Ethanol Sensor Using Zn_1−x Cd _x O (x = 0.00 and 0.10) Nanorods by Fiber-Optic Technique

A fiber-optic ethanol sensor with fully stripped cladding region coated with the sensing materials such as Zn_1−x Cd _x O (x = 0.00 and 0.10) nanorods has been proposed in this work. The formation of rods (diameter: 25–45 nm and length: 150–190 nm for ZnO and diameter: 20 nm and length: 130 nm for Zn_0.90Cd_0.10O) is confirmed by high resolution transmission electron microscopy (HRTEM) in both the samples. Since refractive index is related to band gap, here band gap of Zn_1−x Cd _x O (x = 0.00 and 0.10) nanorods are deduced using UV-Vis absorption studies. The change in refractive index of the cladding and the phenomenon of evanescent wave absorption are used in the sensing principle here, to study the sensitivity towards ethanol. The intensity variation is maximum at the wavelength of 654 nm and 663 nm for ZnO and Zn_0.90Cd_0.10O nanorods, respectively and their sensitivity towards ethanol is found to be 38% and 20%, respectively.