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

Abstract

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.