High-Temperature Forward and Reverse Current Transport Mechanisms of AlGaN-Based Solar-Blind UV Photodetector

Abstract

This article describes the fabrication and comprehensive characterization of the metal-organic chemical vapor deposition (MOCVD)-grown back-illuminated Al0.42Ga0.580.58-based p-i-n solar-blind ultraviolet (UV) photodetector (PD). The results reveal that the manufactured device exhibits a cutoff wavelength of approximately 285 nm, which is in agreement with the bandgap of Al0.42Ga0.580.58. In addition, a solar-blind/visible light rejection ratio of over <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{4}}$ </tex-math></inline-formula> and a photocurrent/dark current ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{4}}$ </tex-math></inline-formula> can be obtained for the p-i-n UV PD. Moreover, the current–voltage–temperature ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} - {V} - {T}$ </tex-math></inline-formula> ) measurements were performed to explore the forward and reverse current transport mechanisms for the high-temperature reliability analysis of the device. The tunneling current was found to make the dominant contribution to the forward current. Furthermore, carrier-hopping conduction and Poole–Frenkel emission models convincingly explained the observed reverse temperature-dependent dark <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} - {V}$ </tex-math></inline-formula> characteristics.