Long‐Term, High‐Voltage, and High‐Temperature Stable Dual‐Mode, Low Dark Current Broadband Ultraviolet Photodetector Based on Solution‐Cast r‐GO on MBE‐Grown Highly Resistive GaN

Abstract New generation of hybrid photodetectors may provide the optimal solution for compact, highly sensitive, durable, and reliable broadband ultraviolet (BUV) sensors. A high‐performance dual‐mode BUV photodetector based on melding of highly resistive GaN and reduced graphene oxide is reported. Under zero bias, the device exhibits a sub‐picoampere dark current, high light‐to‐dark current (I_Light/I_Dark) ratio of ≈3.8 × 10³ and high BUV–visible rejection ratio (≈1.8 × 10²) with fast rise and fall times. The photodetector displays remarkable stability when subject to extreme operating conditions. The photoresponse of the detector shows a dark current of ≈2.41 nA at ± 200 V bias, I_Light/I_Dark ratio of ≈200 and high BUV–vis rejection ratio (≈7 × 10²). The response time of device is typically in the range of 15–27 ms measured at 12 Hz light chopping frequency. When subjected to high working temperature of up to 116 °C, it shows a stable optical switching response. In addition, the device displays impressive long‐term stability with no change in photoresponse even after a period of 28 months. This unique combination of low dark current, dual‐mode operation, and no aging effects upon prolonged exposure to high‐operating voltage, high‐temperature, and BUV radiation is attractive for a variety of harsh environment applications.