| AVS 59th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Thursday Sessions |
| Session GR+AS+NS+SS-ThM |
| Session: | Graphene Nanostructures |
| Presenter: | W.K. Lee, Naval Research Laboratory |
| Authors: | W.K. Lee, Naval Research Laboratory J.T. Robinson, Naval Research Laboratory R. Stine, Naval Research Laboratory C.R. Tamanaha, Naval Research Laboratory D. Gunlycke, Naval Research Laboratory M. Haydell, U.S. Naval Academy E. Cimpoiasu, U.S. Naval Academy W. King, University of Illinois at Urbana Champaign P.E. Sheehan, Naval Research Laboratory |
| Correspondent: | Click to Email |
One route to realizing graphene as a material for digital-type devices is through the lithographic patterning of graphene nanoribbons (GNRs). GNRs enable band gap engineering that is dependent on nanoribbon width and edge state. We employed two complementary AFM-based lithography techniques to pattern GNRs: (1) thermal dip-pen nanolithography (tDPN)1 and (2) thermochemical nanolithography (TCNL)2. Though inverse in approach, both techniques generate GNRs into a larger sheet of insulating chemically-modified graphene. Both lithographies were performed on CVD-grown single-layered graphene (SLG) on SiO2/Si substrates using heated AFM probes. The first approach, tDPN, used the heated probe to deposit narrow polystyrene (PS) ribbons on pristine graphene. The areas of the graphene not protected by the polymer were then fluorinated, converting them to a highly insulating state, which leaves behind a chemically isolate GNR channel. We show that the PS protected ribbon was the only conductive pathway for active device. Secondly, we use the converse approach by using the heated AFM probe to locally reduce fluorographene back to graphene, leaving behind a conductive GNR channel. Both techniques can generate a wide range of nanoribbon widths while avoiding electron beams which can damage graphene. We discuss the relative merits of each strategy, as well as their impact on electrical properties (e.g., doping).
1. WK Lee et al., Nano Letters, 11, 5461, 2011
2. Z Wei et al., Science, 328, 1371, 2010