Role of Nonequivalent Atomic Step Edges in the Growth of InGaN by Plasma-Assisted Molecular Beam Epitaxy

In this work, we study the growth mechanisms of InGaN in plasma-assisted molecular beam epitaxy (PAMBE). We demonstrate that for a metal-rich regime, in the range in which growth temperature limits the maximum In content, growth rate depends on gallium flux. This mechanism was investigated by the growth of InGaN/InGaN multi quantum wells (MQWs). We show that for constant growth temperature and nitrogen flux, the growth rate of MQWs decreases with decreasing gallium flux. We demonstrate also that at constant growth temperature and gallium flux, the In content in InGaN layers depends on nitrogen flux. We present an InGaN growth model that describes indium incorporation as a function of gallium and nitrogen fluxes, assuming that nonequivalent atomic step edges play an important role in indium incorporation mechanisms in PAMBE.