High-temperature ultraviolet photodetector and amplifying integrated circuits based on AlGaN/GaN heterostructure

Abstract In this work, an ultraviolet (UV) photodetection and amplifying integrated circuit (IC) based on an AlGaN/gallium nitride (GaN) heterostructure is demonstrated. The IC consists of a metal-heterostructure-metal photodetector (MHM-PD) and a high-electron-mobility transistor (HEMT)-based amplifier. The photoresponse of the MHM-PD increases at elevated temperatures due to the spatial separation of the photocarriers under the polarization electric field at the AlGaN/GaN heterointerface, as well as the photo-enhanced leakage current through the metal-heterostructure junction. At 250 °C, MHM-PD achieves a peak photoresponsivity of 14.5 A W −1 and a UV-to-visible rejection ratio of 10 4 . As the thermal chuck temperature increases from 25 °C to 250 °C, the performance of the HEMT-based amplifier shows good thermal stability. Finally, the IC achieves a photoresponse of over 10 6 V W −1 and a switching frequency of 50 kHz at 250 °C with rise and decay time constants of 3.95 μ s and 2.8 μ s, respectively. These results show that the IC has a high-sensitivity and high-speed UV detection capability.