First-principles Study on Infrared Absorptions of Transition Metal-doped ZnO with Oxygen Vacancy

Using first-principle theory, the infrared absorptions of transition metal (Mn, Fe, Co, Ni)-doped ZnO were investigated. The results indicate that the absorptions of Mn- and Co-incorporated ZnO without oxygen vacancy are reduced, while those of Fe- and Ni-doped ZnO are raised. This is consistent with the previous experimental results. The effects of oxygen vacancy on the absorptions of the doped systems were predicted. When a neutral oxygen vacancy is introduced, all doping elements decrease the absorptions. On the contrary, the absorptions of the doped systems are enhanced if the vacancies are charged. Degraded absorptions can be obtained by increasing the permeability. However, the appearance of anti-bonding states may cause enhanced absorptions. In the current study, Mn-doped ZnO is the most suitable for use as low infrared absorption materials.