Effect of Grain Size on the Response to Oxygen Gas of CuFeTe₂ Ceramics

Abstract

Oxygen gas sensor based on oxygen intercalation in the layered semiconductor CuFeTe₂ has been developed. In this study, fine powder was obtained by pulverizing CuFeTe₂ single crystal. Three groups with the range of grain size: 0 - 20 µm, 20 - 40 µm and 40 - 63 µm, was divided by sieves from the powder. CuFeTe₂ ceramics was synthesized with each group. We measured the response to oxygen gas of these ceramics. Sensitivity is defined as a saturation value of resistance change rate when oxygen intercalation occurs. It has been shown from experimental results that the sensitivity improved by 7.0 times with making grain size smaller from 40 - 63 µm to 0 - 20 µm.