Analysis and atomic simulation of electron structures and defects in ZnO nano-crystal for its optimal doping with Al

Electrical and structural properties of zinc oxide (ZnO) unit cell and aluminum doped ZnO (AZO) super cell have been studied using density functional theory (DFT) and SIESTA package. According to the calculation of the formation energies for vacancy of Zn and O, it is observed that vacancy of O atom in Zn-rich and vacancy of Zn in O-rich conditions are more probable and stable. For AZO structure, it has been acquired that Zn atom tends to be substituted by Al in Zn-rich and O-rich conditions and creates n-type semiconductor. Finally, the electron density of states (DOS) and defects energies for the structures have been investigated.