Photoelectron spectroscopy of MoS 2 at the sulfur 2p absorption edge

Abstract

The sulfur 2p absorption edge and valence-band resonant photoelectron spectra of molybdenum disulfide (MoS 2), obtained using synchrotron radiation, are compared to the Mo4p edge results from previous work. A pre-edge feature in the S2p data shows transitions to unoccupied, dominantly Mo4d anti-bonding levels, indicating that significant covalent interactions exist between Mo and S valence orbitals. Resonant enhancement of valence-band photoelectron shake-up peaks is observed at the S2p → Mo4d excitation energies, while the sulfur ( L 2,3 VV) Auger peak dominates the spectrum when the S2p ionization threshold is reached. Anti-resonant intensity modulation of main valence band peaks is observed at photon energies corresponding to the S2p → Mo4d pre-edge feature. The results show that the principal decay channel after the S2p → Mo4d excitation leads to the enhancement of final states having S(3p) 4 Mo(4d) 3 electron configurations.