Density functional theory based HSE06 calculations to probe the effects of defect on electronic properties of monolayer TMDCs

Defects usually play an important role in modifying the properties of the materials, therefore in this investigation an attempt has been made to understand the effect of chalcogen vacancy defect in various monolayer transition metal dichalcogenides (TMDCs). En route to probe the effect of defect, the density functional theory (DFT) calculations have been carried out. The results obtained from DFT calculations reveal that: (i) the nature of both chalcogen and metal significantly influences the dissociation energy, (ii) the work function of defective TMDC alters only marginally for both single or double vacancies, (iii) chalcogen vacancy converts direct gap (KV -> KC) semiconductors into indirect gap semiconductors (Gamma V -> KC), and (iv) electronic bands clearly indicate that the dorbital of the transition metal plays a vital role in the formation of impurity band.

Automated summary

This study investigates the effect of chalcogen vacancy defects in monolayer transition metal dichalcogenides, revealing significant influences on dissociation energy, work function, and band gap structure. Particularly, the d orbitals of the transition metal are shown to play a vital role in the formation of impurity bands.