Modulating Electronic Properties of Monolayer MoS₂via Electron-Withdrawing Functional Groups of Graphene Oxide

Abstract

Modulation of the carrier concentration and electronic type of monolayer (1L) MoS₂ is highly important for applications in logic circuits, solar cells, and light-emitting diodes. Here, we demonstrate the tuning of the electronic properties of large-area 1L-MoS₂ using graphene oxide (GO). GO sheets are well-known as hole injection layers since they contain electron-withdrawing groups such as carboxyl, hydroxyl, and epoxy. The optical and electronic properties of GO-treated 1L-MoS₂ are dramatically changed. The photoluminescence intensity of GO-treated 1L-MoS₂ is increases by more than 470% compared to the pristine sample because of the increase in neutral exciton contribution. In addition, the A1g peak in Raman spectra shifts considerably, revealing that GO treatment led to the formation of p-type doped 1L-MoS₂. Moreover, the current vs voltage (I-V) curves of GO-coated 1L-MoS₂ field effect transistors show that the electron concentration of 1L-MoS₂ is significantly lower in comparison with pristine 1L-MoS₂. Current rectification is also observed from the I-V curve of the lateral diode structure with 1L-MoS₂ and 1L-MoS₂/GO, indicating that the electronic structure of MoS₂ is significantly modulated by the electron-withdrawing functional group of GO.