My Encounter with
NANOTECHNOLOGY
Hardev Singh VIRK
Visiting Professor
Sri Guru Granth Sahib World
University, Fatehgarh Sa...
Birth of Nanotechnology
“There's Plenty of Room at the Bottom”
• On December 29, 1959, Richard P. Feynman
gave the seminal...
Changing Idea into Reality
Eric Drexler of MIT, the Chemist, established
the modern field of nanotechnology, with a
draft ...
NANO
•

“NANO” means “DWARF” in Greek.

•

Mathematically nano is ten to the power of minus nine …….. Make sense?

•

If t...
• AFM Imaging of ATOMS of GOLD (Au 111)
Atomic Lattice Structure of HOPG in 3D
Topography using Atomic Force Microscope
The Incredible Tininess of Nano
The pinhead
sized dot is a
million nm

Billions of nanometers
A two meter tall male is
two...
Why Study Nanomaterials?
• Nanostructures (< 30 nm) have become an
exciting research field.
• – New physics phenomena affe...
Quantum Confinement Effects
– Quantum dots (0-D): confined states, and no
freely moving ones
– Nanowires (1-D): particles ...
Routes to Nanotechnology
• Physical, chemical, biological and nature’s self
assembly.
• Top-down and bottom-up approaches....
My Route to Nanotechnology
• Ion Track Technology Route using Heavy Ion
Beams from GSI, Darmstadt & JINR, Dubna.
• Chemica...
UNILAC at GSI Darmstadt (Germany)
Ion Track Technology
• Ion Track Technology [1] was developed at GSI,
Darmstadt. Ion Track Filters (ITFs) or Tracketched m...
Ion Tracks as Structuring Tools
• Ion tracks are created when high-energetic heavy
ions with energy of about 1 MeV/nucleon...
Latent Pb-Ion Tracks in Mica
Size of Etched ION Tracks
Large Etched Ion Tracks
Nanowire Fabrication
 Template synthesis using polymer and anodic
alumina membranes
 Electrochemical deposition

 Ensur...
Polymer Template Synthesis of
Nanowires
Anodic Alumina Template Preparation
 Anodization of aluminum
 Start with uniform layer of ~1µm Al
 Al serves as the ano...
Anodic alumina (Al2O3) Template

(T. Sands/ HEMI group http://www.mse.berkeley.edu/groups/Sands/HEMI/nanoTE.html)

alumina...
Electrolytic Cell
Replica of Nanowires
Microtubule Fabrication
Electrochemical Synthesis
• Electrochemistry has been used to fabricate
nanowires and heterojunctions of Cu, Cu-Se
and Cd-...
Template Synthesis of Copper
Nanowires
The concept of electro-deposition of metals is an
electrochemical process. The etch...
AFM image of hexagonal pores of
Anodic Alumina Membrane (AAM)
SEM Images of Cu Nanowires using
Electrodeposition Technique
Copper Nanowire Bundles in AAM
Cu Nanowires under Constant Current
Capping Effect of Current Variation
A Garden of Copper Nanoflowers
Copper Nanoflowers grown in Polymer
Template (100nm pores)
Copper Lillies grown due to overdeposition of Copper in AAM
Copper Marigold Flower
SEM micrograph of Nanocrystals of
Polycrystalline Copper
10
20
30
40
50

Position [°2Theta] (Copper (Cu))
60
7 4.29 9 [ °]

6 4.80 9 [ ° ]

KK1
5 0.58 0 [ ° ]

Counts

54 .3 04 [ ...
XRD spectrum of Cu nanowires
Counts
Cu polycrystalline

1600

400

0
30

40

50

60

70

Position [°2Theta] (Copper (Cu))
...
SEM Image of CdS Nanowires
HRTEM image showing CdS Nanowire
& Heterojunctions
I-V plot of CdS Nanowire arrays
showing RTD characteristics
SEM image of Cu-Se Nanowires
Cu-Se nanowires exhibit p-n junction
diode characteristics
A Billion Dollar Question …
• What can nanowires offer for semiconductor
nanoelectronics?
• Nonlithographic & extremely co...
Advantages of 1-D Nanowires
• High-quality single-crystal wires with nearly
perfect surface
• Scalable nanostructure with ...
Nanowire Field-Effect Transistor
A single device for numerous applications
Device physics study
• Ambipolar transport
• Ca...
Role of Nanowires for NextGeneration Electronics
• The chemical and physical characteristics of
nanowires, including compo...
Some Observations & Remarks
• Nanotechnology will be the driving force for
next technology revolution.
• Nanowires open do...
Reverse Miceller Route
Nanoparticle Synthesis (ME route)
TEM images of Barium Carbonate
Nanorods
TEM images of Iron Oxalate and
Barium Oxalate Nanocrystals
TEM image of CdO Quantum Dots
Conversion of Quantum Dots of CdO
to Nanorods using EDA
CdS Nanocrystals(CTAB+n-butanol)
CdS Nanoneedles(CTAB+nhexanol)
Ba-M Hexaferrite Crystals (ME)
Ba-M Hexaferrite Crystals (CP)
Ba-hexaferrite ME(after
calcination)
Ba-hexaferrite CP(after calcination)
Hysteresis loops of Ba-hexaferrite
nanoparticles (CP & ME samples)
SEM image of ZnO Nanocrystals in
Ethanol and Nanorod(adding EDA)
TEM image of Ag quantum dots and
embedded nano particles
Thank You !!!
My encounter with nanotechnology
My encounter with nanotechnology
My encounter with nanotechnology
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My encounter with nanotechnology

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This Presentation is based on our Research work carried out in GNDU Amritsar and DAVIET, Jallandhar. We fabricated Ion track filters; nanowires and some Exotic Patterns for the first time in India using simple Techniques.

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My encounter with nanotechnology

  1. 1. My Encounter with NANOTECHNOLOGY Hardev Singh VIRK Visiting Professor Sri Guru Granth Sahib World University, Fatehgarh Sahib (Pb.)India
  2. 2. Birth of Nanotechnology “There's Plenty of Room at the Bottom” • On December 29, 1959, Richard P. Feynman gave the seminal talk at a meeting at Caltech of the American Physical Society. He presented a vision of the precise manipulation of atoms and molecules so as to achieve amazing advances in information technology, mechanical devices, medical devices, and other areas.
  3. 3. Changing Idea into Reality Eric Drexler of MIT, the Chemist, established the modern field of nanotechnology, with a draft of his seminal Ph.D. thesis in the mid 1980s. His 1991 doctoral thesis at MIT was revised and published as the book "Nanosystems, Molecular Machinery Manufacturing and Computation" (1992), which received the Association of American Publishers award for Best Computer Science Book of 1992.
  4. 4. NANO • “NANO” means “DWARF” in Greek. • Mathematically nano is ten to the power of minus nine …….. Make sense? • If the size of your shoe was one nano meter, then a meter would be the distance that you would cover round the world and the sun and back. • One hydrogen atom is 0.1nm. Five atoms of carbon would occupy a space of about 1 nm wide. • The nano world comes just after the femto world (10-15 m) of NUCEI and pico world (10-12m) of atoms. • The nano marks the boundary between the classical and quantum mechanical worlds • Most of the bulk substances behave differently from nanosize particles. A coin of gold is golden yellow in color, but nanoscale gold is red; bulk gold is inert, but nanogold can be a catalyst for chemical reactions.
  5. 5. • AFM Imaging of ATOMS of GOLD (Au 111)
  6. 6. Atomic Lattice Structure of HOPG in 3D Topography using Atomic Force Microscope
  7. 7. The Incredible Tininess of Nano The pinhead sized dot is a million nm Billions of nanometers A two meter tall male is two billion nanometers. DNA Molecules are about 2.5 nm in width Biological cells size is Thousands of nm Hydrogen atom spans 0.1 nm 2 Uranium atoms span 1 nm
  8. 8. Why Study Nanomaterials? • Nanostructures (< 30 nm) have become an exciting research field. • – New physics phenomena affect physical properties. • – Unusual quantum effects and structural properties. • – Promising applications in optics, electronics, thermoelectric, magnetic storage, NEMS (nano-electro-mechanical systems).
  9. 9. Quantum Confinement Effects – Quantum dots (0-D): confined states, and no freely moving ones – Nanowires (1-D): particles travel only along the wire direction – Quantum wells (2-D): confines particles within a thin layer There is no confinement effect in Bulk materials. Refer to energy distribution.
  10. 10. Routes to Nanotechnology • Physical, chemical, biological and nature’s self assembly. • Top-down and bottom-up approaches. • Chemical route to nanotechnology is simpler, cheaper and allows fabrication at bench top conditions. • Reverse micelles (microemulsions route) is a versatile method to produce a variety of nanoparticles.
  11. 11. My Route to Nanotechnology • Ion Track Technology Route using Heavy Ion Beams from GSI, Darmstadt & JINR, Dubna. • Chemical Route of Reverse micelles, coprecipitation, solvo-thermal, sol-gel and seed growth techniques. • Quantum dots, nanorods and nanoneedles of Barium Carbonate, Barium Oxalate, Iron Oxalate, Barium hexaferrite, Zinc Oxide, Cadmium Sulphide, Cadmium Oxide and Silver prepared.
  12. 12. UNILAC at GSI Darmstadt (Germany)
  13. 13. Ion Track Technology • Ion Track Technology [1] was developed at GSI, Darmstadt. Ion Track Filters (ITFs) or Tracketched membranes became precursors to development of nanotechnology during 1990s. ITFs were prepared by bombardment of thin polymer foils using heavy ions. One of the first applications of ITFs was separation of cancer blood cells from normal blood by making use of Nuclepore filters. Author’s group used heavy ion beam facility available at GSI UNILAC, Darmstadt during 1980s for Ion Beam Modification of Materials and to prepare ITFs in our laboratory. • [1] R. Spohr: Ion Tracks and Microtechnology: Principles and Applications (Vieweg Publications, Weisbaden Germany, 1990
  14. 14. Ion Tracks as Structuring Tools • Ion tracks are created when high-energetic heavy ions with energy of about 1 MeV/nucleon (e.g. 140 MeV Xe ions) pass through matter. The extremely high local energy deposition along the path leads to a material transformation within a narrow cylinder of about 10 nm width. Unlike in the more conventional lithographic techniques based on ion or electron beam irradiation, a single heavy ion suffices to transform the material.
  15. 15. Latent Pb-Ion Tracks in Mica
  16. 16. Size of Etched ION Tracks
  17. 17. Large Etched Ion Tracks
  18. 18. Nanowire Fabrication  Template synthesis using polymer and anodic alumina membranes  Electrochemical deposition  Ensures fabrication of electrically continuous wires since only takes place on conductive surfaces  Applicable to a wide range of materials  High pressure injection  Limited to elements and heterogeneously-melting compounds with low melting points  Does not ensure continuous wires  Does not work well for diameters < 30-40 nm  Chemical Vapor Deposition (CVD) or VLS technique  Laser assisted techniques
  19. 19. Polymer Template Synthesis of Nanowires
  20. 20. Anodic Alumina Template Preparation  Anodization of aluminum  Start with uniform layer of ~1µm Al  Al serves as the anode, Pt may serve as the cathode, and 0.3M oxalic acid is the electrolytic solution  Low temperature process (2-50C)  40V is applied  Anodization time is a function of sample size and distance between anode and cathode  Key Attributes of the process (per M. Sander)  Pore ordering increases with template thickness – pores are more ordered on bottom of template  Process always results in nearly uniform diameter pore, but not always ordered pore arrangement  Aspect ratios are reduced when process is performed when in contact with substrate
  21. 21. Anodic alumina (Al2O3) Template (T. Sands/ HEMI group http://www.mse.berkeley.edu/groups/Sands/HEMI/nanoTE.html) alumina template Si substrate 100n m (M. Sander)
  22. 22. Electrolytic Cell
  23. 23. Replica of Nanowires
  24. 24. Microtubule Fabrication
  25. 25. Electrochemical Synthesis • Electrochemistry has been used to fabricate nanowires and heterojunctions of Cu, Cu-Se and Cd-S. The results of our investigations can be exploited for fabrication of nanodevices for application in opto-electronics and nanoelectronics. During failure of our Experiments, exotic patterns ( nanoflowers, nanocrystals, nanobuds) were produced under nature’s self assembly.
  26. 26. Template Synthesis of Copper Nanowires The concept of electro-deposition of metals is an electrochemical process. The etched pores of ITFs used would act as a template. The electrolyte used here was CuSO4.5H2O acidic solution. The rate of deposition of metallic film depends upon: current density, inter-electrode distance, cell voltage, electrolyte concentration, pH value and temperature etc. In our case, electrode distance was kept 0.5 cm and a current of 2mA was applied for 1 hour. The developed microstructures were scanned under SEM for morphological and structural studies.
  27. 27. AFM image of hexagonal pores of Anodic Alumina Membrane (AAM)
  28. 28. SEM Images of Cu Nanowires using Electrodeposition Technique
  29. 29. Copper Nanowire Bundles in AAM
  30. 30. Cu Nanowires under Constant Current
  31. 31. Capping Effect of Current Variation
  32. 32. A Garden of Copper Nanoflowers
  33. 33. Copper Nanoflowers grown in Polymer Template (100nm pores)
  34. 34. Copper Lillies grown due to overdeposition of Copper in AAM
  35. 35. Copper Marigold Flower
  36. 36. SEM micrograph of Nanocrystals of Polycrystalline Copper
  37. 37. 10 20 30 40 50 Position [°2Theta] (Copper (Cu)) 60 7 4.29 9 [ °] 6 4.80 9 [ ° ] KK1 5 0.58 0 [ ° ] Counts 54 .3 04 [ ° ] 5 4.95 6 [ ° ] 48 .9 20 [ ° ] 45 .448 [ ° ] 43 .4 61 [ ° ] 38.2 83 [ °] 3 6.63 7 [ ° ] XRD Spectrum of polycrystalline Copper nanocrystals 60000 40000 20000 0 70
  38. 38. XRD spectrum of Cu nanowires Counts Cu polycrystalline 1600 400 0 30 40 50 60 70 Position [°2Theta] (Copper (Cu)) 80 90
  39. 39. SEM Image of CdS Nanowires
  40. 40. HRTEM image showing CdS Nanowire & Heterojunctions
  41. 41. I-V plot of CdS Nanowire arrays showing RTD characteristics
  42. 42. SEM image of Cu-Se Nanowires
  43. 43. Cu-Se nanowires exhibit p-n junction diode characteristics
  44. 44. A Billion Dollar Question … • What can nanowires offer for semiconductor nanoelectronics? • Nonlithographic & extremely cost-effective • Reduced phonon scattering: High carrier mobility but reduced thermal conductance(?) • Tunable electrical/optical properties • Large surface-to-volume ratio: Sensor sensitivity & memory programming efficiency
  45. 45. Advantages of 1-D Nanowires • High-quality single-crystal wires with nearly perfect surface • Scalable nanostructure with precisely controlled critical dimensions • Best cross-section for surround-gate CMOS • Very cost-effective materials synthesis • High transport low-dimensionality structure • May use as both device and interconnect for ultra-compact logic (e.g., SRAM)
  46. 46. Nanowire Field-Effect Transistor A single device for numerous applications Device physics study • Ambipolar transport • Carrier mobility study • Quantum effect
  47. 47. Role of Nanowires for NextGeneration Electronics • The chemical and physical characteristics of nanowires, including composition, size, electronic and optical properties, can be rationally controlled during synthesis in a predictable manner, thus making these materials attractive building blocks for assembling electronic and optoelectronics nanosystems.
  48. 48. Some Observations & Remarks • Nanotechnology will be the driving force for next technology revolution. • Nanowires open door to a wonderland where the next generation electronics would emerge. • Scope for innovating new synthesis method and complex functional nanostructures. • New device and interconnect concepts will emerge from horizon, driven by materials synthesis.
  49. 49. Reverse Miceller Route
  50. 50. Nanoparticle Synthesis (ME route)
  51. 51. TEM images of Barium Carbonate Nanorods
  52. 52. TEM images of Iron Oxalate and Barium Oxalate Nanocrystals
  53. 53. TEM image of CdO Quantum Dots
  54. 54. Conversion of Quantum Dots of CdO to Nanorods using EDA
  55. 55. CdS Nanocrystals(CTAB+n-butanol)
  56. 56. CdS Nanoneedles(CTAB+nhexanol)
  57. 57. Ba-M Hexaferrite Crystals (ME)
  58. 58. Ba-M Hexaferrite Crystals (CP)
  59. 59. Ba-hexaferrite ME(after calcination)
  60. 60. Ba-hexaferrite CP(after calcination)
  61. 61. Hysteresis loops of Ba-hexaferrite nanoparticles (CP & ME samples)
  62. 62. SEM image of ZnO Nanocrystals in Ethanol and Nanorod(adding EDA)
  63. 63. TEM image of Ag quantum dots and embedded nano particles
  64. 64. Thank You !!!
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