Fig. 2: Optical characterizations of OHVPD- and CVD-WS2 monolayers.
From: Low-defect-density WS2 by hydroxide vapor phase deposition
a Typical Raman spectra showing the characteristic modes of OHVPD- and CVD-WS2 monolayers excited by 532 nm wavelengths. The hollow circles and coloured lines are the experimental and Lorentzian fit curves respectively. b, c Statistic distribution of out-of-plane mode A1g Raman peak width and normalized intensity of longitudinal acoustic at M point in the Brillouin zone LA(M) Raman peak for OHVPD- and CVD-WS2 monolayers. The dashed lines represent the normal distribution curves. d Low-temperature PL spectra of OHVPD- and CVD- WS2 monolayers at 4 K. The solid lines and dashed ones are the experimental and fitted peaks respectively. The fitted peaks can be assigned to neutral exciton (X0), trion (XT), and defect-bound exciton (XD).
