Tin-Assisted Synthesis of ε−Ga2O3 by Molecular Beam Epitaxy

The synthesis of is an element of-Ga2O3 and beta-Ga2O3 by plasma-assisted molecular beam epitaxy on (001) Al2O3 substrates is studied. The growth window of beta-Ga2O3 in the Ga-wrich regime, usually limited by the formation of volatile gallium suboxide, is expanded due to the presence of tin during the growth process, which stabilizes the formation of gallium oxides. X-ray diffraction, transmission electron microscopy, time-of-flight secondary-ion mass spectrometry, Raman spectroscopy, and atomic force microscopy are used to analyze the influence of tin on the layer formation. We demonstrate that it allows the synthesis of phase-pure is an element of-Ga2O3. A growth model based on the oxidation of gallium suboxide by reduction of an intermediate sacrificial tin oxide is suggested.