DFT calculations of optoelectronic properties of cubic In1-xAlx2O3 alloys

The substitutional semiconductor obtained by doping In 2 O 3 with aluminum metal has potential applications in high-quality gas sensors and nanoelectronic devices. The structural and electrooptical properties of new In 1 - x Al x 2 O 3 alloys with compositions corresponding to x = 0, 0.25, 0.75, and 1 are theoretically calculated herein by using density functional theory (DFT). The exchange correlation functional is treated with the Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (GGA) to study the effect of the composition on the structural parameters of In 1 - x Al x 2 O 3 . Additional treatment with the accurate Tran–Blaha modified Becke–Johnson (TB-mBJ) scheme is applied to improve the electronic band structure and optical constants of the compositions. The influence of alloying with Al on the structural parameters, energy bandgap, and electron effective mass is investigated. The direct bandgap of the In 1 - x Al x 2 O 3 alloys increases with increasing Al percentage in the studied compositions. In addition, the influence of pressure on the lattice parameters is also studied. Their linear optical parameters are evaluated in the range of 0–40 eV. The optical results show an improvement in the optical transparency of the studied alloys in the infrared and visible ranges as the Al content x is increased. This suggests that such new In 1 - x Al x 2 O 3 ternary alloys could be promising candidate transparent materials for use in optoelectronic applications.