A high-performance infrared photodetector based on GeTe films and In/Ag bimetallic electrodes

Abstract

GeTe is a significant narrow bandgap semiconductor material with diverse applications in thermoelectrics, phase change storage, and switching. GeTe is also a promising material for infrared photodetectors, characterized by its narrow bandgap and excellent carrier mobility. In this research, GeTe films were fabricated by utilizing magnetron sputtering techniques, and GeTe–In/Ag and GeTe–Ag photodetectors were fabricated. The material structures, optical properties, and electrical properties of these devices after annealing were compared. Under 915 nm light illumination, the GeTe–In/Ag photodetector exhibits superior photoelectric performance compared to the GeTe–Ag photodetector, exhibiting a responsivity of 538 A W⁻¹, a detectivity of about 1.35 × 10¹⁰ Jones, and an external quantum efficiency (EQE) of 727%; these remarkable characteristics can largely be ascribed to the interaction between hole trapping and the recombination of electron–hole pairs. The optoelectronic characteristics of GeTe films indicate considerable potential for use in infrared photodetector applications.