Carbon films with an sp(2) network structure

Laser-arc evaporation of a graphite target has been used to deposit carbon films that exhibit high hardness (45 Cpa) and elastic recovery (85%). High- resolution electron microscopy (HREM) and electron energy loss spectroscopy (EELS) were subsequently used to study the microstructure and bonding of t he resultant layers. The structure of the films from HREM is seen to consis t of a dense array of parallel curved graphene sheet segments packed in var ious orientations. EELS reveals that the films are comprised of mainly sp(2 )-bonded carbon. The results suggest that a form of carbon thin film with f ullerenelike structure can be realized. In order to explain how a predomina ntly sp(2)-bonded material can exhibit such a high hardness, a simple model is proposed to correlate the excellent mechanical properties with the obse rved structure. [S0163-1829(99)00439-7].