The Electronic Properties of O-Doped Pure and Sulfur Vacancy-Defect Monolayer WS₂: A First-Principles Study

• Published in: Materials Vol. 11; no. 2; p. 218
• Main Authors: Wang, Weidong, Bai, Liwen, Yang, Chenguang, Fan, Kangqi, Xie, Yong, Li, Minglin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31.01.2018; MDPI
• Subjects: Band gap; Density functional theory; Divacancies; Doping; Electronic properties; Electronic structure; First principles; first-principles study; monolayer WS2; Monolayers; O-doped; Point defects; Sulfur; sulfur vacancy-defect; Tungsten disulfide; Vacancies; monolayer WS2; electronic properties; sulfur vacancy-defect; O-doped; first-principles study; band gap
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma11020218

Based on the density functional theory (DFT), the electronic properties of O-doped pure and sulfur vacancy-defect monolayer WS₂ are investigated by using the first-principles method. For the O-doped pure monolayer WS₂, four sizes (2 × 2 × 1, 3 × 3 × 1, 4 × 4 × 1 and 5 × 5 × 1) of supercell are discussed to probe the effects of O doping concentration on the electronic structure. For the 2 × 2 × 1 supercell with 12.5% O doping concentration, the band gap of O-doped pure WS₂ is reduced by 8.9% displaying an indirect band gap. The band gaps in 3 × 3 × 1 and 4 × 4 × 1 supercells are both opened to some extent, respectively, for 5.55% and 3.13% O doping concentrations, while the band gap in 5 × 5 × 1 supercell with 2.0% O doping concentration is quite close to that of the pure monolayer WS₂. Then, two typical point defects, including sulfur single-vacancy (V ) and sulfur divacancy (V ), are introduced to probe the influences of O doping on the electronic properties of WS₂ monolayers. The observations from DFT calculations show that O doping can broaden the band gap of monolayer WS₂ with V defect to a certain degree, but weaken the band gap of monolayer WS₂ with V defect. Doping O element into either pure or sulfur vacancy-defect monolayer WS₂ cannot change their band gaps significantly, however, it still can be regarded as a potential method to slightly tune the electronic properties of monolayer WS₂.