Valency Control of Glow Discharge Produced a-SiC:H and its Application to Heterojunction Solar Cells

A new type of amorphous silicon solar cell having a conversion efficiency of 8% level is introduced. The cell has a wide band gap window layer made of hydrogenated amorphous silicon carbide, (a-SiC:H), with a good valency control. Electrical, optical and optoelectronic properties of a-SiC:H have been investigated, together with their valency controllability. A design concept and some key technologies to improve solar cell performance with this new material are demonstrated. A series of technical data on material preparation and cell performance are presented. Clear improvements in cell performance, not only I_DC but also V_DC, have been obtained. The realistic limit of the conversion efficiency in a-Si solar cells is estimated and discussed.