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Martín‐Encinar L, Marqués LA, Santos I, López P, Pelaz L. Concurrent Characterization of Surface Diffusion and Intermixing of Ge on Si: A Classical Molecular Dynamics Study. ADVANCED THEORY AND SIMULATIONS 2023. [DOI: 10.1002/adts.202200848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Affiliation(s)
- Luis Martín‐Encinar
- Departamento de Electricidad y Electrónica E.T.S.I. de Telecomunicación, Universidad de Valladolid Paseo Belén 15 Valladolid 47011 Spain
| | - Luis Alberto Marqués
- Departamento de Electricidad y Electrónica E.T.S.I. de Telecomunicación, Universidad de Valladolid Paseo Belén 15 Valladolid 47011 Spain
| | - Iván Santos
- Departamento de Electricidad y Electrónica E.T.S.I. de Telecomunicación, Universidad de Valladolid Paseo Belén 15 Valladolid 47011 Spain
| | - Pedro López
- Departamento de Electricidad y Electrónica E.T.S.I. de Telecomunicación, Universidad de Valladolid Paseo Belén 15 Valladolid 47011 Spain
| | - Lourdes Pelaz
- Departamento de Electricidad y Electrónica E.T.S.I. de Telecomunicación, Universidad de Valladolid Paseo Belén 15 Valladolid 47011 Spain
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Fujita Y, Abe M. Computational study on 1,3-disilacyclobutane-1,3-diylidene disilylenes: A synthetic strategy for cis
-bent disilenes. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yoshiki Fujita
- Department of Chemistry, Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashihiroshima Hiroshima 739-8526 Japan
| | - Manabu Abe
- Department of Chemistry, Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashihiroshima Hiroshima 739-8526 Japan
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Liang Y, Li F, Wang W, Yang H, Guo J. Formation of Sr adatom chains on SrTiO3 (1 1 0) surface determined by strain. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:365003. [PMID: 27390937 DOI: 10.1088/0953-8984/28/36/365003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The adsorption behavior of Sr adatoms on the SrTiO3 (1 1 0)-(4 × 1) reconstructed surface with Ti2O3 vacancies distributed in a superstructure is studied by scanning tunneling microscopy and density functional theory calculations. With the adsorption amount increasing, all the Sr adatoms between adjacent Ti2O3 vacancies are closely packed along the quasi-1D stripes on the surface with a uniform separation from each other. The formation of such adatom chains is determined by the surface strain relief-the local lattice relaxations in response to Sr adatoms and Ti2O3 vacancies are incompatible, leading to the strong repulsive interaction between them. Consequently the distribution of Sr chains follows the long-range order of the growth template with their length tunable in a certain range by evaporation amount.
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Affiliation(s)
- Yan Liang
- College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, People's Republic of China. Beijing National Laboratory for Condensed Matter Physics & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Yang S, Liu F, Wu C, Yang S. Tuning Surface Properties of Low Dimensional Materials via Strain Engineering. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:4028-4047. [PMID: 27376498 DOI: 10.1002/smll.201601203] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/26/2016] [Indexed: 06/06/2023]
Abstract
The promising and versatile applications of low dimensional materials are largely due to their surface properties, which along with their underlying electronic structures have been well studied. However, these materials may not be directly useful for applications requiring properties other than their natal ones. In recent years, strain has been shown to be an additionally useful handle to tune the physical and chemical properties of materials by changing their geometric and electronic structures. The strategies for producing strain are summarized. Then, the electronic structure of quasi-two dimensional layered non-metallic materials (e.g., graphene, MX2, BP, Ge nanosheets) under strain are discussed. Later, the strain effects on catalytic properties of metal-catalyst loaded with strain are focused on. Both experimental and computational perspectives for dealing with strained systems are covered. Finally, an outlook on engineering surface properties utilizing strain is provided.
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Affiliation(s)
- Shengchun Yang
- School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
- Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Academy of Xi'an Jiaotong University, 215000, Suzhou, P. R. China
| | - Fuzhu Liu
- School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
- Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Academy of Xi'an Jiaotong University, 215000, Suzhou, P. R. China
| | - Chao Wu
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, P. R. China
| | - Sen Yang
- School of Science, MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
- Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Academy of Xi'an Jiaotong University, 215000, Suzhou, P. R. China
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5
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Bosi M, Attolini G, Negri M, Ferrari C, Buffagni E, Frigeri C, Calicchio M, Pécz B, Riesz F, Cora I, Osváth Z, Jiang L, Borionetti G. Defect structure and strain reduction of 3C-SiC/Si layers obtained with the use of a buffer layer and methyltrichlorosilane addition. CrystEngComm 2016. [DOI: 10.1039/c6ce00280c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Lozovoy KA, Kokhanenko AP, Voitsekhovskii AV. Generalized Muller-Kern formula for equilibrium thickness of a wetting layer with respect to the dependence of the surface energy of island facets on the thickness of the 2D layer. Phys Chem Chem Phys 2015; 17:30052-6. [PMID: 26499174 DOI: 10.1039/c5cp05192d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experimental results indicate a particular importance of such a value as the equilibrium thickness of the wetting layer during epitaxial growth according to the Stranski-Krastanow mechanism in systems with a lattice mismatch. In this paper the change in free energy during the transition of atoms from the wetting layer to the island in such systems is considered. Recent experimental results also show that the surface energy of the island's facets depends upon the thickness of the deposited material. So, in this paper the equilibrium thickness of the wetting layer, at which transition from 2D to 3D growth becomes energetically favorable, is calculated with the assumption that the specific energy of the island's facets depends upon the wetting layer thickness. In this approximation a new generalized Muller-Kern formula is obtained. As an illustration of the proposed method, an example of a numerical calculation according to the new formula for the material system of germanium on a silicon (001) surface is given. The result for the found equilibrium thickness of the wetting layer is rather unexpected since it differs from the value obtained in the bounds of the traditional Muller-Kern model.
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Affiliation(s)
- Kirill A Lozovoy
- Department of Radiophysics, National Research Tomsk State University, 36 Lenin Av., Tomsk 634050, Russian Federation.
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Ding H, Virkar AV, Liu M, Liu F. Suppression of Sr surface segregation in La1−xSrxCo1−yFeyO3−δ: a first principles study. Phys Chem Chem Phys 2013; 15:489-96. [DOI: 10.1039/c2cp43148c] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nikiforov AI, Timofeev VA, Teys SA, Gutakovsky AK, Pchelyakov OP. Initial stage growth of GexSi1-x layers and Ge quantum dot formation on GexSi1-x surface by MBE. NANOSCALE RESEARCH LETTERS 2012; 7:561. [PMID: 23043796 PMCID: PMC3492111 DOI: 10.1186/1556-276x-7-561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 09/29/2012] [Indexed: 06/01/2023]
Abstract
Critical thicknesses of two-dimensional to three-dimensional growth in GexSi1-x layers were measured as a function of composition for different growth temperatures. In addition to the (2 × 1) superstructure for a Ge film grown on Si(100), the GexSi1-x layers are characterized by the formation of (2 × n) reconstruction. We measured n for all layers of Ge/GexSi1-x/Ge heterosystem using our software with respect to the video recording of reflection high-energy electron diffraction (RHEED) pattern during growth. The n reaches a minimum value of about 8 for clear Ge layer, whereas for GexSi1-x films, n is increased from 8 to 14. The presence of a thin strained film of the GexSi1-x caused not only the changes in critical thicknesses of the transitions, but also affected the properties of the germanium nanocluster array for the top Ge layer. Based on the RHEED data, the hut-like island form, which has not been previously observed by us between the hut and dome islands, has been detected. Data on the growth of Ge/GexSi1-x/Ge heterostructures with the uniform array of islands in the second layer of the Ge film have been received.
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Affiliation(s)
- Aleksandr I Nikiforov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, Lavrentjeva 13, Novosibirsk, 630090, Russia
| | - Vyacheslav A Timofeev
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, Lavrentjeva 13, Novosibirsk, 630090, Russia
| | - Serge A Teys
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, Lavrentjeva 13, Novosibirsk, 630090, Russia
| | - Anton K Gutakovsky
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, Lavrentjeva 13, Novosibirsk, 630090, Russia
| | - Oleg P Pchelyakov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, Lavrentjeva 13, Novosibirsk, 630090, Russia
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9
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Yuryev VA, Arapkina LV. Ge quantum dot arrays grown by ultrahigh vacuum molecular-beam epitaxy on the Si(001) surface: nucleation, morphology, and CMOS compatibility. NANOSCALE RESEARCH LETTERS 2011; 6:522. [PMID: 21892938 PMCID: PMC3212061 DOI: 10.1186/1556-276x-6-522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/05/2011] [Indexed: 05/31/2023]
Abstract
Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C) and high (≳600°C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.
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Affiliation(s)
- Vladimir A Yuryev
- A. M. Prokhorov General Physics Institute of RAS, 38 Vavilov Street, 119991 Moscow, Russia
| | - Larisa V Arapkina
- A. M. Prokhorov General Physics Institute of RAS, 38 Vavilov Street, 119991 Moscow, Russia
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10
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Paskiewicz DM, Scott SA, Savage DE, Celler GK, Lagally MG. Symmetry in strain engineering of nanomembranes: making new strained materials. ACS NANO 2011; 5:5532-5542. [PMID: 21682324 DOI: 10.1021/nn2009672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Strain in a material changes the lattice constant and thereby creates a material with new properties relative to the unstrained, but chemically identical, material. The ability to alter the strain (its magnitude, direction, extent, periodicity, symmetry, and nature) allows tunability of these new properties. A recent development, crystalline nanomembranes, offers a powerful platform for using and tuning strain to create materials that have unique properties, not achievable in bulk materials or with conventional processes. Nanomembranes, because of their thinness, enable elastic strain sharing, a process that introduces large amounts of strain and unique strain distributions in single-crystal materials, without exposing the material to the formation of extended defects. We provide here prescriptions for making new strained materials using crystal symmetry as the driver: we calculate the strain distributions in flat nanomembranes for two-fold and four-fold elastically symmetric materials. We show that we can controllably tune the amount of strain and the asymmetry of the strain distribution in elastically isotropic and anisotropic materials uniformly over large areas. We perform the experimental demonstration with a trilayer Si(110)/Si((1-x))Ge(x)(110)/Si(110) nanomembrane: an elastically two-fold symmetric system in which we can transfer strain that is biaxially isotropic. We are thus able to make uniformly strained materials that cannot be made any other way.
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11
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Lidorikis E, Bachlechner ME, Kalia RK, Voyiadjis GZ, Nakano A, Vashishta P. Coupling of Length Scales: Hybrid Molecular Dynamics and Finite Element Approach for Multiscale Nanodevice Simulations. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-653-z9.3.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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12
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Snijders PC, Moon EJ, González C, Rogge S, Ortega J, Flores F, Weitering HH. Controlled self-organization of atom vacancies in monatomic gallium layers. PHYSICAL REVIEW LETTERS 2007; 99:116102. [PMID: 17930452 DOI: 10.1103/physrevlett.99.116102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Indexed: 05/25/2023]
Abstract
Ga adsorption on the Si(112) surface results in the formation of pseudomorphic Ga atom chains. Compressive strain in these atom chains is relieved via creation of adatom vacancies and their self-organization into meandering vacancy lines. The average spacing between these line defects can be controlled, within limits, by adjusting the chemical potential mu of the Ga adatoms. We derive a lattice model that quantitatively connects density functional theory (DFT) calculations for perfectly ordered structures with the fluctuating disorder seen in experiment and the experimental control parameter mu. This hybrid approach of lattice modeling and DFT can be applied to other examples of line defects in heteroepitaxy.
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Affiliation(s)
- P C Snijders
- Kavli Institute of NanoScience Delft, Delft University of Technology, 2628 CJ Delft, The Netherlands.
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Moore CJ, Retford CM, Beck MJ, Asta M, Miksis MJ, Voorhees PW. Orientation dependence of strained-Ge surface energies near (001): role of dimer-vacancy lines and their interactions with steps. PHYSICAL REVIEW LETTERS 2006; 96:126101. [PMID: 16605929 DOI: 10.1103/physrevlett.96.126101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Indexed: 05/08/2023]
Abstract
Recent experiments and calculations have highlighted the important role of surface-energy (gamma) anisotropy in governing island formation in the Ge/Si(001) system. To further elucidate the factors determining this anisotropy, we perform atomistic and continuum calculations of the orientation dependence of gamma for strained-Ge surfaces near (001), accounting for the presence of dimer-vacancy lines (DVLs). The net effect of DVLs is found to be a substantial reduction in the magnitude of the slope of gamma vs orientation angle, relative to the highly negative value derived for non-DVL, dimer-reconstructed, strained-Ge(001) surfaces. The present results thus point to an important role of DVLs in stabilizing the (001) surface orientation of a strained-Ge wetting layer.
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Affiliation(s)
- C J Moore
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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Huang L, Liu F, Lu GH, Gong XG. Surface mobility difference between Si and Ge and its effect on growth of SiGe alloy films and islands. PHYSICAL REVIEW LETTERS 2006; 96:016103. [PMID: 16486480 DOI: 10.1103/physrevlett.96.016103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Indexed: 05/06/2023]
Abstract
Based on first-principles calculations of surface diffusion barriers, we show that on a compressive Ge(001) surface the diffusivity of Ge is 10(2)-10(3) times higher than that of Si in the temperature range of 300 to 900 K, while on a tensile surface, the two diffusivities are comparable. Consequently, the growth of a compressive SiGe film is rather different from that of a tensile film. The diffusion disparity between Si and Ge is also greatly enhanced on the strained Ge islands compared to that on the Ge wetting layer on Si(001), explaining the experimental observation of Si enrichment in the wetting layer relative to that in the islands.
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Affiliation(s)
- Li Huang
- Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433, China
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15
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Shklyaev OE, Beck MJ, Asta M, Miksis MJ, Voorhees PW. Role of strain-dependent surface energies in Ge/Si(100) island formation. PHYSICAL REVIEW LETTERS 2005; 94:176102. [PMID: 15904314 DOI: 10.1103/physrevlett.94.176102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 02/04/2005] [Indexed: 05/02/2023]
Abstract
Formation energies for Ge/Si(100) pyramidal islands are computed combining continuum calculations of strain energy with first-principles-computed strain-dependent surface energies. The strain dependence of surface energy is critically impacted by the presence of strain-induced changes in the Ge {100} surface reconstruction. The appreciable strain dependencies of rebonded-step {105} and dimer-vacancy-line-reconstructed {100} surface energies are estimated to give rise to a significant reduction in the surface contribution to island formation energies.
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Affiliation(s)
- O E Shklyaev
- Department of Engineering Science and Applied Mathematics, Northwestern University, Evanston, Illinois 60208, USA
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16
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Lu GH, Liu F. Towards quantitative understanding of formation and stability of Ge hut islands on Si(001). PHYSICAL REVIEW LETTERS 2005; 94:176103. [PMID: 15904315 DOI: 10.1103/physrevlett.94.176103] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Indexed: 05/02/2023]
Abstract
We analyze Ge hut island formation on Si(001), using first-principles calculations of energies, stresses, and their strain dependence of Ge/Si(105) and Ge/Si(001) surfaces combined with continuum modeling. We give a quantitative assessment on strain stabilization of Ge(105) facets, estimate the critical size for hut nucleation or formation, and evaluate the magnitude of surface stress discontinuity at the island's edge and its effect on island stability.
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Affiliation(s)
- Guang-Hong Lu
- School of Science, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
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17
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Mui C, Bent SF, Musgrave CB. A Density Functional Theory Study on the Effect of Ge Alloying on Hydrogen Desorption from SiGe Alloy Surfaces. J Phys Chem B 2004; 108:6336-50. [DOI: 10.1021/jp037948a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Collin Mui
- Department of Chemical Engineering, Stanford University, Stanford California 94305
| | - Stacey F. Bent
- Department of Chemical Engineering, Stanford University, Stanford California 94305
| | - Charles B. Musgrave
- Departments of Chemical Engineering and Materials Science and Engineering, Stanford University, Stanford California 94305
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18
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Freyland W, Zell C, Abedin SE, Endres F. Nanoscale electrodeposition of metals and semiconductors from ionic liquids. Electrochim Acta 2003. [DOI: 10.1016/s0013-4686(03)00378-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Mukhopadhyay I, Freyland W. Thickness induced metal–nonmetal transition in ultrathin electrodeposited Ge films. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)01098-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Lin DS, Wu JL, Pan SY, Chiang TC. Atomistics of Ge deposition on Si(100) by atomic layer epitaxy. PHYSICAL REVIEW LETTERS 2003; 90:046102. [PMID: 12570436 DOI: 10.1103/physrevlett.90.046102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2002] [Indexed: 05/24/2023]
Abstract
Chlorine termination of mixed Ge/Si(100) surfaces substantially enhances the contrast between Ge and Si sites in scanning tunneling microscopy observations. This finding enables a detailed investigation of the spatial distribution of Ge atoms deposited on Si(100) by atomic layer epitaxy. The results are corroborated by photoemission measurements aided by an unusually large chemical shift between Cl adsorbed on Si and Ge. Adsorbate-substrate atomic exchange during growth is shown to be important. The resulting interface is thus graded, but characterized by a very short length scale of about one monolayer.
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Affiliation(s)
- D S Lin
- Institute of Physics, National Chiao-Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan, Republic of China
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21
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Fujikawa Y, Akiyama K, Nagao T, Sakurai T, Lagally MG, Hashimoto T, Morikawa Y, Terakura K. Origin of the stability of Ge(105) on si: a new structure model and surface strain relaxation. PHYSICAL REVIEW LETTERS 2002; 88:176101. [PMID: 12005768 DOI: 10.1103/physrevlett.88.176101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2002] [Indexed: 05/23/2023]
Abstract
The structure of Ge(105)-(1 x 2) grown on Si(105) is examined by scanning tunneling microscopy (STM) and first-principles calculations. The morphology evolution with an increasing amount of Ge deposited documents the existence of a tensile surface strain in Si(105) and its relaxation with increasing coverage of Ge. A detailed analysis of high-resolution STM images and first-principles calculations produce a new stable model for the Ge(105)-(1 x 2) structure formed on the Si(105) surface that includes the existence of surface strain. It corrects the model developed from early observations of the facets of "hut" clusters grown on Si(001).
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Affiliation(s)
- Y Fujikawa
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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22
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Lidorikis E, Bachlechner ME, Kalia RK, Nakano A, Vashishta P, Voyiadjis GZ. Coupling length scales for multiscale atomistics-continuum simulations: atomistically induced stress distributions in Si/Si3N4 nanopixels. PHYSICAL REVIEW LETTERS 2001; 87:086104. [PMID: 11497965 DOI: 10.1103/physrevlett.87.086104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2000] [Indexed: 05/23/2023]
Abstract
A hybrid molecular-dynamics (MD) and finite-element simulation approach is used to study stress distributions in silicon/silicon-nitride nanopixels. The hybrid approach provides atomistic description near the interface and continuum description deep into the substrate, increasing the accessible length scales and greatly reducing the computational cost. The results of the hybrid simulation are in good agreement with full multimillion-atom MD simulations: atomic structures at the lattice-mismatched interface between amorphous silicon nitride and silicon induce inhomogeneous stress patterns in the substrate that cannot be reproduced by a continuum approach alone.
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Affiliation(s)
- E Lidorikis
- Concurrent Computing Laboratory for Materials Simulations, Biological Computation and Visualization Center, Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA
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23
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Qin XR, Swartzentruber BS, Lagally MG. Diffusional kinetics of SiGe dimers on Si(100) using atom-tracking scanning tunneling microscopy. PHYSICAL REVIEW LETTERS 2000; 85:3660-3663. [PMID: 11030975 DOI: 10.1103/physrevlett.85.3660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2000] [Indexed: 05/23/2023]
Abstract
Quantitative measurements of the diffusion of adsorbed mixed Ge-Si dimers on the Si(100) surface have been made as a function of temperature using atom-tracking scanning tunneling microscopy. These mixed dimers are distinguishable from pure Si-Si dimers by their characteristic kinetics-a 180 degrees rotation between two highly buckled configurations. At temperatures at which the mixed dimers diffuse, atomic-exchange events occur, in which the Ge atom in the adsorbed dimer exchanges with a substrate Si atom. Reexchange can also occur when the diffusing Si-Si dimer revisits the original site of exchange.
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Affiliation(s)
- XR Qin
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Qin XR, Swartzentruber BS, Lagally MG. Scanning tunneling microscopy identification of atomic-scale intermixing on Si(100) at submonolayer Ge coverages. PHYSICAL REVIEW LETTERS 2000; 84:4645-4648. [PMID: 10990761 DOI: 10.1103/physrevlett.84.4645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2000] [Indexed: 05/23/2023]
Abstract
The positions of Ge atoms intermixed in the Si(100) surface at very low concentration are identified using empty-state imaging in scanning tunneling microscopy. A measurable degree of place exchange occurs at temperatures as low as 330 K. Contrary to earlier conclusions, good differentiation between Si atoms and Ge atoms can be achieved by proper imaging conditions.
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Affiliation(s)
- XR Qin
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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25
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Omeltchenko A, Bachlechner ME, Nakano A, Kalia RK, Vashishta P, Ebbsjo I, Madhukar A, Messina P. Stress domains in Si(111)/a-Si3N4 nanopixel: ten-million-atom molecular dynamics simulations on parallel computers. PHYSICAL REVIEW LETTERS 2000; 84:318-321. [PMID: 11015900 DOI: 10.1103/physrevlett.84.318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/1998] [Revised: 07/14/1999] [Indexed: 05/23/2023]
Abstract
Parallel molecular dynamics simulations are performed to determine atomic-level stresses in Si(111)/Si(3)N4(0001) and Si(111)/a-Si3N4 nanopixels. Compared to the crystalline case, the stresses in amorphous Si3N4 are highly inhomogeneous in the plane of the interface. In silicon below the interface, for a 25 nm square mesa stress domains with triangular symmetry are observed, whereas for a rectangular, 54 nmx33 nm, mesa tensile stress domains ( approximately 300 A) are separated by Y-shaped compressive domain wall. Maximum stresses in the domains and domain walls are -2 GPa and +2 GPa, respectively.
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Affiliation(s)
- A Omeltchenko
- Concurrent Computing Laboratory for Materials Simulations, Department of Physics & Astronomy, and Department of Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA
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Mui C, Bent SF, Musgrave CB. A Theoretical Study of the Structure and Thermochemistry of 1,3-Butadiene on the Ge/Si(100)-2 × 1 Surface. J Phys Chem A 1999. [DOI: 10.1021/jp991797n] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Collin Mui
- Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025
| | - Stacey F. Bent
- Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025
| | - Charles B. Musgrave
- Departments of Chemical Engineering and Materials Science and Engineering, Stanford University, Stanford, California 94305-5025
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Bachlechner ME, Kalia RK, Nakano A, Omeltchenko A, Vashishta P, Ebbsjö I, Madhukar A, Zhao GL. Structural correlations at Si/Si3N4 interface and atomic stresses in Si/Si3N4 nanopixel-10 million-atom molecular dynamics simulation on parallel computers. Ann Ital Chir 1999. [DOI: 10.1016/s0955-2219(99)00119-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Abstract
The convergent syntheses of molecular caltrops are described starting from tetraethyl orthosilicate and using organolithium additions and Pd/Cu-catalyzed coupling methods. The caltrop core is based on a tetrahedral silicon atom, and there are three legs each bearing sulfur-tipped feet for adhesion to metallic surfaces. The forth prong (arm) is non-sulfur-bearing for projection upward from the surface. Rigid phenyleneethynylene segments are used for the legs and arms. These organosilicon caltrops may have utility as scanning probe microscopy tips.
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Affiliation(s)
- Yuxing Yao
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
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