Visible-Blind Metal-Semiconductor-Metal Photodetectors Based on Undoped AlGaN/GaN High Electron Mobility Transistor Structure

Abstract

Visible-blind Schottky metal-semiconductor-metal photodetectors (MSM-PDs) fabricated on an undoped AlGaN/GaN high electron mobility transistor (HEMT) structure were reported. Dark-current density as low as 1.8 ×10 -8 A/cm 2 at 10 V bias was obtained. A peak responsivity of 114 mA/W at 350 nm was measured under top illumination with a constant irradiation power density of 10 µW/cm 2 , which corresponds to an external quantum efficiency of 40%. The MSM-PDs based on this structure are of advantage for monolithic integration with HEMT circuits in one epitaxial step.