Arrays of strained InAs quantum dots in an (In Ga)As matrix, grown on InP substrates by molecular-beam epitaxy

Abstract

Arrays of strained InAs islands in an (In, Ga)As matrix on an InP(100) substrate are synthesized by molecular-beam epitaxy, and their structural and optical properties are investigated. According to transmission electron microscope and high-energy electron diffraction data, the critical thickness corresponding to the onset of island growth is 3 monolayers. The resulting InAs islands are coherently strained, and their base diameter varies from 20 nm to 90 nm. The formation of islands produces in the photoluminescence spectra a dominant long-wavelength line, which shifts toward lower energies as the effective thickness of the InAs increases. The radiation emitted by the InAs islands spans a wavelength range of 1.65–2 µm.