Band tuning in WS2 monolayer via substitutional doping

First-principles calculations are performed to investigate the band tuning (band structure, band gap and spin splitting) in tungsten disulfide (WS2) monolayer due to nitrogen and phosphorous substitutional doping with various concentrations. Our calculations show doping affects all the lattice parameters and reduces the symmetry point group from P (6) over bar m2 to P3m1. Both nitrogen and phosphorus doping reduce the band gap, in some cases, transfer direct one to indirect and lead to apparent changes in the band structure. However, the changing trend for nitrogen occurs rapidly than that for phosphorus doping. Increasing dopant concentration decreases the spin splitting in the valence band and, contrary increases it remarkably in the conduction band almost in all concentrations, showing doping concentration can affect the spin-orbit coupling and hence the spin splitting in both valence and conduction band. This study clearly shows that dopant concentration can significantly tune the electronic properties of WS2 monolayer and provide a new way for tuning the spin splitting, which is essential in optoelectronic and spintronic devices.

Automated summary

First-principles calculations were used to investigate the band tuning in tungsten disulfide monolayer due to nitrogen and phosphorous doping. The results show that doping affects lattice parameters and reduces the band gap. Nitrogen and phosphorus doping lead to changes in the band structure and doping concentration has a significant impact on spin splitting.