Nanorods to nanosheets structural evolution of NixZn1-xO for NO2 gas sensing application

Abstract In the present study the efforts are taken to fabricate Ni x Zn 1-x O nanostructures (x = 0.04, 0.08, 0.12, 0.16 and 0.2) thin film by simple hydrothermal method. The prepared thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), photoluminescence (PL) spectroscopy and two probe resistivity technique. Interestingly, it was found that the morphology of the nanostructures evolved from rod-like to sheet-like structures with variation in the concentration of Ni in ZnO from x = 0.04 to 0.16. The Ni x Zn 1-x O thin films of all compositions were tested for the gas sensing behavior for the oxidizing gas; NO 2 (Nitrogen dioxide). It is found that, the sensing response increases with increase in the Ni 2+ concentration up to x = 0.16, and then it decreases slightly for further increment in Ni 2+ . The Ni 0.16 Zn 0.84 O film shows higher response (S) = 9.01 for 8 ppm NO 2 at comparatively low operating temperature. Additionally, Ni x Zn 1-x O thin film sensor has potentially detected 1 ppm of NO 2 gas with admirable response ∼1.45.