Investigation of the electron structure of ZnO by the GGA and mBJ calculations associated with the characterization techniques AES and EELS

摘要

The semiconductor ZnO of large gap of 3,4 eV is of great interest for the technological applications as chemical sensors, UV light emission, optical memories, laser emission, solar cells, etc. These applications depend on the electron structure of material.We adopt the density functional theory (DFT) calculation by using the program Wien2K, within the Generalized Gradient Approximation (GGA) and modified Becke–Johnson (mBJ) for studying the electron behavior of ZnO. The features of the valence band derived from the hybridization of Zn-3d and O-2p states. The electron charge density calculated by these simulation methods indicates a charge transfer between zinc and oxygen inducing a difference in electronegativity between both species (Zn and O), responsible to ionic character of bonding in ZnO. The predictions based on the GGA and mBJ calculations are confirmed by the results of the experimental spectroscopic analysis Auger Electron Spectroscopy (AES) and Electron Energy Loss Spectroscopy (EELS).