Formation and Characterization of GaAs Quantum Wires at Giant Step Edges on Vicinal (110) GaAs Surfaces

Abstract

We report the formation of GaAs quantum wires using giant step structure formed during molecular beam epitaxial growth of AlGaAs on vicinal (110) GaAs surfaces. Atomic force microscope observation indicates that the steps extend to over several µm and are coherently aligned. The growth of an AlGaAs/GaAs quantum well (QWL) on the giant step structure forms quantum wires (QWRs) along the step edges. Carrier confinement into the QWRs is caused by the increase of well width (well-width modulation) and the decrease of Al composition in the AlGaAs barriers (barrier-compositional modulation), which are confirmed by transmission electron microscope observation. Redshift and strong polarization parallel to the wire direction in the photoluminescence spectra support carrier confinement into the GaAs QWRs.