Gas sensing properties of CNT-SnO2 Nanocomposite Thin Film Prepared by E-beam Evaporation

This work presents new results on the gas sensing study of CNT-SnO₂ nanocomposite thin film prepared by e-beam evaporation process. The SnO₂ gas sensing layers have been achieved with varying CNT concentration. Structural and morphological characterization by means of SEM TEM and XRD indicate that CNTs is incorporated in form of small fragments uniformly dispersed within SnO₂ crystal and CNT inclusion does not modify surface morphology and slightly alter the crystal structure. Electrical characterizations highlight a very peculiar and interesting behavior for the layer tested. The SnO₂ film´s conductance decreases by more than two orders of magnitude with 1%CNT concentration. As CNT content increases to 1%, CO, ethanol, and particularly NO₂ responses are improved and the working temperature tends to reduce. In addition, 1% CNT-SnO₂ exhibit maximized response to NO₂ with sensitivity of ~10 at very low NO₂ concentration of 250 ppb at 200degC.