Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

SnO₂:CNT thick films for gas sensors were fabricated by screen printing method on alumina substrates and were annealed at 300 °C in air. The nano SnO₂ powders were prepared by solution reduction method using tin chloride (SnCl₂.2H₂O), hydrazine (N₂H₄) and NaOH. Nano SnO₂:CNT sensing materials were prepared by ball-milling for 24h. The weight range of CNT addition on the SnO₂ surface was from 0 to 10 %. The structural and morphological properties of these sensing material were investigated using X-ray diffraction and scanning electron microscopy and transmission electron microscope. The structural properties of the SnO₂:CNT sensing materials showed a tetragonal phase with (110), (101), and (211) dominant orientations. No XRD peaks corresponding to CNT were observed in the SnO₂:CNT powders. The particle size of the SnO₂:CNT sensing materials was about 5~10 nm. The sensing characteristics of the SnO₂:CNT thick films for 5 ppm H₂S gas were investigated by comparing the electrical resistance in air with that in the target gases of each sensor in a test box. The results showed that the maximum sensitivity of the SnO₂:CNT gas sensors at room temperature was observed when the CNT concentration was 8wt%.