Fabrication of SiGe quantum wires and dots by low pressure chemical vapour deposition on patterned silicon substrates

Abstract

AbstractThe growth of SiGe/Si quantum well layers by low pressure chemical vapour deposition on patterned Si substrates has been achieved. Transmission electron microscopy shows the formation of SiGe quantum wires at the bottom of V grooves, at the corners between (001) and {111} planes of incompletely etched V groove structures, and more generally, at all types of convex corner formed by different crystal planes. Photoluminescence spectra of the V grooves and the incompletely etched structures of differing widths were taken. The main photoluminescence peaks of the incompletely etched structures stemfrom the (001) quantum well layer on the bottom. These peaks shift to higher energy as the width of these structures is reduced from 300 to 3 μm. These energetic shifts can be explained by surface diffusion of Gefrom the (001) quantum well into the quantum wires at the (100)–{111} sidewall corners during growth. Using a surface diffusion model with these energetic shifts a Ge surface diffusion length of λ=2·5 ...