The kinetics of a light irradiation enhanced room temperature NO2 gas sensor using hybrid ZnO/ZnTe nanorod structures†

Abstract

This study focuses on fabricating a hybrid structure consisting of ZnO nanorods and ZnTe nanoparticles for NO₂ gas detection, particularly exploring the impact of light irradiation at room temperature (RT). The morphology, physical characteristics, and chemical properties of the ZnO/ZnTe hybrid structure are carefully studied under diverse analytical methods such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and other measurements. The ZnO/ZnTe composite displayed an improved response toward 500 ppb NO₂ under the blue light radiation effect. It demonstrated higher response (more than 2500%), response time (faster than 3000%), and recovery time (faster than 1000%) at RT compared with pure ZnO. Hence, blue light irradiation revealed a more promising sensing performance than UV irradiation's case (200% at sensitivity). The depletion theory, the oxygen vacancy, the catalytic effect of zinc telluride, and the absorption coefficient modulation of the gas sensor based on different materials explained the overall performance of the nanohybrid structured sensor.