In silico studies of the behavior of graphene/nanotube quasi-one-dimensional (1D) structures with covalent bonded graphene and nanotube in strong electric fields with a strength of 10^7–10^8 V/cm have been carried out. The atomic structure, band structure, electron transmission function, electrical conductivity, and regularity of the electronic structure changes in strong fields have been studied. It is found that the electron transmission function of quasi-1D structures has an intensity peak at the Fermi level in contrast to nanotubes and graphene. As a result of quantum molecular dynamics modeling, the regularities of deformation of the atomic framework and its destruction under the action of ponderomotive force have been established. We have found a critical value of the strength at which the electric field detaches the graphene from the tube. It is ~ 2 ∙ 10^8 V/cm. A further increase leads to the detachment of graphene from the tube with its simultaneous destruction.

Using computer materials science methods based on first-principles approaches and high-performance computing, we have studied the effect of hafnium carbide (HfC) nanoparticles on the emission properties of graphene/nanotube hybrid films. The optimal distance between graphene/nanotube structures in the composition of the hybrid film and the optimal mass fraction of HfC nanoparticles, which provide the greatest reduction in the electron work function, have been established. It has been found that partial charge transfer from the nanoparticle HfC to the carbon framework leads to changes in the density of electronic states, resulting in a change of both the Fermi energy and the height of the potential barrier for the emitting electron change, which leads to a decrease in the work function of the electron by 8–10%.