Light-Induced Surface Potential Modification in MoS(2) Monolayers on Au Nanostripe Arrays

In this work, the surface potential (V(S)) of exfoliated MoS(2) monolayers on Au nanostripe arrays with period of 500 nm was investigated using Kelvin probe force microscopy. The surface morphology showed that the suspended MoS(2) region between neighboring Au stripes underwent tensile-strain. In the dark, the V(S) of the MoS(2) region on the Au stripe (V(S)-Au) was larger than that of the suspended MoS(2) region (V(S)-S). However, under green light illumination, V(S)-Au became smaller than V(S)-S. To explain the V(S) modification, band diagrams have been constructed taking into consideration not only the local strain but also the electronic interaction at the MoS(2)/Au interface. The results of this work provide a basis for understanding the electrical properties of MoS(2)-metal contacts and improving the performance of MoS(2)-based optoelectronic devices.