The Evolution Of Fabricated Gold Thin Films To Nano–Micro Particles Under Thermal Annealing Process

Gold (Au) thin films with thickness of 35nm were prepared by electron beam deposition onto flat glass substrates under high vacuum (5.3×10−3Pa) condition and they were annealed in the range of 573–873 K for 1 and 2h in atmospheric pressure. The influence of the annealing temperature on the evolution of Au thin film to nano–micro particles was studied. Moreover, the basic properties of the films, namely morphological, structural and optical were investigated. The X-ray diffraction (XRD) analysis revealed that the Au thin films were cubic structure phase with lattice parameter around a=4.0786Å. The most preferential orientation is along (111) planes for all Au films. The lattice parameter and grain size in the films were calculated by X-ray patterns and correlated with annealing temperatures. The obtained results of ultraviolet–visible spectrometry (UV–Vis) indicate that with increasing annealing temperature, the surface plasmon resonance peak of gold nanocrystallite will disappear which implies the size of particles are grown. Field-emission scanning electron microscopy (FE-SEM) results show that the prepared gold thin films have been converted to nano–micro gold particles in different annealing temperatures. These results lead to controlling the size of produced nanocrystallite.