Crystal Growth Promotion Enables High‐Performance Te_0.7Se_0.3 Thin‐Film Shortwave Infrared Photodetector for Multispectral Imaging Applications

Abstract Tellurium‐selenium (Te_xSe_1‐x) alloy compound is considered as an excellent light absorber layer for thin‐film photodetector applications, owing to its suitable bandgap and excellent optoelectronic performance. Recently, the research on Te_xSe_1‐x photodetectors has achieved considerable progress, especially under electron and/or hole transport layer engineering to improve the device responsivity. However, the intrinsic growth mechanism of Te_xSe_1‐x thin film still needs investigation. In this work, based on the analysis of crystal growth thermodynamics and kinetics, Te_0.7Se_0.3 light absorber with optimal (100) growth orientation can be achieved through thermal evaporation of pre‐alloyed Te_0.7Se_0.3 powder and atmosphere‐assisted slow thermal annealing of Te_0.7Se_0.3 thin film. Thanks to the optimized Te_0.7Se_0.3 light absorber and Te_0.7Se_0.3/ZnO heterojunction interface, the champion self‐powered thin‐film photodetector possesses a wide spectral response range of 300–1600 nm, minimized dark current density of 3.1 × 10⁻⁵ mA cm⁻², accompanied with satisfactory responsivity of 0.06 A W⁻¹ and detectivity of 5.9 × 10⁹ Jones at 1300 nm, and linear dynamic range exceeding 101 dB. Interestingly, an imaging system based on this photodetector can achieve high‐precision color imaging and multispectral imaging from visible light to short wave infrared light, highlighting the intriguing application potential of Te_0.7Se_0.3 photodetectors.