High-Responsivity Ge Schottky Photodetectors With Short-Wave Infrared Transparent Conductive Oxide Electrodes

In this study, we fabricated and demonstrated high-responsivity Ge Schottky photodetectors (PDs) comprising short-wave infrared (SWIR) transparent conductive oxide (TCO) electrodes in a front-side illumination manner. The SWIR-TCO/Ge Schottky heterojunctions exhibited apparent rectifying behavior in both p- and n-type Ge, with Schottky barrier heights of 0.419 and 0.236 eV, respectively. Furthermore, the SWIR-TCO/p-Ge Schottky PDs exhibited a linear responsivity to the incident power and broadband photoresponse at wavelengths in the range of 800–1800 nm owing to the high transparency of TCO. This study achieved the highest photoresponsivity of 0.800 A/W at a wavelength of 1500 nm. The external quantum efficiency increased as the wavelength decreased, peaking to 89.1% at 800 nm.