜太阳电池

在重掺杂非活性单晶硅片上生长一定厚度的SiO2，开窗口后作为衬底，利用快速热化学气相沉积（RTCVD）及区熔再结晶（ZMR）方法制备多晶硅薄膜太阳电池。由于采用了区熔再结晶（ZMR）的方法，获得了取向一致的多晶硅薄膜,为薄膜电池的制备打下了良好的基础,转换效率达到10．21％。     

影响SSP衬底上多晶硅薄膜太阳电池效率的因素

该文分析了颗粒硅带(SSP;Silicon Sheet from Powder)衬底的杂质、缺陷和晶粒尺寸以及电池的电极设计对多晶硅薄膜太阳电池效率的影响;报道了用快速热化学汽相沉积法(RTCVD)在SSP上制备多晶硅薄膜电池的结果;得到电池的开路电压为506.8mV,短路电流为26.69mA,转换效率为8.25%(AM1.5,24℃,Area=1tm2).     

多晶硅薄膜太阳电池的研究与进展

从薄膜的沉积方式和沉积温度以及衬底材料等几方面综合分析了多晶硅薄膜制备工艺的特点及多晶硅薄膜太阳电池的最新研究进展。并以颗粒硅带(SSP)为衬底，采用快热化学气相沉积(RTCVD)法制备了多晶硅薄膜，随后制得的多晶硅薄膜太阳电池的效率达到6．05％。     

颗粒硅带多晶硅薄膜太阳电池的研制

以工业硅粉为原料制备出颗粒硅带（SSP），对颗粒硅带表面形态进行了分析。以SSP为衬底，采用快速热化学气相沉积（RTCVD）法生长多晶硅薄膜，并以此制作出效率为2．93％的颗粒硅带多晶硅薄膜太阳电池，这在国内属首先。并报道了对以SSP为衬底的多晶硅薄膜太阳电池的初步研究结果，同时讨论了该类电源的结构、工艺特点和改进措施。     

玻璃衬底多晶硅薄膜太阳电池的制备

多晶硅薄膜太阳电池兼具单晶硅的高转换效率和多晶硅体电池的长寿命的特点,其制备工艺比非晶硅薄膜材料的制备工艺相对简化。文章介绍了多晶硅薄膜太阳电池材料制备工艺和材料性能;阐述了多晶硅薄膜太阳电池Si3N4膜的沉积和玻璃制绒等关键工艺;综述了玻璃衬底多晶硅薄膜太阳电池的发展现状。     

氧化铝陶瓷衬底多晶硅薄膜区熔再结晶的研究

采用简化的区熔再结晶工艺,即区熔过程中不采用隔离层和盖帽层结构,直接在陶瓷衬底上制备出高 质量的多晶硅薄膜。实验中给出了用X射线衍射方法得到的晶向图谱和光学显微镜、扫描电子显微镜方法得到 的表面形貌,并采用扩散法和正面引电极的方法初步探索了电池的制备工艺,电池的开路电压达到196mV,短 路电流为200μA。     

颗粒硅带为衬底的多晶硅薄膜太阳电池制备工艺

主要阐述了以低纯度颗粒硅带(SSP—Silicon Sheet from Powder)为衬底的多晶硅薄膜(poly-CSiTF)太阳电池的制备，给出制得的太阳电池I—V曲线和光谱响应曲线并由此讨论影响电池性能的可能因素，着重分析了颗粒硅带衬底的作用。目前，在没有任何电池工艺优化的条件下，在低纯度硅带上制得多晶硅薄膜电池的转换效率通常在5％～7％范围(电池面积1cm^2)。     

原生大尺寸籽晶对高效多晶硅铸锭质量的影响

籽晶辅助生长高效铸造多晶硅技术已成为当前市场的主流技术,籽晶的尺寸和形貌对多晶硅形核具有较大的影响。该文研究了原生大尺寸籽晶对高效多晶硅铸锭质量的影响,结果表明,相比碎多晶籽晶,原生大尺寸籽晶生长的晶粒均匀性略好,且位错密度稍低,其生长的硅片制备的电池的平均转换效率提高了0.03%。     

SOI材料上硅薄膜电池的研究

用注氧隔离法在单晶硅衬底中形成SiO2隔离层,制备成SOI(SiliconOnInsulator)衬底,用快速化学汽相沉积(RTCVD)法在此衬底上制备硅薄膜,热扩散形成PN结,制备成薄膜太阳电池,电池表面钝化及减反膜采用的是等离子增强化学气相沉积(PECVD)方法制备的SiN,薄膜电池的电极全部由正面引出,制成的23μm厚薄膜电池的光电转换效率为8 12%(1×1cm2,AM1 5,23℃)。扩展电阻的测量表明电池有良好的PN结特性;量子效率测量表明SiN比常规的热氧化SiO2有更好的减反射和钝化作用;电池的暗特性表明电池具有较高的串联电阻,并分析了正面引电极对串联电阻的影响。     

陶瓷衬底上薄膜电池的初步探索

采用快速热化学气相沉积方法在氧化铝和氮化铝陶瓷衬底上制备多晶硅薄膜及太阳电池。多晶硅薄膜的晶粒尺寸在经过区再结晶后增大且霍尔迁移率提高,但随后的薄膜生长发现薄膜出现裂纹,影响了电池的效率,在Al_2O_3衬底上得到196mV开路电压,1．93mA短路电流；在AIN衬底上得到310mV开路电压,5．31mA短路电流。     

16.0% Efficiency of large area (10 cm×10 cm) thin film polycrystalline silicon solar cell

High efficient large area thin film polycrystalline Si solar cell based on a silicon on insulator (SOI) structure prepared by zone-melting recrystallization (ZMR) is reported. Fabrication process of the via-hole etching for the separation of thin films (VEST) is newly developed. It is found that phosphorus treatment and back surface field (BSF) are quite effective for the VEST structure and the ZMR thin film polycrystalline silicon. The conversion efficiency as high as 16.0% for a practical size (10 cm×10 cm) is achieved. This is the highest for large area thin film polycrystalline Si solar cells ever reported.     

Characterization of thin-film silicon formed by high-speed zone-melting recrystallization process

We have studied the characterization of thin-film silicon formed by high-speed zone-melting recrystallization (ZMR) process. The dependence of crystal quality and solidification-front morphologies on scanning speed of melting heater was investigated by in situ observation of the molten-zone. It is found that solidification-front morphologies become unstable with quickening scanning speed and defect density increased extremely for a relatively thick poly-Si layer. On the contrary, by thinning the poly-Si layer, the solidification-front morphologies were kept stable at even higher scanning speeds and defect density was also kept low. In such ZMR films with low defect density, however, there are two types of subboundaries with and without branches. Furthermore, solar cells with simple structures were fabricated to evaluate the crystal quality of ZMR films. Charateristics of solar cells were strongly affected by the crystal quality of ZMR-Si films. Thus, it was clarified that stable solidification-front morphologies obtained by thinning the poly-Si layer and subboundaries without branches are suitable to obtain a highquality active layer. Consequently, the crystal quality of ZMR-Si films formed by high-speed ZMR process for a relatively thin poly-Si layer of 0.5 μm thickness and high scanning speed of 3.0 mm/s is comparable to that formed at a low scanning speed of 0.1 mm/s.     

Laser structuring of crystalline silicon thin-film solar cells on opaque foreign substrates

Crystalline silicon thin-film solar cells were fabricated on graphite substrates. A laser ablation process was developed for edge isolation of the thin-film cells. The shunt resistance was comparable to otherwise identical cells isolated by plasma etching, while the reproducibility of the laser isolation process was higher. The solar cells were characterized by current-voltage and light beam induced current measurements (LBiC). No interference was detected along the ablated edges. Spatial variations of the minority carrier lifetime are attributed to the grain structure of the seeding layer obtained by the zone melting recrystallization (ZMR).     

High-efficient operation of large-area (100 cm) thin film polycrystalline silicon solar cell based on SOI structure

High-efficient operation of a large-area thin film polycrystalline Si solar cell with a novel structure based on a silicon on insulator (SOI) structure prepared by zone-melting recrystallization (ZMR) is reported. The (100) crystal orientation area over 90% has successfully been obtained by controlling the ZMR conditions, which allowed to form a uniform random pyramidal structure at the cell surface. The effect of hydrogen passivation has also been investigated for further improvement of the cell characteristics. By employing a light trapping structure (textured surface) and hydrogen passivation, an efficiency of 14.22% was obtained for a practical 100 cm² size.     

Physical basis for the design of CdS/CdTe thin film solar cells

Solar cells based on polycrystalline semiconductor thin films have great potential for decreasing the cost of photovoltaic energy. However, this kind of solar cells has characteristics very different from those fabricated on crystalline silicon for which the carrier-transport and behavior is clearly known. Instead, for hetero-junction solar cells made on less known polycrystalline materials the design is almost empirical. In this work, several physical aspects related to the behavior of polycrystalline thin film solar cells will be discussed, and some considerations for an adequate design of this kind of solar cells will be made. For example, the recombination at the grain boundaries and its influence on the short circuit current as a function of the crystallite sizes on the active material is considered. Based on this, the appropriate thickness of each layer and their resistivity will be discussed. As an example, these considerations will be applied to CdS/CdTe heterojunction solar cells, taking into account typical properties of CdTe thin films used for solar cells.     

热壁外延生长GaAs薄膜的结构特征

该文介绍以Si和SnO2／glass两种材料为衬底，采用热壁外延方法，制得GaAs多晶薄膜。采用电子探针(EPMA)测定薄膜的组分、表面与剖面形貌，x射线衍射(xRD)分析薄膜的结构情况。结果表明该薄膜表面呈绒面结构、其晶粒为柱状结构，初步证明这种GaAs多晶薄膜有希望成为新一代廉价、高效太阳电池的候选材料。     

Aluminium-induced crystallisation of silicon on glass for thin-film solar cells

Aluminium-induced crystallisation of amorphous silicon is studied for the formation of continuous polycrystalline silicon thin-films on low-temperature glass substrates. It is shown to be a promising alternative to laser crystallisation and solid-phase crystallisation. Silicon grain sizes of larger than 10 μm are achieved at temperatures of around 475°C within annealing times as short as 1 h. The Al doping concentration of the poly-Si films depends on the annealing temperature, as revealed by Hall effect measurements. A poly-Si/Al/glass structure presented here can serve as a seeding layer for the epitaxial growth of polycrystalline silicon thin-film solar cells, or possibly as the base material with the back contact incorporated.