Monoclinic gallium oxide (Ga₂O₃) is a versatile wide band gap semiconductor material. Ga2O3 thin film-based gas sensors are very promising to detect O₂, H₂, CH₄ and CO at high temperature. At elevated temperature, the conductivity of Ga₂O₃ can be influenced by an ambient atmosphere. But at low temperature, the oxygen-vacancies diffusion is frozen and the bulk electrical conductivity no longer responds to the change in the gas composition. The high working temperature limits the application of Ga₂O₃-based gas sensors. One-dimensional (1D) nanomaterials are considered as ideal candidates for applications due to their large surface area-to-volume ration and the size effect. The 1D nanostructures of well-established gas sensing materials have shown higher sensitivity, fast response, and enhanced capability to detect low concentration gases compared with the corresponding thin film materials. Gas sensors made from 1D nanomaterials showed lower optimal operating temperature, which is favourable for power saving and device integration. Gallium oxide nanowires are synthesised on Au-patterned Si substrate by simple thermal evaporation method from milled gallium oxide powder and graphite powder under Ar atmosphere at 1100℃. The morphology and size of the nanowires are characterized by X-ray diffraction, scanning electron microscopy high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Electrical properties of Ga₂O₃:X nanowires (X=Sn,  Mn, Fe.......) constructed on Au electrode are measured at room temperature for application to gas sensor materials. The conductivity change of n-type semiconducting Ga₂O₃ nanowires is sensitive to NO₂ or H₂S gas at room temperature.

This work was supported by the Seoul R&D program.

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