晶体硅太阳电池金属电极光学损失的理论分析与实验研究

本文基于丝网印刷和丝网印刷后光诱导电镀太阳电池,分析了太阳电池前表面金属电极引起的光学损失的各种情况.考虑到空气-玻璃界面和金属电极两侧边缘区域的反射,通过将金属电极截面近似为半椭圆形模拟了电极的光学损失,计算得到的有效宽度比约为金属电极几何宽度的40%.通过对不同类型样品反射谱的测量计算,同时在理论模拟和实验测量上得到了太阳电池前表面金属电极的光学损失,相应的理论与实验结果相符合. 关键词： 光学损失 有效宽度比 光诱导电镀 反射谱     

立方氮化硼薄膜注入Be的Hall效应研究

本文应用RF溅射法,在n型Si(100)衬底上制备BN薄膜.首次用离子注入工艺,将铍(Be)离子注入到BN薄膜中使之成为p-型.我们用范德堡方法对该薄膜进行了室温下的霍尔效应测量,薄膜为P型导电,电阻率为10-3Ω·cm左右,迁移率14～28 cm2/V·S,载流子浓度1019～1020cm-3,霍尔系数10-1cm-3/C左右,用此法制备的P-BN/n-BN异质结,有明显的整流特性.     

采用两步压强法制备优质微晶硅薄膜

针对氢化微晶硅薄膜吸收系数较低、制备需要较高厚度,从而需要较高沉积速度的问题,考虑到压强对沉积速度及晶化比的重要影响,在分析了单一压强法制备薄膜优缺点的基础上,提出了采用两步法来制备高质量微晶硅薄膜的方法.即先采用高压制备薄膜2min,减小非晶转微晶的孵化层厚度,然后再采用低压制备薄膜18min,提高薄膜的致密度及减小氧含量,最后制备出了光敏性较高,晶化比较大并且光照稳定性也较好的优质氢化微晶硅薄膜.     

SiO2/SiNx:H选择性刻蚀改善光诱导化学镀/电镀多晶硅太阳能电池过镀现象

自对准的光诱导化学镀/电镀技术以其栅线宽度小、工艺快捷高效等优点, 成为制备选择性发射极太阳能电池的理想选择. 然而, 该技术的前序需要HF溶液有效去除重掺杂区表面SiO₂的同时, 避免在SiNx:H掩模上刻蚀出微孔而露出衬底的硅, 否则金属镍和银会在光诱导化学镀/电镀工艺中沉积在微孔中, 导致过镀现象. 这就要求预处理溶液对SiO₂/SiNx:H有很高的选择性刻蚀. 本工作根据实验结果分析了产生过镀现象的原因, 研究了进行SiO₂/SiNx:H选择性刻蚀的可行性. 依据HF刻蚀SiO₂和SiNx:H的机理, 通过调节HF缓释溶液的pH值, 改善了多晶硅太阳能电池的过镀现象.     

Preparation of hydrogenated microcrystalline silicon films with hot-wire-assisted MWECR-CVD system

Intrinsic hydrogenated microcrystalline silicon (\muc-Si:H) films have been prepared by hot-wire-assisted microwave electron-cyclotron-resonance chemical vapour deposition (HW-MWECR-CVD) under different deposition conditions. Fourier-transform infrared spectra and Raman spectra were measured. Optical band gap was determined by Tauc plots, and experiments of photo-induced degradation were performed. It was observed that hydrogen dilution plays a more essential role than substrate temperature in microcrystalline transformation at low temperatures. Crystalline volume fraction and mean grain size in the films increase with the dilution ratio (R=H₂/(H₂+SiH₄)). With the rise of crystallinity in the films, the optical band gap tends to become narrower while the hydrogen content and photo-induced degradation decrease dramatically. The samples, were identified as \mu c-Si:H films, by calculating the optical band gap. It is considered that hydrogen dilution has an effect on reducing the crystallization activation energy of the material, which promotes the heterogeneous solid-state phase transition characterized by the Johnson--Mehl--Avrami (JMA) equation. The films with the needed structure can be prepared by balancing deposition and crystallization through controlling process parameters.