Optical properties of InGaN/GaN SQD nanocolumn and InGaN nanocolumn

We have studied the emission mechanism of InGaN/GaN nanocolumns. We extracted only the effect of localized states and investigated the difference between InGaN/GaN single-quantum-disc (SQD) and InGaN nanocolumns by means of photoluminescence and photoluminescence excitation measurements. The difference between the localized states was interpreted by the band tail model. We conclude that the InGaN nanocolumn has widely distributed localized states, while the InGaN/GaN SQD has a single localized state.