(Invited) III-V/GaP Epitaxy on Si for Advanced Photovoltaics and Green Light Emitters

Abstract

Epitaxy of III-V compound semiconductors on Si-based substrates with lattice constants between Si and Ge is of great interest for photovoltaic applications as it opens a pathway for achieving near ideal bandgap profiles for maximum solar energy conversion efficiency while simultaneously providing a low-cost Si production platform for III-V cell technologies. The same range of lattice constants also enables access to direct gap III-Vs that can fill the "green gap" present in light emitting devices. This presentation focuses on the materials and III-V/Si heteroepitaxy issues that are currently being addressed, which can lead to breakthrough technologies for both photovoltaics and light emitting devices. We focus on an approach in which the grading between Si and Ge (GaAs) is achieved via wider bandgap GaAsyP1-y metamorphic buffers, from GaP to GaAs, enabling access to the underlying Si as an active solar cell component.