A New Route to Nondestructive Top-Contacts for Molecular Electronics on Si: Pb Evaporated on Organic Monolayers

Lovrinčić, Robert; Kraynis, Olga; Har-Lavan, Rotem; Haj-Yahya, Abd-Elrazek; Li, Wenjie; Vilan, Ayelet

doi:10.1021/jz302153z

Cited by 28 publications

(37 citation statements)

References 39 publications

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“…The current densities measured here (+0.07, −0.11 A cm −2 at ± 0.5V) are in the middle of this range. They are about 10 times less than the 0.9 A cm −2 current density, found with highly‐doped n– Si(100) at the same bias potential . The higher current for Si(100) agrees with the observation that the exponential decay factor (β) for tunneling is smaller for Si(100) than for Si(111) .…”

Section: Resultssupporting

confidence: 80%

“…They are about 10 times less than the 0.9 A cm −2 current density, found with highly‐doped n– Si(100) at the same bias potential . The higher current for Si(100) agrees with the observation that the exponential decay factor (β) for tunneling is smaller for Si(100) than for Si(111) . The ∼0.1 A cm −2 current density that we find here is ∼10 2 times smaller than the maximum values, reported for MmM junctions (∼10 A cm −2 for Au‐SC16/graphene) .…”

Section: Resultssupporting

confidence: 78%

“…Based on this reasoning, we showed recently that Pb can be evaporated on molecular monolayers without damaging them. We found transport characteristics of Si‐ML/evaporated Pb junctions to be comparable to those of Hg, except for the difference in interface electrostatics, due to the difference in the work‐function between Pb and Hg …”

Section: Introductionmentioning

confidence: 73%

“…The chamber was evacuated to a pressure ≤5.0 . 10 −6 Torr and Pb was evaporated at 4 Å s −1 to a thickness of 150 nm; then, without breaking vacuum, 50 nm of Au was deposited at 1 Å s −1 on top of the Pb to prevent its oxidation and minimize Pb environmental hazard …”

Section: Methodsmentioning

confidence: 99%

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Fabrication of Reproducible, Integration‐Compatible Hybrid Molecular/Si Electronics

Lovrinčić

Kraynis

et al. 2014

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Reproducible molecular junctions can be integrated within standard CMOS technology. Metal-molecule-semiconductor junctions are fabricated by direct Si-C binding of hexadecane or methyl-styrene onto oxide-free H-Si(111) surfaces, with the lateral size of the junctions defined by an etched SiO2 well and with evaporated Pb as the top contact. The current density, J, is highly reproducible with a standard deviation in log(J) of 0.2 over a junction diameter change from 3 to 100 μm. Reproducibility over such a large range indicates that transport is truly across the molecules and does not result from artifacts like edge effects or defects in the molecular monolayer. Device fabrication is tested for two n-Si doping levels. With highly doped Si, transport is dominated by tunneling and reveals sharp conductance onsets at room temperature. Using the temperature dependence of current across medium-doped n-Si, the molecular tunneling barrier can be separated from the Si-Schottky one, which is a 0.47 eV, in agreement with the molecular-modified surface dipole and quite different from the bare Si-H junction. This indicates that Pb evaporation does not cause significant chemical changes to the molecules. The ability to manufacture reliable devices constitutes important progress toward possible future hybrid Si-based molecular electronics.

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 73%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Fabrication of Reproducible, Integration‐Compatible Hybrid Molecular/Si Electronics

Lovrinčić

Kraynis

et al. 2014

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“…Certain terminal groups in the monolayer may be efficient in reducing penetration of metal atoms through the monolayer [234][235][236][237][238][239][240][241]. Recently, thermally evaporated Pb [242] has been reported to limit the number of short-circuits. Atomic layer deposition (ALD) is a vapor phase technique that permits the deposition of a variety of thin film materials, including metals and metal oxides, from the vapour phase [243,244].…”

Section: Deposition Of the Top Contact Electrodementioning

confidence: 99%

Nanofabrication techniques of highly organized monolayers sandwiched between two electrodes for molecular electronics

2014

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Molecular electronics [1,2] is a promising field of research based on the idea that a single molecule or two dimensional assemblies of molecules (monomolecular films) can work as wires, switches, rectifiers, etc. Molecules are the smallest functional units and therefore it is expected that the use of molecules will permit to catch up with the limits of miniaturization (MM: more Moore), with an increase in device density by a factor of several orders of magnitude compared to today's state of the art. At the same time due to quantum effects novel and remarkable properties of organic and organometallic compounds at the nanoscale devices will result in increased performance (MtM: more than Moore) together with the appearance of new functions not possible with conventional semiconductors, and also cheaper devices due to the non-dependence of expensive materials used today in CMOS (complementary metal-oxide semiconductor) technology such as hafnium oxide. Nowadays, the number of research groups from different disciplines of science contributing to molecular electronics is gradually growing, and this field is becoming of great scientific and technological interest [1,3-8]. Since the seminal work of Aviram and Ratner in 1974 who firstly suggested that a single molecule could function as a rectifier [9], molecules have been experimentally demonstrated to work as switches, molecular wires or rectifiers, and a new field of opportunities is opened due to the understanding of electron transport through single entities or assemblies of molecules and expansion towards work on molecular spintronics, vibronic effects, excitation of the molecular junction with polarized light, quantum interference and decoherence, molecular chirality, molecular stretching and distortion as well as work on thermoelectric response in molecular junctions.Abstract: It is expected that molecular electronics, i.e., the use of molecules as critical functional elements in electronic devices, will lead in the near future to an industrial exploitable novel technology, which will open new routes to high value-added electronic products. However, despite the enormous advances in this field several scientific and technological challenges should be surmounted before molecular electronics can be implemented in the market. Among these challenges are the fabrication of reliable, robust and uniform contacts between molecules and electrodes, the deposition of the second (top) contact electrode, and development of assembly strategies for precise placement of molecular materials within device structures. This review covers advances in nanofabrication techniques used for the assembly of monomolecular films onto conducting or semiconducting substrates as well as recent methods developed for the deposition of the top contact electrode highlighting the advantages and limitations of the several approaches used in the literature. This contribution also aims to define areas of outstanding challenges in the nanofabrication of monomolecular layers sandwiched between two electro...

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Ultrasmooth and Photoresist‐Free Micropore‐Based EGaIn Molecular Junctions: Fabrication and How Roughness Determines Voltage Response

Karuppannan

Troadec

et al. 2019

Adv Funct Materials

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In molecular electronics, it is critical to minimize the sources that can result in defective electrodes, such as contaminations related to the fabrication process (photoresist and organic residues) or roughening of the electrode during etching, because these defects hamper the formation of well‐organized molecular structures. Junctions based on micropores are desirable as they are scalable, but micropores are not fabricated on ultrasmooth template‐stripped electrodes, and may suffer from stray capacitances and leakage currents across the insulating matrix. A method is reported to fabricate micropores in AlOx on template‐stripped Au based on a two‐step etch process so that the Au surface is not in direct contact with photoresistance during the fabrication process. These junctions do not suffer from stray capacitances or leakage currents, enable temperature variable measurements down to 8.5 K, have excellent current retention characteristics, and are stable for at least 2 months. By analyzing the normalized differential conductance curves and detailed comparison against junctions with cone‐shaped tips of EGaIn and EGaIn stabilized in a through‐hole in polydimethylsiloxane, how the surface roughness of top electrodes affects the effective contact area, influences the symmetry of the response of the junctions, and how the electrical characteristics scale with molecular length are established.

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A New Route to Nondestructive Top-Contacts for Molecular Electronics on Si: Pb Evaporated on Organic Monolayers

Cited by 28 publications

References 39 publications

Fabrication of Reproducible, Integration‐Compatible Hybrid Molecular/Si Electronics

Fabrication of Reproducible, Integration‐Compatible Hybrid Molecular/Si Electronics

Nanofabrication techniques of highly organized monolayers sandwiched between two electrodes for molecular electronics

Ultrasmooth and Photoresist‐Free Micropore‐Based EGaIn Molecular Junctions: Fabrication and How Roughness Determines Voltage Response

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