Composition dependent Fermi level shifting of Au decorated MoS_2 nanosheets

摘要

In the present work, shifting of Fermi level of MoS_2 nanosheets due to decoration of Au nanoparticles (Au NPs) is reported. Au NPs are grown on MoS_2 nanosheets by chemical reduction method. The structural analysis of pristine MoS_2 and Au NPs decorated MoS_2 has been done using X-ray diffraction and transmission electron microscopy. The effect of Au NPs decoration on the Fermi energy level of MoS_2 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 MoS_2 is found to be 4.994 eV, and it increases linearly for Au-MoS_2 with increasing concentration of Au NPs. The gradual increase in the work function values indicate a systematic shifting of Fermi energy level of MoS_2 towards valence band due to decoration of Au NPs.