Morphology and Photoluminescence of Zinc Oxide Nanorods Obtained by Carbothermal Synthesis at Different Temperatures

摘要

The effect of the temperature of carbothermal synthesis on the morphology and oxygen vacancies concentration in ZnO nanorods (NRs) grown at temperatures from 900 to 1100 °C with and without the thin film ZnO sublayer on Si substrates was investigated. An estimation of the number of adsorption centers in the obtained samples was carried out by analyzing the luminescence spectra. The NRs with the maximum concentration of oxygen vacancies were synthesized at 1100 °C using the ZnO sublayer. Such NRs are more suitable for use in gas sensors. We made the CO sensor as follows: ZnO NRs were removed by ultrasound and placed on an 2D-array of Au square micro-islands. The sensor based on NRs coated with Au nanoparticles (NPs) showed a maximum sensitivity of 535% to 100 ppm CO at room temperature. The response time was 40 s and the recovery time was 45 s. Thus, coating zinc oxide NRs with Au NPs substantially effective reduce the maximum sensitivity temperature of the sensor. NRs with a minimum concentration of oxygen vacancies were synthesized at 925 °C without ZnO sublayer. Such NRs are more suitable for the use in UV photodetectors and photodiodes.