Characterization of gold nanoparticle thin film prepared by electrophoretic deposition method

Gold nanoparticle thin films were deposited on copper substrate using electrophoretic deposition (EPD) method. At first, gold nanoparticles were synthesized, using pulsed laser ablation method of a high-purity gold target in distilled water. Ablation was carried out, employing the fundamental wavelength of a Q-switched Nd:YAG laser at 1064 nm and pulse width of 7 ns. Suspension of gold nanoparticle was used as the electrolyte of EPD, in which two copper electrodes with 7 mm gap were immersed. Five samples of gold nanoparticle thin films were prepared at different deposition times and applied voltages. Nanoparticles and thin films were characterized by different diagnostics such as X-ray diffraction pattern, atomic force microscopy (AFM), and scanning electron microscopy (SEM) images as well as optical spectroscopy. XRD pattern determined crystalline structure of gold thin films. SEM image showed the effect of deposition time and applied voltage on the morphology of deposited films. AFM results demonstrated the variations in roughness, thickness, and surface quality due to changes in applied voltage and deposition time. Also, the optical properties of thin films were studied by UV-vis reflection spectroscopy.