Light-Induced Surface Potential Modification in MoS₂ Monolayers on Au Nanostripe Arrays

In this work, the surface potential (V_S) of exfoliated MoS₂ monolayers on Au nanostripe arrays with period of 500 nm was investigated using Kelvin probe force microscopy. The surface morphology showed that the suspended MoS₂ region between neighboring Au stripes underwent tensile-strain. In the dark, the V_S of the MoS₂ region on the Au stripe (V_S-Au) was larger than that of the suspended MoS₂ 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 MoS₂/Au interface. The results of this work provide a basis for understanding the electrical properties of MoS₂-metal contacts and improving the performance of MoS₂-based optoelectronic devices.