Atomically Precise Graphene Nanoribbons—The Road Towards Device Integration

Graphene nanoribbons (GNRs) show exciting properties deriving from electron confinement and related band gap tunability¹. The ability to tune GNRs’ electronic and magnetic properties at the single atom level makes them an ideal platform for a wide range of device applications, from classical transistors to spintronics. In this talk, I will overview the necessary steps to bring GNRs from ultra-high vacuum (UHV) to device integration, focusing on the main aspects of synthesis, characterization, substrate transfer, and transport measurements. After the on-surface synthesis in UHV, GNRs are transferred using different methods based on wet² and semi-dry/dry-transfer approaches. Those processes allow the characterization of GNR's fingerprint modes and overall alignment via Raman spectroscopy (in UHV and upon exposure)^3,4 and the characterization of their electronic properties on decoupled substrates such as quasi-free-standing graphene on SiC. We integrate different armchair GNRs (5-, 9-, 17-AGNRs) into field-effect transistors with different gate and contact configurations. We demonstrate the highest I_on current GNR-FET device to date by using a double-gate configuration⁵. 9-AGNR-FETs show I<i>_on</i> currents up to 12μA and I<i>_on</i>/I<i>_off</i> up to 10⁵. By integrating 9-AGNRs into FET devices using graphene and carbon nanotubes⁶ as electrodes, we also report tunable multi-gate devices showing quantum dot behavior with rich Coulomb diamond patterns. Finally, I will present recent developments on a fully dry-transfer approach of GNRs in ultra-high-vacuum and the possibilities of their application in quantum devices.<br/><br/>1. J. Cai <i>et al.</i>, Nature, <b>466</b>, 470-473 (2010)<br/>2. G. Borin Barin <i>et al</i>., ACS Applied Nanomaterials, <b>2</b>, 2184-2192, (2019)<br/>3. R. Darawish <i>et al.</i>, <i>Carbon</i>, <b>218</b>, 118688, (2024)<br/>4. G. Borin Barin <i>et al.</i>, <i>Nanoscale</i>, <b>15</b>, 16766-16774 (2023)<br/>5. Z. Mutlu <i>et al.</i>, <i>IEEE International Electron Devices Meeting</i>, 37.4. 1-37.4. 4, (2021)<br/>6. J. Zhang <i>et al., Nature Electronics,<b>6</b>, 572-581 (2023)</i>