Lattice-mismatched InGaAs nanowires formed on GaAs(1 1 1)B by selective-area MOVPE

Abstract

We grew on GaAs(1 1 1)B InGaAs nanowires with lattice-mismatched composition using catalyst-free selective-area metalorganic vapor phase epitaxy and analyzed the effect of lattice mismatch on crystal structure and quality. An energy dispersive X-ray microscopy analysis indicated that the atomic contents of group-III atoms, Ga and In, were constant with little dispersion along a 2 μm-long nanowire. This indicates that a possible difference in migration length between In and Ga atoms on the sidewall facets has no effect on the compositional distribution along the nanowires with lengths of up to 2 μm. Photoluminescence spectra for InGaAs planar layers grown on GaAs(1 0 0) and GaAs(1 1 1)B substrates showed no peak corresponding to the InGaAs band-edge emission, due to lattice mismatch between the layers and the substrate. However, the nanowires with a lattice mismatch of 2.1% showed a strong and sharp band-edge emission peak at 1.12 eV. This means that crystal quality of the InGaAs nanowires was better than that of the planar layers for a lattice-mismatched system.