Lateral homojunctions of WSe2 through contact surface engineering with SF6 plasma etching

Abstract

Herein, we report a simple contact surface pre-treatment, i.e. SF₆ plasma dry-etching, to achieve efficient n-doping in CVD-grown two-dimensional multilayer WSe₂ nanosheets as well as to build lateral p–n homojunctions with single-metal Nb contacts. The lateral homodiodes exhibit high rectification ratios over 10⁴ and excellent photovoltaic properties with the maximum open circuit voltage reaching up to 350–450 mV. This makes WSe₂-based homodiodes superb self-powered photodetectors for wide-spectrum (from visible to near-infrared) wavelengths, with a photoresponsivity over 100 mA W⁻¹ and a fast response speed of 10 μs. The realization of highly efficient n-doping in the CVD-grown WSe₂ semiconductor and high-performance photodiodes via implementing plasma dry-etching, a standard semiconductor processing, would foresee a promising future for its practical implementation in scale-up production of 2D semiconductor nanoelectronics integrated chips.