Modulating electronic transport properties of MoS₂ field effect transistor by surface overlayers

In situ bottom-gated molybdenum disulfide (MoS₂) field effect transistors (FETs) device characterization and in situ ultraviolet photoelectron spectroscopy and x-ray photoelectron spectroscopy measurements were combined to investigate the effect of surface modification layers of C₆₀ and molybdenum trioxide (MoO₃) on the electronic properties of single layer MoS₂. It is found that C₆₀ decoration keeps MoS₂ FET performance intact due to the very weak interfacial interactions, making C₆₀ as an ideal capping layer for MoS₂ devices. In contrast, decorating MoO₃ on MoS₂ induces significant charge transfer at the MoS₂/MoO₃ interface and largely depletes the electron charge carriers in MoS₂ FET devices.