Evolution of Field Electron Emission Pattern from Multilayered Graphene Induced by Structural Change of Edge

Structures and field emission (FE) properties of exfoliated multilayered graphene have been investigated by in situ transmission electron microscopy (TEM) and field emission microscopy (FEM). TEM revealed that edges of multilayered graphene, which were open before FE measurement, became closed after FE under high emission current, say over a few tens mu A. Corresponding to this change in the edge structure, FEM images evolved from a striped pattern for an open edge to a dim one for a closed edge. The structural change under the high current condition is presumably induced by Joule heating of the graphene tip. (c) 2012 The Japan Society of Applied Physics