Ga2O3/SnO2 core–shell nanowires were synthesized by combining thermal evaporation and atomic layer deposition (ALD), and nanowire network sensors were fabricated by directly depositing them on the substrate with interdigitated Pt electrodes. Crystalline Ga2O3 nanowires of ∼20 nm diameter were grown on Au-catalyzed substrate at 800 °C. ALD-grown SnO2 shell layer was composed of interconnected nanoparticles of <10 nm, and its thickness was varied depending on the number of ALD cycles. The core–shell nanowire sensors exhibited the highest ethanol gas response at 400 °C, which was ∼200 °C lower than that for Ga2O3 nanowire sensor. The 100 cycle SnO2-coated nanowire sensor whose shell thickness was close to the Debye length of SnO2 had higher ethanol gas response in all the temperatures investigated. In addition, the core–shell nanowire sensors showed an order of magnitude higher gas response toward ethanol against other gases, such as H2, CO, and NH3.
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This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MEST) (No. 2011-0000147).
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Jang, YG., Kim, WS., Kim, DH. et al. Fabrication of Ga2O3/SnO2 core–shell nanowires and their ethanol gas sensing properties. Journal of Materials Research 26, 2322–2327 (2011). https://doi.org/10.1557/jmr.2011.189