Synthesis of ZnO nanorods for piezoelectric resonators and sensors

Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements. ZnO nanorod arrays being good piezoelectric materials possess large surface area, which provides extra benefits for chemisorption and photodetection. Highly oriented nanorod arrays are typically prepared onto highly crystalline substrates, whereas the nanorods growth onto metal contacts meets significant technological difficulties. In this paper, we report on carbothermal, electrochemical, and hydrothermal techniques of ZnO nanorod arrays synthesis on metal contacts. The optical and structural properties of the obtained nanorods were studied using scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, and luminescence spectroscopy. A reliable technique was developed for obtaining ohmic contact with the grown nanorods. I–U curves of prepared contact were studied. Carbothermal synthesis made it possible to obtain the most crystallinely perfect, homogeneous, and dense arrays of nanorods and control the concentration of point defects by changing the synthesis parameters over a wide range. The electrochemical synthesis demonstrated excellent results for synthesis of ZnO nanorods on the surface of resonator electrodes.