Influence of Bi on morphology and optical properties of InAs QDs

Abstract

We study the tsurface morphology and photoluminescence (PL) property of InAs quantum dots (QDs) on GaAs using bismuth (Bi) in the layer prior to or after the growth of QDs. Incorporating Bi in the layer prior to the QD deposition delays the onset of InAs QD formation resulting in a decrease in QD height and density. As a surfactant, adding Bi in the GaAs capping layer at a high growth temperature reduces the In surface diffusion length leading to uniform and well preserved InAs QDs in terms of height and density. The incorporation of 3% Bi at a low growth temperature, which forms a GaAsBi capping layer, can effectively lower the PL transition energy up to 163 meV and reduce the PL linewidth, leading to an emission wavelength of 1.365 μm at 77 K.