KCS

The development of sensing materials, which influence the practical gas sensing performance is critically important for the further evolution of semiconducting metal oxide gas sensor. Especially, cobalt oxides have attracted great interest in their potential applications as solid-state sensors because of their chemical stability and semiconducting properties. In this study, we are reporting the spontaneous deposition of Co₃O₄ nanoplates on interdigitated electrodes and its application to gas sensors. Inducing the phase transition of h-CoO to Co(OH)₂ and consecutive thermal oxidation on silicon substrate results in efficient deposition between Co₃O₄ and the substrate without any additional deposition processes. The efficient deposition of Co₃O₄ nanoplates is applicable for acetone gas sensors. Gas-sensing properties of Co₃O₄ nanoplates were investigated using a characterization system with a temperature-controlled hot chuck in a water-cooled steel chamber. The gas response is defined as the ratio of resistance, R = R_g/R_a, where R_a and R_g are the resistance in an air and in a gas atmosphere, respectively. The real-time gas response of Co₃O₄ nanoplates were measured under the standard condition with the exposure of 1 ppm acetone gas at 200 °C. The Co₃O₄ nanoplates exhibited quite higher gas sensitivity, and better stability than previous results.