Effect of various defects on mechanical and electronic properties of zinc-oxide graphene-like structure: A DFT study

In current study ab-initio based density functional theory (DFT) calculations were employed to determine the effect of different types of defect including the point (Stone-Wales (SW) and atom vacancies) and shape defects on mechanical and electronic properties of zinc oxide (ZnO) graphene-like sheet. Also, the density of states calculations (DOS) were done to give a better understanding of the electronic behavior of this structure under applied defects. With this purpose, different defects were applied to the surface of the ZnO graphene-like sheet and Young's modulus was calculated theoretically. Results showed that all applied defects had a negative effect on Young's modulus. SW defect had the lowest effect on Young's modulus among point defects. In terms of vacancy defects, increasing in the number of extracted atoms decreased modulus reversely. We also found from vacancy defects that extracting Zn atom decreased the properties more than extracting oxygen atom. So Zn atom has a higher effect on ZnO graphene-like sheet strength and stability compared to oxygen atom. The lowest obtained Young's modulus occurred in three atom vacancy with two missed Zn atoms. Furthermore, circular and square shape defects with various diameters were created on ZnO graphene-like sheet and Young's modulus was again considered.