The surface oxidation effect on photocurrent in WSe_1.95Te_0.05 nanosheets

Surface oxidation effect on photocurrent responsibility was detected in WSe_1.95Te_0.05 nanosheets, and the photocurrent response depends on the light wavelength. It is enhanced at the wavelength of 405 nm, while showing no change at the wavelength of 532 nm and suppressed at the wavelength of 808 nm. The incident photon-to-current efficiency (IPCE) is expected to increase at 405 nm wavelength, remain unchanged at 532 nm wavelength, and decrease at 808 nm wavelength. Therefore, WO₃ contributes to the intrinsic properties. The trend of photocurrent change after half-year exposure corresponds to the absorbance change from pristine WSe_1.95Te_0.05 to WO₃. The wavelength-dependent photocurrent responsibility is understood as the wavelength-dependent IPCE of WO₃ that is from the surface-oxidized WSe_1.95Te_0.05.