Solid Carbon Products of Isobutane Decomposition in Laser Plasma

Abstract

In this work, the properties of carbon films fabricated upon the action of laser plasma on the simple gaseous hydrocarbons have been studied. The change in the properties of these films caused by subsequent thermal or laser treatment has been investigated. Carbon films deposited on a cold substrate have a complex nature, which is similar to the nature of tholins. These films contain carbon atoms in the sp2- and sp3-hybrid states in proportional amounts, as well as various structural fragments containing hydrogen and oxygen. Thermal annealing of carbon films leads to a decrease in the concentration of hydrogen and oxygen-containing structures, unification of the structure based on carbon atoms in sp3 hybridization and formation of a so-called diamond-like structure. It was shown that carbon films are formed by spherical particles with an average diameter of 7–8 nm. Laser annealing and fabrication of a film with direct constant laser exposure leads to formation of a graphene-like structure meaning sp2 hybridization of carbon.