Indium induced step transformation during InGaN growth on GaN

The surface-step evolution of InGaN quantum-wells (QWs) was studied on GaN (0001). While the GaN template is dominated by single-monolayer steps the frequency of multiple-layer steps increases significantly when InGaN/GaN single- or multiple-QWs are grown. It is proposed that the InGaN multiple-layer step structure arises to partially accommodate the in-plane film strain which is insufficient to trigger bulk InGaN relaxation. This intrinsic multiple-layer step restructuring, when coupled with the strong piezoelectric fields present in the wurtzite group III-nitrides, could explain the enhanced carrier localization in InGaN QWs.