InAs quantum dots (QDs) are grown on an In_0.53Ga_0.47As interlayer and embedded in an InP(100) matrix. They are fabricated via droplet epitaxy (DE) in a metal organic vapor phase epitaxy (MOVPE) reactor. Formation of metallic indium droplets on the In_0.53Ga_0.47As lattice-matched layer and their crystallization into QDs is demonstrated for the first time in MOVPE. The presence of the In_0.53Ga_0.47As layer prevents the formation of an unintentional non-stoichiometric 2D layer underneath and around the QDs, via suppression of the As-P exchange. The In_0.53Ga_0.47As layer affects the surface diffusion leading to a modified droplet crystallization process, where unexpectedly the size of the resulting QDs is found to be inversely proportional to the indium supply. Bright single dot emission is detected via micro-photoluminescence at low temperature, ranging from 1440 to 1600 nm, covering the technologically relevant telecom C-band. Transmission electron microscopy investigations reveal buried quantum dots with truncated pyramid shape without defects or dislocations.

Read full paper: Droplet epitaxy of InAs/InP quantum dots via MOVPE by using an InGaAs interlayer