EXPERIMENTAL STUDIES OF CORRELATIONS BETWEEN GAS SENSOR RESPONSE AND SURFACE CHEMISTRY FOR SnO_2 (110)

In experimental study of the tin dioxide gas sensor, in situ sheet conductivity wasmeasured with ultrahigh vacuum four point resistivity probe. Surface composition and stoi-chiometry were detected using XPS. Four separate structure phases were obtained by LEED atdifferent annealing temperature, and emission was observed throughout the band gap up to theFermi level with UPS. Furthermore, effects of annealing temperature and dosed oxygen pressureon the surface reconstruction, O/Sn ratio, sheet conductivity, variation of the work function andband bending have been also investigated. The results help us to reveal the relationships betweenthe electronic and electrical properties of the material and its native defects structure. It is es-pecially useful to provide a more complete understanding of the basic operation mechanisms forsuch sensing materials.

EXPERIMENTAL STUDIES OF CORRELATIONS BETWEEN GAS SENSOR RESPONSE AND SURFACE CHEMISTRY FOR SnO_2 (110)

In experimental study of the tin dioxide gas sensor, in situ sheet conductivity was measured with ultrahigh vacuum four point resistivity probe. Surface composition and stoi- chiometry were detected using XPS. Four separate structure phases were obtained by LEED at different annealing temperature, and emission was observed throughout the band gap up to the Fermi level with UPS. Furthermore, effects of annealing temperature and dosed oxygen pressure on the surface reconstruction, O/Sn ratio, sheet conductivity, variation of the work function and band bending have been also investigated. The results help us to reveal the relationships between the electronic and electrical properties of the material and its native defects structure. It is es- pecially useful to provide a more complete understanding of the basic operation mechanisms for such sensing materials.