High sensitivity chlorine gas sensors using CdIn2O4 thick film prepared by co-precipitation method

Gas-sensing properties to dilute Cl{sub 2} have been investigated for CdIn{sub 2}O{sub 4} thick film sensors prepared by co-precipitation method. Cadmium nitrate and indium nitrate were mixed in de-ionized water. The 0.1 M NaOH was added to the mixed solution. The co-precipitate obtained was washed, filtered, dried, and calcined at 600-900 deg. C for 4 h. The CdIn{sub 2}O{sub 4} sensor prepared using the powder calcined at 600 deg. C showed high sensitivity (S=R{sub g}/R{sub a}) to dilute Cl{sub 2} at 250 deg. C. In particular, the CdIn{sub 2}O{sub 4} sensor showed the sensitivity as high as 1200 even to 0.2 ppm Cl{sub 2}. The crystal structure and surface morphology were examined by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively.