Isotropic optical response and edge plasmons in MoS[formula omitted] monolayer induced by oxygen absorption

Abstract

Defects play a crucial role in altering the electronic and optical characteristics of two-dimensional (2D) semiconductors, which is highly significant for the advancement of next-generation electronic and optoelectronic devices. In this study, we employ first-principles density functional theory (DFT) and time-dependent DFT calculations to explore the impact of oxygen defects on the electronic, optical, and plasmonic properties of monolayer MoS2. Our calculations reveal that the presence of an oxygen defect in the absorption position of the MoS2 monolayer leads to a predominant photoabsorption in the visible region of the electromagnetic spectrum, as well as an isotropic optical response and the emergence of edge plasmons. Conversely, when an oxygen defect is located in the adsorption position of the MoS2 monolayer, it generates deep midgap states within the bandgap, resulting in an anisotropic optical response and the partial decay of edge plasmons. By obtaining a comprehensive understanding of the effects of defects on photoabsorption and plasmonics, our study provides valuable insights for enhancing the performance of optical and plasmonic devices based on 2D materials.