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/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 ℃, MHM-PD achieves a peak photoresponsivity of 14.5 A/W and a UV-to-visible rejection ratio of 104. As the thermal chuck temperature increases from 25 ℃ to 250 ℃, the performance of the HEMT-based amplifier shows good thermal stability. Finally, the IC achieves a photoresponse of over 106 V/W and a switching frequency of 50 kilohertz at 250 ℃ with rise and decay time constants of 3.95 μs and 2.8 μs, respectively. These results show that the IC has a high-sensitivity and high-speed UV detection capability.