Enhanced Gas Sensing Properties of Bi2O3-Core/In2O3-Shell Nanorod Gas Sensors

摘要

The Bi2O3 nanowires are highly sensitive to low concentrations of NO2 in ambient air and are almost insensitive to most other common gases. However, it still remains a challenge to enhance their sensing performance and detection limit. This study examined the influence of the encapsulation of β-Bi2O3 nanorods with In2O3 on the NO2 gas sensing properties. β-Bi2O3-core/In2O3-shell nanorods were fabricated by a two-step process comprising the thermal evaporation of Bi2O3 powders and sputter-deposition of In2O3. Multiple networked β-Bi2O3-core/In2O3-shell nanorod sensors showed the responses of 12~(-1)56% at 1-5 ppm NO2 at 300 °C. These response values were 1.3-2.7 times larger than those of bare β-Bi2O3 nanorod sensors at 1-5 ppm NO2. The enhancement in the response of β-Bi2O3 nanorods to NO2 gas by the encapsulation by In2O3 can be accounted for based on the space-charge model.