GaN quantum-dot formation by self-assembling droplet epitaxy and application to single-electron transistors

Abstract

GaN quantum dots were formed on an AlGaN/SiC substrate by gas-source molecular beam epitaxy using a self-assembling technique with Ga droplets. The photoluminescence properties of the quantum dots obtained at several crystallization temperatures were investigated. High photoluminescence intensity was observed from GaN quantum dots formed without a wetting layer at a crystallization temperature of 700 °C. Single-electron transistors formed using GaN quantum-dot islands exhibited Coulomb blockade phenomena with negative conductance at 2.7 K and a clear Coulomb staircase at 200 K.