High-temperature characteristics of GaN/InGaN multiple-quantum-well UV photodetectors fabricated on sapphire substrate: Analysis of photovoltaic and carrier transit time properties

To accomplish a high-temperature operation of GaN/InGaN multiple-quantum-well (MQW) UV photodetectors (UV-PDs), the investigation of device performances at high-temperature regimes is truly essential. Therefore, in the present work, GaN/InGaN MQW-based UV-PDs on sapphire are fabricated and their photovoltaic and carrier transit time characteristics are investigated at different temperatures. Our results suggest that the temperature has a strong impact on various photovoltaic properties: we noticed an increase in short circuit current density and a significant lowering in open circuit voltage and power conversion efficiency when the ambient temperature increases from 25 to 300 °C. The time-dependent photo-response characteristics at different temperatures suggest that both the rise time and fall time are reduced at high temperatures, indicating the thermal activation of localized charges at an exacerbated temperature.