Investigation of electronic and optical properties of molybdenum disulfide modulated by surface functionalization

Abstract

This thesis aims to investigate unique electronic and optical properties of surface-modified MoS2 and to further extend its potential applications. We begin with an investigation of the effects of C60, molybdenum trioxide (MoO3), cesium carbonate (Cs2CO3) on the modulation of MoS2 properties. It is found that negligible charge transfer takes place at the C60/MoS2 interface. In contrast, the MoO3 decoration layer depletes the electron charge carriers, and boosts the photoluminescence of MoS2. We also found that the electron charge carrier concentration increases dramatically due to the decoration by Cs2CO3, leading to the emergence of trions and reduction of photoluminescence. After that, plasmonic metal nanostructures was functionalized on MoS2 to further manipulate the properties. We demonstrate that, by combining MoS2 with plasmonic gold nanoparticles (Au NPs), the MoS2 based phototransistor realizes wavelength-dependent photocurrent enhancement. Furthermore, we systematically investigate the Au/MoS2 interface and found that Au weakly interact with the underlying MoS2.