Dual-functional ultraviolet photodetector with graphene electrodes on AlGaN/GaN heterostructure

Abstract

A dual-functional ultraviolet (UV) photodetector with a large UV-to-visible rejection ratio is presented, in which interdigitated finger-type two-dimensional graphene electrodes are introduced to an AlGaN/GaN heterostructure. Two photocurrent generation mechanisms of photovoltaic and photoconductive dominances coexist in the device. The dominance of the mechanisms changes with the induced bias voltage. Below a threshold voltage, the device showed fairly low responsivities but fast response times, as well as a constant photocurrent against the induced bias. However, the opposite characteristics appeared with high bias voltage. Specifically, above the threshold voltage, the device showed high responsivities with additional gain, but slow rise and recovery times. For instance, the responsivity of 10.9 A/W was observed with the gain of 760 at the induced bias voltage of 5 V. This unique multifunctionality enabled by the combination of an AlGaN/GaN heterostructure with graphene electrodes facilitates the development of a single device that can achieve multiple purposes of photodetection.

Graphene/AlGaN Schottky barrier photodiodes and its application for array devices

“…With increasing Al content, the Schottky barrier height becomes larger. For comparison, Bishma et al reported a Schottky barrier height of 0.15-0.65 eV for a graphene/AlGaN junction, 21,22) Fisichella et al reported a value of 0.4 eV, 23) and Kumer et al reported a value of 1.14 eV. 24) In contrast, our devices have a barrier height of 1.2-1.7 eV depending on the Al content, which is larger than these reported values.…”

Achieving High Responsivity and Detectivity in a Quantum-Dot-in-Perovskite Photodetector

“…Photodetectors have been widely applied as essential elements in numerous fields, such as optical communication, biomedical imaging, industrial inspection, and infrared surveillance . So far, most of the commercially available photodetectors are fabricated with inorganic materials (such as III–V or Si-based compounds), which show a weak response to the incoming optical signals due to a low-energy photon utilization. − Recently, organic–inorganic halide perovskite materials have attracted much attention in self-powered photodetectors. − For instance, the p-i-n junction structured self-powered photodetectors exhibit high photosensitivity and fast photoresponse at zero bias without consuming power. Thus, self-powered photodetectors with high responsivity have their own great potential in next-generation wireless telecommunication systems.…”

Advances in Self-Powered Ultraviolet Photodetectors Based on P-N Heterojunction Low-Dimensional Nanostructures

“…However, a high density of dislocations and other structural defects hinders their use. In the future, improving the crystallization quality of AlGaN will still be an important way to promote the performance of AlGaN-based UV photodetectors [ 102 , 103 ].…”