Structure and surface properties of the sensing materials have been recognized as the primary consideration for fabricating metal oxide semiconductor gas sensors. In this study, one-dimensional ZnO nanowires with large length-to-diameter ratio were firstly synthesized by a facile hydrothermal method. Then, different contents of ultra-fine In₂O₃ nanoparticles were directly grown on their surface. The structural characterization confirmed that the In₂O₃ nanoparticles were only 3∼5 nm in diameter and well dispersed on the surface of ZnO nanowires. The gas sensing results showed that the ultra-fine In₂O₃ nanoparticles gave rise to a significant improvement in NO₂ response at their optimal operating temperature of 150 °C. The highest response of 54.6 to 1 ppm NO₂ was obtained for the sensor based on In₂O₃/ZnO composites with the In/Zn molar ratio of 5%, which was about 8 times higher than that of pure ZnO nanowires. Importantly, a high response of 18.4 to a relatively low NO₂ concentration of 250 ppb was also observed for In₂O₃-functionalized ZnO nanowires. The enhanced NO₂ sensing mechanisms of ZnO nanowires functionalized with ultra-fine In₂O₃ nanoparticles were discussed.

传感材料的结构和表面特性已被认为是制造金属氧化物半导体气体传感器的主要考虑因素。本研究首先采用简便的水热法合成了长径比大的一维ZnO纳米线。然后，将不同含量的超细In ₂ O ₃纳米颗粒直接生长在其表面上。结构表征证实，In ₂ O ₃纳米粒子的直径仅为3-5 nm，并且很好地分散在ZnO纳米线的表面上。气体感测结果表明，超细In ₂ O ₃纳米颗粒显着改善了NO _2。最佳工作温度为150°C时的响应。基于In / O摩尔比为5％的In ₂ O ₃ / ZnO复合材料的传感器获得了54.6至1 ppm NO ₂的最高响应，这比纯ZnO纳米线的响应高约8倍。重要的是，对于In ₂ O ₃功能化的ZnO纳米线，还观察到了相对较低的250 ppb NO ₂浓度的18.4的高响应。讨论了用超细In ₂ O ₃纳米粒子功能化的ZnO纳米线增强的NO ₂传感机制。