ИСТИНА

A simple way of fabrication of dffraction structures with the help of deposition of SiO2 colloidal microspheres on vertical glass substrate has been proposed [1]. The method is based on an intermittent, "stick-slip" motion of the suspension meniscus during liquid evaporation. The deposition was carried out at different temperatures (from 27 to 50 C). Ethanol-based suspensions with a SiO2 concentration in the range of 0.2 to 0.83 g/L, both narrow-dispersed with SiO2 particle diameter of about 200-300 nm and polydisperse, were used. As a result, the structures consisting of parallel ridges of deposited SiO2 microspheres repeating with a period of 140-200 µm and empty gaps between them have been prepared. The formation of such structures is possible only at temperatures higher than the critical value of about 30±C, and their period enhances with the temperature increase. Further modification of the structures with the purpose of their strengthening has been realized with the help of high-dose Ag+ implantation (4 ¤ 10^16 ions/cm^2,ion energy of 30 keV) followed by sonication [1]. The real laser diffraction patterns have been obtained for prepared structures. He-Ne gas laser with the wavelength 632.8 nm was used for the laser dffraction experiments. The second hierarchical level of obtained structures is connected with the self-assembly of the microspheres. A preparation of two-level structure consisting of parallel bands of hexagonally packed monolayer of microspheres is possible. REFERENCES 1. M.S. Ashurov, T.A. Kazakova, A.L. Stepanov, and S.O. Klimonsky, Appl. Phys. A, Vol. 122, 1054, 2016.