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

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 approximate to 3.8 x 10(3) and high BUV-visible rejection ratio (approximate to 1.8 x 10(2)) 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 approximate to 2.41 nA at +/- 200 V bias, I-Light/I-Dark ratio of approximate to 200 and high BUV-vis rejection ratio (approximate to 7 x 10(2)). 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 degrees 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.