Since my April 1 posting on graphene, I have found three interesting developments. In the first [arXiv:0912.5485], an international collaboration reports synthesis and roll-to-roll transfer of large area graphene. This marks a huge step forward in making graphene available for applications. In my opinion, the copper etch makes the method more expensive than it might otherwise appear. Considerable work remains here.
IBM reports [arXiv:1003.5702] a new technique for synthesizing electronically interesting graphene on SiC. In the conventional approach, silicon is sublimated from SiC(0001), leaving behind a monolayer of carbon which is covalently bonded to the substrate. IBM has found that subsequent treatment with oxygen at 250 C suffices to grow an oxide layer between the SiC substrate and the carbon layer. The carbon immediately rearranges its bonding to graphene.
IBM also reports [arXiv:0912.4794] on photocurrent response in bilayer and trilayer graphene field effect transistors all the way out to 40 GHz. While most research has been directed toward electronic applications, IBM points out that the photonic properties are every bit as interesting and technologically promising. Although they have so far demonstrated up to 40 GHz response,
[f]urther analysis suggests that the intrinsic bandwidth of such graphene FET based photodetectors may exceed 500 GHz. Most notably, the generation and transport of the photo-carriers in such graphene photodetectors are fundamentally different from those in currently known semiconductor photodetectors, leading to a remarkably high bandwidth, zero source-drain bias (hence zero dark current) operation, and good internal quantum efficiency.