Distinguishing Lead and Molecule States in Graphene-Based Single-Electron Transistors

Gehring, Pascal; Sowa, Jakub K.; Cremers, Jonathan; Wu, Qingqing; Sadeghi, Hatef; Sheng, Yuewen; Warner, Jamie H.; Lambert, Colin J.; Briggs, G. Andrew D.; Mol, Jan A.

doi:10.1021/acsnano.7b00570

Cited by 56 publications

(69 citation statements)

References 32 publications

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“…The bonding and antibonding MOs both lie above the Fermi energy and will henceforth be referred to as the LUMO and LUMO+1 respectively 29 . The choice of the site energies above is not of critical importance, particularly since many currently available experimental techniques allow electrostatic control of the molecular energy levels through a gate electrode 20,[30][31][32] . We begin by considering transport in the absence of any vibrational coupling.…”

Section: Resultsmentioning

confidence: 99%

Environment-assisted quantum transport through single-molecule junctions

Sowa

Mol

Briggs

et al. 2017

Phys. Chem. Chem. Phys.

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Single-molecule electronics has been envisioned as the ultimate goal in the miniaturisation of electronic circuits. While the aim of incorporating single-molecule junctions into modern technology still proves elusive, recent developments in this field have begun to enable experimental investigation of fundamental concepts within the area of chemical physics. One such phenomenon is the concept of Environment-Assisted Quantum Transport which has emerged from the investigation of exciton transport in photosynthetic complexes. Here, we study charge transport through a two-site molecular junction coupled to a vibrational environment. We demonstrate that vibrational interactions can significantly enhance the current through specific molecular orbitals. Our study offers a clear pathway towards finding and identifying environment-assisted transport phenomena in charge transport settings.

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Section: Resultsmentioning

confidence: 99%

Environment-assisted quantum transport through single-molecule junctions

Sowa

Mol

Briggs

et al. 2017

Phys. Chem. Chem. Phys.

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“…By contrast, the effect of out-of-plane wrinkles (outsized ripples with an aspect ratio larger than 1) 36 present on CVD-grown graphene (commonly used in the fabrication of graphene electrodes) on the energetic states of molecules remain to be fully clarified. 37 Further information on site-dependent discrepancies in molecular resonance will aid efforts to predict the performance of large-scale devices integrated with electrodes made from graphene and other 2-D layered materials. 38 Here we report the adsorption patterns and electronic states of pentacene adsorbed on wrinkled and flat regions of CVD-grown graphene, measured using atomic force microscopy (AFM), scanning tunneling microscopy (STM), and spectroscopy (STS).…”

Section: Introductionmentioning

confidence: 99%

Graphene wrinkle effects on molecular resonance states

et al. 2018

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Wrinkles are a unique class of surface corrugations present over diverse length scales from Kinneyia-type wrinkles in Archean-era sedimentary fossils to nanoscopic crinkling in two-dimensional crystals. Lately, the role of wrinkles on graphene has been subject to debate as devices based on graphene progress towards commercialization. While the topology and electronic structure of graphene wrinkles is known, data on wrinkle geometrical effects on molecular adsorption patterns and resonance states is lacking. Here, we report molecular superstructures and enhancement of free-molecular electronic states of pentacene on graphene wrinkles. A new trend is observed where the pentacene energy gap scales with wrinkle height, as wrinkles taller than 2 nm significantly screen metal induced hybridization. Combined with density functional theory calculations, the impact of wrinkles in tuning molecular growth modes and electronic structure is clarified at room-temperature. These results suggest the need to rethink wrinkle engineering in modular devices based on graphene and related 2D materials interfacing with electronically active molecules.

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“…Several groups have reported the fabrication of molecular devices using few‐layer or single‐layer graphene (SLG) as electrodes ,. Two distinct experimental approaches have been demonstrated to construct graphene nano‐gaps, i. e. the dash‐line lithographic plasma etching and the feedback‐controlled electroburning ,,,.…”

Section: Introductionmentioning

confidence: 99%

Efficient Fabrication of Stable Graphene‐Molecule‐Graphene Single‐Molecule Junctions at Room Temperature

et al. 2018

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We present a robust approach to fabricate stable single-molecule junctions at room temperature using single-layer graphene as nanoelectrodes. Molecular scale nano-gaps in graphene were generated using an optimized fast-speed feedback-controlled electroburning process. This process shortened the time for creating a single nano-gap to be less than one minute while keeping a yield higher than 97 %. To precisely control the gap position and minimize the effects of edge defects and the quantum confinement, extra-narrow grooves were pre-patterned in the graphene structures with oxygen plasma etching. Molecular junctions were formed by bridging the nano-gaps with amino-functionalized hexaphenyl molecules by taking advantage of chemical reactions between the amino groups at the two ends of the molecules and the carboxyl groups at the edges of graphene electrodes. Electronic transport measurements and transition voltage spectroscopy analysis verified the formation of single-molecule devices. First-principles quantum transport calculations show that the highest occupied molecular orbital of hexaphenyl is closer to the Fermi level of the graphene electrodes and thus the devices exhibit a hole-type transport characteristics. Some of these molecular devices remained stable up to four weeks, highlighting the potential of graphene nano-electrodes in the fabrication of stable single-molecule devices at room temperature.

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Distinguishing Lead and Molecule States in Graphene-Based Single-Electron Transistors

Cited by 56 publications

References 32 publications

Environment-assisted quantum transport through single-molecule junctions

Environment-assisted quantum transport through single-molecule junctions

Graphene wrinkle effects on molecular resonance states

Efficient Fabrication of Stable Graphene‐Molecule‐Graphene Single‐Molecule Junctions at Room Temperature

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