Growth of stacked InAs/InP quantum dot structures

We report on the growth of self-assembled InAs/InP quantum dots (QDs) on the lattice matched GaInAsP buffer by low pressure Metal Organic Chemical Vapor Deposition and discuss the effects of a thin GaAs interlayer, the QD growth time, and the V/III ratio on the QD nucleation. The GaAs interlayer reduces the As/P exchange reaction, consumes the indium layer segregated on the GaInAsP buffer surface and causes some gallium diffusion to the QDs. As a result, the QD photoluminescence (PL) emission wavelength blue shifts, the PL intensity increases and the PL linewidth decreases. As the QD growth time increases, the PL emission wavelength red-shifts but the PL linewidth increases due to further QD size fluctuations. An increase in the V/III ratio reduces the QD density and in general increases the QD size. The PL intensity is enhanced in stacked QD structures without any linewidth broadening compared to that of a single QD layer structure.