Responsivity optimization of methane gas sensor through the modification of hexagonal nanorod and reduction of defect states

A hydrothermal growth technique is introduced to synthesize hexagonal high sensitive zinc oxide (ZnO) with a large surface to volume ratio. Pre and post treatments are carried out to obtain suitable resistive performance, which enhanced sensing performance of the device. The morphological structure of synthesized ZnO under different conditions (such as reaction time solution concentrations) is characterized by scanning electron microscope (SEM). X ray diffraction (XRD) verifies the crystallinity in fabricated ZnO nanorod. X-ray photoelectron spectroscopy (XPS) is performed to measure the elemental composition corresponding to binding energy before and after treatment. Optical properties for as-grown sample and uniform ZnO nanorod are characterized through Photoluminescence (PL). Sensing properties depending on the shape, size, distribution of hexagonal nanorod, position of the IDE and temperature are investigated. The highest sensor response is achieved for the hexagonal nanorod which is uniform in shape, distribution and for the position of IDE below the sensing layer.