Gallium oxide has been attracting much interest due to its tremendous potential for power device application. The (BxGa1−x)2O3 ternary alloys of monoclinic and orthorhombic phases with the B-content covering the full composition were studied using first-principles density functional theory calculations. The effect of the B-content on the structural and electronic properties of (BxGa1−x)2O3 alloys is discussed. The formation enthalpy of the ternary alloys has been investigated, indicating the feasibility of synthesizing (BxGa1−x)2O3 alloys depending on the specified growth temperature condition. In addition, the increase in the B-content in (BxGa1−x)2O3 alloys generally leads to the decrease in lattice constants, implying possible tensile strain if grown on the Ga2O3 substrate. Our analysis on the electronic properties shows that all (BxGa1−x)2O3 alloys exhibit indirect gap property, in which the bandgap increases from 4.83 eV to 6.86 eV in the monoclinic phase and from 5.32 eV to 11.27 eV in the orthorhombic phase when the B-content increases from 0% to 100%. The band alignment between Ga2O3 and B2O3 in the (100)-direction is also presented, showing a type-II and type-I alignment for monoclinic-based and orthorhombic-based alloys, respectively. Our results showed an extremely large conduction band offset of 5.76 eV between orthorhombic-based Ga2O3 and B2O3 alloys. Our studies regarding the electronic and structural properties provide important insight regarding the potential of (BxGa1−x)2O3 alloys for III-oxide-based electronic and optoelectronic device applications.

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