Fig. 2: Evolution of MoS2 low-temperature PL with increasing annealing temperature.
From: The role of chalcogen vacancies for atomic defect emission in MoS2
a Compared to as-exfoliated MoS2 on hBN (top panel) the broad L-band is strongly reduced after successive mild annealing. At 510 K, an emission line XL appears at 1.75 eV (bottom panel). The spectra were normalized to the intensity of the exciton to highlight relative changes between the L-band, the trion and the free exciton emission. b PL spectra of fully encapsulated MoS2. With increasing annealing temperature, the intensity of XL increases. Dashed lines highlight neutral exciton (0XA), trion (−XA), and XL. The spectra are presented as measured without further normalization. c Integrated intensity of the L-band in a as function of annealing temperature. The change in L-band emission is related to the desorption rate of adsorbates from the MoS2. d Arrhenius plot of thermal defect generation rate extracted from the change in intensity of XL between subsequent annealing steps, which is denoted as ΔInt(XL). The activation barrier EA extracted from the fit (red line) is (0.71 ± 0.13) eV consistent with formation of sulfur vacancies.
