Two-step growth of VSe2 films and their photoelectric properties

We put forward a two-step route to synthesize vanadium diselenide (VSe2), a typical transition metal dichalcogenide (TMD). To obtain the VSe2 film, we first prepare a vanadium film by electron beam evaporation and we then perform selenization in a vacuum chamber. This method has the advantages of low temperature, is less time-consuming, has a large area, and has a stable performance. At 400 degrees C selenization temperature, we successfully prepare VSe2 films on both glass and Mo substrates. The prepared VSe2 has the characteristic of preferential growth along the c-axis, with low transmittance. It is found that the contact between Al and VSe2/Mo is ohmic contact. Compared to Mo substrate, lower square resistance and higher carrier concentration of the VSe2/Mo sample reveal that the VSe2 film may be a potential material for thin film solar cells or other semiconductor devices. The new synthetic strategy that is developed here paves a sustainable way to the application of VSe2 in photovoltaic devices.