Electronic structure of ZnO thin films doped with group III elements

Abstract

First-principles calculations based on density functional theory are performed to understand the electronic properties of III group elements doped ZnO as functions of the dopant atoms content. The results reveal that the lattice constants of Ga, In, Tl, Y, Sc and La doped ZnO increase linearly with the doping increasing, while for B and Al doped ZnO observed decreases lattice parameters with increases dopant content in ZnO. According to the results, the optical band gap of all ZnO doped systems is broadened due to the increase of doping concentrations. Substitutional In, Al, Ga atoms contribute significantly delocalized s orbitals in the conduction band states, which are expected to increase the mobility of the material. The covalent bonding of Ga, In, Tl, Y, Sc and La doped ZnO is found to weaken with the increase of dopant content, whereas we observed more covalent bonds in B and Al doped ZnO. The simulation and calculation results are in good agreement with the existing experimental data and the study can provide a theoretical basis for future applications of group III elements doped ZnO.