ИСТИНА

The ability to easily obtain complex patterns of semiconductor material by inkjet printing using nanoparticle sols opens up wide prospects for the use of nanosilicon (nc-Si). The disadvantage of nc-Si films obtained from sols is their low conductivity. There are several reasons for the low conductivity of nc-Si films: low concentration of free carriers in nanoparticles, Coulomb blockade, low density of films, traps on the surface of nanoparticles, barriers on the boundaries between Si nanoparticles. The purpose of the study is to determine the density of films obtained by different methods from the nc-Si sols for further investigation of the influence of film density on their transport properties. In our work we used nc-Si, obtained by laser pyrolysis of silane. Sol was prepared by sonication of nc-Si powder in ethanol. From the nc-Si sol, films on glass substrates were prepared by the following methods: drop-casting, ultrasonic assisted drop-casting, spin-coating, deposition of the nc-Si on a substrate in a centrifugal field. The thickness of the films was determined by step-profilometry, and SEM, the surface density of the nc-Si in the films was determined by spectrophotometry. From the data obtained, the bulk density of the films was calculated. The resulting films have a density of 2-10 times less than theoretically possible for the closest packing of spheres of silicon. Step-profilometry gives a film thickness that is underestimated by a factor of 1.3-3 as compared to the SEM data. A thin layer of titanium was deposited on top of the film to obtain correct data by step-profilometry. This work was supported by Russian Foundation for Basic Research grant № 17-03-01269.