Deposition of Na2WO4 films by ultrasonic spray pyrolysis: effect of thickness on the crystallographic and sensing properties |
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Authors: | B. Abdallah M. Kakhia S. Abou Shaker |
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Affiliation: | Department of Physics, Atomic Energy Commission, Damascus, Syria |
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Abstract: | Na2WO4 films have been grown on Si (1 0 0) and glass substrate using ultrasonic spray pyrolysis. The films are prepared from aqueous solution containing Na2WO4·2H2O at 475 °C temperature and characterized by XRD and SEM techniques and the chemical composition of the films have been verified by EDX and PIXE and its formula Na2WO4 is confirmed by XRD. The evolution of the crystallinity was studied as a function of film thickness ranging from 2500 to 4200 nm, which corresponds to a deposition time from 10 to 30 min, respectively. The crystalline quality was found to improve, where the grain size values increased with increasing thickness. Atomic Force Microscopy (AFM) was used to study the morphology evolution with the deposition time, where porous films were found due to the synthesis parameters, and a better sensing response to gases was developed with increasing thickness. Thus, this study demonstrates the possibility of utilizing Na2WO4 thick films as a sensor element for the detection of ethanol vapor at room temperature, where thicker films exhibit excellent ethanol vapor sensing properties with a maximum sensitivity at 25 °C in air atmosphere with fast response time. |
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Keywords: | Na2WO4 films ultrasonic spray pyrolysis structure sensing properties |
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