Microcrystalline SiO and its Application to Solar Cell

Abstract

As microcrystalline silicon oxide (μc-SiO) is reported to be more promising material than microcrystalline silicon carbide for the application to solar cells, both of high efficiency amorphous (top cell) and microcrystalline (bottom cell) silicon solar cells fabricated on tin oxide coated glass substrate have been developed by using μc-SiO p-layer and buffer i-layer. High VHF frequency of 60 MHz and carbon dioxide gas are used for their deposition. ZnO deposited by DC sputtering is coated on Asahi’s type U tin oxide in order to promote the crystallization of the μc-SiO p-layer. It was found that the top cell with this novel mc-SiO p-layer has higher cell efficiency than the one with normal SiO p-layer. Furthermore, the microcrystalline bottom cell with novel μc-SiO p-layer and μc-SiO buffer layer has higher performance than the one with normal μc-Si p-layer. Up to now, an efficiency of more than 15% has been achieved with a-SiO/a-SiGe/μc-Si tandem cell.