Design of a self-powered 2D Te/PtSe2 heterojunction for room-temperature NIR detection†

Abstract

The advent of two-dimensional (2D) materials with exceptional properties has opened avenues for the development of high-performance infrared (IR) detectors through innovative approaches. Nevertheless, the intricate preparation procedures have constrained the deployment of 2D materials in IR detection applications due to their complex fabrication processes, sharply raised contact resistances, and severe interfacial recombination of 2D materials. In this study, we present a novel magnetron sputtering method for the preparation of 2D Te films, which are then combined with PtSe₂ films to form heterojunction devices with high performance due to the good interfacial contacts that reduces interface recombination. By modulating the growth temperature, we obtained Te films grown at the optimal growth temperature of 200 °C, which exhibited a uniform nanorod structure and high crystal quality with a narrow band gap of 0.4 eV and good light absorption in the IR region. The built-in electric field formed at the heterojunction interface can effectively separate the photogenerated carriers, thereby enhancing the device's optoelectronic performance and allowing operation at zero bias, which reduces the impact of dark current on the device. Under the light illumination of 850 nm at zero bias, the device exhibits a maximum responsivity of 10.9 mA W⁻¹, specific detectivity of 9.3 × 10¹¹ Jones, EQE of 1.6%, and I_light/I_dark ratio of 9.6 × 10⁴.