Optimizing the Charge Carrier Dynamics of Thermal Evaporated Te_xSe_1‐x Films for High‐Performance Short‐Wavelength Infrared Photodetection

Abstract Short‐wavelength infrared photo‐sensing materials are dominated by germanium, indium gallium arsenide, indium antimonide, and mercury cadmium telluride. However, the complex fabrication process and high production cost hinder their widespread applications. Recently, Te_xSe_1‐x has shown great potential for infrared photodetection, but Te_xSe_1‐x‐based devices are still suffering from extremely high dark current and poor device performance. In this work, high‐quality Te_xSe_1‐x films are fabricated by thermal evaporation and low‐temperature annealing. The optoelectronic properties of the Te_xSe_1‐x thin films are systematically investigated and optimized. The absorption spectrum is carefully tuned to cover the broad range from 300 to 1600 nm by modulating the ratio of Te and Se. Photodiodes based on the optimized Te_xSe_1‐x thin films are also fabricated, and achieve high responsivity, reduced dark and low noise current density, and a fast response time of <850 ns. Then, prototypical devices based on Te_0.65Se_0.35 thin films are demonstrated for optical communications, indicating the great potential for next‐generation, low‐cost short‐wavelength infrared photodetection.