Mist CVD for tailoring five Ga2O3 polymorphs via epitaxial growth techniques

Recently, Ga2O3 has garnered significant attention as an ultrawide bandgap semiconductor, possessing a bandgap of approximately 5 eV. Ga2O3 exists in five polymorphs: α, β, γ, δ, and κ phases. This presentation will discuss the control of these five polymorphs using mist chemical vapor deposition (CVD) and epitaxial techniques. From an epitaxial growth standpoint, maintaining a small lattice mismatch between the thin films of interest and the underlying layers, such as substrates and buffer layers, is of significant importance. For instance, among these five polymorphs, the existence of the δ-phase remains a subject of debate within the Ga2O3 research community. Nevertheless, the utilization of small lattice-mismatched β-Fe2O3 buffer layers, grown using mist CVD, has enabled the growth of δ- Ga2O3 epitaxial thin films. In addition to discussing the δ-phase, this presentation will also encompass the epitaxial growth of the other four polymorphs of Ga2O3.