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

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer enhanced properties for photoelectric conversion.
• Photodetectors are vital for intelligent sensing, requiring high performance.

Purpose of the Study:

• Investigate 2H-MoTe2-based field-effect transistors (FETs) for photodetection.
• Optimize MoTe2 photodetector performance through annealing and heterojunction formation.

Main Methods:

• Air annealing of 2H-MoTe2 at specific temperatures.
• Fabrication and characterization of MoTe2 FETs and MoTe2/MoSe2 van der Waals heterojunctions.
• Performance evaluation including responsivity, external quantum efficiency (EQE), and dark current.

Main Results:

• Air annealing improved transconductance by 230% and carrier mobility by 41% in MoTe2 FETs via defect healing.
• Optimized MoTe2 photodetector achieved responsivity of 3.53 A W⁻¹ and EQE of 652% at 808 nm.
• MoTe2/MoSe2 heterojunction exhibited ultralow dark current (<10⁻¹³ A) and peak responsivity of 3.32 A W⁻¹ at 671 nm.

Conclusions:

• Air annealing is an effective method to enhance charge transport in 2D MoTe2 for photodetection.
• MoTe2 and its heterojunctions demonstrate significant potential for high-performance visible-to-near-infrared (Vis-NIR) optoelectronic applications.