Formation of multiple quantum wires by strain-induced lateral-layer ordering process

Abstract

Quantum wire heterostructures have been grown in situ using gas source molecular beam epitaxy. Lateral composition variation was achieved in the Ga x In 1- x P material system via a strain-induced lateral-layer ordering process occurring spontaneously when (GaP) n/(InP) n short-period superlattices are grown on (100)-oriented on-axis GaAs substrates. This results in a quasi-periodic modulation of the Ga x In 1- x P composition along the [110] direction with a periodicity of 95 °A. Thin (≈200°A) layers of these laterally ordered regions imbedded between bulk lattice-matched Ga 0.51In 0.49P epilayers in the longitudinal direction form quantum wire arrays. The formation of multiple quantum wires is confirmed by cross-sectional transmission electron microscopy. The Ga x In 1- x P multiple quantum wire heterostructure exhibits highly polarized photoluminescence spectra with peak intensity ratios of over 24 for the two orthogonal polarizations as a result of strain-induced lateral-layer ordering.