Ion-beam modification of metastable gallium oxide polymorphs

Abstract Structural changes under the action of Al+ irradiation have been investigated by X-ray diffraction for polymorphic Ga2O3 layers grown by halide vapor phase epitaxy on c-plane sapphire and consisting predominantly of α-phase with inclusions of e(κ)-phase. As a result of irradiation, some new reflections appear, which can be interpreted in two ways – either as a phase transition of the α- and/or e(κ)-phase to the more stable β-phase, or as a selective radiation-stimulated strain of the e(κ)-phase, i.e., an increase in the interplanar distance of a family of planes parallel to the surface. The discussed ion-stimulated phenomena have to be taken into account when utilizing ion implantation to modify Ga2O3 properties.