Fig. 3

Raman spectra of MoOx films with x = 2.8 after H2S annealing at 300 °C under (a) 100 Pa and (b) 50 kPa for 10 min, followed by Ar annealing at 1100 °C for 10 min. XPS spectra of (c) the as-deposited MoOx films with x = 2.8, and (d) after H2S annealing at 300 °C under 100 Pa and 50 kPa for 10 min.