Product Code: ICAL09_N207

Laser-Assisted Synthesis of Epitaxial Graphite and Graphene on Sic Single Crystals (Invited Presentation, 40 minutes)
Authors:
Alberto Salleo, Stanford University; Stanford CA USA
Michael Toney, Slac; Menlo Park CA USA
Sangwon Lee, Stanford University; Stanford CA USA
Presented at ICALEO 2009

Much exciting materials physics centered around graphene has been uncovered since the realization that self-standing graphene sheets are stable. The synthesis of graphene however is still problematic.
We present an alternative route to epitaxial graphene (EG) synthesis that promises to be scalable and possibly expanded to SiC-on-Si substrates. We use pulsed excimer laser radiation (λ=248 nm, ~25 ns) to induce the graphitization of the (0001) surface of 4H-SiC single crystals. The graphitized surface is characterized by RHEED, scanning Auger spectroscopy, AFM, Raman spectroscopy, TEM and synchrotron-based x-ray diffraction. Auger spectroscopy suggests the formation of very thin (<2nm) graphite layers on the SiC surface upon laser irradiation. AFM demonstrates the existence of single-layer steps on the irradiated surface and the existence of few graphite layers is confirmed by TEM. X-ray diffraction corroborates the existence of a very thin (~1.5 nm) graphitic layer on the SiC surface. Finally, Raman spectroscopy shows a prominent single-component 2D peak, further suggesting that the material synthesized by laser processing is similar to thermal graphene. Laser-processing however offers many advantages, such as scalability, synthesis on different substrates than single crystal SiC and the opportunity to synthesize and pattern EG in a single step.