Scalable Straining of Graphene by Laser Shock

Ji Li, G.J. Cheng
Purdue University, US

Keywords: scalable, strain engineering, graphene, laser shock

Summary:

Graphene, an atom-thick layer of carbon, has attracted significant attention since its experimental discovery in 2004. As the mother of all graphitic materials such as fullerenes, carbon nanotubes and graphite, graphene possesses unusual properties, including structural perfection, low density, excellent electrical properties, zero effective mass near the Dirac point, long mean free path, and also superior mechanical properties. However, graphene has limited functionality, particularly for semiconductor application because of its almost strict linear energy dispersion relation near the charge neutrality point (Dirac point) in the electronic band structure. In this study, laser shock pressure is applied on graphene sheet, resulting in sudden deforming of graphene film onto substrate surface with nano-scale curved patterns. Scanning electronic microscope (SEM) and atomic force microscop (AFM) were used to observe the surface of the graphene after laser shock operation. The critical pressure needed to break the graphene film is also studied, revealing that a pressure level between 1-2 GPa is enough to break holes larger than 70 nm in diameter. Thus, a smaller pressure should be used to shape graphene film into corresponding mold without damaging the film.