Properties of orthorhombic Ga2O3 alloyed with In2O3 and Al2O3

Ga2O3 is a promising wide-bandgap material for electronic applications. The metastable orthorhombic κ phase is of particular interest due to its large predicted spontaneous electrical polarization. Here, we investigate how the properties of the orthorhombic phase can be tuned by alloying with In2O3. In particular, we determine how the lattice constants, bandgap, and band offsets change over the full range of possible alloy compositions. For completeness, we also compare to alloys with Al2O3. Lattice constants decrease linearly with Al content, while the bandgaps and conduction-band offsets increase non-linearly, with a bowing of 1.41 eV. Alloying with In2O3 allows to increase the lattice constants linearly and to decrease the bandgaps and conduction-band offsets non-linearly, with a bowing of 0.31 eV. Alloying, therefore, allows for the modification of the structural and electronic properties over a wide range, opening the possibility to tailor the alloy properties to specific applications.