Realization of High‐Performance Photoresponsivity of Sb₂Se₃‐Based Phototransistors by Using Hybrid Structure and Optimizing Annealing Temperature

Abstract

Antimony selenide (Sb2Se3) is attracting attention as a candidate material with a high potential for photodetection due to its high absorption coefficient and excellent stability compared to other light‐absorbing materials. However, Sb2Se3‐based photodetectors are found to yield rather low responsivity in the visible and near‐infrared regions. Herein, the hybrid structure of ZnON/Sb2Se3 is for the first time adopted to increase the performance of Sb2Se3‐based phototransistors. It is shown that ZnON with high mobility enhances the photoresponse by promoting the recirculation of photocarriers. The (Sb4Se6)n ribbons of Sb2Se3 are found to be vertically oriented when annealed at 200 °C, inducing photocarriers to ZnON more easily than laterally oriented ribbons. The 200 °C‐annealed phototransistors give high responsivity of 2.14 × 104 A/W−1 (650 nm) and 2.47 × 104 A/W (905 nm), the latter being the highest among Sb2Se3‐based photodetectors. Further, the 200 °C‐annealed phototransistors exhibit superb stability, showing over 92% of the initial responsivity and over 81% detectivity even after being exposed to air for 5 weeks without passivation. It is further shown that the optimal devices reveal remarkably stable detectivity of 4.76 × 1013 Jones and 5.95 × 1013 Jones for 650 nm and 905 nm light, respectively.