On the correlations between the excitonic luminescence efficiency and the QW numbers in multiple InGaN/GaN QW structure

In this work, we compare the luminescence results obtained on InGaN/GaN multiple quantum well (QW) structures with different numbers of QWs. Structures are designed for scintillating applications, where large QW number covering particle penetration depth is necessary, and fast luminescence response is required. Special attention is devoted to increase the intensity of fast excitonic QW emission and to decrease the luminescence of the QW defect band, which has slower luminescence response and is undesired for fast scintillator applications. We found that increasing the In content in QWs suppresses the defect band luminescence and decreasing the QW growth rate increases the photoluminescence (PL) intensity of excitonic luminescence. We also show that increasing the number of InGaN further improves the PL properties of InGaN QWs. The photoluminescence and cathodoluminescence characteristics are compared and discussed.