Graphene tunnelling junctions: beyond the breaking point

03 oktober 2018 om 11:20 uur

Molecular electronics is a burgeoning field of research that aims to integrate single molecules as active elements in electronic devices. Obtaining a complete picture of the charge transport properties in molecular junctions is the first step towards realizing functionality at the nanoscale. Researchers from Delft University of Technology have now studied the charge transport in a novel system, the ‘graphene mechanical break junction’, which for the first time allowed direct experimental observation of quantum interference effects in bilayer graphene as a function of nanometer-displacements.

This new platform could potentially be used for electronic fingerprinting of biomolecules, from DNA to proteins, which in turn can have important implications for the diagnosis and treatment of diseases. The research was partly funded by the Graphene Flagship.


Nanogaps separating two electrodes are envisaged as the basis for the next generation of sensing technologies. The aim is to exploit quantum electron tunneling as the sensing principle, in which the electronic structure of the target molecule trapped in the nanogap is directly probed. Graphene, a monolayer of carbon atoms in a hexagonal lattice, combines many of the requisites for an electrical sensor material: high conductivity, atomic thinness, flexibility, chemical inertness in air and liquid, and mechanical strength, as well as its compatibility with standard lithographic patterning techniques.


At the Kavli Institute of Nanoscience in Delft, a research group is developing robust graphene-based mechanically controlled break junctions (MCBJs), which allow the formation of a size-adjustable tunnelling gap at the sub-nanometre scale, i.e. the size can be tailored to the size of the biomolecule to be probed.


Mind the gap

The MCBJ experiment is conceptually very simple. The device consists of a graphene bowtie structure supported on a flexible metal substrate. The substrate is gradually bent, causing stretching of the graphene. This graphene bridge eventually breaks and a nanoscopic gap is formed. Importantly, the junction conductance can be reversibly switched by almost six orders of magnitude during 1,000 opening-closing cycles; i.e. it acts as an electrical switch that can be turned on-off mechanically. The impressive mechanical stability allows for the collection of statistically significant data, capturing various behaviours of the junctions over time and in different environments (e.g. different molecule orientations, in air, vacuum, liquid).


In collaboration with the theory group led by Prof Jaime Ferrer at the University of Oviedo (Spain), the researchers also confirmed the interference of electron waves during measurements in air at room temperature. The findings are an important step for both fundamental physics and for future applications of graphene as an electromechanical switch or biosensing platform.


Electronic fingerprinting

The graphene MCBJ is a unique device that is on the one hand a model system for studying quantum transport at room temperature, and on the other can be a powerful sensing tool to probe biomolecules with very high resolution. The researchers are currently exploring the potential of this platform for electronic fingerprinting of biomolecules, including amino acids and short peptides: the aim is to discriminate molecules with slight chemical difference according to their electronic structure, which can be ‘read' when the molecules are trapped in the nanogap. This would provide the first steps into 'tunneling-based' biosensing with graphene, an compelling vision at the Departments of Quantum and Bionanoscience at TU Delft.


Hoe vindt u het als wij ook Engelstalige artikelen publiceren?

Stem hier


Gerelateerd nieuws

Hoe kun je de complexiteit van high tech systemen aanpakken?

Hoe kun je de complexiteit van high tech systemen aanpakken?

TNO, Obeo en Altran gaan samenwerken aan oplossingen voor de complexiteit van high tech systemen. Het menselijk brein kan deze volgens hen namelijk eigenlijk niet meer overzien.

In de maak: de aerodynamische kappen van de snelste ligfiets ter wereld (video)

In de maak: de aerodynamische kappen van de snelste ligfiets ter wereld

Vorig jaar won Lieke de Cock het wereldkampioenschap snelfietsen door met 120 km/u door de Nevadawoestijn te scheuren. Dit deed ze in een aerodynamische hightech ligfiets van het Human Power Team. Dit jaar staan de…

Botsende zwarte gaten spotten met Heisenbergs onzekerheid

Botsende zwarte gaten spotten met Heisenbergs onzekerheid

Werner Heisenberg, een van de pioniers van de kwantumtheorie in de jaren ’20 van de vorige eeuw zou er vermoedelijk versteld van staan. Uitgerekend het legendarische onzekerheidsprincipe dat hij ooit formuleerde, wordt…




Gratis nieuwsbrief



Product van de maand

MGBS de slanke versie binnen de MGB serie

Ter aanvulling op de MGB serie heeft EUCHNER de MGBS uitgebracht, die uitkomst biedt op plaatsen met weinig ruimte en op...

Focus op


Machineveiligheid, systemen en componenten

B&R Industriële Automatisering BV *
B&R Industriële Automatisering BV *

Perfection in Automation

Pilz Nederland
Pilz Nederland

Voor industriële (veilige) automatiseringsoplossingen

Ringspann Benelux BV
Ringspann Benelux BV

Partner in aandrijf- en opspantechniek

Rotero Holland BV
Rotero Holland BV

Stappenmotor - Servomotor - Elektro Magneet


Specialist in plaatbewerking

Download gratis engineering boeken

A gratis boeken downloaden



6 mei 2019, Leuven

Vezelversterkte kunststof composieten

In deze cursus krijg je handvatten voor het toepassen van kunststof composiet materialen in je eigen werk...

Meer agendapunten »