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.

Thin films of few-layer WS2 nanosheets and WSe2 nanosheets were directly grown on W substrates via a scalable infrared-heating CVD method. The WSe2 nanosheets are in unique feather-like assembly, and...