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E XPLORING THE N ANOLANDSCAPE Scanning Probe Microscopy

E XPLORING THE N ANOLANDSCAPE Scanning Probe Microscopy. I MAGE G ALLERY. The Nanoscale. Atomic diameter ~ 0.3 nm = 3 Å Microelectronics interconnect ~ 0.25 µm http://www.intel.com/technology//itj/q31998/articles/art_1.htm Red blood cell (5µm). Proximal Probes. History. Topografiner

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E XPLORING THE N ANOLANDSCAPE Scanning Probe Microscopy

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  1. EXPLORING THE NANOLANDSCAPEScanning Probe Microscopy

  2. IMAGE GALLERY

  3. The Nanoscale • Atomic diameter ~ 0.3 nm = 3 Å • Microelectronics interconnect ~ 0.25 µm • http://www.intel.com/technology//itj/q31998/articles/art_1.htm • Red blood cell (5µm)

  4. Proximal Probes

  5. History • Topografiner • Tunneling through a controllable vacuum gap • Scanning Tunneling Microscope • Atomic Force Microscope (Scanning Force Microscope)

  6. Operation of a Scanning Probe Microscope • Scanning with sub-Angstrom precision • Probe detection (e.g., current, force, position, …) • Electronicsprocessing • Computer control • Image processing • Vibration isolation • Environmental control (e.g., vacuum, atmosphere, fluid; temperature)

  7. Scanning Tunneling Microscope Omicron

  8. Scanning Force Microscope

  9. Tunneling • One-dimensional tunneling • Density of electronic statesof sample and tip = sample wavefunction = tip wavefunction = workfunction

  10. Forces Typical: Contact vs. non-contact modes ... Forces to atto-newton (10-18 N) range ...

  11. Themes • IMAGING • INTERROGATING • MANIPULATING atoms and nanoscale objects

  12. IMAGING ATOMS AND NANOSCALE OBJECTS

  13. Large-scale  Atomic-scale Gold Grating 30 µm  30 µmSTM Graphite 4.2 nm  4.2 nmSTM DiNardo

  14. Semiconductor Surfaces - Si(100) Tilted dimer SymmetricDimer Unreconstructed L) OccupiedR) Unoccupied Hamers, 1986

  15. Temperature-dependent Reconstructions • Low-temperature Si(100)-c(42) vs. (2  1) • Domain boundaries, p(2  2) regions Wolkow, 1992

  16. Homoepitaxial Growth - Si(100) Mo, 1988

  17. Fractional Images • Probing atomic orbitals • Frequency-modulatedAtomic Force Microscopy • Si tip / Si(111)-77 Si atom Giessibl, 2000

  18. Metal Surfaces Wahlström, 1998

  19. 0.4 ML Ag/Cu(110) c(102) model a, b) 230230 nm2 c) 5.45.4 nm2 d) 3.83.8 nm2 Sprunger, 1996

  20. Interfaces - Cross-sectional Imaging Ohmori, 1999

  21. Molecular Adsorption - CO/Pt(111) Pederson, 1996

  22. Faulted Layer Orientation Change Interstitial Defect Recovery Line Defect Vacancy Coatings - Colloidal Latex Particles Brennan, 2000

  23. Coatings - Latexes

  24. Carbon Nanotubes Odom, 1998

  25. Overlapping Nanotubes Avouris, 1999

  26. Nanotube Shapes and Forces Avouris, 1999

  27. Biological Macromolecules - Collagen Brennan, 2000

  28. Biological Macromolecules - Fibronectin Brennan, 1999

  29. INTERROGATING ATOMS AND NANOSCALE OBJECTS

  30. Visualizing the Tunnel JunctionSTM-TEM Naitoh, 1996

  31. Scanning Ohnishi, 1998

  32. Bias-dependent imaging ~ Graphite DiNardo

  33. Bias-dependent imaging ~ GaAs(110) • GaAs(110) (cleaved) surface Feenstra, 1987

  34. Spectroscopy ~ on the Nanoscale • Beam techniques average over surface species • SPM techniques measure density of states related to the atom (or molecule) under the tip • electronic spectrum - measure dI/dV [or (dI/dV)/(I/V)] Hamers, 1986

  35. Electronic SpectroscopyAtom by Atom • Reconstructed Si(100)-21 surface • Dimers • Occupied electronic states of dimers (between atoms) • Unoccupied electronic states of dimers (away from atoms) Hamers, 1986

  36. Defects • Atomic-sized defects • Al/Si(111)-√3√3 structure • different electronic states Hamers, 1988

  37. Chemical Reactivity NH3 reacted with the Si(111)-77 surface Wolkow, 1988

  38. Vibrational SpectroscopyMolecule by Molecule Lauhon, 2000

  39. Chemical Reactions Electron-induced dissociation product -pyridine on Cu(100) at 8K Lauhon, 2000

  40. Surface DiffusionChasing Atoms with the Atom Tracker Swartzentruber, 1996

  41. H-enhanced diffusion of Pt atoms an STM movie ... Horch, 1999

  42. Electrostatic Force Microscopy (EFM) • Application • Topography of integrated circuit • Monitoring an active integrated circuit Digital Instruments, www.di.com

  43. Scanning Capacitance Microscopy Nakakura, 1999

  44. Magnetic Force Microscopy (MFM) • Magnetic tip interaction with surface • Application: Disk drive • Morphology • Magnetic structure Digital Instruments, www.di.com

  45. Scanning Chemical Microscopy • Measure chemical interaction between the tip and sample • Functionalize the tip with hydrophobic or hydrophilic species • Scan over surface and measure adhesion force or friction force

  46. Carbon Nanotube Tips- Functionalization - Wong, 1998

  47. Scanning Chemical Microscopy Frisbee, 1994 / Wong, 1998

  48. Adhesion Forces Wong, 1998

  49. Friction Force Microscopy • Macroscopic friction forces • Microscopic friction forces

  50. Polymer Thin Films Polypropylene film (a) AFM + (b) FFM, (c) non-contact AFM Nie, 1999

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