Growth of β-Ga2O3on Al2O3and GaAs using metal-organic vapor-phase epitaxy

Epitaxial layers of monoclinic β-Ga2O3 were successfully grown on (0001) sapphire and (11)As GaAs substrates using metal-organic vapor-phase epitaxy (MOVPE). Triethylgallium (TEGa) and N2O were used as precursors for gallium and oxygen, respectively. Growth conditions could be determined, where β-Ga2O3 grows epitaxially on c -plane sapphire and (11)As GaAs substrates. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements identify a epitaxial relationship with (01) β-Ga2O3 || (0001) sapphire and (01) β-Ga2O3 || (11)As GaAs. The observed sixfold rotational in-plane symmetry results from differently oriented rotational domains of monoclinic β-Ga2O3 with twofold symmetry. Thin films deposited on substrates of other orientation show the formation of the low-temperature modification α-Ga2O3. Optical transmission spectra measured in the spectral range from 200 nm to 2000 nm show a well-distinct absorption edge at about 5 eV for layers grown on c - and a -plane sapphire. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)