First-principles investigation on the optoelectronic performance of Mg doped and Mg–Al co-doped ZnO

• The band gap increases with the content of Mg increasing.
• In the range of 500–600 nm, the absorption and reflection decrease with Mg content increasing.
• The absorption peak of Mg–Al co-doping presents a blue shift.
• Mg–Al co-doping creates the decrease of average transmittance in UV region.

We investigate the band structure, density of states and optical properties of Mg doped and Mg–Al co-doped ZnO by adopting the first-principles calculation of plane wave ultra-soft pseudo-potential technology based on the density function theory (DFT). By introducing the impurity atoms of Mg, the band gap increases with increasing the content of Mg but decreases in the Mg–Al co-doped ZnO structure, while the electrical conductivity increases apparently. Both the absorptivity and the reflectivity of the optical properties decline significantly after co-doping. Specifically, the blue shift arises in the absorption edge and the absorptivity decreases with the increase of Mg content in the range of 350–600 nm. Our analysis indicates that the Mg–Al doping can enhance the transmittance with a certain thickness.

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