Optimized Synthesis and Device Integration of Long 17-Atom-Wide Armchair Graphene Nanoribbons

TL;DR

This paper presents an optimized synthesis method for long, stable 17-atom-wide armchair graphene nanoribbons, enabling their integration into electronic devices like FETs for advanced nanoelectronics.

Contribution

It introduces a refined bottom-up synthesis protocol producing longer GNRs with enhanced stability suitable for device integration.

Findings

Achieved average GNR length of ~17 nm through temperature ramping and high surface coverage assembly.

Confirmed GNR stability under ambient and harsh chemical conditions via Raman spectroscopy.

Demonstrated electronic transport in GNR-based FETs with graphene electrodes.

Abstract

Seventeen-carbon-atom-wide armchair graphene nanoribbons (17-AGNRs) are promising candidates for high-performance electronic devices due to their narrow electronic bandgap. Atomic precision in edge structure and width control is achieved through a bottom-up on-surface synthesis (OSS) approach from tailored molecular precursors in ultra-high vacuum (UHV). This synthetic protocol must be optimized to meet the structural requirements for device integration, with ribbon length being the most critical parameter. Here, we report optimized OSS conditions that produce 17-AGNRs with an average length of approximately 17 nm. This length enhancement is achieved through a gradual temperature ramping during an extended annealing period, combined with a template-like effect driven by monomer assembly at high surface coverage. The resulting 17-AGNRs are comprehensively characterized in UHV using scanning probe techniques and Raman spectroscopy. Raman measurements following substrate transfer enabled the characterization of the length distribution of GNRs on the device substrate and confirmed their stability under ambient conditions and harsh chemical environments, including acid vapors and etchants. The increased length and ambient stability of the 17-AGNRs lead to their reliable integration into device architectures. As a proof of concept, we integrate 17-AGNRs into field-effect transistors (FET) with graphene electrodes and confirm that electronic transport occurs through the GNRs. This work demonstrates the feasibility of integrating narrow-bandgap GNRs into functional devices and contributes to advancing the development of carbon-based nanoelectronics.