Effects of Cu, Ag and Au on electronic and optical properties of α-Ga2O3 oxide according to first-principles calculations

Ga2O3 is a promising semiconductor material, but, improving its electronic and optical properties is important for the development of semiconductor materials. To improve the electronic and optical properties, we used the first-principles calculations to study the effects of alloying elements on the electronic and optical properties of alpha-Ga2O3. Three alloying elements comprising Cu, Ag and Au were considered. The results showed that the Cu -doped alpha-Ga2O3 has greatly stability compared with Ag and Au doped alpha-Ga2O3. These alloying elements can expand the volume and lattice of alpha-Ga2O3 because of the discrepancy in the valence electronic density. Impor-tantly, we calculated the directional band gap of alpha-Ga2O3 as 2.970 eV. It should be noted that the band gap calculated for the transition metal-doped alpha-Ga2O3 is smaller than that for the parent alpha-Ga2O3 because adding the alloying element changes the electronic balance between the Ga atom and O atom near the Fermi level. This result demonstrates the ultraviolet properties of alpha-Ga2O3. However, adding alloying elements (Cu, Ag and Au) leads to migration from the ultraviolet region to the visible light region. In particular, these alloying elements can improve the storage optical properties of the parent Ga2O3.