Progress on AlGaN-based solar-blind ultraviolet photodetectors and focal plane arrays

Abstract

Solar-blind ultraviolet (UV) photodetectors (PDs) have attracted tremendous attention in the environmental, industrial, military, and biological fields. As a representative III-nitride material, AlGaN alloys have broad development prospects in the field of solar-blind detection due to their superior properties, such as tunable wide bandgaps for intrinsic UV detection. In recent decades, a variety of AlGaN-based PDs have been developed to achieve high-precision solar-blind UV detection. As integrated optoelectronic technology advances, AlGaN-based focal plane arrays (FPAs) are manufactured and exhibit outstanding solar-blind imaging capability. Considering the rapid development of AlGaN detection techniques, this paper comprehensively reviews the progress on AlGaN-based solar-blind UV PDs and FPAs. First, the basic physical properties of AlGaN are presented. The epitaxy and p-type doping problems of AlGaN alloys are then discussed. Diverse PDs, including photoconductors and Schottky, metal–semiconductor–metal (MSM), p-i-n, and avalanche photodiodes (APDs), are demonstrated, and the physical mechanisms are analyzed to improve device performance. Additionally, this paper summarizes imaging technologies used with AlGaN FPAs in recent years. Benefiting from the development of AlGaN materials and optoelectronic devices, solar-blind UV detection technology is greeted with significant revolutions.

Current advances in solar-blind photodetection technology: using Ga2O3 and AlGaN

“…20 In addition, AlGaN has the advantages of high breakdown field, absorption coefficient, electron mobility and saturation velocity, together with good thermal stability, thereby making it the most suitable for applications such as UV photodetection, LEDs, LDs, high-speed electronics, and high-frequency transistors operating at elevated temperatures in extreme environmental conditions. 36,37…”

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

“…Thus, it is of great research value to develop wide-bandgap semiconductor photodetectors tailored to the various solar UV bands and blind to the visible and IR emissions [ 89 , 90 ]. Although a variety of semiconductor photodetectors are able to respond to UV photons, it has been recognized that GaN-based photodetectors are excellent candidates for the detection of UV radiation, and moreover, AlGaN-based photodetectors with threshold energies of 3.4 eV (GaN) up to 6.2 eV (AlN) can be fabricated by a proper choice of the Al mole fraction, which provides a good opportunity for deep UV detection [ 91 , 92 , 93 , 94 ].…”

Microstructural analysis of GaN films grown on (1 0 0) MgF$_2$ substrate by 4D nanobeam diffraction and energy-dispersive X-ray spectrometry

“…Here we focus on III-nitrides as solarblind photodetectors [2,3] and in particular on high-quality GaN photocathodes as part of UV microchannel plate (MCP) detectors for application in astronomy as conceptionalized previously [4]. For such applications, GaN has to be combined with window materials, which are highly transparent in the deep UV.…”