Lateral WSe₂ Homojunction through Metal Contact Doping: Excellent Self‐powered Photovoltaic Photodetector

Abstract Here an IR‐heating chemical vapor deposition (CVD) approach enabling fast 2D‐growth of WSe₂ thin films is reported, and the great potential of metal contact doping in building CVD‐grown WSe₂‐based lateral homojunction is demonstrated by contacting with TiN/Ni metals in favor of holes/electrons injection. Shortening nanosheet channel to ≈2 µm leads to pronounced enhancement in the performance of diode. The fabricated WSe₂‐based diode exhibits high rectification ratios without the need of gate modulation and can work efficiently as photovoltaic cell, with maximum open circuit voltage reaching up to 620 mV and a high power conversion efficiency over 15%, empowering it as superb self‐powered photodetector for visible to near‐infrared lights, with photoresponsivity over 0.5 A W⁻¹ and a fast photoresponse speed of 10 µs under 520 nm illumination. It is of practical significance to achieve well‐performed photovoltaic devices with CVD‐grown WSe₂ using fab‐friendly metals and simple processing, which will help pave the way toward future mass production of optoelectronic chips.