Composition dependent Fermi level shifting of Au decorated MoS2 nanosheets

In the present work, shifting of Fermi level of MoS2 nanosheets due to decoration of Au nanoparticles (Au NPs) is reported. Au NPs are grown on MoS2 nanosheets by chemical reduction method. The structural analysis of pristine MoS2 and Au NPs decorated MoS2 has been done using X-ray diffraction and transmission electron microscopy. The effect of Au NPs decoration on the Fermi energy level of MoS2 nanosheets have been monitored by scanning Kelvin probe microscopy, which measures the work function in terms of contact potential difference. The work function of pristine MoS2 is found to be 4.994 eV, and it increases linearly for Au-MoS2 with increasing concentration of Au NPs. The gradual increase in the work function values indicate a systematic shifting of Fermi energy level of MoS2 towards valence band due to decoration of Au NPs.