Figure 5.

Transport, photoluminescence, and photoemission measurements of WSe₂/Au at various annealing temperatures. a) Device structure schematic of a WSe₂ field‐effect transistor. b) I _d–V _g of the WSe₂ device as functions of annealing temperature. c) Hole and electron mobility at different gate voltages of the device as functions of annealing temperature. d) Annealing temperature dependence of photoluminescence spectra. e,f) Synchrotron‐based X‐ray photoemission spectra of W4f, W5p3/2, and Se3d core‐level peak regions for WSe₂ on Au film annealed at various temperatures. These spectra can be well fitted by two components with constant peak positions and full width at half maximum (FWHM). g) Valence band and h) narrow valence band for WSe₂ on Au film annealed at various temperatures. The Fermi surface feature is indicated by the dashed red circle while the mid‐gap feature positions denoted by the black vertical markings (see the Experimental Section for details).