Gas-sensing property of a nitrogen-doped zinc oxide fabricated by combustion synthesis

Among the various factors affecting the gas-sensing performance of ZnO, crystal defects have attracted less attention. In this letter, the gas-sensing property of a nitrogen doped ZnO powder was studied in detail in comparison with a nitrogen-free two-dimensional porous ZnO flake, which has been reported to possess a unique morphology favoring the gas-sensing performance. The nitrogen doped ZnO powders, which are several hundred nanometers in size, were fabricated in a flash by a solution combustion approach. The N/Zn atomic ratio was determined to be 0.04 by an elemental analysis. When compared with the nitrogen-free porous ZnO flakes, the nitrogen doped ZnO particles possessed more oxygen deficient species within the matrix of ZnO, and in turn exhibited a significantly improved gas-sensing property for detecting ethanol and acetone. The crystal defects arising from the nitrogen doping are thus argued to be more effective to improve the gas-sensing property of ZnO when compared with other efforts to control the particle size, surface area and the particulate morphology.