Effect of indium concentration on morphology of ZnO nanostructures grown by using CVD method and their application for H2 gas sensing

ZnO nanostructures of nanorods and nanonails morphology were grown by mixing indium powder with zinc powder in chemical vapor deposition process. The effect of indium concentration on the morphology of ZnO is investigated. The results show the morphology of the ZnO nanorods gradually changes to nanonails shape with increase in the indium concentration in the reaction mixture. The surface morphology and structural properties were investigated by using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The grown nanorods and nanonails were used for the fabrication of gas sensor for the detection of H2 gas. The results obtained indicate that the H2 gas response of the nanorods and nanonails highly depend on the morphology induced by the indium incorporation. The sensitivity decreased with increase in the concentration of indium in the ZnO nanorods. The sensitivity of 45%, 81%, 50%, 12%, and 10% were obtained for indium wt% of 0%, 0.5%, 1%, 2.5% and 5% respectively, operating temperature at 300 °C. Similar trend of sensitivity decreasing with increase in the indium concentration with operating temperature to 220 °C. The sensitivity of 65.5%, 92%, 61%, 6%, and 5% were obtained for samples with indium wt% of 0%, 0.5%, 1%, 2.5% and 5% respectively.