Uncovering Semiconductor Band Structure Effects in Au/n‐WS ₂ Schottky Devices Using Ballistic Electron Emission Microscopy

When fabricating semiconductor devices based on 2D transition metal dichalcogenides (TMD), it is important to understand both the Ohmic and Schottky metal/semiconductor contacts as these contacts directly impact device performance, reproducibility and are important constituents of the interconnects in electronic circuit design. Despite intense ongoing research, a robust understanding of the nature of the metal/TMD contact remains lacking. In this article, the Au/n‐WS 2 Schottky interface is studied using ballistic electron emission microscopy (BEEM), which is a nanoscale probe of the metal/TMD Schottky interface. The nanoscale Schottky barrier height of the Au/WS 2 interface is reported at 0.86 ± 0.03 eV and a second threshold at 1.04 ± 0.06 eV, which corresponds to the secondary conduction band satellite minima in the band structure of WS 2 located at 0.20 ± 0.09 eV above the first minimum, in good agreement to theoretically simulated band structures. The results show that BEEM has the energy resolution to uncover contributions from the conduction band satellite minima of WS 2 in a device structure, which can be difficult using conventional techniques.