Magnetron sputtering fabrication and photoelectric properties of WSe2 film solar cell device

Abstract Tungsten diselenide (WSe 2 ) films with different growing orientations exhibit diverse photoelectric properties. The WSe 2 film with C-axis⊥substrate texture has been prepared and applied to thin-film solar cells. W nanofilms with a thickness of 270 nm were deposited onto the Mo bottom electrode and then heat-treated in selenium vapor to synthesize WSe 2 films with a thickness of 1 μm. ZnO films were deposited onto WSe 2 films to form a P-N junction and ITO films were deposited subsequently as the conductive layer. X-ray diffractometry, scanning electron microscopy and UV-vis-NIR spectro-analysis instrument were employed to analyze the phase composition, optical absorptivity and micromorphology of WSe 2 films and the WSe 2 solar cell device. WSe 2 films exhibit excellent photoelectric performance with an optical absorption coefficient greater than 10 5  cm −1 across the visible spectrum. The calculated direct and indirect band gap of the WSe 2 films is 1.48 eV and 1.25 eV, respectively. With the application of standard glass/Mo/WSe 2 /ZnO/ITO/Ag device structure, the open-circuit voltage of the battery device is 82 mV. The short-circuit current density is 2.98 mA/cm 2 and the filling factor is 0.32. The photoelectric conversion efficiency of the WSe 2 film solar cell device is 0.79%.