AlGaN Ultraviolet Metal–Semiconductor–Metal Photodetectors with Reduced Graphene Oxide Contacts

Bhishma Pandit,Jaehee Cho

doi:10.3390/app8112098

Abstract

AlGaN semiconductors are promising materials in the field of ultraviolet (UV) detection. We fabricated AlGaN/GaN UV metal–semiconductor–metal (MSM) photodiodes with two back-to-back interdigitated finger electrodes comprising reduced graphene oxide (rGO). The rGO showed high transparency below the wavelength of 380 nm, which is necessary for a visible-blind photodetector, and showed outstanding Schottky behavior on AlGaN. As the photocurrent, dark current, photoresponsivity, detectivity, and cut-off wavelength were investigated with the rGO/AlGaN MSM photodiodes with various Al mole fractions, systematic variations in the device characteristics with the Al mole fraction were confirmed, proving the potential utility of the device architecture combining two-dimensional materials, rGO, and nitride semiconductors.

Highlights

The III-nitride semiconductors and alloys thereof have been studied extensively because of their wide and direct bandgaps, high breakdown voltages, high mechanical and chemical stabilities, and low reverse leakage currents
We investigated reduced graphene oxide (rGO)/AlxGa1–xN MSM photodiodes with various Al mole an enhanced photo-to-dark current ratio and tunable cut-off wavelength depending on the Al mole fractions, x
We investigated rGO/Alx Ga1–x N MSM photodiodes with various Al mole fractions, x

Summary

Introduction

The III-nitride semiconductors and alloys thereof have been studied extensively because of their wide and direct bandgaps, high breakdown voltages, high mechanical and chemical stabilities, and low reverse leakage currents These promising properties have inspired the use of III-nitride semiconductors for many applications such as light-emitting diodes, laser diodes, photodetectors, high electron mobility transistors, field-effect transistors, Schottky diodes, and solar cells [1,2,3,4,5]. Among these applications, ultraviolet (UV) photodetectors that are usable in visible- to solar-blind conditions have drawn significant attention for use in missile plume detection, flame engine sensors, ozone layer monitoring, and secure intersatellite communication systems [6,7]. Such devices present low dark currents, low noise, high response speeds, and no doped layers [9,10]

Methods

Results

Conclusion