Photodetector based on 2H-WSe2 grown by physical vapor deposition method

The controlled preparation of the most stable 2H phase in transition metal dichalcogenides (TMDCs) is essential for advancing electronic and optoelectronic devices in applied research. Bilayer WSe2 demonstrates a lower defect density, superior carrier mobility, and enhanced stability compared to monolayer WSe2. Addressing the challenge of controllably and rapidly preparing bilayer WSe2 with a 2H-phase structure is a focal point of interest. In this study, we present a physical vapor deposition (PVD) method enabling one-step, controllable growth of 2H-phase bilayer WSe2 on SiO2/Si substrates using a solid precursor. The fine control of the WSe2 central stacking area is achieved by precisely adjusting the temperature of the reverse gas flow, leading to the formation of a complete 2H-phase bilayer WSe2. Optoelectronic devices based on 2H-phase bilayer WSe2 exhibit improved detectivity, underscoring the significance of these findings for the design and fabrication of high-performance optoelectronic devices.