A dual-gate phototransistor based on van der Waals heterostructure for short-wave infrared photodetection

Alloying tellurium (Te) with selenium (Se) to form SexTe1−x alloys offers a promising alternative for short-wave infrared (SWIR) photodetection due to its widely tunable bandgap and inherent one-dimensional crystal structure that minimizes surface dangling bonds. However, achieving simultaneously low dark current and high specific detectivity in SexTe1−x-based photodetectors remains challenging. Here, we demonstrate a dual-gate phototransistor utilizing a graphene/h-BN/Se0.3Te0.7 heterostructure for high-performance SWIR photodetection. The fabricated device exhibits a field-effect mobility of 72.1 cm2 V−1 s−1 and a subthreshold swing of 3.8 V/dec. Under 1550 nm SWIR illumination, it achieves a responsivity of 2.12 A/W and a specific detectivity of 1.57 × 1010 Jones at room temperature, marking a clear performance improvement over the previously reported SexTe1−x-based photodetectors. This work demonstrates that the synergistic integration of dual-gate modulation provides a scalable route toward high-performance SWIR photodetection systems.