Patterning, Characterization, and Chemical Sensing Applications of Graphene Nanoribbon Arrays Down to 5 nm Using Helium Ion Beam Lithography

• Published in: ACS nano Vol. 8; no. 2; pp. 1538 - 1546
• Main Authors: Abbas, Ahmad N, Liu, Gang, Liu, Bilu, Zhang, Luyao, Liu, He, Ohlberg, Douglas, Wu, Wei, Zhou, Chongwu
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25.02.2014
• Subjects: Alignment; Arrays; Detection; Electronics; Graphene; Ion beams; Lithography; Nanostructure; Patterning; graphene nanoribbon; field-effect transistor; array; helium ion beam lithography
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/nn405759v

Bandgap engineering of graphene is an essential step toward 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 ultranarrow 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 parts per billion (ppb) levels. The results show the potential of HIBL fabricated GNRs for the electronic and sensing applications.