Dilute CH[sub 3]SH Sensing Characteristics of CdGa[sub 2]O[sub 4] Thick Film Prepared by Sol-Gel Method

Abstract

Sensing properties to dilute volatile sulfides such as H 2 S, CH 3 SH. and (CH 3 ) 2 S have been investigated for CdGa 2 O 4 thick film sensor prepared by sol-gel method. Cadmium nitrate and gallium nitrate were mixed in an aqueous solution of citric acid. After reflux and evaporation of the solution, the gel obtained was ground and calcined at 800°C for 8 h in air. The CdGa 2 O 4 sensor prepared using the powder calcined at 800°C showed high sensitivity as well as good selectivity to dilute CH 3 SH at 300°C. In particular, the CdGa 2 O 4 sensor showed sensitivity as high as 20 even to 0.01 ppm CH 3 SH. The crystal structure and surface morphology were examined by means of X-ray diffraction analysis and scanning electron microscopy, respectively.