Single-Molecule Transport at a Rectifying GaAs Contact

Vezzoli, Andrea; Brooke, Richard J.; Ferri, Nicolò; Higgins, Simon J.; Schwarzacher, Walther; Nichols, Richard J.

doi:10.1021/acs.nanolett.6b04663

Cited by 29 publications

(46 citation statements)

References 51 publications

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“…The prepared metal-molecule(s)-semiconductor devices behave like Schottky diodes as discussed in the Introduction, and we reported on the effect of the molecular wire (the insulator of the Schottky diode) in our previous publication. 1 We found that on heavily doped nGaAs HD the rectication ratio RR, which is dened as the ratio of the current owing in forward bias to the current owing in reverse bias at a xed magnitude of bias potential, was remarkably dependent on the nature of the molecular wire employed. The saturated a,u-alkanedithiols (ADT) 4ADT, 5ADT, 6ADT and 7ADT showed an almost constant RR at AE1 V of approximately 12 ( Fig.…”

Section: Resultsmentioning

confidence: 83%

“…The charge carrier depletion at the semiconductor interface results in a larger charge ow when the junction is biased in one direction (forward bias) than the other (reverse bias), resulting in asymmetric I-V characteristics. We recently reported this behaviour using gallium arsenide (GaAs) as electrode, 1 and it was also demonstrated on silicon, 7 in both cases using a molecular wire with appropriate contacting ends and a Au metallic electrode. Using a semiconducting electrode allows for a ner tuning of the junction properties, as the type of its doping (n-or p-type), can be used to control the nature of the majority charge carrier, and the doping density will affect the concentration of charge carriers (and therefore the semiconductor conductivity), and the size of the space charge layer.…”

Section: Introductionmentioning

confidence: 92%

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Charge transport at a molecular GaAs nanoscale junction

et al. 2018

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In recent years, the use of non-metallic electrodes for the fabrication of single-molecule junctions has developed into an elegant way to impart new properties to nanodevices. Integration of molecular junctions in a semiconducting platform would also speed technological deployment, as it would take advantage of established industrial infrastructures. In a previous proof-of-concept paper, we used simple α,ω-dithiol self-assembled monolayers on a gallium arsenide (GaAs) substrate to fabricate molecular Schottky diodes with a STM. In the devices, we were also able to detect the contribution of a single-molecule to the overall charge transport. The prepared devices can also be used as photodiodes, as GaAs is a III-V direct bandgap (1.42 eV at room temperature) semiconductor, and it efficiently absorbs visible light to generate a photocurrent. In this contribution, we demonstrate that fine control can be exerted on the electrical behaviour of a metal-molecule-GaAs junction by systematically altering the nature of the molecular bridge, the type and doping density of the semiconductor and the light intensity and wavelength. Molecular orbital energy alignment dominates the charge transport properties, resulting in strongly rectifying junctions prepared with saturated bridges (e.g. alkanedithiols), with increasingly ohmic characteristics as the degree of saturation is reduced through the introduction of conjugated moieties. The effects we observed are local, and may be observed with electrodes of only a few tens of nanometres in size, hence paving the way to the use of semiconducting nanoelectrodes to probe molecular properties. Perspectives of these new developments for single molecule semiconductor electrochemistry are also discussed.

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Section: Resultsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 92%

Charge transport at a molecular GaAs nanoscale junction

et al. 2018

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“…Another new concept for a metal‐molecule‐semiconductor device employing Au tip/molecule/GaAs substrate was achieved by Nichols et al With low doped GaAs, molecular junctions displayed rectification ratios as particularly high as >10 3 in the dark and a high photocurrent in reverse biases. It should be noticed that the replacement of gold electrodes with conventional GaAs or silicon semiconductor materials reduces the gap between molecular electronic and traditional microelectronics . Figure B shows a porphyrin‐C60 dyad molecule in the gold‐ITO (indium tin oxide) tunnel junction.…”

Section: Stimuli‐responsive Materials For Electrical Switchesmentioning

confidence: 99%

Electrical and spin switches in single‐molecule junctions

Duan

Huang

et al. 2019

InfoMat

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Single-molecule electrical and spin switches have been one of the main research focuses in molecular electronics and spintronics because they may form the most important elements for the future information technology, thus attracting great attention in the scientific community and witnessing significant progresses benefiting from the combination of physics, chemistry, materials, and engineering. The key issue of constructing single-molecule switches is the development of stimulus-responsive systems that provide bistable or multiple states. In this review, we summarize the recent advances of this field in terms of the external stimulus that induces the switching. A variety of external stimuli, such as light, electric field, magnetic field, mechanical force, and chemical stimulus, have been successfully employed to activate the reversible switching in single-molecule junctions by manipulating molecular structures, conformations, electronic states, and spin states. As a burgeoning field, we finally put forward the challenges in molecular electronics and spintronics that need to be solved, which will initiate intense research. K E Y W O R D Selectrical switch, single-molecule junction, spin switch, stimuli-responsive system

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“…[5][6][7][8][9][10][11][12][13][14][15][16][17] In particular, scanning tunneling microscopy shows strong ability to form different types of molecular junctions (tip and substrate can be different materials), which makes it possible to realize new type of functional devices and to observe novel phenomenon. [18][19][20][21] Meanwhile, the effects of molecular anchors, [22][23][24][25] electrode material, [7,8] and external environment on the properties of single-molecule junctions have been investigated, [25][26][27][28] which is a large step toward the construction of functional molecular electronic devices. Nonetheless, a number of challenges still need to be overcome before single-molecule devices can be widely used as commercial products.…”

Section: Doi: 101002/smll201703815mentioning

confidence: 99%

Shaping the Atomic‐Scale Geometries of Electrodes to Control Optical and Electrical Performance of Molecular Devices

Zhao

Liu

Mayer³

et al. 2018

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A straightforward method to generate both atomic-scale sharp and atomic-scale planar electrodes is reported. The atomic-scale sharp electrodes are generated by precisely stretching a suspended nanowire, while the atomic-scale planar electrodes are obtained via mechanically controllable interelectrodes compression followed by a thermal-driven atom migration process. Notably, the gap size between the electrodes can be precisely controlled at subangstrom accuracy with this method. These two types of electrodes are subsequently employed to investigate the properties of single molecular junctions. It is found, for the first time, that the conductance of the amine-linked molecular junctions can be enhanced ≈50% as the atomic-scale sharp electrodes are used. However, the atomic-scale planar electrodes show great advantages to enhance the sensitivity of Raman scattering upon the variation of nanogap size. The underlying mechanisms for these two interesting observations are clarified with the help of density functional theory calculation and finite-element method simulation. These findings not only provide a strategy to control the electron transport through the molecule junction, but also pave a way to modulate the optical response as well as to improve the stability of single molecular devices via the rational design of electrodes geometries.

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Single-Molecule Transport at a Rectifying GaAs Contact

Cited by 29 publications

References 51 publications

Charge transport at a molecular GaAs nanoscale junction

Charge transport at a molecular GaAs nanoscale junction

Electrical and spin switches in single‐molecule junctions

Shaping the Atomic‐Scale Geometries of Electrodes to Control Optical and Electrical Performance of Molecular Devices

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