Enhanced NO2 gas sensing properties of Bi2O3-core / Ga2O3-shell nanowires

초록

Bi2O3-core/Ga2O3-shell nanowires were fabricated by a two step process comprising thermal evaporation of Bi2O3 powders and sputter-deposition of Ga2O3. Transmission electron microscopy and X-ray diffraction analyses revealed that the core of a typical core-shell nanobelt comprised a simple tetragonal-structured single crystal Bi2O3 and that the shell comprised an amorphous Ga2O3. Multiple networked Bi2O3-core/Ga2O3-shell nanowire sensors showed the sensitivity of 7.41% at a NO2 concentration of 10 ppm at 300 oC. This sensitivity value is more than six times larger than that of bare Bi2O3 nanowire sensors at the same NO2 concentration. The enhancement in the sensitivity of Bi2O3 nanowires to NO2 gas by sheathing the nanowires with Ga2O3 can be accounted for based on the space-charge model.