Effect of hydrogenation of carbon atom on its deposition on graphene

Abstract

This article discusses the possibility of graphene functionalization by the deposition of carbon atoms with different degrees of hydrogenation and the effect of hydrogenation on the probability of precipitation using computer simulation. According to the results of computer simulation, the binding energy of the single carbon atom, methine, methylene and methyl is more than 1 eV. This corresponds to chemisorption, which means that the chemical bonds are generated due to unpaired valent electrons of the incident particles and defect-free graphene. Methane does not have unpaired valent electrons and in the range of investigated deposition energies its chemisorption on graphene is not observed. The free carbon atom with various degrees of its hydrogenation is considered: methane CH, methylene CH2, methyl CH3 and methane CH4. It is established that if the deposited particles C, CH, CH2 and CH3 form a bound state with graphene, these particles are located near the characteristic points with a different probability of location above graphene at these points. The processes of deposition of hydrogenated and non-hydrogenated carbon atoms with kinetic energies of 1.0, 1.2, 1.5, 2.3 and 3.1 eV on graphene are studied. It is found that the processes of deposition of non-hydrogenated and hydrogenated carbon atoms on defect-free graphene depend on the degree of hydrogenation of the carbon atom: the more hydrogenated the carbon atom is, the less its probability of chemisorption on graphene. Methane, as a fully hydrogenated carbon atom, does not chemisorb on graphene at deposition energies from 1 to 3.1 eV. It is also observed that the maximum probability of chemisorption of C, CH, CH2 and CH3 on graphene took place at deposition energy of about 2.3 eV.