High-performance solar-blind photodetector based on AlGaN/GaN heterostructure

Development of wide-band gap III-nitride semiconductors has been a subject of intense focus since the 1990s, primarily driven by the quest for blue lasers and high-brightness light-emitting diodes (LEDs). In parallel, III-nitrides have been studied extensively for use in ultraviolet (UV) photodetectors because they offer intrinsic visible- or solar-blind detection, which would eliminate the need for expensive and efficiency-limiting optical filters to remove out-of-band visible or solar photons. Such detectors would be well suited for numerous applications in the defense, commercial, and scientific arenas, including covert space-to-space communications, early missile-threat detection, chemical and biological threat detection and spectroscopy, flame detection and monitoring, UV environmental monitoring, and UV astronomy. In this paper, we considered an AlGaN/GaN photodetector grown on sapphire substrate. We studied I-V characteristics and we simulated the current as a function of voltage in darkness; we got a dark current of order 10^-7 for a concentration of 1e19 cm^-3. In the spectral response, we obtained a high current and flux spectral density for a wavelength of 350 nm for different x.