CVD growth of Ge1−xSnx using large scale Si process for higher efficient multi-junction solar cells

Abstract

Multi-junction solar cell efficiency gains due to GeSn and SiGeSn have already shown that a need exists for significant advancement in growing this material in a commercially available CVD chamber. Ge1-xSnx films have been grown via an Epsilon RPCVD single wafer CVD deposition tool on Si using a relaxed Ge buffer layer. The material and optical properties of these films have been characterized for various compositions. We present the characterization of strained Ge1-xSnx with x = 0.9 % to 7 % and photoluminescence of Ge1-xSnx grown via a commercial CVD reactor. This commercial growth accessibility shows that this ternary material should allow for further advancements in multi-junction photovoltaics using Si CMOS compatible processes.