Influence of $As4$ flux on the growth kinetics, structure, and optical properties of $InAs∕GaAs$ quantum dots Available to Purchase

We report the effects of variations in $As4$ growth flux on the evolution of molecular beam epitaxy grown InAs quantum dots (QDs) and their structures and optical properties. For InAs QDs grown under As-stable conditions, evaluated through photoluminescence and atomic force microscopy (AFM) measurements, it is evident that QD size increases with $As4$ pressure along with improvement in size uniformity. Furthermore, transmission electron microscopy measurements for InAs layers of critical thicknesses (⁠$∼1.7$ ML) showed decreasing QD density with increasing $As4$ pressure accompanied by a strong reduction in photoluminescence (PL) integral intensity. These show that high $As4$ fluxes suppress InAs QD formation while the decreasing PL intensity seems to indicate cluster formation that features nonradiative recombination. AFM measurements show larger and denser QDs for samples grown at higher $As4$ pressures. These are explained on the basis of adatom condensation during surface cooling and the influence of $As4$ pressure on indium incorporation.