Surface, subsurface and buried interface structure at the atomic scale; pushing the limits of medium energy ion scattering

原子尺度的表面、次表面和埋入界面结构；

• 批准号: EP/E021786/1
• 负责人: David Woodruff
• 金额: $ 45.05万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE021786%2F1
• 关键词: Surface; subsurface; buried; interface; structure

Solid surfaces are important in many practical situations, such as heterogeneous catalysis, corrosion and the way one solid bonds to another to make electronic devices. Often it is just the outermost one or two atomic layers of the solid which determine these properties, and over the last 30 years a range of specialised techniques have been developed which probe only these few layers and are not influenced by the underlying bulk solid for which a range of other analytical methods exist. Medium energy ion scattering (MEIS) is essentially unique in bridging the gap between these sets of methods; it can be used to probe only the outermost few atomic layers, but can also probe the subsurface up to a few hundred atomic layers below the surface. On these depth scales it can provide both compositional and structural information, and has the unusual advantage of being especially sensitive to how a solid surface may be modified by the presence of adsorbed atoms and molecules.This project seeks to exploit these special advantages, using the UK national MEIS facility at Daresbury, to investigate model systems which typify a number of different surface and near-surface systems and phenomena. One example is the problem of oxide surfaces, of great importance in heterogeneous catalysis but relatively unexplored, especially in terms of their surface structure. Ultra-thin oxide films on metals are especially relevant to their applications, and MEIS will be used to determine both the oxide surface and oxide/metal interface structure in specific systems, notably Pd(111)/V2O3. The reactivity of surfaces is known to often be strongly influenced by surface defects, such as atomic steps, yet detailed information on the structure of these steps and the way the atoms relax at the reduced coordination sites is lacking; MEIS investigations are planned to address this problem. The technique is also ideally suited to investigate distortions of a metal surface induced by adsorbed molecules, and it is proposed to exploit this to probe thiol/metal interfaces, in particular; these form the basis of many self-assembled monolayers, yet the interface structure is poorly understood. Finally, the combination of structural and compositional information provided by MEIS is of great value in studying the surface and near-surface properties of metal alloy surfaces and surface alloys, and specific model systems of this type are proposed for study, including systems of interest in magnetism.A further theme of the proposed research involves investigations of the fundamental physics of the MEIS technique itself, notably the nature of inelastic energy loss, which gives MEIS its depth resolution, and neutralisation, which influences the ion yields and thus the quantification. A better understanding of these processes should benefit the whole MEIS user community, allowing more detailed and more reliable information to be extracted from MEIS experiments.

固体表面在许多实际情况中都很重要，例如多相催化、腐蚀以及一种固体与另一种固体结合以制造电子设备的方式。通常，决定这些特性的只是固体最外层的一两个原子层，在过去 30 年里，已经开发出一系列专门技术，仅探测这几层，而不受下面的散装固体的影响。还存在一系列其他分析方法。中能离子散射 (MEIS) 在弥补这些方法之间的差距方面本质上是独一无二的；它只能用于探测最外面的几个原子层，但也可以探测表面以下数百个原子层的地下。在这些深度尺度上，它可以提供成分和结构信息，并且具有对固体表面如何通过吸附原子和分子的存在进行修改特别敏感的独特优势。该项目旨在利用这些特殊优势，利用位于达斯伯里的英国国家 MEIS 设施，用于研究代表许多不同地表和近地表系统和现象的模型系统。一个例子是氧化物表面问题，它在多相催化中非常重要，但相对而言尚未得到探索，特别是在其表面结构方面。金属上的超薄氧化膜与其应用尤其相关，MEIS 将用于确定特定系统中的氧化物表面和氧化物/金属界面结构，特别是 Pd(111)/V2O3。众所周知，表面的反应性通常受到表面缺陷的强烈影响，例如原子台阶，但缺乏有关这些台阶结构以及原子在还原配位位点松弛方式的详细信息； MEIS 计划开展调查来解决这一问题。该技术还非常适合研究由吸附分子引起的金属表面的变形，并且建议利用该技术来探测硫醇/金属界面，特别是；这些形成了许多自组装单层的基础，但人们对界面结构知之甚少。最后，MEIS提供的结构和成分信息的结合对于研究金属合金表面和表面合金的表面和近表面性能具有重要价值，并且提出了此类特定模型系统进行研究，包括感兴趣的系统拟议研究的另一个主题涉及对 MEIS 技术本身的基础物理的研究，特别是非弹性能量损失的性质（它赋予 MEIS 深度分辨率）和中和作用（影响离子产率，从而影响定量）。更好地理解这些过程应该有利于整个 MEIS 用户社区，从而可以从 MEIS 实验中提取更详细、更可靠的信息。

项目成果

Silver sulphide growth on Ag(111): A medium energy ion scattering study

Ag(111) 上硫化银的生长：中能离子散射研究

• DOI: http://dx.10.1016/j.susc.2010.04.009
• 发表时间: 2010
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Window A

V2O3(0001) surface termination: phase equilibrium.

V2O3(0001) 表面终止：相平衡。

• DOI: http://dx.10.1103/physrevlett.107.016105
• 发表时间: 2011
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: Window AJ

The structure of epitaxial V2O3 films and their surfaces: A medium energy ion scattering study

外延 V2O3 薄膜及其表面的结构：中能离子散射研究

• DOI: http://dx.10.1016/j.susc.2012.07.015
• 发表时间: 2012
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Window A

Direct observation and theory of trajectory-dependent electronic energy losses in medium-energy ion scattering.

中能离子散射中轨迹相关电子能量损失的直接观察和理论。

• DOI: http://dx.10.1103/physrevlett.102.096103
• 发表时间: 2009
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: Hentz A

Surface relaxation in Cu(410)-O: A medium energy ion scattering study

Cu(410)-O 中的表面弛豫：中能离子散射研究

• DOI: http://dx.10.1016/j.susc.2010.02.001
• 发表时间: 2010
• 期刊: Surface Science
• 影响因子: 1.9
• 作者: Sheppard D