The Influence of Deposition Time on the Structural, Morphological, Optical and Electrical Properties of ZnO-rGO Nanocomposite Thin Films Grown in a Single Step by USP

Abstract

Thin films of nanocomposite of zinc oxide–reduced graphene oxide (ZnO-rGO) deposited on soda-lime glass substrates were prepared using ultrasonic spray pyrolysis (USP) at 460 °C. The preparation process does not use harsh acids and is environmentally friendly. The deposition period of 2, 3.5 and 5 min resulted in compact, uniform samples with thicknesses of 148, 250 and 365 nm, respectively. After performing structural, morphological, optical and electrical characterization of the prepared nanocomposite, an influence of the deposition time on the physical properties of the obtained films was determined. TEM analyses indicate that the ZnO-rGO nanocomposite presents ZnO nanoparticles anchored on graphene sheets, while XRD, X-ray Photoelectron Spectroscopy (XPS) and Raman results show the presence of a ZnO phase in the ZnO-rGO films. HR-SEM studies showed changes of the ZnO-rGO thin films morphology due to the incorporation of graphene into the ZnO films. Here, the particles of ZnO are similar to small grains of rice and graphene films have the appearance of a little “rose”. As the thickness of the film increases with deposition time, it reduces the structure of resistance of the nanocomposite thin films to 135 Ω. In addition, the optical transmission of the thin films in the visible region resulted affected. Here, we report a simple methodology for the preparation of ZnO-rGO nanocomposite thin films.