Modulating Electronic Properties of Monolayer MoS₂ via Electron-Withdrawing Functional Groups of Graphene Oxide

Modulation of the carrier concentration and electronic type of monolayer (1L) MoS 2 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-MoS 2 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-MoS 2 are dramatically changed. The photoluminescence intensity of GO-treated 1L-MoS 2 is increases by more than 470% compared to the pristine sample because of the increase in neutral exciton contribution. In addition, the A 1g peak in Raman spectra shifts considerably, revealing that GO treatment led to the formation of p-type doped 1L-MoS 2 . Moreover, the current vs voltage ( I–V ) curves of GO-coated 1L-MoS 2 field effect transistors show that the electron concentration of 1L-MoS 2 is significantly lower in comparison with pristine 1L-MoS 2 . Current rectification is also observed from the I–V curve of the lateral diode structure with 1L-MoS 2 and 1L-MoS 2 /GO, indicating that the electronic structure of MoS 2 is significantly modulated by the electron-withdrawing functional group of GO.