Novel high-efficiency c-Si compound heterojunction solar cells: HCT (Heterojunction with Compound Thin-layer)

A new concept of developing high-efficiency c-Si heterojunction solar cells is proposed in this work. By replacing a-Si:H thin films in HIT solar cells with appropriate compound semiconductors, we propose novel heterojunction structures which allow higher efficiency than that of HIT solar cells, and this novel type of solar cells is denominated HCT (Heterojunction with Compound Thin-layer). The compound heterojunction materials are preliminarily selected from binary semiconductors whose lattice constants, energy bands and coefficients of thermal expansion match the ones of c-Si, and their feasibilities are investigated by using a solar cell numerical modeling tool, wxAMPS. The modeling investigation indicates that HCT possess better energy band structures at hetero-interfaces than HIT. Finally, this paper concludes the compound selection standards, and suggests several novel research topics in the real device implementation of high-efficiency HCT solar cells.