Influence of heat treatment on CH/sub 4/ sensing characteristics of K-, Ca-, Mg-doped SnO/sub 2/ sensors

Crystallite size is closely related to CH/sub 4/ sensitivity for SnO/sub 2/ sensors. The crystallite size is growing during heat treatments such as calcinations and sintering. To develop highly sensitive methane gas sensors some dopants as crystallite growth inhibitors are added to SnO/sub 2/ powder. This paper is mainly concerned with effect of heat treatment of SnO/sub 2/ doped with various grain growth inhibitors on CH/sub 4/ sensitivity. We fabricated thick film methane gas sensors using SnO/sub 2/ powders doped with K, Ca, and Mg. There is the optimum sintering temperature and time. Sensitivity is more affected by temperature than by time. And the sensitivity is exactly the same order as crystallite size.