Optimized graphene electrodes for contacting graphene nanoribbons

Atomically precise graphene nanoribbons (GNRs) are a promising emerging class of designer quantum materials with electronic properties that are tunable by chemical design. However, many challenges remain in the device integration of these materials, especially regarding contacting strategies. We report on the device integration of uniaxially...

Benchmark and application of unsupervised classification approaches for univariate data

Unsupervised machine learning, and in particular data clustering, is a powerful approach for the analysis of datasets and identification of characteristic features occurring throughout a dataset. It is gaining popularity across scientific disciplines and is particularly useful for applications without a priori knowledge of the data structure....

Controlled Quantum Dot Formation in Atomically Engineered Graphene Nanoribbon Field-Effect Transistors

Graphene nanoribbons (GNRs) have attracted strong interest from researchers worldwide, as they constitute an emerging class of quantum-designed materials. The major challenges toward their exploitation in electronic applications include reliable contacting, complicated by their small size (<50 nm), and the preservation of their physical...

Single-molecule functionality in electronic components based on orbital resonances

In recent years, a wide range of single-molecule devices has been realized, enabled by technological advances combined with the versatility offered by synthetic chemistry. In particular, single-molecule diodes have attracted significant attention with an ongoing effort to increase the rectification ratio between the forward and reverse...

Quantum interference-induced conductance variation in mechanosensitive single-molecule junction

A great interest of molecular electronics comes from its change in electronic structure through external stimuli, which provides functionality at the single-molecule level. Mechanically-controlled break junction (MCBJ) is a great tool for characterizing molecular properties and their response to different stimuli including light, solvent and...

Robust graphene-based molecular devices

One of the main challenges to upscale the fabrication of molecular devices is to achieve a mechanically stable device with reproducible and controllable electronic features that operates at room temperature1,2. This is crucial because structural and electronic fluctuations can lead to significant changes in the transport characteristics at...

A reference-free clustering method for the analysis of molecular break-junction measurements

Single-molecule break-junction measurements are intrinsically stochastic in nature, requiring the acquisition of large datasets of “breaking traces” to gain insight into the generic electronic properties of the molecule under study. For example, the most probable conductance value of the molecule is often extracted from the conductance...

Large Conductance Variations in a Mechanosensitive Single-Molecule Junction

An appealing feature of molecular electronics is the possibility of inducing changes in the orbital structure through external stimuli. This can provide functionality on the single-molecule level that can be employed for sensing or switching purposes if the associated conductance changes are sizable upon application of the stimuli. Here, we...

Mechanical Tuning of Through-Molecule Conductance in a Conjugated Calix[4]pyrrole

A conformationally flexible calix[4]pyrrole possessing a conjugated electronic structure (an N-substituted oxoporphyrinogen (OxP) related to porphyrin) was used to investigate the influence of mechanical stretching on the single-molecule conductance of these molecules using the mechanically-controlled break junction (MCBJ) technique. The...

Design of an efficient coherent multi-site single-molecule rectifier

We propose the design of a single-molecule diode with a rectification ratio exceeding a million. The employed mechanism is based on coherent resonant charge transport across a molecule that consists of four conjugated sites coupled by non-conjugated bridges. Using density functional theory calculations, we rationalize the design of the...

A gate-tunable single-molecule diode

In the pursuit of down-sizing electronic components, the ultimate limit is the use of single molecules as functional devices. The first theoretical proposal of such a device, predicted more than four decades ago, is the seminal Aviram–Ratner rectifier that exploits the orbital structure of the molecule. The experimental realization of single...

Synthesis of 1,2-biphenylethane based single-molecule diodes

We have described the synthesis of novel biphenylethane-based wires for molecular electronics. Exceptional single-molecule diode behavior was predicted for unsymmetrically substituted biphenylethane derivatives, synthesized here using the so far unexplored unsymmetrically substituted 1,2-bis(4-bromophenyl)ethanes as key intermediates, which were...

Probing the local environment of a single OPE3 molecule using inelastic tunneling electron spectroscopy

We study single-molecule oligo(phenylene ethynylene)dithiol junctions by means of inelastic electron tunneling spectroscopy (IETS). The molecule is contacted with gold nano-electrodes formed with the mechanically controllable break junction technique. We record the IETS spectrum of the molecule from direct current measurements, both as a...

Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

We report on an experimental investigation of transport through single molecules, trapped between two gold nano-electrodes fabricated with the mechanically controlled break junction (MCBJ) technique. The four molecules studied share the same core structure, namely oligo(phenylene ethynylene) (OPE3), while having different aurophilic anchoring...

Charge Transport Through Single-Molecule Junctions: Experiments and Theory

In the pursuit of down-sizing electronic components, the ultimate limit is the use of single molecules as functional devices. Molecules can also provide additional functionalities compared to semiconductors. Using synthetic chemistry, an almost endless choice of molecular structures and compositions is available. With the proper knowledge, one...

Current-induced nanogap formation and graphitization in boron-doped diamond films

A high-current annealing technique is used to fabricate nanogaps and hybrid diamond/graphite structures in boron-doped nanocrystalline diamond films. Nanometer-sized gaps down to ?1?nm are produced using a feedback-controlled current annealing procedure. The nanogaps are characterized using scanning electron microscopy and electronic transport...

Charge transport in a zinc-porphyrin single-molecule junction

We have investigated charge transport in ZnTPPdT-Pyr (TPPdT: 5,15-di(p-thiolphenyl)-10,20-di(p-tolyl)porphyrin) molecular junctions using the lithographic mechanically controllable break-junction (MCBJ) technique at room temperature and cryogenic temperature (6 K). We combined low-bias statistical measurements with spectroscopy of the molecular...