Single-phase κ-Ga2O3 films deposited by metal-organic chemical vapor deposition on GaAs and ternary BxGa(1-x)As templates

For the first time, single-phase κ-Ga 2 O 3 films were grown on (001) p-type GaAs and B x Ga (1-x) As /GaAs templates using Metal-Organic Chemical Vapor Deposition (MOCVD). The films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). TEM investigations revealed a thin polycrystalline nucleation layer followed by well-oriented columnar growth of the κ-phase in the Ga 2 O 3 /GaAs sample, while segregation and diffusion effects in the ternary alloy led to boron accumulation on the template surface, which reacted with oxygen during the first stage of Ga 2 O 3 deposition to form a thin amorphous oxide ( a -BGaO) at the interface between Ga 2 O 3 and the BGaAs/GaAs template. Again, columnar growth of large [001]-oriented grains of the orthorhombic κ-phase occurred on the amorphous nucleation layers, which resulted in a compact gallium oxide film. These polycrystalline or amorphous interlayers are important as they provide a suitable platform for growth of phase-pure orthorhombic κ-Ga 2 O 3 on III-V cubic substrates. This work paves the way to the integration of κ-Ga 2 O 3 and III-V semiconductors, for preparing heterojunctions for novel electronic and optoelectronic devices.