1. 1 E XPLORING THE N ANOLANDSCAPE Scanning Probe Microscopy

2. 2 I MAGE G ALLERY

3. 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. 4 Proximal Probes

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

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

7. 7 Scanning Tunneling Microscope Omicron

8. 8 Scanning Force Microscope

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

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

11. 11 Themes IMAGING INTERROGATING MANIPULATING atoms and nanoscale objects

12. 12 IMAGING ATOMS AND NANOSCALE OBJECTS

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

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

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

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

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

18. 18 Metal Surfaces Wahlström, 1998

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

20. 20 Interfaces - Cross-sectional Imaging Ohmori, 1999

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

22. 22 Coatings - Colloidal Latex Particles VacancyRecovery Faulted Layer Interstitial DefectLine DefectOrientation Change Brennan, 2000

23. 23 Coatings - Latexes

24. 24 Carbon Nanotubes Odom, 1998

25. 25 Overlapping Nanotubes Avouris, 1999

26. 26 Nanotube Shapes and Forces Avouris, 1999

27. 27 Biological Macromolecules - Collagen Brennan, 2000

28. 28 Biological Macromolecules - Fibronectin Brennan, 1999

29. 29 INTERROGATING ATOMS AND NANOSCALE OBJECTS

30. 30 Visualizing the Tunnel Junction STM-TEM Naitoh, 1996

31. 31 Scanning Ohnishi, 1998

32. 32 Bias-dependent imaging ~ Graphite DiNardo

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

34. 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. 35 Electronic Spectroscopy Atom 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. 36 Defects Atomic-sized defects –Al/Si(111)-√3  √3 structure –different electronic states Hamers, 1988

37. 37 Chemical Reactivity NH 3 reacted with the Si(111)-7  7 surface Wolkow, 1988

38. 38 Vibrational Spectroscopy Molecule by Molecule Lauhon, 2000

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

40. 40 Surface Diffusion Chasing Atoms with the Atom Tracker Swartzentruber, 1996

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

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

43. 43 Scanning Capacitance Microscopy Nakakura, 1999

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

45. 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. 46 Carbon Nanotube Tips - Functionalization - Wong, 1998

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

48. 48 Adhesion Forces Wong, 1998

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

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

51. 51 nN Bond Forces Strength of a Covalent Bond Grandbois, 1999

52. 52 Ballistic Electron Emission Microscopy - BEEM Three-terminal setup Probe potential barrier at interface between metal and semiconductor Electrons are forward-focused without scattering (ballistic)

53. 53 BEEM Bell, 2000

54. 54 MANIPULATING ATOMS AND NANOSCALE OBJECTS

55. 55 Moving Atoms Xe –Physisorbed noble gas - (low temperature) Fe –Quantum “Corrals” Eigler, 1991 / Crommie, 1993

56. 56 Confined Electrons Reflections of free electron (waves) at boundaries Standing waves solutions One-dimensional free electron solution (infinite barrier)

57. 57 Quantum Corral Crommie, 1993

58. 58 Forming Nanowires Ohnishi, 1998

59. 59 Nanowire modeling Okamoto, 1999

60. 60 Measuring Currents through One- and Two-atomic-row Nanowires Ohnishi, 1998

61. 61 Nanoelectronics Nanoscale channels Nanoscale objects Currents - description based on quantum- mechanical transport

62. 62 Nanoscale patterning Desorption –H-terminated Si(100) Deposition –Fe(CO) 5 Adams, 1996

63. 63 Nanotube Circuits Avouris, 1999

64. 64 Nanotube FET Martel, 1998 / Avouris, 1999

65. 65 Diamond-like Carbon Films STMAFM Mercer, 1996

66. 66 Protein-folding Forces Rief, 1999

67. 67 Comparison of Force Curves Rief, 1999

68. 68 Related Techniques Scanning Near-field Optical Microscopy Scanning Thermal Microscopy

69. 69 Some Acronyms... STM STS AFM TM-AFM FFM, LFM CFM