Reduction of Schottky Barrier Height for Au-WS2 Interface with Iodine Doping - A Physical Insight

In this work, using Density functional theory (DFT) simulations, we have shown the reduction of Schottky Barrier Height (SBH) for Au-WS 2 interface with Iodine doping. The detailed physics behind this observation is also discussed. The Iodine (I) dopant is found to be an ideal donor than Chlorine (Cl) and Bromine (Br) because of its less electronegativity and larger atomic size. This fact is verified and supported by Mulliken analysis. Also, the I-doped structure is more stable, which can be observed from the interfacial distance and work of separation calculation. We have also validated this molecular doping at the contact part of the electrode region in a two-terminal device using Non-Equilibrium Greens Function (NEGF) formalism. In this work, all monolayer, interface, and device analyses show that Iodine is a better n-type dopant compared to Cl.