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Yao X, Wang J, Yuan S, Zhang X, Wu G, Wang X, Yang SW. A theoretical guide for fabricating a conductive molecular wire on a silicon surface via an in situ surface polymerization reaction. NANOSCALE 2015; 7:15277-15283. [PMID: 26325688 DOI: 10.1039/c5nr03621f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It has been a long-standing goal to make conductive molecular wires or linear polymer chains on traditional semiconductors or insulator substrates to satisfy the ongoing miniaturization in electronic devices. Here, we have proposed a surface in situ polymerization reaction for a pre-absorbed molecule, 4-hydrazinyl-3-(pyridin-4-ylmethyl)-benzaldehyde (HPyMB), to produce a conductive molecular wire on a silicon surface. Our first-principles calculations show that HPyMB molecules can absorb alternatively on the exposed Si atoms created via ultrahigh vacuum scanning tunneling microscopy on a hydrogen passivated H-Si(001)2 × 1 surface along the [110] direction. The adsorption is exothermic and its generated energy is sufficient for the following intermolecular dehydration polymerization reaction to overcome the activation energy barriers and thereafter form a molecular wire on the surface. This polymerized molecular wire is mechanically stable since it is chemically bonded onto the surface. After polymerization, the system becomes conductive due to the charge transfer from the molecule-surface bonds to their pyridine rings. More importantly, by removing 1.1 electrons from the system, the surface polymer chain is the sole conductive channel. Furthermore, its conducting nature remains robust even under a large external electric field. Our findings open a new window for the fabrication of conductive molecular wires or polymer chains on semiconductor surfaces, and provide insights into the mechanism behind the molecular wire conductivity.
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Affiliation(s)
- Xiaojing Yao
- Department of Physics, Southeast University, Nanjing, 211189, P. R. China.
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52
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Wang H, Li S, He H, Yu A, Toledo F, Han Z, Ho W, Wu R. Trapping and Characterization of a Single Hydrogen Molecule in a Continuously Tunable Nanocavity. J Phys Chem Lett 2015; 6:3453-3457. [PMID: 26291093 DOI: 10.1021/acs.jpclett.5b01501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using inelastic electron tunneling spectroscopy with the scanning tunneling microscope (STM-IETS) and density functional theory calculations (DFT), we investigated properties of a single H2 molecule trapped in nanocavities with controlled shape and separation between the STM tip and the Au (110) surface. The STM tip not only serves for the purpose of characterization, but also is directly involved in modification of chemical environment of molecule. The bond length of H2 expands in the atop cavity, with a tendency of dissociation when the gap closes, whereas it remains unchanged in the trough cavity. The availability of two substantially different cavities in the same setup allows understanding of H2 adsorption on noble metal surfaces and sets a path for manipulating a single chemical bond by design.
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Affiliation(s)
- Hui Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
| | - Shaowei Li
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
| | - Haiyan He
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
- Department of Physics, University Science and Technology of China , Hefei, Anhui 230026, China
| | - Arthur Yu
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
| | - Freddy Toledo
- Department of Chemistry, University of California , Irvine, California 92697-2025, United States
| | - Zhumin Han
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
| | - W Ho
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
- Department of Chemistry, University of California , Irvine, California 92697-2025, United States
| | - Ruqian Wu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Department of Physics and Astronomy, University of California , Irvine, California 92697-4575, United States
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53
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Park JY, Kim SM, Lee H, Nedrygailov II. Hot-electron-mediated surface chemistry: toward electronic control of catalytic activity. Acc Chem Res 2015; 48:2475-83. [PMID: 26181684 DOI: 10.1021/acs.accounts.5b00170] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Energy dissipation at surfaces and interfaces is mediated by excitation of elementary processes, including phonons and electronic excitation, once external energy is deposited to the surface during exothermic chemical processes. Nonadiabatic electronic excitation in exothermic catalytic reactions results in the flow of energetic electrons with an energy of 1-3 eV when chemical energy is converted to electron flow on a short (femtosecond) time scale before atomic vibration adiabatically dissipates the energy (in picoseconds). These energetic electrons that are not in thermal equilibrium with the metal atoms are called "hot electrons". The detection of hot electron flow under atomic or molecular processes and understanding its role in chemical reactions have been major topics in surface chemistry. Recent studies have demonstrated electronic excitation produced during atomic or molecular processes on surfaces, and the influence of hot electrons on atomic and molecular processes. We outline research efforts aimed at identification of the intrinsic relation between the flow of hot electrons and catalytic reactions. We show various strategies for detection and use of hot electrons generated by the energy dissipation processes in surface chemical reactions and photon absorption. A Schottky barrier localized at the metal-oxide interface of either catalytic nanodiodes or hybrid nanocatalysts allows hot electrons to irreversibly transport through the interface. We show that the chemicurrent, composed of hot electrons excited by the surface reaction of CO oxidation or hydrogen oxidation, correlates well with the turnover rate measured separately by gas chromatography. Furthermore, we show that hot electron flows generated on a gold thin film by photon absorption (or internal photoemission) can be amplified by localized surface plasmon resonance. The influence of hot charge carriers on the chemistry at the metal-oxide interface are discussed for the cases of Au, Ag, and Pt nanoparticles on oxide supports and Pt-CdSe-Pt nanodumbbells. We show that the accumulation or depletion of hot electrons on metal nanoparticles, in turn, can also influence catalytic reactions. Mechanisms suggested for hot-electron-induced chemical reactions on a photoexcited plasmonic metal are discussed. We propose that the manipulation of the flow of hot electrons by changing the electrical characteristics of metal-oxide and metal-semiconductor interfaces can give rise to the intriguing capability of tuning the catalytic activity of hybrid nanocatalysts.
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Affiliation(s)
- Jeong Young Park
- Center for Nanomaterials
and Chemical Reactions, Institute for Basic Science, Daejeon 305-701, Republic of Korea
- Graduate
School of EEWS, KAIST, Daejeon 305-701, Republic of Korea
| | - Sun Mi Kim
- Center for Nanomaterials
and Chemical Reactions, Institute for Basic Science, Daejeon 305-701, Republic of Korea
- Graduate
School of EEWS, KAIST, Daejeon 305-701, Republic of Korea
| | - Hyosun Lee
- Center for Nanomaterials
and Chemical Reactions, Institute for Basic Science, Daejeon 305-701, Republic of Korea
- Graduate
School of EEWS, KAIST, Daejeon 305-701, Republic of Korea
| | - Ievgen I. Nedrygailov
- Center for Nanomaterials
and Chemical Reactions, Institute for Basic Science, Daejeon 305-701, Republic of Korea
- Graduate
School of EEWS, KAIST, Daejeon 305-701, Republic of Korea
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54
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Kim H, Chang YH, Jang WJ, Lee ES, Kim YH, Kahng SJ. Probing Single-Molecule Dissociations from a Bimolecular Complex NO-Co-Porphyrin. ACS NANO 2015; 9:7722-7728. [PMID: 26172541 DOI: 10.1021/acsnano.5b03466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Axial coordinations of diatomic NO molecules to metalloporphyrins play key roles in dynamic processes of biological functions such as blood pressure control and immune response. Probing such reactions at the single molecule level is essential to understand their physical mechanisms but has been rarely performed. Here we report on our single molecule dissociation experiments of diatomic NO from NO-Co-porphyrin complexes describing its dissociation mechanisms. Under tunneling junctions of scanning tunneling microscope, both positive and negative energy pulses gave rise to dissociations of NO with threshold voltages, +0.68 and -0.74 V at 0.1 nA tunneling current on Au(111). From the observed power law relations between dissociation rate and tunneling current, we argue that the dissociations were inelastically induced with molecular orbital resonances by stochastically tunneling electrons, which is supported with our density functional theory calculations. Our study shows that single molecule dissociation experiments can be used to probe reaction mechanisms in a variety of axial coordinations between small molecules and metalloporphyrins.
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Affiliation(s)
- Howon Kim
- †Department of Physics, Korea University, 1-5 Anam-dong, Seongbuk-gu, Seoul, 136-713, Republic of Korea
| | - Yun Hee Chang
- ‡Graduate School of Nanoscience and Technology, KAIST, Daejeon 305-701, Republic of Korea
| | - Won-Jun Jang
- †Department of Physics, Korea University, 1-5 Anam-dong, Seongbuk-gu, Seoul, 136-713, Republic of Korea
| | - Eui-Sup Lee
- ‡Graduate School of Nanoscience and Technology, KAIST, Daejeon 305-701, Republic of Korea
| | - Yong-Hyun Kim
- ‡Graduate School of Nanoscience and Technology, KAIST, Daejeon 305-701, Republic of Korea
| | - Se-Jong Kahng
- †Department of Physics, Korea University, 1-5 Anam-dong, Seongbuk-gu, Seoul, 136-713, Republic of Korea
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55
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Minato T, Kajita S, Pang CL, Asao N, Yamamoto Y, Nakayama T, Kawai M, Kim Y. Tunneling Desorption of Single Hydrogen on the Surface of Titanium Dioxide. ACS NANO 2015; 9:6837-6842. [PMID: 26158720 DOI: 10.1021/acsnano.5b01607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigated the reaction mechanism of the desorption of single hydrogen from a titanium dioxide surface excited by the tip of a scanning tunneling microscope (STM). Analysis of the desorption yield, in combination with theoretical calculations, indicates the crucial role played by the applied electric field. Instead of facilitating desorption by reducing the barrier height, the applied electric field causes a reduction in the barrier width, which, when coupled with the electron excitation induced by the STM tip, leads to the tunneling desorption of the hydrogen. A significant reduction in the desorption yield was observed when deuterium was used instead of hydrogen, providing further support for the tunneling-desorption mechanism.
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Affiliation(s)
- Taketoshi Minato
- †International Advanced Research and Education Organization, Tohoku University, Sendai 980-8578, Japan
- ‡Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Saitama 351-0198, Japan
| | - Seiji Kajita
- §Department of Physics, Chiba University, 1-33 Yayoi, Inage, Chiba 263-0022, Japan
| | - Chi-Lun Pang
- ∥Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | - Naoki Asao
- ⊥WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
| | - Yoshinori Yamamoto
- ⊥WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
| | - Takashi Nakayama
- §Department of Physics, Chiba University, 1-33 Yayoi, Inage, Chiba 263-0022, Japan
| | - Maki Kawai
- #Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Yousoo Kim
- ‡Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Saitama 351-0198, Japan
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56
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Ballard JB, Dick DD, McDonnell SJ, Bischof M, Fu J, Owen JHG, Owen WR, Alexander JD, Jaeger DL, Namboodiri P, Fuchs E, Chabal YJ, Wallace RM, Reidy R, Silver RM, Randall JN, Von Ehr J. Atomically Traceable Nanostructure Fabrication. J Vis Exp 2015:e52900. [PMID: 26274555 DOI: 10.3791/52900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.
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Affiliation(s)
| | - Don D Dick
- Department of Physics, University of Texas at Dallas
| | - Stephen J McDonnell
- Department of Materials Science and Engineering, University of Texas at Dallas
| | - Maia Bischof
- Materials Science and Engineering, University of North Texas
| | - Joseph Fu
- National Institute of Standards and Technology
| | | | | | | | - David L Jaeger
- Materials Science and Engineering, University of North Texas
| | | | | | - Yves J Chabal
- Department of Materials Science and Engineering, University of Texas at Dallas
| | - Robert M Wallace
- Department of Materials Science and Engineering, University of Texas at Dallas
| | - Richard Reidy
- Materials Science and Engineering, University of North Texas
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57
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Park JY, Baker LR, Somorjai GA. Role of hot electrons and metal-oxide interfaces in surface chemistry and catalytic reactions. Chem Rev 2015; 115:2781-817. [PMID: 25791926 DOI: 10.1021/cr400311p] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jeong Young Park
- †Center for Nanomaterials and Chemical Reactions, Institute for Basic Science, Daejeon 305-701, South Korea.,‡Graduate School of EEWS, KAIST, Daejeon 305-701, South Korea
| | - L Robert Baker
- §Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Gabor A Somorjai
- ∥Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.,⊥Materials Sciences and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, California 94720, United States
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58
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Li H, Su TA, Zhang V, Steigerwald ML, Nuckolls C, Venkataraman L. Electric Field Breakdown in Single Molecule Junctions. J Am Chem Soc 2015; 137:5028-33. [DOI: 10.1021/ja512523r] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haixing Li
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Timothy A. Su
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Vivian Zhang
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Michael L. Steigerwald
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Colin Nuckolls
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
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59
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Huang K, Leung L, Lim T, Ning Z, Polanyi JC. Vibrational excitation induces double reaction. ACS NANO 2014; 8:12468-12475. [PMID: 25489788 DOI: 10.1021/nn5053074] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electron-induced reaction at metal surfaces is currently the subject of extensive study. Here, we broaden the range of experimentation to a comparison of vibrational excitation with electronic excitation, for reaction of the same molecule at the same clean metal surface. In a previous study of electron-induced reaction by scanning tunneling microscopy (STM), we examined the dynamics of the concurrent breaking of the two C-I bonds of ortho-diiodobenzene physisorbed on Cu(110). The energy of the incident electron was near the electronic excitation threshold of E0=1.0 eV required to induce this single-electron process. STM has been employed in the present work to study the reaction dynamics at the substantially lower incident electron energies of 0.3 eV, well below the electronic excitation threshold. The observed increase in reaction rate with current was found to be fourth-order, indicative of multistep reagent vibrational excitation, in contrast to the first-order rate dependence found earlier for electronic excitation. The change in mode of excitation was accompanied by altered reaction dynamics, evidenced by a different pattern of binding of the chemisorbed products to the copper surface. We have modeled these altered reaction dynamics by exciting normal modes of vibration that distort the C-I bonds of the physisorbed reagent. Using the same ab initio ground potential-energy surface as in the prior work on electronic excitation, but with only vibrational excitation of the physisorbed reagent in the asymmetric stretch mode of C-I bonds, we obtained the observed alteration in reaction dynamics.
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Affiliation(s)
- Kai Huang
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto , 80 St. George Street, Toronto, Ontario M5S SH6, Canada
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60
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Kepenekian M, Robles R, Rurali R, Lorente N. Spin transport in dangling-bond wires on doped H-passivated Si(100). NANOTECHNOLOGY 2014; 25:465703. [PMID: 25355047 DOI: 10.1088/0957-4484/25/46/465703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
New advances in single-atom manipulation are leading to the creation of atomic structures on H-passivated Si surfaces with functionalities important for the development of atomic and molecular based technologies. We perform total-energy and electron-transport calculations to reveal the properties and understand the features of atomic wires crafted by H removal from the surface. The presence of dopants radically change the wire properties. Our calculations show that dopants have a tendency to approach the dangling-bond wires, and in these conditions, transport is enhanced and spin selective. These results have important implications in the development of atomic-scale spintronics showing that boron, and to a lesser extent phosphorous, convert the wires in high-quality spin filters.
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Affiliation(s)
- Mikaël Kepenekian
- Institut des Sciences Chimiques de Rennes UMR 6226, CNRS-Université de Rennes 1, Rennes, France. ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain
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61
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Formation of quantum spin Hall state on Si surface and energy gap scaling with strength of spin orbit coupling. Sci Rep 2014; 4:7102. [PMID: 25407432 PMCID: PMC4236754 DOI: 10.1038/srep07102] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 10/13/2014] [Indexed: 12/03/2022] Open
Abstract
For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ≥0.5 eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.
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62
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Park JY, Kim SM, Lee H, Naik B. Hot Electron and Surface Plasmon-Driven Catalytic Reaction in Metal–Semiconductor Nanostructures. Catal Letters 2014. [DOI: 10.1007/s10562-014-1333-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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63
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Affiliation(s)
- Taketoshi Minato
- Office of Society-Academia Collaboration for Innovation; Kyoto University; Gokasho, Uji Kyoto 611-0011 Japan
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64
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Smith R, Brázdová V, Bowler DR. Hydrogen adsorption and diffusion around Si(0 0 1)/Si(1 1 0) corners in nanostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:295301. [PMID: 24957137 DOI: 10.1088/0953-8984/26/29/295301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
While the diffusion of hydrogen on silicon surfaces has been relatively well characterized, both experimentally and theoretically, diffusion around corners between surfaces, as will be found on nanowires and nanostructures, has not been studied. Motivated by nanostructure fabrication by Patterned Atomic Layer Epitaxy, we present a density functional theory study of the diffusion of hydrogen around the edge formed by the orthogonal (0 0 1) and (1 1 0) surfaces in silicon. We find that the barrier from (0 0 1) to (1 1 0) is approximately 0.3 eV lower than from (1 1 0) to (0 0 1), and that it is comparable to diffusion between rows on a clean surface, with no significant effect on the hydrogen patterns at the growth temperatures used.
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Affiliation(s)
- Richard Smith
- London Centre for Nanotechnology, UCL, 17-19 Gordon St, London WC1H 0AH, UK. Department of Physics & Astronomy, UCL, Gower St, London WC1E 6BT, UK. Thomas Young Centre, UCL, Gower St, London WC1E 6BT, UK
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65
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Katano S, Kim Y, Kawai M, Trenary M. Surface hydrogenation reactions at the single-molecule level. CHEM REC 2014; 14:819-26. [PMID: 25044803 DOI: 10.1002/tcr.201402028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Indexed: 11/12/2022]
Abstract
Hydrogenation and dehydrogenation reactions on metal surfaces are among the most important in heterogeneous catalysis. Such reactions can be observed and characterized at the single-molecule level with low temperature scanning tunnelling microscopy (LT-STM). A brief review of such studies is presented. A specific example, the hydrogenation of methyl isocyanide to methyl aminocarbyne on the Pt(111) surface, is described in detail. This reaction was first identified in a study with reflection absorption infrared spectroscopy, a technique that averages over monolayer quantities of molecules. The example illustrates the importance of characterization of surface reactions with complementary techniques in order to properly interpret the single-molecule LT-STM images. A second example of the complementary nature of LT-STM and other surface characterization methods is the tip-induced dehydrogenation on Pt(111) of acetonitrile, the more stable isomer of methyl isocyanide.
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Affiliation(s)
- Satoshi Katano
- Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577, Japan.
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66
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Zachreson C, Martin AA, Aharonovich I, Toth M. Electron beam controlled restructuring of luminescence centers in polycrystalline diamond. ACS APPLIED MATERIALS & INTERFACES 2014; 6:10367-10372. [PMID: 24932526 DOI: 10.1021/am501865t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Color centers in diamond are becoming prime candidates for applications in photonics and sensing. In this work we study the time evolution of cathodoluminescence (CL) emissions from color centers in a polycrystalline diamond film under electron irradiation. We demonstrate room-temperature activation of several luminescence centers through a thermal mechanism that is catalyzed by an electron beam. CL activation kinetics were measured in realtime and are discussed in the context of electron induced dehydrogenation of nitrogen-vacancy-hydrogen clusters and dislocation defects. Our results also show that (unintentional) electron beam induced chemical etching can take place during CL analysis of diamond. The etching is caused by residual H2O molecules present in high vacuum CL systems.
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Affiliation(s)
- Cameron Zachreson
- School of Physics and Advanced Materials, University of Technology , Sydney, Broadway, New South Wales 2007, Australia
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67
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Utecht M, Pan T, Klamroth T, Palmer RE. Quantum Chemical Cluster Models for Chemi- and Physisorption of Chlorobenzene on Si(111)-7×7. J Phys Chem A 2014; 118:6699-704. [DOI: 10.1021/jp504208d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuel Utecht
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam-Golm, Germany
| | - Tianluo Pan
- Nanoscale
Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K
| | - Tillmann Klamroth
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam-Golm, Germany
| | - Richard E. Palmer
- Nanoscale
Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K
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68
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Lee WCT, McKibbin SR, Thompson DL, Xue K, Scappucci G, Bishop N, Celler GK, Carroll MS, Simmons MY. Lithography and doping in strained Si towards atomically precise device fabrication. NANOTECHNOLOGY 2014; 25:145302. [PMID: 24633016 DOI: 10.1088/0957-4484/25/14/145302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigate the ability to introduce strain into atomic-scale silicon device fabrication by performing hydrogen lithography and creating electrically active phosphorus δ-doped silicon on strained silicon-on-insulator (sSOI) substrates. Lithographic patterns were obtained by selectively desorbing hydrogen atoms from a H resist layer adsorbed on a clean, atomically flat sSOI(001) surface with a scanning tunnelling microscope tip operating in ultra-high vacuum. The influence of the tip-to-sample bias on the lithographic process was investigated allowing us to pattern feature-sizes from several microns down to 1.3 nm. In parallel we have investigated the impact of strain on the electrical properties of P:Si δ-doped layers. Despite the presence of strain inducing surface variations in the silicon substrate we still achieve high carrier densities (>1.0 × 10(14) cm(-2)) with mobilities of ∼100 cm(2) V(-1) s(-1). These results open up the possibility of a scanning-probe lithography approach to the fabrication of strained atomic-scale devices in silicon.
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Affiliation(s)
- W C T Lee
- Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
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69
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Lyding J, Shen TC, Abeln G, Wang C, Scott P, Tucker J, Avouris PH, Walkup R. Ultrahigh Vacuum Scanning Tunneling Microscope-Based Nanolithography and Selective Chemistry on Silicon Surfaces. Isr J Chem 2013. [DOI: 10.1002/ijch.199600003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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70
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71
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Naydenov B, Boland JJ. Engineering the electronic structure of surface dangling bond nanowires of different size and dimensionality. NANOTECHNOLOGY 2013; 24:275202. [PMID: 23765570 DOI: 10.1088/0957-4484/24/27/275202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate how the local density of electronic states evolves as the size and dimensionality of surface dangling bond nanowires are modified. These wires were fabricated using the probe of a scanning tunneling microscope on a hydrogen passivated n-type Si(100)-(2 × 1) surface. We demonstrate that by varying the number and arrangement of dangling bonds on the surface it is possible to arbitrarily engineer the electronic characteristic of a surface nanowire from that of a semiconductor with a controllable band gap to that of a metal.
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Affiliation(s)
- Borislav Naydenov
- School of Chemistry and Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
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72
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Zheng H, Weismann A, Berndt R. Manipulation of subsurface donors in ZnO. PHYSICAL REVIEW LETTERS 2013; 110:226101. [PMID: 23767734 DOI: 10.1103/physrevlett.110.226101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/17/2013] [Indexed: 06/02/2023]
Abstract
Single donors close to the ZnO(0001) surface are investigated with scanning tunneling microscopy. Their binding energies and depths are determined from spatially resolved spectra of the differential conductance. At elevated bias of the STM tip, vertical motion of the donors can be induced. The direction of the motion can be controlled by the bias polarity.
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Affiliation(s)
- Hao Zheng
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany.
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73
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Lee JH, Kim SW, Cho JH. Antiferromagnetic ordering of dangling-bond electrons at the stepped Si(001) surface. J Chem Phys 2013; 138:104702. [PMID: 23514508 DOI: 10.1063/1.4794162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using first-principles density-functional calculations, we explore the possibility of magnetic order at the rebonded DB step of the Si(001) surface. The rebonded DB step containing threefold coordinated Si atoms can be treated as a one-dimensional dangling-bond (DB) wire along the step edge. We find that Si atoms composing the step edge are displaced up and down alternatively due to Jahn-Teller-like distortion, but, if Si dimers on the terrace are passivated by H atoms, the antiferromagnetic (AFM) order can be stabilized at the step edge with a suppression of Jahn-Teller-like distortion. We also find that the energy preference of AFM order over Jahn-Teller-like distortion is enhanced in an oscillatory way as the length of DB wires decreases, showing the so-called quantum size effects.
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Affiliation(s)
- Jun-Ho Lee
- Department of Physics and Research Institute for Natural Sciences, Hanyang University, 17 Haengdang-Dong, Seongdong-Ku, Seoul 133-791, South Korea
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74
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Kim SM, Lee SJ, Kim SH, Kwon S, Yee KJ, Song H, Somorjai GA, Park JY. Hot carrier-driven catalytic reactions on Pt-CdSe-Pt nanodumbbells and Pt/GaN under light irradiation. NANO LETTERS 2013; 13:1352-1358. [PMID: 23428162 DOI: 10.1021/nl400367m] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Hybrid nanocatalysts consisting of metal nanoparticle-semiconductor junctions offer an interesting platform to study the role of metal-oxide interfaces and hot electron flows in heterogeneous catalysis. Here, we report that hot carriers generated upon photon absorption significantly impact the catalytic activity of CO oxidation. We found that Pt-CdSe-Pt nanodumbbells exhibit a higher turnover frequency by a factor of 2 during irradiation by light with energy higher than the bandgap of CdSe, while the turnover rate on bare Pt nanoparticles did not depend on light irradiation. We found that Pt nanoparticles deposited on a GaN substrate under light irradiation exhibit changes in catalytic activity of CO oxidation that depends on the type of doping of the GaN. We suppose that hot electrons are generated upon the absorption of photons by the semiconducting nanorods or substrates, whereafter the hot electrons are injected into the Pt nanoparticles, resulting in the change in catalytic activity. The results imply that hot carrier flows generated during light irradiation significantly influence the catalytic activity of CO oxidation, leading to potential applications as a hot electron-based catalytic actuator.
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Affiliation(s)
- Sun Mi Kim
- Graduate School of EEWS (WCU) and NanoCentury KI, KAIST (Korea Advanced Institute of Science and Technology), Daejeon 305-701, Republic of Korea
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75
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Katano S, Kim Y, Trenary M, Kawai M. Orbital-selective single molecule reactions on a metal surface studied using low-temperature scanning tunneling microscopy. Chem Commun (Camb) 2013; 49:4679-81. [DOI: 10.1039/c3cc40949j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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76
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Kim SM, Park D, Yuk Y, Kim SH, Park JY. Influence of hot carriers on catalytic reaction; Pt nanoparticles on GaN substrates under light irradiation. Faraday Discuss 2013; 162:355-64. [DOI: 10.1039/c2fd20133j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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77
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Zenichowski K, Nacci C, Fölsch S, Dokić J, Klamroth T, Saalfrank P. STM-switching of organic molecules on semiconductor surfaces: an above threshold density matrix model for 1,5 cyclooctadiene on Si(100). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394009. [PMID: 22964350 DOI: 10.1088/0953-8984/24/39/394009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The scanning tunnelling microscope (STM)-induced switching of a single cyclooctadiene molecule between two stable conformations chemisorbed on a Si(100) surface is investigated using an above threshold model including a neutral ground state and an ionic excited state potential. Switching was recently achieved experimentally with an STM operated at cryogenic temperatures (Nacci et al 2008 Phys. Rev. B 77 121405(R)) and rationalized by a below threshold model using just a single potential energy surface (Nacci et al 2009 Nano Lett. 9 2997). In the present paper, we show that experimental key findings on the inelastic electron tunnelling (IET) switching can also be rationalized using an above threshold density matrix model, which includes, in addition to the neutral ground state potential, an anionic or cationic excited potential. We use one and two-dimensional potential energy surfaces. Furthermore, the influence of two key parameters of the density matrix description, namely the electronic lifetime of the ionic resonance and the vibrational lifetimes, on the ground state potential are discussed.
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Affiliation(s)
- K Zenichowski
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam-Golm, Germany
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78
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Ryan PM, Livadaru L, DiLabio GA, Wolkow RA. Organic Nanostructures on Hydrogen-Terminated Silicon Report on Electric Field Modulation of Dangling Bond Charge State. J Am Chem Soc 2012; 134:12054-63. [DOI: 10.1021/ja3017208] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Peter M. Ryan
- Department
of Physics, University of Alberta, Edmonton,
Alberta, Canada T6G
2E1
- National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton,
Alberta, Canada T6G 2M9
| | - Lucian Livadaru
- Department
of Physics, University of Alberta, Edmonton,
Alberta, Canada T6G
2E1
- National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton,
Alberta, Canada T6G 2M9
| | - Gino A. DiLabio
- Department
of Physics, University of Alberta, Edmonton,
Alberta, Canada T6G
2E1
- National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton,
Alberta, Canada T6G 2M9
| | - Robert A. Wolkow
- Department
of Physics, University of Alberta, Edmonton,
Alberta, Canada T6G
2E1
- National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton,
Alberta, Canada T6G 2M9
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79
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Chen S, Xu H, Goh KEJ, Liu L, Randall JN. Patterning of sub-1 nm dangling-bond lines with atomic precision alignment on H:Si(100) surface at room temperature. NANOTECHNOLOGY 2012; 23:275301. [PMID: 22710411 DOI: 10.1088/0957-4484/23/27/275301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have patterned sub-1 nm dangling-bond (DB) lines on a H-terminated Si(100)-2 × 1 surface aligned with atomic precision at room temperature using a scanning tunneling microscope (STM) to controllably desorb hydrogen atoms from a H:Si(100) surface. In order to achieve continuous and aligned DB lines, we have performed a detailed investigation of the effects of patterning parameters such as the writing voltage, writing current and electron dosage, as well as STM tip apex geometry on the fabrication and alignment of Si DB lines. We show that there exists an optimum set of patterning parameters which enables us to obtain near-perfect Si DB lines and align them with near atomic precision in a highly controllable manner. In addition, our results indicate that the pattern quality is weakly dependent on the STM tip apex quality when the patterning parameters are within the optimum parameter space.
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Affiliation(s)
- S Chen
- Zyvex Asia Pte Ltd, 4 Battery Road, #25-01 Bank of China Building, 049908, Singapore
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80
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Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography. Nat Commun 2012; 3:935. [DOI: 10.1038/ncomms1907] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/14/2012] [Indexed: 11/08/2022] Open
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81
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He KT, Wood JD, Doidge GP, Pop E, Lyding JW. Scanning tunneling microscopy study and nanomanipulation of graphene-coated water on mica. NANO LETTERS 2012; 12:2665-72. [PMID: 22612064 DOI: 10.1021/nl202613t] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We study interfacial water trapped between a sheet of graphene and a muscovite (mica) surface using Raman spectroscopy and ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at room temperature. We are able to image the graphene-water interface with atomic resolution, revealing a layered network of water trapped underneath the graphene. We identify water layer numbers with a carbon nanotube height reference. Under normal scanning conditions, the water structures remain stable. However, at greater electron energies, we are able to locally manipulate the water using the STM tip.
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Affiliation(s)
- Kevin T He
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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82
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Jung W, Cho D, Kim MK, Choi HJ, Lyo IW. Time-resolved energy transduction in a quantum capacitor. Proc Natl Acad Sci U S A 2011; 108:13973-7. [PMID: 21817067 PMCID: PMC3161544 DOI: 10.1073/pnas.1102474108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The capability to deposit charge and energy quantum-by-quantum into a specific atomic site could lead to many previously unidentified applications. Here we report on the quantum capacitor formed by a strongly localized field possessing such capability. We investigated the charging dynamics of such a capacitor by using the unique scanning tunneling microscopy that combines nanosecond temporal and subangstrom spatial resolutions, and by using Si(001) as the electrode as well as the detector for excitations produced by the charging transitions. We show that sudden switching of a localized field induces a transiently empty quantum dot at the surface and that the dot acts as a tunable excitation source with subangstrom site selectivity. The timescale in the deexcitation of the dot suggests the formation of long-lived, excited states. Our study illustrates that a quantum capacitor has serious implications not only for the bottom-up nanotechnology but also for future switching devices.
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Affiliation(s)
- Woojin Jung
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Doohee Cho
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Min-Kook Kim
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Hyoung Joon Choi
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - In-Whan Lyo
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
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83
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Xu Y, He KT, Schmucker SW, Guo Z, Koepke JC, Wood JD, Lyding JW, Aluru NR. Inducing electronic changes in graphene through silicon (100) substrate modification. NANO LETTERS 2011; 11:2735-2742. [PMID: 21661740 DOI: 10.1021/nl201022t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have performed scanning tunneling microscopy and spectroscopy (STM/STS) measurements as well as ab initio calculations for graphene monolayers on clean and hydrogen(H)-passivated silicon (100) (Si(100)/H) surfaces. In order to experimentally study the same graphene piece on both substrates, we develop a method to depassivate hydrogen from under graphene monolayers on the Si(100)/H surface. Our work represents the first demonstration of successful and reproducible depassivation of hydrogen from beneath monolayer graphene flakes on Si(100)/H by electron-stimulated desorption. Ab initio simulations combined with STS taken before and after hydrogen desorption demonstrate that graphene interacts differently with the clean and H-passivated Si(100) surfaces. The Si(100)/H surface does not perturb the electronic properties of graphene, whereas the interaction between the clean Si(100) surface and graphene changes the electronic states of graphene significantly. This effect results from the covalent bonding between C and surface Si atoms, modifying the π-orbital network of the graphene layer. The local density of states shows that the bonded C and Si surface states are highly disturbed near the Fermi energy.
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Affiliation(s)
- Y Xu
- Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China.
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84
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Pitters JL, Livadaru L, Haider MB, Wolkow RA. Tunnel coupled dangling bond structures on hydrogen terminated silicon surfaces. J Chem Phys 2011; 134:064712. [PMID: 21322726 DOI: 10.1063/1.3514896] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study both experimentally and theoretically the electronic behavior of dangling bonds (DBs) at a hydrogen terminated Si(100)-2×1 surface. Dangling bonds behave as quantum dots and, depending on their separation, can be tunnel coupled with each other or completely isolated. On n-type highly doped silicon, the latter have a net charge of -1e, while coupled DBs exhibit altered but predictable filling behavior derived from an interplay between interdot tunneling and Coulomb repulsion. We found good correlation between many scanning tunneling micrographs of dangling bond structures and our theoretical results of a corresponding extended Hubbard model. We also demonstrated chemical methods to prevent tunnel coupling and isolate charge on a single dangling bond.
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Affiliation(s)
- Jason L Pitters
- National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9, Canada.
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85
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Pitters JL, Dogel IA, Wolkow RA. Charge control of surface dangling bonds using nanoscale Schottky contacts. ACS NANO 2011; 5:1984-1989. [PMID: 21309605 DOI: 10.1021/nn103042m] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Titanium silicide (TiSi2) nanoscale Schottky contacts were prepared on hydrogen-terminated n-type Si (100) surfaces. The Schottky contact created a region of upward band bending surrounding the TiSi2 contacts. The surface band bending was observed as a sloping surface depression using the scanning tunneling microscope. Scanning tunneling spectroscopy measurements also show shifted I/V data consistent with upward band bending. Charge control of dangling bonds was accomplished through a distance relationship between the dangling bond and the TiSi2 contact. The lowered chemical potential in the near contact region removes the ability of dangling bonds to become negatively charged while dangling bonds outside the close contact region remain fully charged. Methods to actively control dangling bond charge states are discussed.
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Affiliation(s)
- Jason L Pitters
- National Institute for Nanotechnology, Edmonton, Alberta, Canada.
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86
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Robertson J. Theory of Electron Field Emission From Diamond And Diamond-Ldxe Carbon. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-498-197] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTIt is shown that the facile electron field emission from diamond and diamond-like carbon occurs because surface groups such as C-H can produce large changes in electron affinity, so that electric fields from the anode can be focused towards unhydrogenated surface areas of high affinity, the fields ending on negative charges in an underlying depletion layer. The resulting downwards band bending creates very large fields which cause Fowler-Nordheim emission, while not exceeding the material's breakdown field, which is the highest for any solid.
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87
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Lee MV, Scipioni R, Boero M, Silvestrelli PL, Ariga K. The initiation mechanisms for surface hydrosilylation with 1-alkenes. Phys Chem Chem Phys 2011; 13:4862-7. [DOI: 10.1039/c0cp01992e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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88
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XIE R, SONG Y, WAN L, YUAN H, LI P, XIAO X, LIU L, YE S, LEI S, WANG L. Two-Dimensional Polymerization and Reaction at the Solid/Liquid Interface: Scanning Tunneling Microscopy Study. ANAL SCI 2011; 27:129-38. [DOI: 10.2116/analsci.27.129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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89
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Imprinting Atomic and Molecular Patterns. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/b978-0-08-096355-6.00004-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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90
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Liu Q, Wang KD, Xiao XD. Surface dynamics studied by time-dependent tunneling current. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11467-010-0108-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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91
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92
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Rogge S. Nanoelectronics: single dopants learn their place. NATURE NANOTECHNOLOGY 2010; 5:100-101. [PMID: 20130587 DOI: 10.1038/nnano.2010.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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93
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Scappucci G, Capellini G, Lee WCT, Simmons MY. Atomic-scale patterning of hydrogen terminated Ge(001) by scanning tunneling microscopy. NANOTECHNOLOGY 2009; 20:495302. [PMID: 19893153 DOI: 10.1088/0957-4484/20/49/495302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this paper we demonstrate atomic-scale lithography on hydrogen terminated Ge(001). The lithographic patterns were obtained by selectively desorbing hydrogen atoms from a H resist layer adsorbed on a clean, atomically flat Ge(001) surface with a scanning tunneling microscope tip operating in ultra-high vacuum. The influence of the tip-to-sample bias on the lithographic process have been investigated. Lithographic patterns with feature-sizes from 200 to 1.8 nm have been achieved by varying the tip-to-sample bias. These results open up the possibility of a scanning-probe lithography approach to the fabrication of future atomic-scale devices in germanium.
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Affiliation(s)
- G Scappucci
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
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94
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Song YJ, Erwin SC, Rutter GM, First PN, Zhitenev NB, Stroscio JA. Making Mn substitutional impurities in InAs using a scanning tunneling microscope. NANO LETTERS 2009; 9:4333-4337. [PMID: 19788272 DOI: 10.1021/nl902575g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We describe in detail an atom-by-atom exchange manipulation technique using a scanning tunneling microscope probe. As-deposited Mn adatoms (Mn(ad)) are exchanged one-by-one with surface In atoms (In(su)) to create a Mn surface-substitutional (Mn(In)) and an exchanged In adatom (In(ad)) by an electron tunneling induced reaction Mn(ad) + In(su) --> Mn(In) + In(ad) on the InAs(110) surface. In combination with density-functional theory and high resolution scanning tunneling microscopy imaging, we have identified the reaction pathway for the Mn and In atom exchange.
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Affiliation(s)
- Young Jae Song
- Center for Nanoscale Science and Technology, NIST, Gaithersburg, Maryland 20899, USA.
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95
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Sessi P, Guest JR, Bode M, Guisinger NP. Patterning graphene at the nanometer scale via hydrogen desorption. NANO LETTERS 2009; 9:4343-4347. [PMID: 19883050 DOI: 10.1021/nl902605t] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have demonstrated the reversible and local modification of the electronic properties of graphene by hydrogen passivation and subsequent electron-stimulated hydrogen desorption with an scanning tunneling microscope tip. In addition to changing the morphology, we show that the hydrogen passivation is stable at room temperature and modifies the electronic properties of graphene, opening a gap in the local density of states. This insulating state is reversed by local desorption of the hydrogen, and the unaltered electronic properties of graphene are recovered. Using this mechanism, we have "written" graphene patterns on nanometer length scales. For patterned regions that are roughly 20 nm or greater, the inherent electronic properties of graphene are completely recovered. Below 20 nm we observe dramatic variations in the electronic properties of the graphene as a function of pattern size. This reversible and local mechanism for modifying the electronic properties of graphene has far-reaching implications for nanoscale circuitry fabricated from this revolutionary material.
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Affiliation(s)
- Paolo Sessi
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA
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96
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Hahn JR, Ho W. Vibrational mode specific bond dissociation in a single molecule. J Chem Phys 2009; 131:044706. [DOI: 10.1063/1.3187940] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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97
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Yoder NL, Fakonas JS, Hersam MC. Control and Characterization of Cyclopentene Unimolecular Dissociation on Si(100) with Scanning Tunneling Microscopy. J Am Chem Soc 2009; 131:10059-65. [DOI: 10.1021/ja9010546] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Nathan L. Yoder
- Department of Materials Science and Engineering, Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108
| | - James S. Fakonas
- Department of Materials Science and Engineering, Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108
| | - Mark C. Hersam
- Department of Materials Science and Engineering, Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108
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98
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Walsh MA, Hersam MC. Atomic-Scale Templates Patterned by Ultrahigh Vacuum Scanning Tunneling Microscopy on Silicon. Annu Rev Phys Chem 2009; 60:193-216. [DOI: 10.1146/annurev.physchem.040808.090314] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Michael A. Walsh
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208;
| | - Mark C. Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208;
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208;
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99
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Ferng SS, Wu ST, Lin DS, Chiang TC. Mediation of chain reactions by propagating radicals during halogenation of H-masked Si(100): Implications for atomic-scale lithography and processing. J Chem Phys 2009; 130:164706. [DOI: 10.1063/1.3122987] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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100
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Fuhrer A, Füchsle M, Reusch TCG, Weber B, Simmons MY. Atomic-scale, all epitaxial in-plane gated donor quantum dot in silicon. NANO LETTERS 2009; 9:707-710. [PMID: 19119868 DOI: 10.1021/nl803196f] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nanoscale control of doping profiles in semiconductor devices is becoming of critical importance as channel length and pitch in metal oxide semiconductor field effect transistors (MOSFETs) continue to shrink toward a few nanometers. Scanning tunneling microscope (STM) directed self-assembly of dopants is currently the only proven method for fabricating atomically precise electronic devices in silicon. To date this technology has realized individual components of a complete device with a major obstacle being the ability to electrically gate devices. Here we demonstrate a fully functional multiterminal quantum dot device with integrated donor based in-plane gates epitaxially assembled on a single atomic plane of a silicon (001) surface. We show that such in-plane regions of highly doped silicon can be used to gate nanostructures resulting in highly stable Coulomb blockade (CB) oscillations in a donor-based quantum dot. In particular, we compare the use of these all epitaxial in-plane gates with conventional surface gates and find superior stability of the former. These results show that in the absence of the randomizing influences of interface and surface defects the electronic stability of dots in silicon can be comparable or better than that of quantum dots defined in other material systems. We anticipate our experiments will open the door for controlled scaling of silicon devices toward the single donor limit.
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Affiliation(s)
- A Fuhrer
- University of New South Wales, Sydney, New South Wales 2052, Australia.
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