Imaging Graphene via Low Voltage FESEM

Pursuing novel materials with intriguing properties is always an active field on the horizon of materials science. One paradigm is graphene which has attracted enormous passions and stimulated extensive research efforts all over the world since its discovery in 2004. With a monolayer of sp2 -bonded carbon atoms arranged in a honeycomb crystal lattice, graphene is a basic building block for all graphitic materials, from wrapping up into 0D fullerenes, or rolling into 1D nanotubes, to stacking into 3D graphite. For quite a long time, such a 2D graphitic layer had been described as a vintage model because this structure is not stable in theory. The success of obtaining free-standing graphene, for the first time, by mechanical exfoliation of highly oriented pyrolytic graphite (HOPG) has immediately entranced both scientists in academia trying to understand the basic behavior of matter and those working in industry trying to explore novel applications. Predicted by theories and followed by experimental demonstrations, graphene possesses unique electrical, mechanical and optical properties. Currently graphene-based nanoelectronics are the subject of intense focus. For instance, the high intrinsic mobility in graphene makes it an attractive material for high-speed electronics, and its high optical transmittance coupled with high conductivity suggests graphene as an excellent transparent conductive electrode in flat panel displays, touch screens and cathode ray tubes. In order for graphene to fulfill this promise in large-scale manufacturing of high-performance electronics, high-quality graphene with large dimensions is needed. Among several techniques for graphene synthesis, chemical vapor deposition (CVD) is the most promising approach for this purpose owing to the high quality of CVD graphene on large surface as well as the compatibility of CVD with current standard wafer-scale lithography and integrated circuit fabrication processes.