A high-speed ITO-InAlAs-InGaAs schottky-barrier photodetector

Abstract

A high-speed and high-sensitivity vertical indium-tin-oxide-InAlAs-InGaAs Schottky barrier photodetector has been designed, fabricated, and characterized. The devices had dark current densities as low as 8.87 × 10-5 A/cm-2 at an applied bias of 5 V. The responsivity for all the devices tested ranged from 0.55-0.60 A/W at a wavelength of 131 μm, and 0.563-0.583 A/W at 1.55 μm. The 15-μm diameter devices exhibited a -3 dB bandwidth of 19 and 25 GHz at a wavelength of 1.55 μm and an applied bias of 5 and 10 V, respectively. These are the best values of responsivity and bandwidth for a vertical InGaAs-based Schottky-barrier photodetector reported to date.