Formation and transformation of carbon nanoparticles under electron irradiation

Abstract

This article reviews the phenomena occurring during irradiation of graphitic nanoparticles with high-energy electrons. A brief introduction to the physics of the interaction between energetic electrons and solids is given with particular emphasis on graphitic materials. Irradiation effects are discussed, starting from microscopic mechanisms that lead to structural alterations of the graphite lattice. It is shown how random displacements of the atoms and their subsequent rearrangements eventually lead to topological changes of the nanoparticles. Examples are the formation of carbon onions, morphological changes of carbon nanotubes, or the coalescence of fullerenes or nanotubes under electron irradiation. Irradiation-induced phase transformations in nanoparticles are discussed, e.g. the transformation of graphite to diamond, novel metal-carbon phases in nanocomposite materials or modified phase equilibria in metal crystals encapsulated in graphitic shells.

Ion and electron irradiation-induced effects in nanostructured materials

“…We discuss at length not only the physics behind irradiation of nanostructures but also the technical applicability of irradiation for nanoengineering of nanosystems. We stress that although several review articles on the subject focused on carbon nanosystems, [72][73][74] ion implantation onto nanomaterials, 75 atomistic simulations of irradiation effects, 76,77 and focused electron/ion beams 78 have recently been published, the field has been developing quite fast following the discoveries of new important nanomaterials, such as graphene, 79,80 which motivates reanalyzing and reviewing the literature.…”

The contribution made by lattice vacancies to the Wigner effect in radiation-damaged graphite

“…In isolation, graphene sheets behave more like pieces of woven silk fabric, which can fold and wrinkle, than fixed, flat layers of a stiff mesh. The sheets can roll up into tubes, scrolls, balls, onion-like forms, and fold over upon themselves in complex ways [7][8][9][10][11].…”

In-situ high-pressure transmission electron microscopy for Earth and materials sciences

“…If the graphitic networks are curved on the nanometer scale and the temperature is raised to above ∼300 °C, structural reorganization occurs around the relatively immobile vacancies in the networks, causing their shrinkage ( Fig. 1) (Banhart 1999(Banhart , 2004Krasheninnikov et al 2005). If they are in the form of closed containers that enclose condensed materials, compression of the enclosed materials occurs (Banhart and Ajayan 1996).…”