Size Distribution And Orientation Of Dewetted Gold Particles On Oxide Substrates

Dewetted nanoparticle arrays with specific size distribution and orientation have been widely used in plasma technology,sensors and synthesis of one-dimensional nanostructures owing to their unique optical,electrical,magnetic or catalytic properties.The present researches mainly focus on the influence of treatment parameters.However,the substrates also have significant influence on the distribution and orientation of dewetted particles.In this paper,based on the phenomenon found in the previous research of our group,that is,oxide substrate grows during heat treatment,the influence of the substrate on the size distribution and orientation of the dewetted particles were separately studied without introducing additional components.The results of this study can provide new ideas for tailoring dewetted nanoparticles.The main conclusions are summarized as follows:(1)The bimodal distribution of dewetted gold nanoparticles on MgAl₂O₃,Sr Ti O₃,Ti O₂ and ZnO single crystal is related to the growth of substrates.The additional surface diffusion of gold atoms accompanied by the growth of oxide substrates during dewetting process,is responsable for the size bimodal distribution of particles.(2)According to the comparison of bases obtained in lattice match and mismatch system,we found that the shape of the oxide bases had no effect on the size distribution of the dewetted particles.(3)The result of Au film dewetted on ZnO substrates(mismatch system),indicated that the morphology of the substrate and the phase of particles changed with the increasing temperature and prolonging annealing time.Au₃Zn and Au₅Zn₃ phases were found in particles with a higher temperature.Preferred orientations of particles on substrates were observed.(4)The cut-off surfaces had great effect on the morphology of nanostructures grown from substrate,and slightly influenced the phase and orientation of particles in Au-ZnO system.