459844 Large Area Graphene Nanoribbons By Wetting Transparency-Assisted Block Copolymer Lithography

Tuesday, November 15, 2016: 10:15 AM
Imperial A (Hilton San Francisco Union Square)
Reika Katsumata1, Maruthi N. Yogeesh2, Helen Wong1, Sunshine X. Zhou3, Stephen Sirard4, Richard D. Piner5, Zilong Wu2,6, Wei Li2,6, Alvin L. Lee6, Mattew Carlson1, Michael J. Maher7, Deji Akinwande2,6 and Christopher J. Ellison8, (1)McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, (2)Microelectronics Research Center, The University of Texas at Austin, Austin, TX, (3)McKetta Department of Chemical Engineering, The University of Texas at Autsin, Austin, TX, (4)Lam Research Corporation, Austin, TX, (5)Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, (6)Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX, (7)Department of Chemistry, University of Texas, Austin, TX, (8)The University of Texas at Austin, Austin, TX

Graphene plasmons have gained considerable attention during the last decade due to their potential to overcome current challenges facing traditional plasmonic materials, such as gold’s limited spatial resolution and extinction wavelengths. In particular, patterning graphene into nanoribbons (graphene nanoribbons, GNR) allows for tunability in the emerging fields of mid-infrared and terahertz spectroscopy based devices. However, the fabrication of GNR arrays for these plasmonic devices often includes a low-throughput electron beam lithography step that cannot be easily scaled to large areas. In this study, we developed a new and more scalable GNR fabrication method based on block copolymer (BCP) lithography. To pattern graphene into GNRs, lamellae-forming BCP domains must be oriented perpendicular to substrate and then selectively etched. However, perpenducular orientation can only be achieved when the surface energy of the underlying substrate is neutral or non-preferential to wetting either block of the BCP. Extensive contact angle and surface energy measurements indicated that the surface neutrality of the underlying substrate is mostly retained even with a single layer of graphene coating the top of the underlying substrate. This is due to the wetting transparency of graphene. Using wetting transparency-assisted BCP lithography, we successfully fabricated large-area (cm2 scale) GNR arrays with 20 nm nanoribbon widths. The optical properties of the GNR arrays were studied by Fourier transform infrared spectroscopy, and a clear plasmonic extinction peak in the mid-infrared region (~1600 cm-1) was observed. This GNR fabrication method could be useful for high-throughput production of a broad range of mid-infrared plasmonic devices, including modulators, biosensors, and photodetectors.

Extended Abstract: File Not Uploaded