Xing Group AFM Presentation

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Presentation delivered by Dr. Grace Xing at the Culver Academies campus on her research and the importance of AFM and SEM imaging techniques.

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Xing Group AFM Presentation

  1. 1. 1<br />Nano Materials and Nano Scale Imaging<br />Prof. Grace Xing<br />Dr. Chuanxin Lian<br />Electrical Engineering Department<br />University of Notre Dame<br />
  2. 2. 2<br />Outline<br />Introduction to Xing Group and Research<br />Discussion of Optics<br />History<br />Ranges of Visual Resolution<br />Scanning Electron Microscopy (SEM) <br />Fundamentals<br />Operation Scheme<br />Atomic Force Microscopy (AFM)<br />Scanning Tunneling Microscopy (STM)<br />Demonstration of AFM imaging<br />
  3. 3. Xing Group Members<br />3<br />
  4. 4. Graphene Group<br />4<br />
  5. 5. Nitride Group<br />5<br />
  6. 6. Our Labs<br />6<br />AFM<br />
  7. 7. III-V Nitride<br />7<br />III-V <br />nitride<br />Diamond<br />Rock<br />Salt<br />
  8. 8. Graphene<br />sp2 hybridization<br />Orbital figs from Pulfrey<br />Hopping energy:<br />y<br />(lattice constant)<br />pi-orbital<br /><ul><li> Sigma-orbitals hold the atoms together.</li></ul> (3 electrons/carbon atom, one left over)<br /><ul><li> Pi-orbitals are responsible for conduction.</li></ul> (1 electron/carbon atom)<br />x<br />sigma-orbital<br />Real-space picture<br />8<br />
  9. 9. Energy bands in solid  different conductivity<br />Real space coordinates<br />
  10. 10. Let us understand “Scale” and “Electronics”<br />10<br />
  11. 11. The Scale of Our Existence<br />The universe covers about 40 orders-of-magnitude (factors of 10) in size.<br />We sit somewhere in the middle!<br />
  12. 12. The Size of the Familiar<br />10 meters<br />1 meter<br />(Photos from CERN and Scientific American)<br />
  13. 13. The Size of the Familiar<br />1000 meters<br />100 meters<br />
  14. 14. The Size of the Familiar<br />100,000 meters<br />105 meters<br />10,000 meters<br />104 meters<br />
  15. 15. The Not-So Familiar<br />107 meters<br />106 meters<br />
  16. 16. The Not-So Familiar<br />109 meters<br />Orbit of the moon<br />108 meters<br />
  17. 17. The Not-So Familiar<br />1011 meters<br />Orbit of Venus and Mars<br />1010 meters<br />
  18. 18. The Not-So Familiar<br />1013 meters<br />Solar System<br />1012 meters<br />Inner Solar System<br />
  19. 19. The Not-So Familiar<br />1014 meters<br />
  20. 20. The Fantastic<br />1021 meters<br />1020 meters<br />
  21. 21. The Fantastic<br />1023 meters<br />Local Group<br />1022 meters<br />Magellanic Clouds<br />
  22. 22. The Fantastic<br />1026 meters<br />
  23. 23. Now Heading Down in Size<br />0.1 meters<br />1 meter<br />
  24. 24. Small but Gross!<br />0.001 meters<br />10-3 meters<br />0.01 meters<br />10-2 meters<br />
  25. 25. Small but Gross!<br />0.00001 meters<br />10-5 meters<br />0.0001 meters<br />10-4 meters<br />
  26. 26. 10-7 meters<br />10-6 meters<br />
  27. 27. 10-9 meters<br />DNA Molecules<br />10-8 meters<br />DNA Strand<br />
  28. 28. 10-14 meters<br />10-13 meters<br />Carbon Nucleus<br />Carbon Atom<br />
  29. 29. 10-16 meters<br />?<br />10-15 meters<br />Proton Quarks<br />
  30. 30. Small but Familiar<br />CMOS Integrated Circuit<br />10-5 meters<br />
  31. 31. Do You Own a Computer?<br />Oxford English Dictionary, 1933<br />
  32. 32. ENIAC<br />17,500 Tubes<br />174 kW!<br />How Fast?<br />5,000 additions per second!!<br />
  33. 33. What’s a Bug?<br />Aiken Relay Calculator, 1947<br />
  34. 34. The First Transistor<br />This gets you a Nobel Prize!<br />
  35. 35. First Integrated Circuit<br />Jack Kilby, Texas Instruments, 1959<br />This also gets you a Nobel Prize!<br />
  36. 36. Planar Integrated Circuits<br />Robert Noyce, 1961<br />0.6 Inches<br />In 1968 <br />Robert Noyce, Gordon Moore and Authur Rock found what company?<br />Intel<br />
  37. 37. Silicon Wafers Today<br />300 mm Si wafer<br />
  38. 38. ICs are Small (Sort-of)<br />1983<br />1968<br />
  39. 39. Cleanrooms – The tiniest dust particle is a boulder<br />
  40. 40. Intel 45 nm Penryn Dual-Core<br />107 mm2<br />400 million<br /> transistors<br />45 nm <br />Process <br />Technology<br />65 W, ~1V<br />(High performance chips up to 178 W, 0.7 V)<br />
  41. 41. Notre Dame Class Project<br />Notre Dame music chip - 7k transistors, 7 mm die<br />
  42. 42. Molecular Motors<br />Protein “propeller” and F1-ATPase “motor” <br />Single (big) molecule<br />
  43. 43. Summary on scale and electronics<br />Electronics has come a long way very quickly.<br />Electronic devices are everywhere.<br />Nanotechnology promises to continue this progress into the future.<br />You are the ones to do it! Enjoy!!<br />
  44. 44. 44<br />source<br />How do we see an object?<br />target<br />detector<br />…and often you’ll need a lens<br />
  45. 45. 45<br />Requirements of Vision<br />The light that reaches the eye must have a color between red (760nm) and blue (400nm) – or a mixture of these colors<br />The light that reaches the eye must be sufficiently bright – usually requires a sufficiently bright source<br />www.uvabcs.com/uvlight-typical.php , August 31, 2009<br />UV UV UV<br />C B A<br />visible light<br />infrared<br />760<br />wavelength in nm<br />3000<br />290<br />320<br />760<br />400<br />
  46. 46. 46<br />Object and Source Matching<br />
  47. 47. 47<br />Seeing Atomic Structure<br /><ul><li>Light must be about 0.1nm in wavelength to see atomic structure: x-rays
  48. 48. But our eyes can’t detect x-rays - 0.1nm light - (5000 times smaller wavelength than we can see)
  49. 49. Options
  50. 50. Use x-rays and detector (to replace the eye)
  51. 51. Use particles (e.g. electrons) and detector
  52. 52. Electrons of the appropriate wavelength are easier to produce and direct than light – Scanning Electron Microscope (SEM)
  53. 53. Alternate imaging techniques
  54. 54. Atomic Force Microscope (AFM)
  55. 55. Scanning Tunneling Microscope (STM)</li></li></ul><li>48<br />Scanning Electron Microscope<br />Michael Crocker<br />
  56. 56. 49<br />Let’s bounce something else at the surface!<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />e-<br />Basic Idea?<br />Animal sight and traditional microscopes collect deflected light<br />Some are “reflected”<br />Some are absorbed<br />
  57. 57. 50<br />Electron Beam Column<br />Beam created from heated filament<br />Beam travels through a vacuum<br />Electro-magnetic fields act as lenses<br />Electron beam hits the sample in a precise location<br />Scattered and “secondary” electrons are detected<br />Beam scans back and forth<br />http://bioweb.usu.edu/emlab/TEM-SEM%20Teaching/How%20SEM%20works.html<br />
  58. 58. 51<br />Electrons Hit Surface and Detection<br />Primary electrons come from the beam<br />Some scatter back, others dislodge electrons<br />http://www4.nau.edu/microanalysis/Microprobe-SEM/Signals.html<br />
  59. 59. 52<br />Example Images<br />http://gsc.nrcan.gc.ca/labs/ebeam/sem_gallery_e.php<br />
  60. 60. 53<br />Atomic Force Microscope<br />Valerie Goss<br />
  61. 61. 54<br />What is the AFM?<br />An analogue!<br />We can sense with our hands by touching.<br />
  62. 62. 55<br />AFM cantilever and AFM tips<br />www.veeco.com<br />
  63. 63. 56<br />The powerful, versatile AFM<br />Resolutions: <br />X and Y 2 -10 nm<br />Z 0.05 nm<br />Microstructure of solids:<br />CD, glass beads, circuits<br />Biological samples:<br />skin cross section, viruses, bacteria, blood, DNA and RNA<br />~30 um scan<br />www.nanotech-now.com/.../antonio-siber.htm Aug 27, 2009 <br />
  64. 64. ND Logo “written” by AFM tip<br />57<br />Anodic<br />oxidation<br />
  65. 65. 58<br />Scanning Tunneling Microscope<br />Rebecca Quardokus<br />
  66. 66. 59<br />Scanning Tunneling Microscopy (STM)<br />Electrons tunnel!<br />With a higher probability than cars <br />STM measures the current created by tunneling electrons<br />Images courtesy of<br />http://www.ieap.uni-kiel.de and www.renault.com<br />
  67. 67. 60<br />Scanning Tunneling Microscopy (STM)<br />C60 “Bucky Balls”<br />Each C60 diameter is ~ 10Å<br />1 Å = 1x 10-10 m<br />Image courtesy of<br />http://nano.tm.agilent.com<br />
  68. 68. 61<br />Scanning Tunneling Microscopy (STM)<br />Xenon on Nickel<br />Individual atoms? That’s small!<br />Iron on Copper<br />Images courtesy of <br />http://www.almaden.ibm.com<br />

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