Cooperative effects and dipole formation at semiconductor and self-assembled-monolayer interfaces

Natan, Amir; Zidon, Yigal; Shapira, Yoram; Kronik, Leeor

doi:10.1103/physrevb.73.193310

Cited by 103 publications

(153 citation statements)

References 41 publications

(31 reference statements)

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“…His solar cell interests led to work hybrid molecular/non-molecular materials, which evolved into his other present activities, understanding electronic transport across (bio)molecules, exploring how molecules can control such transport, looking for novel science in such systems and for possible relevance to solar cells. changes in molecular energy levels upon contacting [47][48][49][50][51][52] and effects due to intermolecular interactions [21,[53][54][55] is accumulating. Such effects need to be clarified to isolate unique molecular contributions, be they purely molecular ones or due to interactions with the environment.…”

Section: Why Alkanes? Insulating Versus Conjugated Moleculesmentioning

confidence: 99%

“…Transport across molecular monolayers on Si was measured for benzene derivatives [62,63] to study the effect of changing the molecular dipole, [43,53] following our earlier work on GaAs. [64] Such molecules are expected to conduct much better than alkyl monolayers.…”

Section: Other Work On Molecular Electronics With Simentioning

confidence: 99%

“…While the pillow effect on the substrate is commonly included in the measured change in substrate work function upon molecule adsorption (by KP or UPS, see Table 1), measuring a pillow effect of the deposited contact is problematic. The reason is that a strong dipole effect is commonly achieved by the terminal groups of the molecules, [17,53,63,114,119] which are the ones most likely to interact with the deposited metal contact, via polarization or even charge transfer (i.e., change of m Me/Hg ). [49,64] One way to study the effect of such direct interactions is to add a second monolayer on the metal side as a dipolar [109] or blocking [120] layer.…”

Section: Pillow Effectmentioning

confidence: 99%

“…[53] To a first approximation, the molecular dipole can be viewed as a constant contribution to C I , which affects the shape of the potential profile C I (x) across the monolayer. The effect of a dipolar layer was reviewed by Ishii et al [125] and the importance of the layer's uniformity has been discussed intensively.…”

Section: Molecular Dipolementioning

confidence: 99%

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Molecules on Si: Electronics with Chemistry

et al. 2009

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Basic scientific interest in using a semiconducting electrode in molecule‐based electronics arises from the rich electrostatic landscape presented by semiconductor interfaces. Technological interest rests on the promise that combining existing semiconductor (primarily Si) electronics with (mostly organic) molecules will result in a whole that is larger than the sum of its parts. Such a hybrid approach appears presently particularly relevant for sensors and photovoltaics. Semiconductors, especially Si, present an important experimental test‐bed for assessing electronic transport behavior of molecules, because they allow varying the critical interface energetics without, to a first approximation, altering the interfacial chemistry. To investigate semiconductor‐molecule electronics we need reproducible, high‐yield preparations of samples that allow reliable and reproducible data collection. Only in that way can we explore how the molecule/electrode interfaces affect or even dictate charge transport, which may then provide a basis for models with predictive power.To consider these issues and questions we will, in this Progress Report, review junctions based on direct bonding of molecules to oxide‐free Si. describe the possible charge transport mechanisms across such interfaces and evaluate in how far they can be quantified. investigate to what extent imperfections in the monolayer are important for transport across the monolayer. revisit the concept of energy levels in such hybrid systems.

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Section: Why Alkanes? Insulating Versus Conjugated Moleculesmentioning

confidence: 99%

Section: Other Work On Molecular Electronics With Simentioning

confidence: 99%

Section: Pillow Effectmentioning

confidence: 99%

Section: Molecular Dipolementioning

confidence: 99%

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Molecules on Si: Electronics with Chemistry

et al. 2009

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“…To model a two-dimensional periodic infinite surface in the xy-plane, the repeated-slab approach is employed [33][34][35]. Five layers of gold atoms are used to represent the metal surface (figure 2a).…”

Section: Introductionmentioning

confidence: 99%

Interface electronic structures of reversible double-docking self-assembled monolayers on an Au(111) surface

Zhang

Wang

et al. 2014

Phil. Trans. R. Soc. A.

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Double-docking self-assembled monolayers (DDSAMs), namely self-assembled monolayers (SAMs) formed by molecules possessing two docking groups, provide great flexibility to tune the work function of metal electrodes and the tunnelling barrier between metal electrodes and the SAMs, and thus offer promising applications in both organic and molecular electronics. Based on the dispersion-corrected density functional theory (DFT) in comparison with conventional DFT, we carry out a systematic investigation on the dual configurations of a series of DDSAMs on an Au(111) surface. Through analysing the interface electronic structures, we obtain the relationship between single molecular properties and the SAM-induced work-function modification as well as the level alignment between the metal Fermi level and molecular frontier states. The two possible conformations of one type of DDSAM on a metal surface reveal a strong difference in the work-function modification and the electron/hole tunnelling barriers. Fermi-level pinning is found to be a key factor to understand the interface electronic properties.

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Intramolecular Dipole Coupling and Depolarization in Self‐Assembled Monolayers

Sushko

Shluger

2008

Adv Funct Materials

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Quantum mechanical and classical atomistic computational methods are used to simulate the chain‐length dependence of depolarization effects in S(CH2)n−1CH3 and S(CH2)n−1COOH self‐assembled monolayers on gold (111) surface. These calculations show that due to weak cooperative effects, the electrostatic properties of alkanethiol monolayers are well described by the gas phase dipole moments of the molecules. However, depolarization in monolayers with the molecules carrying head‐ and tail‐group dipoles, such as COOH‐terminated monolayers, strongly depends on the degree of intramolecular dipole coupling. Thus the electrostatic properties of self‐assembled monolayers can be engineered by changing the length of the aliphatic spacer between the polar groups. The transition from strong to weak coupling regime was found to be accompanied by the change in the sign of the asymptotic value of electrostatic potential above the surface of the monolayers and hence in the sign of the metal work function change. Therefore, the use of weakly polarizable spacers between the polar groups inside the molecules forming the SAM is beneficial for accessing a wider range of work‐function changes.

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Cooperative effects and dipole formation at semiconductor and self-assembled-monolayer interfaces

Cited by 103 publications

References 41 publications

Molecules on Si: Electronics with Chemistry

Molecules on Si: Electronics with Chemistry

Interface electronic structures of reversible double-docking self-assembled monolayers on an Au(111) surface

Intramolecular Dipole Coupling and Depolarization in Self‐Assembled Monolayers

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