Self-organized growth of quantum-dot structures

We found a new self-organizing growth mode in the metalorganic vapor-phase epitaxy (MOVPE) on high-index GaAs (311)B substrates to form well-ordered arrays of quantum-dots. The spontaneous interaction of strained InGaAs layers with AlGaAs buffer layers results in high-density rows of disk-shaped InGaAs quantum dots buried within AlGaAs microcrystals due to lateral mass transport. The size and distance of the disks are controlled independently in the mesoscopic size range by the In composition and the InGaAs layer thickness, respectively, without affecting the uniformity and the shape. The photoluminescence spectra exhibit narrow linewidth and high efficiency at room temperature. Buried quantum disk structures are formed also on other GaAs (n11)B substrates and on InP (311)B substrates, indicating this growth mode to be universal in the strained layer growth on high-index semiconductor surfaces.