of Graphene Nanoribbon Arrays Down to 5 nm Using Helium Ion Beam

Submitted for the MAR14 Meeting of The American Physical Society Patterning, Characterization and Chemical Sensing Applications of Graphene Nanoribbon Arrays Down to 5 nm Using Helium Ion Beam Lithography1 AHMAD ABBAS, GANG LIU, BILU LIU, LUYAO ZHANG, HE LIU, University of Southern California, DOUGLAS OHLBERG, HP Labs, WEI WU, CHONGWU ZHOU, University of Southern California — Bandgap engineering of graphene is an essential step towards employing graphene in electronic and sensing applications. Recently, graphene nanoribbons (GNRs) were used to create a bandgap in graphene and function as a semiconducting switch. Although GNRs with widths of <10 nm have been achieved, problems like GNR alignment, width control, uniformity, high aspect ratios, and edge roughness must be resolved in order to introduce GNRs as a robust alternative technology. Here we report patterning, characterization and superior chemical sensing of ultra-narrow aligned GNR arrays down to 5 nm width using helium ion beam lithography (HIBL) for the first time. The patterned GNR arrays possess narrow and adjustable widths, high aspect ratios, and relatively high quality. Field-effect transistors were fabricated on such GNR arrays and temperature-dependent transport measurements show the thermally activated carrier transport in the GNR array structure. Furthermore, we have demonstrated exceptional NO2 gas sensitivity of the 5 nm GNR array devices down to ppb levels. The results show the potential of HIBL fabricated GNRs for the electronic and sensing applications. 1We would like to thank HP labs for the use of helium ion microscope. We thank Professor Kang L. Wang and Stephen B. Cronin for help with some of the experiments. We acknowledge the office of Naval Research for financial support. Ahmad Abbas University of Southern California Date submitted: 15 Nov 2013 Electronic form version 1.4