Thermal Stabilization of the Geometric Parameters of an Array of Silver Nanoparticles Obtained by Vacuum-Thermal Evaporation on an Unheated Substrate

Abstract

The nanoscale state for many substances differs significantly from the massive state. During the formation of arrays of silver nanoparticles by condensation on a cold substrate, the initial condensate is unstable. For the formation of stable arrays with a shape close to spherical, subsequent weak heat treatment is required. In this work the behavior of an array of silver nanoparticles during low-temperature annealing is shown. Using atomic force microscopy, the evolution of an array of silver nanoparticles formed on the SiO2 surface by vacuum-thermal evaporation onto an unheated substrate during in-situ heating to a temperature of 200°C is studied. A qualitative assessment of the effect of temperature on the geometry of nanoparticle arrays is obtained. It is experimentally shown that a sharp coarsening of silver nanoparticles and a decrease in their number on the surface take place in the narrow temperature range of 75 to 100°C, while in the temperature range of 100 to 200°C, there are no noticeable changes in the array of silver nanoparticles. After the statistical processing of the obtained data, the average size of the formed particles and their density per unit area at each stage of the experiment are determined. The corresponding dependences are obtained.