Effect of particle size and dopant on properties of SnO2-based gas sensors

2019-11-07 16:53:43

sintering size particle concentration oxide

责任者: Zhang, G.;Liu, M. 单位: Sch. of Mater. Sci. & Eng., Georgia Inst. of Technol., Atlanta, GA, USA 来源出处: Sensors and Actuators B (Chemical)(Sens. Actuators B, Chem. (Switzerland)),10 Sept. 2000,B69(1-2):144-52 摘要: The effect of composition, microstructure, and defect chemistry on sensing performance of gas sensors based on CuO-doped SnO2 is investigated using sol-gel derived nano-sized powders (about 20 nm). The particle size of copper oxide doped tin oxide is varied by annealing at different temperatures and a significant grain growth is observed at temperatures above 1000°C due to the liquid phase sintering effect of copper oxide. The reduction of particle size to nanometers, or to the dimension comparable to the thickness of charge depletion layer, leads to a dramatic improvement in sensitivity and speed of response. It appears that the substitution of Sn by Cu in the cassiterite structure increases the concentration of oxygen vacancies and decreases the concentration of free electrons. In particular, the existence of cuprous ions (Cu+), due to partial reduction of Cu2+ during sintering, plays an important role in enhancing the sensor response to nitric oxide (NO) and CO2 关键词: annealing;gas sensors;grain growth;nanostructured materials;particle size;semiconductor doping;semiconductor materials;sintering;sol-gel processing;tin compounds;composition;microstructure;defect chemistry;sol-gel synthesis;nanosized powder;copper oxide doped tin oxide;annealing;grain growth;liquid phase sintering;cassiterite structure;oxygen vacancy concentration;free electron concentration;nitric oxide detection;carbon dioxide detection;particle size;gas sensor;charge depletion layer;1000 C;SnO2:CuO;NO;CO2