Fabrication and characterization of InGaAs/GaAs strained quantum wires grown by molecular beam epitaxy

Abstract

Strained InGaAs/GaAs quantum wires have been fabricated by a combination of electron beam (EB) lithography, dry and wet etching, migration-enhanced epitaxial (MEE) and molecular beam epitaxial (MBE) regrowth. Three different fabrication processes have been investigated. It was found that wet etching after dry etching removed most of the damage induced by the dry etching process, which produced high quality quantum wires. From the transmission electron microscopy (TEM) study, all samples showed good interfaces and regrown layers. However, photoluminescence (PL) measurement showed that only sample that was etched in citric acid after the patterning and dry etching and then regrown had high radiative efficiency, and showed strong PL for wire widths down to 190 nm. A high-resolution transmission electron microscopy (HRTEM) lattice image showed that relevant atoms were perfectly aligned across the lateral heterointerface of the InGaAs quantum wire and GaAs barrier layer.