The electronic, optical and magnetic properties of graphene nanoribbons (GNRs) can be engineered by controlling their edge structure and width with atomic precision through bottom-up fabrication based on molecular precursors. This approach offers a unique platform for all-carbon electronic devices but requires careful optimization of the growth conditions to match structural requirements for successful device integration, with GNR length being the most critical parameter. In this work, we study the growth, characterization, and device integration of 5-atom wide armchair GNRs (5-AGNRs), which are expected to have an optimal band gap as active material in switching devices. 5-AGNRs are obtained via on-surface synthesis under ultra-high vacuum conditions from Br- and I-substituted precursors. We show that the use of I-substituted precursors and the optimization of the initial precursor coverage quintupled the average 5-AGNR length. This significant length increase allowed us to integrate 5-AGNRs into devices and to realize the first field-effect transistor based on narrow bandgap AGNRs that shows switching behavior at room temperature. Our study highlights that optimized growth protocols can successfully bridge between the sub-nanometer scale, where atomic precision is needed to control the electronic properties, and the scale of tens of nanometers relevant for successful device integration of GNRs.
@article{arxiv.2202.01101,
title = {Growth optimization and device integration of narrow-bandgap graphene nanoribbons},
author = {Gabriela Borin Barin and Qiang Sun and Marco Di Giovannantonio and Cheng-Zhuo Du and Xiao-Ye Wang and Juan Pablo Llinas and Zafer Mutlu and Yuxuan Lin and Jan Wilhelm and Jan Overbeck and Colin Daniels and Michael Lamparski and Hafeesudeen Sahabudeen and Mickael L. Perrin and José I. Urgel and Shantanu Mishra and Amogh Kinikar and Roland Widmer and Samuel Stolz and Max Bommert and Carlo Pignedoli and Xinliang Feng and Michel Calame and Klaus Müllen and Akimitsu Narita and Vincent Meunier and Jeffrey Bokor and Roman Fasel and Pascal Ruffieux},
journal= {arXiv preprint arXiv:2202.01101},
year = {2022}
}