Abstract
Uniform InGaAs Quantum dots were fabricated by modified droplet epitaxy method termed Separated-Phase Enhanced Epitaxy with Droplets (SPEED). Due to the surface diffusion length difference between In and Ga, highly dense Ga droplets were formed around InGa alloy droplets. During the crystallization process of the droplets, these highly dense Ga droplets effectively prevented the two-dimensional growth of InGaAs. Moreover, phase separation effect was enhanced during the annealing process. As the result, InGaAs quantum dots, whose size was smaller than that of droplets, were formed in the upper part of the sample with a flat surface. These quantum dots provide narrow (21.6 meV) photoluminescence spectra. From the magneto-photoluminescence measurements, the sizes of quantum dots were estimated to be 10 nm and 3.7 nm in lateral and vertical directions, respectively.
