The characteristics of sputterd Zinc Oxide film as a $H_2$, CO gas detector were studied. Their geometrical factors and electrical factors were measured by XRD(X-ray diffractometers), SEM(Scanning Electron Microscopy) and Hall Measurement, the effects of geometrical factors and electrical factors to gas detection ability were analyzed. As a result, their electron transport mechanisms are characterized by thermally assisted electron mobility and their detection ability is higher for CO four times than that of $H_2$.
