Characterization of band alignment at a metal-MoS₂ interface by Kelvin probe force microscopy

Transition metal dichalcogenides, such as MoS2, have garnered considerable attention because of their significant potential in device applications. A limiting factor in their development is the formation of a Schottky barrier with strong Fermi-level pinning at the metal-MoS2 interface. Herein, we report Kelvin probe force microscopy (KPFM) measurements of the work function (WF) modulation at this interface. We found an increase in the WF at the metal-MoS2 interface, depending on the layer number and the contact metal used, indicating the formation of a Schottky barrier. These variations potentially arise from the layer-number-dependent strength of Fermi-level pinning in MoS2. Visualization and calculation of WF modulation at metal-MoS2 interfaces using the KPFM method can help understand the structure and properties of such interfaces.