Title : Study the effect of doping with silver nanoparticles on the properties of zirconium dioxide membranes and their effect on it as NO_2 gas sensor
Abstract:
In this research, zirconium dioxide ZrO2 thin films were prepared by pulsed laser deposition method. The deposition process was carried out on glass bases at a temperature of 300°C and a vacuum pressure of 10-3 mbar.
The structural, optical and sensitive properties of the prepared films were studied.
The structural properties were studied using X-ray diffraction and finding structural parameters. It was found that the prepared films were of a quaternary phase. It was also found that the process of adding impurities led to improving the crystalline structure of the prepared films. When calculating the structural parameters such as lattice constants and crystalin size, it was observed that there was an increase in the grain size from (30 – 100 nm) after adding impurities (nano-silver), also it was found that the preferred plane for crystal growth is (011).
The surface topography was also studied through the results of the scanning electron microscope, where the results showed that the surfaces of all the membranes were uniform, homogeneous, and free of cracks, in addition to the presence of spherical-shaped grains on the surface, and that the doping process led to an increase in the surface roughness. The results of the atomic force microscope showed that the doping process led to an increase in the surface roughness rate.
The optical measurements showed that the transmittance value of the membranes reached 95% and decreased when increases the impurities ratio to 15% at a doping percentage of 9%. There was also an increase in optical absorbance when doping percentages increased. After studying the optical energy gap, it was found that its 4.31 eV for pure films and it was decreased when impurities were added to reach (2.9 eV) at a doping rate of 9%.
Gas sensor for NH3 gas was prepared from pure and doped (ZrO2) films, and the sensitivity of the films was studied and found that the maximum sensitivity for pure films was (20 %) and the maximum sensitivity of the ZrO2 impregnated films was (56 %) at an operating temperature of 250?C when the film was 9% impregnated.
