Bottom-up fabrication of graphene nanoribbons: from ultra-high vacuum to device integration

Place: IMDEA Nanociencia conference room.

Abstract: 

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 give an overview of the necessary steps to bring GNRs from ultra-high vacuum (UHV) to device integration focusing on the synthesis, characterization and transport measurements of atomically-precise graphene nanoribbons. After the UHV bottom-up growth, GNRs are transferred using different transfer methods based on wet-processes such as polymer-free2 and/or an electrochemical delamination method3, as well as semi-dry/dry-transfer methods. Those processes allow the characterization of GNRs fingerprint modes via Raman spectroscopy3,4 as well as the characterization of their electronic properties on decoupled substrates such as quasi-free-standing graphene. Next, I will show our progress on integrating different armchair GNRs (5-, 9-, 17-AGNRs)5,6 into field-effect transistors with different gate and contact configurations. As a brief overview, we recently demonstrated the highest Ion current GNR-FET device to date by using a double-gate configuration7. 9-AGNR-FETs showed Ion currents up to 12μA and Ion/Ioff up to 105. By integrating 9-AGNRs into FET devices using graphene8 and carbon nanotubes9 as electrodes we also demonstrated tunable multi-gate devices showing quantum dot behavior with rich Coulomb diamond patterns.

1. J. Cai et al., Nature, 466, 2010.
2. G. Borin Barin et al., ACS Applied Nanomaterials, 2, 2019.
3. Overbeck & Borin Barin et al., Pssb, 12, 2019.
4. Overbeck & Borin Barin et al., ACS Nano, 19, 2019.
5. Llinas et al., Nature Communications, 8, 2017.
6. Borin Barin et al., Small, 18, 2022.
7. Mutlu et al., IEEE International Electron Devices Meeting (IEDM), 37.4. 1-37.4. 4, 2021.
8. Jian Zhang et al., Advanced Electronic Materials, 2201204, 2023.
9. Jian Zhang et al., arXiv:2209.04353, 2023.