Polarity-Reversible Te/WSe2 van der Waals Heterodiode for a Logic Rectifier and Polarized Short-Wave Infrared Photodetector

As a p-type elemental material with high carrier mobility, superior ambient stability, and anisotropic crystal structure, emerging two-dimensional (2D) tellurium (Te) has been considered a successor to black phosphorus for developing infrared-related optoelectronics. Nevertheless, the lack of a scalable thickness engineering strategy remains an obstacle to unleashing its full potential. Te-based electronics with logic functions are also less explored. Herein, we propose a novel wet-chemical thinning method for 2D Te, with the merits of scalability and site-specific thickness patterning capability. A polarity-switchable van der Waals (vdW) heterodiode with a high rectification ratio of 2.4 x 103 is realized on the basis of Te/WSe2. The electronic application of this unique characteristic is demonstrated by fabricating a logic half-wave rectifier, in which the rectifying states are switchable via electrostatic gating control. Besides, the narrow band gap of Te endows the device with a broad spectral response from visible to short-wave infrared. The room-temperature responsivity reaches 5.2 A W-1 at the telecom wavelength of 1.55 mu m, with an external quantum efficiency of 420% and detectivity of 6.8 x 109 Jones. In particular, owing to the intrinsic in-plane anisotropy of Te, the device exhibits a favorable photocurrent anisotropic ratio of similar to 3. Our study demonstrates the enormous potential of Te for novel electronics, promoting the development of elemental 2D materials.

Automated summary

This study introduces a novel wet-chemical thinning method for 2D tellurium, achieving scalability and site-specific thickness patterning capability. A polarity-switchable van der Waals heterodiode with a high rectification ratio is realized based on tellurium/WSe2, demonstrating its electronic application through fabricating a logic half-wave rectifier.