Atomically precise graphene nanoribbons (GNRs) are increasingly attracting interest due to their largely modifiable electronic properties, which can be tailored by controlling their width and edge structure during chemical synthesis. In recent years, the exploitation of GNR properties for electronic devices has focused on GNR integration into field-effect-transistor (FET) geometries. However, such FET devices have limited electrostatic tunability due to the presence of a single gate. Here, we report on the device integration of 9-atom wide armchair graphene nanoribbons (9-AGNRs) into a multi-gate FET geometry, consisting of an ultra-narrow finger gate and two side gates. We use high-resolution electron-beam lithography (EBL) for defining finger gates as narrow as 12 nm and combine them with graphene electrodes for contacting the GNRs. Low-temperature transport spectroscopy measurements reveal quantum dot (QD) behavior with rich Coulomb diamond patterns, suggesting that the GNRs form QDs that are connected both in series and in parallel. Moreover, we show that the additional gates enable differential tuning of the QDs in the nanojunction, providing the first step towards multi-gate control of GNR-based multi-dot systems.
@article{arxiv.2210.03366,
title = {Tunable quantum dots from atomically precise graphene nanoribbons using a multi-gate architecture},
author = {Jian Zhang and Oliver Braun and Gabriela Borin Barin and Sara Sangtarash and Jan Overbeck and Rimah Darawish and Michael Stiefel and Roman Furrer and Antonis Olziersky and Klaus Müllen and Ivan Shorubalko and Abdalghani H. S. Daaoub and Pascal Ruffieux and Roman Fasel and Hatef Sadeghi and Mickael L. Perrin and Michel Calame},
journal= {arXiv preprint arXiv:2210.03366},
year = {2022}
}