High-performance 2D MoTe2-based photodetectors with superior Vis-NIR detection capability

Abstract

Photodetectors are crucial components for photoelectric conversion in intelligent sensing applications, and their performance can be significantly enhanced by using two-dimensional (2D) materials. In this study, we present a detailed investigation of 2H-MoTe₂-based field-effect transistors (FETs) for photodetection. We demonstrate that air annealing at specific temperatures effectively improves charge transport properties by stabilizing the electrical polarity, enhancing transconductance by 230% and carrier mobility by 41%, primarily through defect healing in the MoTe₂ lattice. The optimized 2D MoTe₂ photodetector exhibits an impressive responsivity of 3.53 A W⁻¹ and an external quantum efficiency (EQE) of 652% at 808 nm under 0.08 mW mm⁻². Furthermore, the constructed MoTe₂/MoSe₂ van der Waals heterojunction exhibits excellent rectifying behavior and ultralow dark current (<10⁻¹³ A at V_gs = −30 V). It delivers a peak responsivity of 3.32 A W⁻¹ at 671 nm, with an EQE of 614% and a photocurrent-to-dark-current ratio of 466 under 0.009 mW mm⁻². These results highlight the potential of 2D materials, particularly MoTe₂ and its heterojunctions, for high-performance visible-to-near-infrared(Vis-NIR) photodetection, paving the way for advanced applications in optoelectronics.