Effects of growth parameters on the surface morphology of InAs quantum dots grown on GaAs/Ge/Si1−xGex/Si substrate

Abstract

We present the heterogeneous growth of InAs quantum dots (QDs) on Si platform using GaAs/Ge/Si1−xGex/Si substrate. Self-assembled InAs QDs were grown on GaAs/Ge/Si1−xGex/Si substrate by employing molecular beam epitaxy (MBE). The areal density, width and height of QDs were characterized using atomic force microscopy (AFM). The undulation originating from the graded Si1−xGex/Si substrate causes no noticeable change in dot densities and dot dimensions across the undulated surface. The effects of V/III ratio and InAs coverage on structural properties of the QDs were investigated. The dot density increases with increasing V/III ratio and QDs with high density of 1011cm−2 were obtained, attributed to the reduced diffusion length of the adatoms. Lateral dimension of the QDs increases as the InAs coverage increases. The QDs coalesce at 3.0 monolayer (ML) InAs coverage. This work is beneficial to those working on III–V on Si integration.