LASER METHOD FOR PRODUCING CARBON DIAMOND-LIKE THIN FILMS

10.25712/ASTU.1811-1416.2022.04.005

Abstract

The laser method of direct evaporation of carbon targets in the range of laser radiation energies of      4-6 J makes it possible to obtain a vapor-gas phase of carbon with predominant sp³-hybridization of electrons. During the condensation of such carbon onto an amorphous silicate glass substrate, tetragonal diamond-like clusters are assembled in the form of a two-dimensional film, in which the concentration of graphite-like clusters formed by carbon due to sp²-bonds is significantly lower. That is, the structure of such a film is a composite material in which the properties of the composite will depend on the ratio of diamond-like and graphite-like phases. The conducted studies of the structural state of carbon diamond-like films confirm the presence of both diamond-like and graphite-like clusters with a size of no more than 1 nm. Electron microscopy reliably captures tetragonal (diamond-like) clusters. Electron diffraction indicates that the crystallographic parameters – the interplane distances of the planes (111) and (220) d₁₁₁ = 0.207 nm, d₂₂₀= 0.119 nm approximately correspond to diamond, equal respectively for large-crystal diamond d₁₁₁ = 0.205 nm and d₂₂₀=0.125 nm. If electron microscopy does not allow to fix graphite-like clusters in the film structure, then Raman-spectroscopy, which fixes a G-peak of about 1600 cm^-1 and a D-peak, the so-called D-mode due to disordering in graphite (disorder peak).  A line about 1393 cm^-1  in the raman scattering spectra identifies the presence of graphite-like clusters with disordered stacking of graphene planes.