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Dielectric‐Screening Reduction‐Induced Large Transport Gap in Suspended Sub‐10 nm Graphene Nanoribbon Functional Devices
Author(s) -
Schmidt Marek E.,
Muruganathan Manoharan,
Kanzaki Teruhisa,
Iwasaki Takuya,
Hammam Ahmed M. M.,
Suzuki Shunei,
Ogawa Shinichi,
Mizuta Hiroshi
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201903025
Subject(s) - materials science , graphene nanoribbons , graphene , optoelectronics , dielectric , band gap , substrate (aquarium) , focused ion beam , nanotechnology , ion , chemistry , oceanography , organic chemistry , geology
The predicted quasiparticle energy gap of more than 1 eV in sub‐6 nm graphene nanoribbons (GNRs) is elusive, as it is strongly suppressed by the substrate dielectric screening. The number of techniques that can produce suspended high‐quality and electrically contacted GNRs is small. The helium ion beam milling technique is capable of achieving sub‐5 nm patterning; however, the functional device fabrication and the electrical characteristics are not yet reported. Here, the electrical transport measurement of suspended ≈6 nm wide mono‐ and bilayer GNR functional devices is reported, which are obtained through sub‐nanometer resolution helium ion beam milling with controlled total helium ion budget. The transport gap opening of 0.16–0.8 eV is observed at room temperature. The measured transport gap of the different edge orientated GNRs is in good agreement with first‐principles simulation results. The enhanced electron–electron interaction and reduced dielectric screening in the suspended quasi‐1D GNRs and anti‐ferromagnetic coupling between opposite edges in the zigzag GNRs substantiate the observed large transport gap.