Presentation Information
[1P44]First-principles analysis of electronic states of defects in WS2 thin films
*Yuki Hatakeyama1, Anh Khoa Augustin Lu1,2, Satoshi Watanabe1 (1. Department of Materials Engineering, The University of Tokyo, Japan, 2. Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan)
WS2 thin films are promising materials for as post-silicon devices due to their predicted high mobility, yet measured mobilities are significantly lower, likely due to defect effects. In this study, we investigate the stability and electronic states of two types of defects, oxygen substitution at a sulfur site (OS) and sulfur vacancies (VS), in monolayer WS2 using first-principles calculations based on density functional theory. Calculated formation energies show that OS is more stable than VS regardless of the sulfur chemical potential or the choice of exchange-correlation potential (generalized gradient approximation (GGA) or meta-GGA). We also found that OS causes band gap reduction, indicating the emergence of defect states in the vicinity of the band edges.