Effect of RF power on optical, structural and gas sensor Characteristics of ZnO thin films prepared by RF plasma.

This paper investigates, the effect of RF power on the structural , optical properties of ZnO thin films. It was prepared by RF magnetic sputtering at 400 °C on a glass substrate. and working pressure (5×10-2Torr), and different energy values (50, 70W). The effect of different radiofrequency powers. X-ray diffraction (XRD) and (Uv-Vis) methods were used to explore the structural and optical characteristics of thin films.The growth rate and much more increased when the RF power was increased. The results on the crystal structure demonstrated that polycrystalline patterns are common in nature for all produced ZnO thin films, the hexagonal phase as well as the (002) plane's favored direction. The grain size of the films was determined between (14-20 nm), indicating that all of these films had a nanocrystalline structure. Data on the optical properties of the produced films The ZnO film was ideal for solar cell applications because it had excellent transmittance values in the visible region (95%), The energy gap was within the range of (3.30-3.34 eV ) for pure zinc oxide films prepared with different values of power, and we note that there is a slight increase in the energy gap when increasing the power. Gas sensors were tested at various mixing ratios (NO2 97 %, air 3 %) and operational temperatures (25, 100, 200, and 300 °C) and using a bias voltage (6V). A temperature of about 300 °C was found to be the ideal working temperature for the sample. greatest sensitivity (88 %) with a quick response time (17 sec) and the fastest recoveries(63 sec), which take place at a temperature of 300°C. The result we came to was that the impact of power on the surface topography and Crystal structure induced the creation of large-surface-area nanocrystals, which is highly advantageous, and raises the sensor's sensitivity.