MBE growth of GaP on a Si substrate

It is shown that single-crystal GaP buffer layers can be formed on a Si substrate by molecular-beam epitaxy, with the “migration-enhanced epitaxy” procedure applied in the stage in which the nucleating layer is formed. When a GaP layer is produced on a $p$-type silicon substrate, a $p$–$n$ junction is created in a natural way between the $p$-Si substrate and the surface $n$-Si layer produced by the diffusion of phosphorus into the substrate during the course of the epitaxial growth of GaP. This $p$–$n$ junction can be used as the first junction of a silicon-based multijunction photovoltaic converter.