Improvement of the quality of InGaAs/InP quantum wires due to epitaxial overgrowth

Abstract

Using high-resolution electron beam lithography and a dry etching process, we fabricated InGaAs/InP quantum wires down to a geometrical wire width of 65 nm. In order to reduce surface recombination and surface depletion effects, the quantum wires were buried in an epitaxial layer of InP by low-pressure metalorganic vapor phase epitaxy (LPMOVPE). By optical studies and magnetotransport measurements, an overall improvement of the wire properties due to the epitaxial overgrowth is demonstrated. The quantum efficiency determined from luminescence experiments increased by two orders of magnitude for 65 nm wide quantum wires. Magnetotransport measurements yield an improvement of transport properties in overgrown wires. This article presents a recently developed in situ etching and overgrowth process in the LPMOVPE reactor which reduces the surface effects.