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A study of energetic particle impacts on solid surfaces by scanning probe microscopy.

机译:通过扫描探针显微镜研究高能粒子对固体表面的影响。

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摘要

Particle-solid interactions and the modification of solid surfaces have been of scientific and technological interest for years. In this dissertation, three independent projects were performed to study energetic impacts on solid surfaces using scanning probe microscopy (SPM).; (1) Epi-ready Ge(111) and chemomechanically polished Ge(100) surfaces were implanted with 40 to 200 keV germanium (Ge), cobalt (Co), iron (Fe) ions at a dose of {dollar}5times10sp{lcub}14{rcub}{dollar} to {dollar}5times10sp{lcub}17{rcub}{dollar} ions/cm{dollar}sp2.{dollar} Cellular nanostructures were observed by scanning tunneling microscopy (STM), contact mode and tapping mode atomic force microscopy (AFM). We have shown that the appearance of columnar/granular structures in AFM images of ion bombarded nanometer cellular structures created on germanium surfaces is due to severe image distortion when the tip radius r is close to or greater than the hole radius R.; (2) Very flat {dollar}rm Insb{lcub}0.22{rcub}Gasb{lcub}0.78{rcub}As{dollar} layers grown by metalorganic vapor phase epitaxy (MOVPE) on GaAs(100) surfaces were bombarded with a low dose (10{dollar}sp{lcub}11{rcub}{dollar} ions cm{dollar}sp2){dollar} of arsenic and boron ions at 35 keV. AFM observations show craters with average diameters of 14.6 nm and 11.4 nm for As{dollar}sp+{dollar} and B{dollar}sp+{dollar} respectively and that each crater is correlated with a single ion impact. The mechanism of the formation of the craters is discussed.; (3) Highly oriented pyrolitic graphite (HOPG) was irradiated with 1.8 MeV electrons at 45{dollar}spcirc{dollar} and near grazing (86{dollar}spcirc){dollar} angles of incidence. For near grazing incidence, at a dose of {dollar}5times10sp{lcub}12{rcub}{dollar} electrons cm{dollar}sp{lcub}-2{rcub},{dollar} features of nm size are observed. These are attributed to the effects of single electron-carbon interactions in the top surface layers. At a dose of {dollar}5times10sp{lcub}14{rcub}{dollar} electrons cm{dollar}sp{lcub}-2{rcub}{dollar} (near grazing incidence) both STM and AFM observations show an anomalously large (period 2.5 to 17 nm) superperiodicity superimposed on the normal 0.246 nm atomic spacing of graphite. We propose that near grazing incidence electron irradiation causes a break-up of the surface layers into fragments, largely retaining the six-fold atomic rings, that rotate by a small angle resulting in the observed pattern by interaction with the deeper bulk-structure layers.
机译:多年以来,颗粒与固体之间的相互作用以及固体表面的修饰一直是科学技术上的关注点。本文通过扫描探针显微镜(SPM)研究了三个独立的项目,研究了能量对固体表面的影响。 (1)用40到200 keV的锗(Ge),钴(Co),铁(Fe)离子注入Epi-ready Ge(111)和化学机械抛光的Ge(100)表面,剂量为{dollar} 5×10sp {lcub } 14 {rcub} {dollar}至{dollar} 5×10sp {lcub} 17 {rcub} {dollar}离子/cm{dollar}sp2。{dollar}通过扫描隧道显微镜(STM),接触模式和攻丝观察到了细胞纳米结构。模式原子力显微镜(AFM)。我们已经表明,在锗表面上产生的离子轰击纳米蜂窝结构的AFM图像中,柱状/颗粒结构的出现是由于当尖端半径r接近或大于孔半径R时严重的图像变形所致。 (2)用金属有机汽相外延(MOVPE)在GaAs(100)表面上生长的非常平坦的{intal} rm Insb {lcub} 0.22 {rcub} Gasb {lcub} 0.78 {rcub} As {dollar}层用低能量轰击剂量(35keV)的砷和硼离子剂量(10 {dollar} sp {lcub} 11 {rcub} {dollar}离子cm {dollar} sp2){dollar}。原子力显微镜的观察表明,As {dollar} sp + {dollar}和B {dollar} sp + {dollar}的陨石坑的平均直径分别为14.6 nm和11.4 nm,每个陨石坑与单个离子影响相关。讨论了火山口形成的机理。 (3)以1.8MeV电子以45 {spcirc {dollar}和接近掠入射(86 {spcirc){dollar的入射角辐照了高度取向的热解石墨(HOPG)。对于近乎掠食的发生率,以{dols} 5×10sp {lcub} 12 {rcub} {dollar}电子cm {dollar} sp {lcub} -2 {rcub}的剂量,观察到纳米大小的特征。这些归因于顶表面层中单电子-碳相互作用的影响。在{dolph} 5×10sp {lcub} 14 {rcub} {dollar}电子的剂量下,cm {dollar} sp {lcub} -2 {rcub} {dollar}(接近掠食发生率),STM和AFM观测均显示异常大(周期为2.5至17 nm)的周期性,叠加在石墨的正常0.246 nm原子间距上。我们提出接近掠入射的电子辐射会导致表面层破裂成碎片,大部分保留六重原子环,这些原子环以较小角度旋转,从而通过与较深的体结构层相互作用而产生观察到的图案。

著录项

  • 作者

    Chen, Yunjie.;

  • 作者单位

    The Chinese University of Hong Kong (People's Republic of China).;

  • 授予单位 The Chinese University of Hong Kong (People's Republic of China).;
  • 学科 Engineering Chemical.; Physics Condensed Matter.; Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 141 p.
  • 总页数 141
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化工过程(物理过程及物理化学过程);工程材料学;
  • 关键词

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