Crossover point of the field effect transistor and interconnect applications in turbostratic multilayer graphene nanoribbon channel

Ryota Negishi,Seyed Ali Mojtahedzadeh,Hirofumi Tanaka,Yoshihiro Kobayashi,Katsuma Yamamoto,Nobuya Mori

doi:10.1038/s41598-021-89709-z

Ryota Negishi, Seyed Ali Mojtahedzadeh + Show 4 more

Open Access

https://doi.org/10.1038/s41598-021-89709-z

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Abstract

The electrical transport properties of a turbostratic multilayer graphene nanoribbon (GNR) with various number of layers (1–8 layers) were investigated using a field effect transistor with a single GNR channel. In the turbostratic multilayer GNR with 5 layers or less, the carrier mobility and Ion/Ioff ratio in the FETs were improved by slightly increasing the conductance with increasing the number of layers, meaning that the excellent semiconducting characteristic. The improvement of the carrier transport properties promotes by the turbostratic stacking structure. In the turbostratic multilayer GNR with 6 layers or more, although the Ion/Ioff ratio degraded, the conductance extremely improved with increasing the number of layers. This indicates that the turbostratic multilayer GNR with thicker number of layers becomes the significantly lower resistivity wire as a metallic characteristic. We revealed that the crossover point of the physical properties between the semiconducting and metallic characteristics is determined by the strength to screen the surrounding environment effects such as charged impurity on the substrate. Our comprehensive investigation provides a design guidance for the various electrical device applications of GNR materials.

Highlights

MethodsThe pristine graphene nanoribbon (GNR) used as a growth template were synthesized by unzipping of double-walled carbon nanotubes (CNTs) (Tokyo Ohka Kogyo Co. Ltd.)[22]
We found that the carrier transport properties such as the semiconducting and metallic characteristics observed in the multilayer graphene nanoribbon (GNR) with a narrow width (18–25 nm) are determined by strength to screen the charges of the impurity on the device substrate as a surrounding environment
The root mean square (RMS) surface roughness of the grown GNR and substrate evaluated from the height profiles along R–R′, S–S′ and T–T′ lines in Fig. 1f is almost the same value (0.10–0.11 nm) among them, and the value is lower than a monolayer graphene step height

Summary

Methods

The pristine GNRs used as a growth template were synthesized by unzipping of double-walled CNTs (Tokyo Ohka Kogyo Co. Ltd.)[22]. The synthesized GNRs were dispersed on the SiO2 (300 nm)/Si substrate, and the samples were preheated at 350 °C for 20 min in air under atmospheric pressure to remove the poly (m-phenylenevinylene-co-2,5-dioctoxy-p-phenylenevinylene (PmPV) used as a surfactant for the stabilization of unzipped GNRs in the solution. The graphene layers were grown on the GNR template using a sloped-temperature CVD apparatus with e thanol[60, 61]. The CVD apparatus can regulate the temperatures separately in three zones, resulting in individual control over the decomposition reaction of the carbon feedstock and the growth of graphene layers by activated carbon species. The temperatures used in this study were 900 °C and 720–744 °C for the decomposition and graphene layer growth, respectively

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Discussion

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