Investigation on Temperature Sensing of Nanostructured Zinc Oxide Synthesized via Oxalate Route

摘要

A detailed study is reported of the synthesis and characterization of n- type ZnO nanomaterial and its application as temperature sensor. The ZnO nanomaterial has been synthesized through pyrolysis of the oxalate produced by a conventional precipitation method. It is synthesized by flash heating the oxalate at 450°C for 15 min. Pellet of this material was prepared and used as a sensing element. The variations in resistance of sensing pellet at different temperatures were recorded. The relative resistance was decreased linearly with increasing temperatures over the range, 120°C - 260°C. The activation energy of ZnO calculated from Arrhenius plot was found 1.12 eV. Temperature response in terms of the relative variation, ΔR, of sensor resistance to a given temperature was measured. Scanning electron micrograph of the sensing element has been studied. Pellet of the ZnO is comprised of nanorods of varying diameters and different lengths. Diameter of ZnO nanorods varies from 75 to 300 nm. X-ray diffraction pattern of the sensing element reveal their nano-crystalline nature. Optical characterization of the sensing material was carried out by UV-visible spectrophotometer. By UV-Vis spectra, the estimated value of band gap of ZnO was found 4.7 eV.