Epitaxial Growth of (-201) β-Ga₂O₃ on (001) Diamond Substrates

Heteroepitaxial growth of β-Ga₂O₃ on (001) diamond by metal-organic chemical vapor deposition (MOCVD) is reported. A detailed study was performed with Transmission Electron Microscopy (TEM) elucidating the epitaxial relation of (-201) β-Ga₂O₃||(001) diamond and [010]/[-13-2] β-Ga₂O₃ ||[110]/[1-10] diamond, with the presence of different crystallographically related epitaxial variants apparent from selected area diffraction patterns. A model explaining the arrangement of atoms along ⟨110⟩ diamond is demonstrated with a lattice mismatch of 1.03-3.66% in the perpendicular direction. Dark field imaging showed evidence of arrays of discrete defects at the boundaries between different grains. Strategies to reduce the density of defects are discussed.