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Li T, Peiris CR, Aragonès AC, Hurtado C, Kicic A, Ciampi S, MacGregor M, Darwish T, Darwish N. Terminal Deuterium Atoms Protect Silicon from Oxidation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:47833-47844. [PMID: 37768872 DOI: 10.1021/acsami.3c11598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
In recent years, the hybrid silicon-molecular electronics technology has been gaining significant attention for applications in sensors, photovoltaics, power generation, and molecular electronics devices. However, Si-H surfaces, which are the platforms on which these devices are formed, are prone to oxidation, compromising the mechanical and electronic stability of the devices. Here, we show that when hydrogen is replaced by deuterium, the Si-D surface becomes significantly more resistant to oxidation when either positive or negative voltages are applied to the Si surface. Si-D surfaces are more resistant to oxidation, and their current-voltage characteristics are more stable than those measured on Si-H surfaces. At positive voltages, the Si-D stability appears to be related to the flat band potential of Si-D being more positive compared to Si-H surfaces, making Si-D surfaces less attractive to oxidizing OH- ions. The limited oxidation of Si-D surfaces at negative potentials is interpreted by the frequencies of the Si-D bending modes being coupled to that of the bulk Si surface phonon modes, which would make the duration of the Si-D excited vibrational state significantly less than that of Si-H. The strong surface isotope effect has implications in the design of silicon-based sensing, molecular electronics, and power-generation devices and the interpretation of charge transfer across them.
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Affiliation(s)
- Tiexin Li
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Chandramalika R Peiris
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Albert C Aragonès
- Departament de Ciència de Materials i Química Física, Universitat de Barcelona, Marti i Franquès 1, 08028 Barcelona, Spain
- Institut de Química Teòrica i Computacional (IQTC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
| | - Carlos Hurtado
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Anthony Kicic
- Occupation, Environment and Safety, School of Population Health, Curtin University, Bentley, Western Australia 6102, Australia
- Wal-Yan Respiratory Research Centre, Telethon Kids Institute, The University of Western Australia, Nedlands, Western Australia 6009, Australia
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, Western Australia 6009, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Simone Ciampi
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Melanie MacGregor
- Flinders Institute for Nanoscale Science & Technology, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Tamim Darwish
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, New South Wales 2234, Australia
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
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Photoreactivity of Deep VB Titania Attained Via Molecular Layer Deposition; Interplay of Metal Oxide Thin Film Built-in Strain and Molecular Effects. Top Catal 2020. [DOI: 10.1007/s11244-020-01390-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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3
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Garg M, Tak BR, Rao VR, Singh R. Giant UV Photoresponse of GaN-Based Photodetectors by Surface Modification Using Phenol-Functionalized Porphyrin Organic Molecules. ACS APPLIED MATERIALS & INTERFACES 2019; 11:12017-12026. [PMID: 30821954 DOI: 10.1021/acsami.8b20694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Organic molecular monolayers (MoLs) have been used for improving the performance of various electronic device structures. In this work, the concept of organic molecular surface modification is applied for improving the performance of GaN-based metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs). Organic molecules of phenol-functionalized metallated porphyrin (hydroxyl-phenyl-zinc-tetra-phenyl-porphyrin (Zn-TPPOH)) were adsorbed on GaN, and Ni/Zn-TPPOH/GaN/Zn-TPPOH/Ni PD structures were fabricated. This process was beneficial in two ways: first, the reverse-bias dark current was reduced by 1000 times, and second, the photocurrent was enhanced by ∼100 times, in comparison to the dark and photocurrent values obtained for Ni/GaN/Ni MSM PDs, at high voltages of ±10 V. The responsivity of the devices was increased from 0.22 to 4.14 kA/W at 5 μW/cm2 optical power density at -10 V bias and at other voltages also. In addition to this, other PD parameters such as photo-to-dark current ratio and UV-to-visible rejection ratio were also enhanced. The spectral selectivity of the PDs was improved, which means that the molecularly modified devices became more responsive to UV spectral region and less responsive to visible spectral region, in comparison to bare GaN-based devices. Photoluminescence measurements, power-dependent photocurrent characteristics, and time-resolved photocurrent measurements revealed that the MoL was passivating the defect-related states on GaN. In addition, Kelvin probe force microscopy showed that the MoL was also playing with the surface charge (due to surface states) on GaN, leading to increased Schottky barrier height in dark conditions. Resultant to both these phenomena, the reverse-bias dark current was reduced for metal/MoL/GaN/MoL/metal PD structures. Further, the unusual photoconductive gain in the molecularly modified devices has been attributed to Schottky barrier lowering for UV-illuminated conditions, leading to enhanced photocurrent.
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Gankin A, Mervinetsky E, Alshanski I, Buchwald J, Dianat A, Gutierrez R, Cuniberti G, Sfez R, Yitzchaik S. ITO Work Function Tunability by Polarizable Chromophore Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2997-3004. [PMID: 30707589 DOI: 10.1021/acs.langmuir.8b03943] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The ability to tune the electronic properties of oxide-bearing semiconductors such as Si/SiO2 or transparent metal oxides such as indium-tin oxide (ITO) is of great importance in both electronic and optoelectronic device applications. In this work, we describe a process that was conducted on n-type Si/SiO2 and ITO to induce changes in the substrate work function (WF). The substrates were modified by a two-step synthesis comprising a covalent attachment of coupling agents' monolayer followed by in situ anchoring reactions of polarizable chromophores. The coupling agents and chromophores were chosen with opposite dipole orientations, which enabled the tunability of the substrates' WF. In the first step, two coupling agents with opposite molecular dipole were assembled. The coupling agent with a negative dipole induced a decrease in WF of modified substrates, while the coupling agent with a positive dipole produced an increase in WFs of both ITO and Si substrates. The second modification step consisted of in situ anchoring reaction of polarizable chromophores with opposite dipoles to the coupling layer. This modification led to an additional change in the WFs of both Si/SiO2 and ITO substrates. The WF was measured by contact potential difference and modeled by density functional theory-based theoretical calculations of the WF for each of the assembly steps. A good fit was obtained between the calculated and experimental trends. This ability to design and tune the WF of ITO substrates was implemented in an organic electronic device with improved I- V characteristics in comparison to a bare ITO-based device.
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Affiliation(s)
| | | | | | - Jörg Buchwald
- Institute for Materials Science and Max Bergmann Center of Biomaterials , TU Dresden , Dresden 01062 , Germany
| | - Arezoo Dianat
- Institute for Materials Science and Max Bergmann Center of Biomaterials , TU Dresden , Dresden 01062 , Germany
| | - Rafael Gutierrez
- Institute for Materials Science and Max Bergmann Center of Biomaterials , TU Dresden , Dresden 01062 , Germany
| | - Gianaurelio Cuniberti
- Institute for Materials Science and Max Bergmann Center of Biomaterials , TU Dresden , Dresden 01062 , Germany
- Dresden Center for Computational Materials Science , TU Dresden , Dresden 01062 , Germany
| | - Ruthy Sfez
- Azrieli College of Engineering , Jerusalem 9103501 , Israel
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Yitzchaik S, Gutierrez R, Cuniberti G, Yerushalmi R. Diversification of Device Platforms by Molecular Layers: Hybrid Sensing Platforms, Monolayer Doping, and Modeling. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14103-14123. [PMID: 30253096 DOI: 10.1021/acs.langmuir.8b02369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Inorganic materials such as semiconductors, oxides, and metals are ubiquitous in a wide range of device technologies owing to the outstanding robustness and mature processing technologies available for such materials. However, while the important contribution of inorganic materials to the advancement of device technologies has been well established for decades, organic-inorganic hybrid device systems, which merge molecular functionalities with inorganic platforms, represent a newer domain that is rapidly evolving at an increasing pace. Such devices benefit from the great versatility and flexibility of the organic building blocks merged with the robustness of the inorganic platforms. Given the overwhelming wealth of literature covering various approaches for modifying and using inorganic devices, this feature article selectively highlights some of the advances made in the context of the diversification of devices by surface chemistry. Particular attention is given to oxide-semiconductor systems and metallic surfaces modified with organic monolayers. The inorganic device components, such as semiconductors, metals, and oxides, are modified by organic monolayers, which may serve as either active, static, or sacrificial components. We portray research directions within the broader field of organic-inorganic hybrid device systems that can be viewed as specific examples of the potential of such hybrid device systems given their comprehensive capabilities of design and diversification. Monolayer doping techniques where sacrificial organic monolayers are introduced into semiconducting elements are reviewed as a specific case, together with associated requirements for nanosystems, devices, and sensors for controlling doping levels and doping profiles on the nanometric scale. Another series of examples of the flexibility provided by the marriage of organic functional monolayers and inorganic device components are represented by a new class of biosensors, where the organic layer functionality is exploited in a functioning device for sensing. Considerations for relying on oxide-terminated semiconductors rather than the pristine semiconductor material as a platform both for processing and sensing are discussed. Finally, we cover aspects related to the use of various theoretical and computational approaches to model organic-inorganic systems. The main objectives of the topics covered here are (i) to present the advances made in each respective domain and (ii) to provide a comprehensive view of the potential uses of organic monolayers and self-assembly processes in the rapidly evolving field of molecular-inorganic hybrid device platforms and processing methodologies. The directions highlighted here provide a perspective on a future, not yet fully realized, integrated approach where organic monolayers are combined with inorganic platforms in order to obtain versatile, robust, and flexible systems with enhanced capabilities.
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Affiliation(s)
- Shlomo Yitzchaik
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Givat Ram Jerusalem , 91904 Israel
| | | | | | - Roie Yerushalmi
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Givat Ram Jerusalem , 91904 Israel
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Gankin A, Sfez R, Mervinetsky E, Buchwald J, Dianat A, Medrano Sandonas L, Gutierrez R, Cuniberti G, Yitzchaik S. Molecular and Ionic Dipole Effects on the Electronic Properties of Si-/SiO 2-Grafted Alkylamine Monolayers. ACS APPLIED MATERIALS & INTERFACES 2017; 9:44873-44879. [PMID: 29206026 DOI: 10.1021/acsami.7b12218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, we demonstrate the tunability of electronic properties of Si/SiO2 substrates by molecular and ionic surface modifications. The changes in the electronic properties such as the work function (WF) and electron affinity were experimentally measured by the contact potential difference technique and theoretically supported by density functional theory calculations. We attribute these molecular electronic effects mainly to the variations of molecular and surface dipoles of the ionic and neutral species. We have previously shown that for the alkylhalide monolayers, changing the tail group from Cl to I decreased the WF of the substrate. Here, we report on the opposite trend of WF changes, that is, the increase of the WF, obtained by using the anions of these halides from Cl- to I-. This trend was observed on self-assembled alkylammonium halide (-NH3+ X-, where X- = Cl-, Br-, or I-) monolayer-modified substrates. The monolayer's formation was supported by ellipsometry measurements, X-ray photoelectron spectroscopy, and atomic force microscopy. Comparison of the theoretical and experimental data suggests that the ionic surface dipole depends mainly on the polarizability and the position of the counter halide anion along with the organization and packaging of the layer. The described ionic modification can be easily used for facile tailoring and design of the electronic properties Si/SiO2 substrates for various device applications.
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Affiliation(s)
- Alina Gankin
- Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus, Givat Ram, Jerusalem 91904, Israel
- Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Ruthy Sfez
- Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus, Givat Ram, Jerusalem 91904, Israel
- Department of Advanced Materials Engineering, Azrieli College of Engineering , Jerusalem 9103501, Israel
| | - Evgeniy Mervinetsky
- Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus, Givat Ram, Jerusalem 91904, Israel
- Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | | | | | | | | | | | - Shlomo Yitzchaik
- Institute of Chemistry, The Hebrew University of Jerusalem , Safra Campus, Givat Ram, Jerusalem 91904, Israel
- Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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Agarwala A, Kaynan N, Zaidiner S, Yerushalmi R. Surface modification of metal oxides by polar molecules in a non-polar, polarizable solvent system. Chem Commun (Camb) 2014; 50:5397-9. [DOI: 10.1039/c3cc47140c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Yaffe O, Ely T, Har-Lavan R, Egger D, Johnston S, Cohen H, Kronik L, Vilan A, Cahen D. Effect of Molecule-Surface Reaction Mechanism on the Electronic Characteristics and Photovoltaic Performance of Molecularly Modified Si. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:22351-22361. [PMID: 24205409 PMCID: PMC3814651 DOI: 10.1021/jp4027755] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/27/2013] [Indexed: 06/02/2023]
Abstract
We report on the passivation properties of molecularly modified, oxide-free Si(111) surfaces. The reaction of 1-alcohol with the H-passivated Si(111) surface can follow two possible paths, nucleophilic substitution (SN) and radical chain reaction (RCR), depending on adsorption conditions. Moderate heating leads to the SN reaction, whereas with UV irradiation RCR dominates, with SN as a secondary path. We show that the site-sensitive SN reaction leads to better electrical passivation, as indicated by smaller surface band bending and a longer lifetime of minority carriers. However, the surface-insensitive RCR reaction leads to more dense monolayers and, therefore, to much better chemical stability, with lasting protection of the Si surface against oxidation. Thus, our study reveals an inherent dissonance between electrical and chemical passivation. Alkoxy monolayers, formed under UV irradiation, benefit, though, from both chemical and electronic passivation because under these conditions both SN and RCR occur. This is reflected in longer minority carrier lifetimes, lower reverse currents in the dark, and improved photovoltaic performance, over what is obtained if only one of the mechanisms operates. These results show how chemical kinetics and reaction paths impact electronic properties at the device level. It further suggests an approach for effective passivation of other semiconductors.
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Affiliation(s)
- Omer Yaffe
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Tal Ely
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Rotem Har-Lavan
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - David
A. Egger
- Institute of Solid State Physics, Graz University of Technology, A-8010 Graz, Austria
| | - Steve Johnston
- National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Hagai Cohen
- Department of Chemical Research
Support, Weizmann Institute of Science,
Rehovoth 76100, Israel
| | - Leeor Kronik
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Ayelet Vilan
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - David Cahen
- Department of Materials &
Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
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9
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Collins G, O'Dwyer C, Morris M, Holmes JD. Palladium-catalyzed coupling reactions for the functionalization of Si surfaces: superior stability of alkenyl monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11950-11958. [PMID: 23968278 DOI: 10.1021/la402480f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Palladium-catalyzed Suzuki, Heck, and Sonogashira coupling reactions were studied as reaction protocols for organic modification of Si surfaces. These synthetically useful protocols allow for surface modification of alkene, alkyne, and halide terminated surfaces. Surface oxidation and metal contamination were assessed by X-ray photoelectron spectroscopy. The nature of the primary passivation layer was an important factor in the oxidation resistance of the Si surface during the secondary functionalization. Specifically, the use of alkynes as the primary functionalization layer gave superior stability compared to alkene analogues. The ability to utilize Pd-catalyzed coupling chemistries on Si surfaces opens great versatility for potential molecular and nanoscale electronics and sensing/biosensing applications.
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Affiliation(s)
- Gillian Collins
- Department of Chemistry and the Tyndall National Institute, University College Cork , Cork, Ireland
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Alderman N, Danos L, Grossel MC, Markvart T. Kelvin probe studies of alkyl monolayers on silicon (111) for surface passivation. RSC Adv 2013. [DOI: 10.1039/c3ra42526f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Burtman V, Zelichonok A, Pakoulev AV. Molecular photovoltaics in nanoscale dimension. Int J Mol Sci 2011; 12:173-225. [PMID: 21339983 PMCID: PMC3039949 DOI: 10.3390/ijms12010173] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 12/01/2010] [Accepted: 12/15/2010] [Indexed: 11/16/2022] Open
Abstract
This review focuses on the intrinsic charge transport in organic photovoltaic (PVC) devices and field-effect transistors (SAM-OFETs) fabricated by vapor phase molecular self-assembly (VP-SAM) method. The dynamics of charge transport are determined and used to clarify a transport mechanism. The 1,4,5,8-naphthalene-tetracarboxylic diphenylimide (NTCDI) SAM devices provide a useful tool to study the fundamentals of polaronic transport at organic surfaces and to discuss the performance of organic photovoltaic devices in nanoscale. Time-resolved photovoltaic studies allow us to separate the charge annihilation kinetics in the conductive NTCDI channel from the overall charge kinetic in a SAM-OFET device. It has been demonstrated that tuning of the type of conductivity in NTCDI SAM-OFET devices is possible by changing Si substrate doping. Our study of the polaron charge transfer in organic materials proposes that a cation-radical exchange (redox) mechanism is the major transport mechanism in the studied SAM-PVC devices. The role and contribution of the transport through delocalized states of redox active surface molecular aggregates of NTCDI are exposed and investigated. This example of technological development is used to highlight the significance of future technological development of nanotechnologies and to appreciate a structure-property paradigm in organic nanostructures.
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Affiliation(s)
- Vladimir Burtman
- Department of Geology and Geophysics, University of Utah, 115 South 1460 East, Room 383, Salt Lake City, UT 84112, USA
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Kuo CH, Liu CP, Lee SH, Chang HY, Lin WC, You YW, Liao HY, Shyue JJ. Effect of surface chemical composition on the work function of silicon substrates modified by binary self-assembled monolayers. Phys Chem Chem Phys 2011; 13:15122-6. [DOI: 10.1039/c1cp20590k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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13
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Miozzo L, Yassar A, Horowitz G. Surface engineering for high performance organic electronic devices: the chemical approach. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b922385a] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Bashouti MY, Tung RT, Haick H. Tuning the electrical properties of Si nanowire field-effect transistors by molecular engineering. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:2761-2769. [PMID: 19771570 DOI: 10.1002/smll.200901402] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposed facets of n-type silicon nanowires (Si NWs) fabricated by a top-down approach are successfully terminated with different organic functionalities, including 1,3-dioxan-2-ethyl, butyl, allyl, and propyl-alcohol, using a two-step chlorination/alkylation method. X-ray photoemission spectroscopy and spectroscopic ellipsometry establish the bonding and the coverage of these molecular layers. Field-effect transistors fabricated from these Si NWs displayed characteristics that depended critically on the type of molecular termination. Without molecules the source-drain conduction is unable to be turned off by negative gate voltages as large as -20 V. Upon adsorption of organic molecules there is an observed increase in the "on" current at large positive gate voltages and also a reduction, by several orders of magnitude, of the "off" current at large negative gate voltages. The zero-gate voltage transconductance of molecule-terminated Si NW correlates with the type of organic molecule. Adsorption of butyl and 1,3-dioxan-2-ethyl molecules improves the channel conductance over that of the original SiO(2)-Si NW, while adsorption of molecules with propyl-alcohol leads to a reduction. It is shown that a simple assumption based on the possible creation of surface states alongside the attachment of molecules may lead to a qualitative explanation of these electrical characteristics. The possibility and potential implications of modifying semiconductor devices by tuning the distribution of surface states via the functionality of attached molecules are discussed.
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Affiliation(s)
- Muhammad Y Bashouti
- The Department of Chemical Engineering and Russell Berrie Nanotechnology Institute Technion - Israel Institute of Technology, Haifa, Israel
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15
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Yang F, Hunger R, Roodenko K, Hinrichs K, Rademann K, Rappich J. Vibrational and electronic characterization of ethynyl derivatives grafted onto hydrogenated Si(111) surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9313-9318. [PMID: 19601568 DOI: 10.1021/la900871g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Covalent grafting of ethynyl derivatives (-C triple bond C-H, -C triple bond C-CH3, -C triple bond C-aryl) onto H-terminated Si(111) surfaces was performed by a one-step anodic treatment in Grignard electrolytes. The electrochemical grafting of such ethynyl derivatives, which tends to form ultrathin polymeric layers, can be controlled by the current and charge flow passing through the Si electrode. The prepared ultrathin layers cover the Si surface and had a thickness up to 20 nm, as investigated by the scanning electron microscopy (SEM) technique. Exchanging Cl for Br in the ethynyl Grignard reagent leads to very thin layers, even under the same electrochemical conditions. However, for all ethynyl derivatives, high-resolution synchrotron X-ray photoelectron spectroscopy (SXPS) investigations reveal the incorporation of halogen atoms in the organic layers obtained. Moreover, it was observed that the larger the end group of the ethynyl derivative, the thinner the thickness of the ultrathin polymeric layers as measured by both SXPS and SEM techniques after low and high current flow respectively. For the first time, these new types of ultrathin organic layers on Si surfaces were investigated using infrared spectroscopic ellipsometry (IRSE). The different possible reaction pathways are discussed.
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Affiliation(s)
- F Yang
- Helmholtz-Zentrum Berlin for Materialien und Energie GmbH, Institut for Si-Photovoltaik Kekulestrasse 5, 12489 Berlin, Germany.
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16
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Goykhman I, Korbakov N, Bartic C, Borghs G, Spira ME, Shappir J, Yitzchaik S. Direct Detection of Molecular Biorecognition by Dipole Sensing Mechanism. J Am Chem Soc 2009; 131:4788-94. [DOI: 10.1021/ja809051p] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ilya Goykhman
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Nina Korbakov
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Carmen Bartic
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Gustaaf Borghs
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Micha E. Spira
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Joseph Shappir
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
| | - Shlomo Yitzchaik
- Institute of Chemistry, School of Engineering, Department of Neurobiology, The Hebrew University of Jerusalem, Safra Campus - Givat Ram, 91904, Jerusalem, Israel, and IMEC, MCP/ART, Cell Based Sensors & Circuits, Kapeldreef 75, 3001 Heverlee, Belgium
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18
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Peor N, Sfez R, Yitzchaik S. Variable density effect of self-assembled polarizable monolayers on the electronic properties of silicon. J Am Chem Soc 2008; 130:4158-65. [PMID: 18314981 DOI: 10.1021/ja077933g] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic structures at the Si/SiO2/molecule interfaces were studied by Kelvin probe techniques (contact potential difference) and compared to theoretical values derived by the Helmholtz equation. Two parameters influencing the electronic properties of n-type <100> Si/SiO2 substrates were systematically tuned: the molecular dipole of coupling agent molecules comprising the layer and the surface coverage of the chromophoric layer. The first parameter was checked using direct covalent grafting of a series of trichlorosilane-containing coupling agent molecules with various end groups causing a different dipole with the same surface number density. It was found that the change in band bending (DeltaBB) clearly indicated a major effect of passivation due to two-dimensional polysiloxane network formation, with minor differences resulting from the differences in the end groups' capacity to act as "electron traps". The change in electron affinity (DeltaEA) parameter increased upon increasing the dipole of the end group comprising the monolayer, resulting in a range of 600 mV. Moreover, a shielding effect of the aromatic spacer compared with the aliphatic spacer was found and estimated to be about 200 mV. The density effect was examined using the 4-[4-(N,N-dimethylamino phenyl)azo]pyridinium halide chromophore which has a calculated dipole of more than 10 D. It was clearly shown that upon increasing surface chromophoric coverage an increase in the electronic effects on the Si substrate was observed. However, a major consequence of depolarization was also detected while comparing the experimental and calculated values.
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Affiliation(s)
- Naama Peor
- The Institute of Chemistry and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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He T, Ding H, Peor N, Lu M, Corley DA, Chen B, Ofir Y, Gao Y, Yitzchaik S, Tour JM. Silicon/Molecule Interfacial Electronic Modifications. J Am Chem Soc 2008; 130:1699-710. [DOI: 10.1021/ja0768789] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tao He
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Huanjun Ding
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Naama Peor
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Meng Lu
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - David A. Corley
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Bo Chen
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yuval Ofir
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yongli Gao
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shlomo Yitzchaik
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - James M. Tour
- Departments of Chemistry, Computer Science, Mechanical Engineering and Materials Science, and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, and Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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20
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Seitz O, Böcking T, Salomon A, Gooding JJ, Cahen D. Importance of monolayer quality for interpreting current transport through organic molecules: alkyls on oxide-free Si. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:6915-22. [PMID: 16863239 DOI: 10.1021/la060718d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We study the effect of monolayer quality on the electrical transport through n-Si/C(n)H(2n+1)/Hg junctions (n = 12, 14, and 18) and find that truly high quality layers and only they, yield the type of data, reported by us in Phys. Rev. Lett. 2005, 95, 266807, data that are consistent with the theoretically predicted behavior of a Schottky barrier coupled to a tunnel barrier. By using that agreement as our starting point, we can assess the effects of changing the quality of the alkyl monolayers, as judged from ellipsometer, contact angle, XPS, and ATR-FTIR measurements, on the electrical transport. Although low monolayer quality layers are easily identified by one or more of those characterization tools, as well as from the current-voltage measurements, even a combination of characterization techniques may not suffice to distinguish between monolayers with minor differences in quality, which, nevertheless, are evident in the transport measurement. The thermionic emission mechanism, which in these systems dominates at low forward bias, is the one that is most sensitive to monolayer quality. It serves thus as the best quality control. This is important because, even where tunneling characteristics appear rather insensitive to slightly diminished quality, their correct analysis will be affected, especially if layers of different lengths are also of different quality.
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Affiliation(s)
- Oliver Seitz
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel.
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21
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Balakrishnan S, Gun'ko YK, Perova TS, Moore RA, Venkatesan M, Douvalis AP, Bourke P. Dendrite-like self-assembly of magnetite nanoparticles on porous silicon. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2006; 2:864-9. [PMID: 17193135 DOI: 10.1002/smll.200500521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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22
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Lenfant S, Guerin D, Tran Van F, Chevrot C, Palacin S, Bourgoin JP, Bouloussa O, Rondelez F, Vuillaume D. Electron Transport through Rectifying Self-Assembled Monolayer Diodes on Silicon: Fermi-Level Pinning at the Molecule−Metal Interface. J Phys Chem B 2006; 110:13947-58. [PMID: 16836346 DOI: 10.1021/jp053510u] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the synthesis and characterization of molecular rectifying diodes on silicon using sequential grafting of self-assembled monolayers of alkyl chains bearing a pi group at their outer end (Si/sigma-pi/metal junctions). We investigate the structure-performance relationships of these molecular devices, and we examine the extent to which the nature of the pi end group (change in the energy position of their molecular orbitals) drives the properties of these molecular diodes. Self-assembled monolayers of alkyl chains (different chain lengths from 6 to 15 methylene groups) functionalized by phenyl, anthracene, pyrene, ethylene dioxythiophene, ethylene dioxyphenyl, thiophene, terthiophene, and quaterthiophene were synthesized and characterized by contact angle measurements, ellipsometry, Fourier transform infrared spectroscopy, and atomic force microscopy. We demonstrate that reasonably well-packed monolayers are obtained in all cases. Their electrical properties were assessed by dc current-voltage characteristics and high-frequency (1-MHz) capacitance measurements. For all of the pi groups investigated here, we observed rectification behavior. These results extend our preliminary work using phenyl and thiophene groups (Lenfant et al., Nano Lett. 2003, 3, 741). The experimental current-voltage curves were analyzed with a simple analytical model, from which we extracted the energy position of the molecular orbital of the pi group in resonance with the Fermi energy of the electrodes. We report experimental studies of the band lineup in these silicon/alkyl pi-conjugated molecule/metal junctions. We conclude that Fermi-level pinning at the pi group/metal interface is mainly responsible for the observed absence of a dependence of the rectification effect on the nature of the pi groups, even though the groups examined were selected to have significant variations in their electronic molecular orbitals.
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Affiliation(s)
- S Lenfant
- Institut d'Electronique, Micro-électronique et Nanotechnologie, CNRS "Molecular Nanostructures & Devices" Group, BP 60069, avenue Poincaré, F-59652 Cedex, Villeneuve d'Ascq, France
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23
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Ofir Y, Zenou N, Goykhman I, Yitzchaik S. Controlled Amine Functionality in Self-Assembled Monolayers via the Hidden Amine Route: Chemical and Electronic Tunability. J Phys Chem B 2006; 110:8002-9. [PMID: 16610900 DOI: 10.1021/jp057251k] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A synthetic strategy for fabricating a dense amine functionalized self-assembled monolayer (SAM) on hydroxylated surfaces is presented. The assembly steps are monitored by X-ray photoelectron spectroscopy, Fourier transform infrared- attenuated total reflection, atomic force microscopy, variable angle spectroscopic ellipsometry, UV-vis surface spectroscopy, contact angle wettability, and contact potential difference measurements. The method applies alkylbromide-trichlorosilane for the fabrication of the SAM followed by surface transformation of the bromine moiety to amine by a two-step procedure: S(N)2 reaction that introduces the hidden amine, phthalimide, followed by the removal of the protecting group and exposing the free amine. The use of phthalimide moiety in the process enabled monitoring the substitution reaction rate on the surface (by absorption spectroscopy) and showed first-order kinetics. The simplicity of the process, nonharsh reagents, and short reaction time allow the use of such SAMs in molecular nanoelectronics applications, where complete control of the used SAM is needed. The different molecular dipole of each step of the process, which is verified by DFT calculations, supports the use of these SAMs as means to tune the electronic properties of semiconductors and for better synergism between SAMs and standard microelectronics processes and devices.
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Affiliation(s)
- Yuval Ofir
- Department of Inorganic and Analytical Chemistry & the HU Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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24
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Sfez R, Peor N, Cohen SR, Cohen H, Yitzchaik S. In situ SFM study of 2D-polyaniline surface-confined enzymatic polymerization. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b609388d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Faber EJ, de Smet LCPM, Olthuis W, Zuilhof H, Sudhölter EJR, Bergveld P, van den Berg A. SiC Linked Organic Monolayers on Crystalline Silicon Surfaces as Alternative Gate Insulators. Chemphyschem 2005; 6:2153-66. [PMID: 16208740 DOI: 10.1002/cphc.200500120] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Herein, the influence of silicon surface modification via Si-C(n)H(2n+1) (n=10,12,16,22) monolayer-based devices on p-type 100 and n-type 100 silicon is studied by forming MIS (metal-insulator-semiconductor) diodes using a mercury probe. From current density-voltage (J-V) and capacitance-voltage (C-V) measurements, the relevant parameters describing the electrical behavior of these diodes are derived, such as the diode ideality factor, the effective barrier height, the flatband voltage, the barrier height, the monolayer dielectric constant, the tunneling attenuation factor, and the fixed charge density (Nf). It is shown that the J-V behavior of our MIS structures could be precisely tuned via the monolayer thickness. The use of n-type silicon resulted in lower diode ideality factors as compared to p-type silicon. A similar flatband voltage, independent of monolayer thickness, was found, indicating similar properties for all silicon-monolayer interfaces. An exception was the C10-based monolayer device on p-type silicon. Furthermore, low values of N(f) were found for monolayers on p-type silicon (approximately 6 x 10(11) cm(-2)). These results suggest that Si--C linked monolayers on flat silicon may be a viable material for future electronic devices.
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Affiliation(s)
- Erik J Faber
- BIOS, Lab-on-a-Chip Group, MESA+Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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26
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Takabayashi S, Ohashi M, Mashima K, Liu Y, Yamazaki S, Nakato Y. Surface structures, photovoltages, and stability of n-Si(111) electrodes surface modified with metal nanodots and various organic groups. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:8832-8. [PMID: 16142967 DOI: 10.1021/la050423k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The surface structures, photovoltages, and stability of n-Si(111) electrodes surface-modified with Pt nanodots and organic groups were studied in an I-/I3- redox electrolyte, using alkyls of varied chain length and those having a double bond and ester at the terminal as the organic groups. The n-Si was first modified with the organic groups, and then Pt was electrodeposited on it. Linear sweep voltammetry revealed that, for the modification with alkyls, the overvoltage for the Pt deposition became significantly larger with increasing alkyl chain length, though this does not necessarily hold for the modification with alkyls having a double bond and ester. Scanning electron microscopic inspection showed that the Pt particle density decreased and the particle size increased, with increasing alkyl chain length. The photovoltaic characteristics and stability for the n-Si electrodes modified with the organic groups were much improved by the Pt nanodot coating, though they became somewhat inferior with increasing alkyl chain length. On the basis of these results, it is concluded that surface alkylation at high coverage together with coating with small Pt nanodots gives efficient and stable n-Si electrodes.
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Affiliation(s)
- Susumu Takabayashi
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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27
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Simmonett AC, Wheeler SE, Henry F. Schaefer III*. The Vinyl Radical and Fluorinated Vinyl Radicals, C2H3-nFn (n = 0−3), and Corresponding Anions: Comparison with the Isoelectronic Complexes [X···YC≡CZ]-. J Phys Chem A 2004. [DOI: 10.1021/jp031240e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Andrew C. Simmonett
- Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602
| | - Steven E. Wheeler
- Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602
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28
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Gershewitz O, Grinstein M, Sukenik CN, Regev K, Ghabboun J, Cahen. Effect of Molecule−Molecule Interaction on the Electronic Properties of Molecularly Modified Si/SiOx Surfaces. J Phys Chem B 2003. [DOI: 10.1021/jp035764q] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Liu YJ, Yu HZ. Molecular Passivation of Mercury−Silicon (p-type) Diode Junctions: Alkylation, Oxidation, and Alkylsilation. J Phys Chem B 2003. [DOI: 10.1021/jp034791d] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yong-Jun Liu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Hua-Zhong Yu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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30
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Gershevitz O, Sukenik CN, Ghabboun J, Cahen D. Molecular monolayer-mediated control over semiconductor surfaces: evidence for molecular depolarization of silane monolayers on Si/SiO(x). J Am Chem Soc 2003; 125:4730-1. [PMID: 12696890 DOI: 10.1021/ja029529h] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We show that, for molecules with particularly strong dipoles, their organization into a monomolecular layer can lead to depolarization, something that limits the range over which the substrate's work function can be changed. It appears that, with molecules, depolarization is achieved by changes in orientation and conformation, rather than by charge transfer to the substrate as is common for atomic layers.
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Affiliation(s)
- Olga Gershevitz
- Chemistry Department, Bar-Ilan University, Ramat Gan 52900, Israel
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31
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Kang JK, Musgrave CB. A quantum chemical study of the self-directed growth mechanism of styrene and propylene molecular nanowires on the silicon (100) 2×1 surface. J Chem Phys 2002. [DOI: 10.1063/1.1476005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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32
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Ashkenasy G, Cahen D, Cohen R, Shanzer A, Vilan A. Molecular engineering of semiconductor surfaces and devices. Acc Chem Res 2002; 35:121-8. [PMID: 11851390 DOI: 10.1021/ar990047t] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Grafting organic molecules onto solid surfaces can transfer molecular properties to the solid. We describe how modifications of semiconductor or metal surfaces by molecules with systematically varying properties can lead to corresponding trends in the (electronic) properties of the resulting hybrid (molecule + solid) materials and devices made with them. Examples include molecule-controlled diodes and sensors, where the electrons need not to go through the molecules (action at a distance), suggesting a new approach to molecule-based electronics.
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33
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Rienstra-Kiracofe JC, Tschumper GS, Schaefer HF, Nandi S, Ellison GB. Atomic and molecular electron affinities: photoelectron experiments and theoretical computations. Chem Rev 2002; 102:231-82. [PMID: 11782134 DOI: 10.1021/cr990044u] [Citation(s) in RCA: 855] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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34
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Wu DG, Ghabboun J, Martin JML, Cahen D. Tuning of Au/n-GaAs Diodes with Highly Conjugated Molecules. J Phys Chem B 2001. [DOI: 10.1021/jp012708l] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Deng Guo Wu
- Department of Materials and Interfaces, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Jamal Ghabboun
- Department of Materials and Interfaces, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Jan M. L. Martin
- Department of Materials and Interfaces, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel
| | - David Cahen
- Department of Materials and Interfaces, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel
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35
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Cheng J, Robinson DB, Cicero RL, Eberspacher T, Barrelet CJ, Chidsey CED. Distance Dependence of the Electron-Transfer Rate Across Covalently Bonded Monolayers on Silicon. J Phys Chem B 2001. [DOI: 10.1021/jp0123740] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jun Cheng
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - David B. Robinson
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Ronald L. Cicero
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Todd Eberspacher
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Carl J. Barrelet
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
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36
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Katz HE, Johnson J, Lovinger AJ, Li W. Naphthalenetetracarboxylic Diimide-Based n-Channel Transistor Semiconductors: Structural Variation and Thiol-Enhanced Gold Contacts. J Am Chem Soc 2000. [DOI: 10.1021/ja000870g] [Citation(s) in RCA: 333] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Howard E. Katz
- Contribution from Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974
| | - Jerainne Johnson
- Contribution from Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974
| | - Andrew J. Lovinger
- Contribution from Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974
| | - Wenjie Li
- Contribution from Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974
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37
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Abstract
Advances in techniques for the nanoscale manipulation of matter are important for the realization of molecule-based miniature devices with new or advanced functions. A particularly promising approach involves the construction of hybrid organic-molecule/silicon devices. But challenges remain--both in the formation of nanostructures that will constitute the active parts of future devices, and in the construction of commensurately small connecting wires. Atom-by-atom crafting of structures with scanning tunnelling microscopes, although essential to fundamental advances, is too slow for any practical fabrication process; self-assembly approaches may permit rapid fabrication, but lack the ability to control growth location and shape. Furthermore, molecular diffusion on silicon is greatly inhibited, thereby presenting a problem for self-assembly techniques. Here we report an approach for fabricating nanoscale organic structures on silicon surfaces, employing minimal intervention by the tip of a scanning tunnelling microscope and a spontaneous self-directed chemical growth process. We demonstrate growth of straight molecular styrene lines--each composed of many organic molecules--and the crystalline silicon substrate determines both the orientation of the lines and the molecular spacing within these lines. This process should, in principle, allow parallel fabrication of identical complex functional structures.
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38
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Abstract
The use of molecules to control electron transport is an interesting possibility, not least because of the anticipated role of molecules in future electronic devices. But physical implementations using discrete molecules are neither conceptually simple nor technically straightforward (difficulties arise in connecting the molecules to the macroscopic environment). But the use of molecules in electronic devices is not limited to single molecules, molecular wires or bulk material. Here we demonstrate that molecules can control the electrical characteristics of conventional metal-semiconductor junctions, apparently without the need for electrons to be transferred onto and through the molecules. We modify diodes by adsorbing small molecules onto single crystals of n-type GaAs semiconductor. Gold contacts were deposited onto the modified surface, using a 'soft' method to avoid damaging the molecules. By using a series of multifunctional molecules whose dipole is varied systematically, we produce diodes with an effective barrier height that is tuned by the molecule's dipole moment. These barrier heights correlate well with the change in work function of the GaAs surface after molecular modification. This behaviour is consistent with that of unmodified metal-semiconductor diodes, in which the barrier height can depend on the metal's work function.
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39
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Cohen R, Kronik L, Shanzer A, Cahen D, Liu A, Rosenwaks Y, Lorenz JK, Ellis AB. Molecular Control over Semiconductor Surface Electronic Properties: Dicarboxylic Acids on CdTe, CdSe, GaAs, and InP. J Am Chem Soc 1999. [DOI: 10.1021/ja9906150] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. Cohen
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - L. Kronik
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - A. Shanzer
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - David Cahen
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - A. Liu
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - Y. Rosenwaks
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - J. K. Lorenz
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
| | - A. B. Ellis
- Contribution from the Departments of Materials and Interfaces and of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel, Department of Physical Electronics, Tel-Aviv University, Ramat-Aviv 69978, Israel, and Department of Chemistry, University of Madison-Wisconsin, Madison, Wisconsin 53706
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