A high-performance short-wave infrared phototransistor based on a 2D tellurium/MoS2 van der Waals heterojunction

Emerging two-dimensional semiconductors, particularly black phosphorus, have attracted great interest for their potential use in room-temperature and low-cost infrared photodetectors. Nevertheless, widespread application with black phosphorus has been substantially delayed by its lack of scalability and low environmental stability. Herein we report the hydrothermal synthesis of air-stable 2D tellurium with tunable thickness ranging from tens of nanometers down to 2.6 nm as well as the fabrication of a Te/MoS2 van der Waals heterojunction for a high-performance short-wave infrared (SWIR) photodetector. The heterostructure exhibits well-behaved field-effect transistor properties with a high ON/OFF ratio of over 107 and a steep subthreshold swing of 150 mV dec−1. Due to the narrow bandgap of Te, the photodetector's response spectrum covers the whole SWIR band with a peak responsivity of 28.4 A W−1, 4.0 A W−1, and 0.87 A W−1 under 980 nm, 1.55 μm, and 3.0 μm illumination, respectively. Accordingly, detectivity up to 2.7 × 1010 and 3.4 × 109 Jones is obtained at 980 nm and 1.55 μm wavelengths, respectively. These findings demonstrate the potential of 2D Te as a new platform for realizing room-temperature SWIR photodetectors. Besides, our study can serve as a reference for other vdW structure designs, thus expanding the research scope for 2D Te-based optoelectronics.