Optical and electrical breakdown of carbon allotropes : mechanisms and applications for data storage

Abstract

As Moore’s law is expected to fail soon, researchers are trying to develop new ways to store data both electrically and optically. Here, we study the structural and morphological transformations occurring when carbon allotropes are subjected to large optical and electrical power densities. We show that textured carbon thin films undergo either graphitization, amorphization or matter loss when annealed by a continuous-wave laser (annealing duration several minutes). We then use 5 ns laser pulses to induce reversible phase changes (graphitization and amorphization) to similar carbon thin films, hence opening the way toward fast optically controlled carbon phase change memories. To improve the cycling ability, we provide a model explaining both the phase changes and the observed degradations. Finally, we develop planar electro-mechanical memories based on graphene, in which a nano-sized gap is created via electrical breakdown. Large resistance changes are controlled by reversible movements of two graphene flakes surrounding the gap, hence opening and closing the electrical contact.