The structure, electronic, magnetic and optical properties of the Co-X (X = B, C, N, O or F) codoped single-layer WS2

We use the first-principle methods to systematically study the structural, electronic, magnetic and optical characteristics of the perfect and Co-X (X = B, C, N, O or F) codoped single-layer WS2. The results show that firstly, all Co-X (X = B, C, N, O or F) codoped single-layer WS2 are easier to form in S-rich environment than in Wrich environment. Second, although the perfect single-layer WS2 is non-magnetic semiconductor (NM-SC), the Co-X (X = B, C, N or F) codoped single-layer WS2 become to magnetic semiconductor (M - SC) with magnetic moments 2, 3, 2 or 2 mu B, while the Co-O codoped single-layer WS2 transforms to magnetic half metal (M-HM) with magnetic moment 1 mu B. Thirdly, comparing with the perfect single-layer WS2, the Co-X (X = B, C, N, O or F) codoped single-layer WS2 show not only the red-shifted absorption edges but also enhanced absorption rate in infrared and visible light region, implying the Co-X (X = B, C, N, O or F) codoped single-layer WS2 have great application prospects in infrared and visible light detection.