First-principles calculations of α-Ga2O3 /Al2O3 superlattice band structures

Ga2O3 devices are expected to be used for high-power applications such as power converters and high electron mobility transistors. To improve the device performance, band-engineering of superlattice structures consisting of Ga2O3 and Al2O3 has been of interest. Here, the bandgap dependencies of α-Ga2O3/Al2O3 superlattices on the superlattice period thickness and the lattice strain were investigated using first-principles calculations. The conduction and valence band offsets at the Ga2O3/Al2O3 interface were also examined. The bandgaps decreased with increasing superlattice period thickness, increased under compressive strain along the a- and b-axes, and decreased under tensile strain.