Formation of GaAs island by Ga-droplet-induced chemical beam epitaxy

Abstract

We report on the formation of self-assembled GaAs quantum dots on GaAs(1 0 0) via chemical beam epitaxy (CBE) technique using triethylgallium (TEGa) and arsine. GaAs quantum dots each with diameter of 50 nm and density of 2.2×10 9 cm −2 were grown from Ga-droplets which are successively supplied with arsine with neither pattern definition nor pre-treatment steps prior to the growth. The density and the size of Ga-droplets are found to be sensitive to the growth conditions, such as the growth temperature, the beam equivalent pressure of TEGa, and the amount of TEGa supplied. The growth of high-density GaAs quantum dots can be achieved by simple change of source supply mode and their characteristics were found to depend not only on the growth conditions but also on the substrate misorientations. Our results demonstrate that Ga-droplet-induced chemical beam epitaxy can be a very effective way to grow quantum dots, even in lattice-matched material systems unlike Stranski–Krastanow growth.