Hydrothermal Synthesis of ZnO Nanorod Arrays on a Chip towards Sensors Applications ☆

Nanostructured wide band gap semiconductor ZnO has exceptional properties and vast applications in gas- and bio- sensors. Recent studies has thus been focused on the controlled synthesis low dimensional ZnO of nanorods or nanowires. The present work reports the synthesis of ZnO nanorod arrays on dendritic islands of seed layer by hydrothermal method towards sensors applications. The ZnO seed layer islands were deposited on a thermally oxidized silicon substrate using a reactive sputtering system. The substrate was further immersed in equimolar aqueous solution (0.005 M) of zinc nitrate and hexamethylenetetramine for the hydrothermal growth of nanorods. The morphology and crystal structure of the ZnO nanorods were performed by field-emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Results show that the diameter and length of the nanorods were 200 nm and 3 µm, respectively. The electrical properties of the fabricated device were investigated by I-V measurement at different temperatures, and the data showed that an Ohmic contact was formed between nanorods and Pt electrodes, and the material exhibited nature semiconducting properties. The synthesized ZnO nanorod arrays are promising for sensing applications.