Characterization of oxygen deficient gallium oxide films grown by PLD

X-ray photoelectron spectroscopy and transmission electron microscopy have been used to investigate the nature and characteristics of oxygen deficient gallium oxide films grown by pulsed laser deposition. The presence of the Ga3+ and Ga+ oxidation states, together with metallic Ga0 was observed by XPS in Ga2O2.3 sub-oxide films. TEM images reveal the presence in a Ga2O3 matrix of gallium oblong particles whose structure studied at nitrogen temperature was found to correspond to the β monoclinic phase of metallic gallium. These results characterize the formation of nanocomposite films with Ga metallic clusters embedded in a stoichiometric Ga2O3 matrix. The nanocomposite film formation is due to a phase separation in the metastable sub-stoichiometric Ga2O2.3 film.