Large negative thermal quenching of yellow luminescence in non-polar InGaN/GaN quantum wells

Large negative thermal quenching (NTQ) of the yellow luminescence (YL) for a temperature increase from 5 to 300 K is observed in non-polar InGaN/GaN quantum well (QW) samples due to the thermal migration of carriers from the InGaN QW layers to the GaN barrier layers for the first time. Such an unusual phenomenon happens only when the carriers are optically excited inside the QW layers, providing solid evidence for the occurrence of thermal transfer of photoexcited carriers from the QW layers to the GaN barrier layers. A simple model considering the thermal transfer of carriers is proposed to interpret the observed NTQ phenomenon. The thermal activation energy of the carriers is determined by fitting the reciprocal temperature dependence of the YL intensity in the Arrhenius plot with the model.