Defects and Properties in Polymorph of ZnO

Abstract

In this work, polymorphic models of the structures of ZnO is considered. We have studied the defects and defects behaviours in Wurtzite, zinc blende, and rocksalt ZnO by using first principles and quantum simulation methods. We used density functional theory (DFT) and molecular dynamics (MD) simulation methods to investigate the structural and electronic properties of defect ZnO. For DFT calculations, a computer code within QUANTUM-ESPRESSO is used. Calculations of energies versus lattice constants display the optimum values of the lattice constants for crystal systems. Results are reported using a step-by-step approach, starting from the primitive cell of bulk ZnO, going to a slab model by including a surface charge defects. Generally, the behaviour of intrinsic defects in ZnO, electronic properties, formation energies and workfunction of ZnO were investigated. The effect of different surface absorbents and surface defects on the workfunction of ZnO were studied using DFT calculations. Anisotropy and optical properties of defects have also been studied.