Keywords: 
• 掺硼氧化锌(BZO)薄膜 /
• In2O3 Sn(ITO)中间层 /
• 表面形貌 /
• 太阳电池

Abstract: Boron-doped zinc oxide (BZO) films with a natural pyramid-textured surface grown by metal organic chemical vapor deposition (MOCVD) have large light trapping effect in thin film silicon solar cells when used as front contact electrodes. However, the surface topography of traditional BZO films is so sharp as to damage the quality of the subsequent silicon thin film materials and to reduce the photovoltaic conversion effciency of the solar cells. In this work, an ultra-thin In2O3:Sn(ITO)film (～4 nm) is used as the interlayer in the sandwiched structure of the multilayer films, i.e. glass/bottom BZO layer /ITO interlayer/top BZO layer. The surface properties can be improved through modulating the thickness of the top BZO layer. Appropriate thickness of top BZO layer and ITO interlayer are helpful for obtaining the cauliflower-like surface morphology and thus the sharp structure becomes relatively gentle, but the surface morphology still keeps a pyramid feature when depositing thicker top BZO layer. The relatively gentle surface morphology could promote crystallization quality of μc-Si:H thin film materials and reduce cracks in intrinsic layer and TCO/P-Si interface defects. Finally, this new sandwiched structure of multilayer ZnO films is applied in μc-Si:H p-i-n thin film solar cells. Compared with traditional BZO films, the quantum efficiency (QE) of solar cells with a sandwiched structure of ZnO increases by about 10%, and both the open-circuit voltage (Voc) and short-circuit current density (Jsc) may increase and thus improve the solar cell efficiency.