Ethanol gas sensor based on Al-doped ZnO nanomaterial with many gas diffusing channels

摘要

ZnO nanomaterial with multi-microstructures is synthesized by using normal pressure thermal evaporation and then doped with different Al_2O_3 contents by grinding in an agate mortar. The as-prepared Al-doped ZnO nanomaterials are characterized by X-ray diffraction and scanning electron microscopy. The characterization results show that all the compounds are wurtzite with hexagonal structure and are well crystallized. Channels/connecting holes arising from many kinds of ZnO microstructures are abundant. Both annealing and Al_2O_3-doping contributes to an increase in the quasi-one-dimensional and tri-dimensional microstructures. The as-prepared Al-doped ZnO nanomaterials show excellent gas responses to ethanol. The sensing mechanism of the ZnO-based nanomaterials with multi-microstructures is further analyzed by using the Effective Specific Surface Model. Excellent sensitivity (～200) companied with short response time (～8s) and recovery time (～10s) to 3000ppm ethanol is obtained with a ZnO-based sensor with 2at.% Al_2O_3 at the operating temperature of -290℃ after the sensor is annealed at 500℃.