A study on morphology dependent nanostructured ZnO thin films: An efficient gas sensing response for acetaldehyde

In this work, kinematically grown highly oriented hexagonal ZnO nanorods and nanograined films were fabri-cated on silicon substrates via pulsed laser deposition method. The structural, morphological, optical properties and the gas sensing studies of ZnO nanostructured thin film were systematically studied. Structural study shows high crystalline films with preferred c-axis orientated nanorods, which are grown over (002) plane nanograined films. Morphological study shows spherical-shaped nanograins and hexagonal vertical rod like structures due to kinematic growth parameters. The optical band gaps of ZnO-NR film at Eg similar to 3.18 eV and 3.46 eV, depicts greater grain boundary resistance to nanorod resistance. The artificial olfaction effect of ZnO nanorods in detecting acetaldehyde (CH3CHO) is found to be 40% more sensitive than ZnO nanograined films. The ZnO nanorods displays a greater sensitivity response for CH3CHO than other target gases. Transient gas Responsive Resistance (TRR) of ZnO nanorods and nanograined films shows increased sensitivity with higher concentration CH3CHO (10 to 100 ppm) at ambient temperature. The study indicates that ZnO nanorods could be a potential material for the detection of CH3CHO gas at room temperature.