Density functional theory study of graphene adhesion on WX2 (X = S and Se) monolayer: Role of atom vacancy and atomic reorganization defects

Defects usually play an important role in the modification of the properties of materials, therefore, scrutiny of defects in various materials have received paramount attention. In this investigation, atom vacancy and atomic reorganization defects in various heterostructures obtained using different pristine (or defect-free) and defective transition metal dichalcogenides (TMDCs) with pristine and defective graphene have been studied using density functional theory (DFT) calculation. Results reveal that: (i) the contact of pristine and defective graphene with various pristine and defective TMDCs is energetically stable, (ii) the stability of these heterostructures driven by dispersion interaction, (iii) the presence of defect significantly influences the work function of the resulting heterostructure, (iv) the pristine graphene/pristine TMDCs heterostructures are metallic in nature with large Schottky barrier (phi(SBH)), (v) the heterostructures involving defective graphene are direct band gap semiconductors, (vi) the heterostructures involving defective WS2 are also direct band gap semiconductors, and (vii) the SW defective graphene with pristine WS2/WSe2 forms type-II heterojunction.

Automated summary

This study investigates the role of defects in modifying the properties of materials, focusing on atom vacancy and atomic reorganization defects in heterostructures. Results show that the contact of graphene with pristine and defective TMDCs is energetically stable, and the stability of these heterostructures is driven by dispersion interaction. The presence of defects significantly influences the work function of the resulting heterostructure, and different types of heterostructures exhibit unique electronic properties such as being metallic or semiconductor in nature.