Figure 1.

Initial characterization of the as-prepared WS₂ sample. (a) Time-resolved photocurrent signal of the pristine WS₂ sample in vacuum and air. The highlighted area corresponds to the time the device was illuminated. (b) Optical image showing the measured device. The channel was 2 μm long. (c, d) Raman spectrum (c) and photoluminescence spectrum (d) of the WS₂ untreated sample were measured with a 532 nm laser. The spectra show the fitted Lorentzian functions for the specific peaks (red curves).