Product Code: ICAL09_N305

Laser Precision-Based Graphene Growth Processes
Authors:
Sarah Bertke, Mound Laser and Photonics Center; Miamisburg OH USA
David Tomich, Air Force Research Laboratory; Wright Patterson Afb OH USA
John Hoelscher, Air Force Research Laboratory; Wright Patterson Afb OH USA
Ronald Jacobsen, Mound Laser & Photonics Center; Miamisburg OH USA
Presented at ICALEO 2009

We report studies of laser methods for fabricating large-area, high-quality graphene. Common methods for graphene growth (PLD, MBE, thermal decomposition of SiC) apply energy evenly across an entire substrate, leading to simultaneous nucleation of graphene crystals in many locations and thus poor continuity over large areas. An alternative is to use a defocused laser to apply energy at a single nucleation site, and then propagate graphene growth by scanning the laser along the substrate. This concept has been applied in two versions. In a variant of established SiC thermal decomposition, the laser can heat a point on a SiC substrate, driving off Si to nucleate graphene, followed by scanning the laser to extend the graphene growth. Alternatively, a highly controlled version of PLD, known as Through Thin Film Ablation (TTFA), can be used to deposit a precise volume of carbon nanoparticles onto a substrate material with a hexagonal-close-packed lattice. The substrate structure then acts as a template for rearrangement the surface carbon into graphene as the heating laser is swept across the surface. Defocussed laser rastering has also been applied to anneal poor quality MBE-grown graphene. Raman spectroscopy characterizes the graphene grown or annealed by these methods.