“…The morphologies of ZnO nanoparticles, nanorods, nanobeads, aligned nanorods, cabbage leaf have been investigated for their gas sensor properties. The gas response and operating temperature of the sensor is mainly depends on materials active surface area, porosity, stoichiometry, defects concentration, crystal orientation, catalytic activity, bond ionicity and work function [5,6]. Three dimensional (3D) hierarchical branching nanowire structures offer a better opportunity while in gas sensor because of large specific surface area [7].…”