Synthesis of nanostructured metal oxides for their use in gas sensors

Abstract

Gallium oxide (Ga2O3) nanowires (NW) were successfully grown using the Vapour-Liquid-Solid method from a metallic source and were later characterized by means of Scanning Electron Microscopy (SEM). X-ray diffraction, SEM and photoluminescence (PL) data from previously grown mixed indium oxide (In2O3) and Ga2O3 nanowires were also analysed. From the analysis of the Ga2O3 nanowires, a severe hindering effect of a marginal concentration of oxygen on the carrier gas mix was observed regarding the synthesis. For the mixed nanowires, an additional PL band to the main direct band-to-band transition was observed in photoluminescence, which may be attributed to optical transitions from surface states located at the outer shell of the nanowires, and possibly involving impurities such as Ga and C. In addition, a coherent shift was observed of both PL bands, probably caused by changes in the dimensions of the crystalline domains