2012 tus lecture 1

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  • 1. Nanoscience and Energy Allen Hermann, Ph.D. Professor of Physics Emeritus, University of Colorado Boulder, Colorado 80309-0390 USA allen.hermann@colorado.edu
  • 2. Lecture 1. Course Introduction and Definitions History, and examples in nature and man-made Quantum nature- theory: quantum confinement Nanomaterials: Dimensionality Chemical varieties and shapes Synthesis Top-down: Lithography Bottom-up: Self-assembly Characterization and Handling Measurements Nanotemplates
  • 3. Lecture 2. Nanocarbon C60, CNT’s Synthesis and e-beam lithography Graphene (synthesis, relativistic QM nature, transport)
  • 4. Lecture 3. Energy and Nanotechnology Review of Alternate Energy Sources Review of Electronic Properties of Solids: Free- electron Fermi gas Energy bands in Solids Semiconductors and doping pn junctions Amorphous semiconductors
  • 5. Lecture 4. Solar cells: Motivation (examples) and Theory pn junctions under illumination Homojunctions Open-circuit voltage, short- circuit current IV curve, fill factor, solar-to- electric conversion efficiency Carrier generation and recombination Defects and minority carrier diffusion Current due to minority carrier diffusion: Solution to the diffusion differential equation under Spatially-homogeneous generation, and under Inhomogeneous generation Effect of an electric field Heterojunctions
  • 6. Lecture 5. Experiment: Types of Solar Cells•Generation I solar cells:Single Crystal Si, Polycrystalline SiGrowth, impurity diffusion, contacts, anti-reflection coatings•Generation II Solar cells:Polycrystalline thin films, crystal structure, deposition techniquesCdS/CdTe (II-VI) cellsCdS/Cu(InGa)Se2 cellsAmorphous Si:H cells•Generation III Solar Cells:•High-Efficiency Multijunction Concentrator Solar cells based onIII-V’s and III-V ternary analogues•Dye-sensitized solar cell•Organic (excitonic) cells•Polymeric cells•Nanostructured Solar Cells including Multicarrier per photon cells,quantum dot and quantum-confined cells
  • 7. Lecture 6. Nanotechnology Fuel Cells Nano-composite materials Nanoelectronics and photonic Devices: Chemical and Biological Detectors Nanomedicine: Disease Detection Implants Delivery of Therapeutics Other nanomedicine Applications Risks
  • 8. Lecture 7. Other Nanotechnology Applications DNA sequencing Filtration Clothing and Sports Composites Other Nanomedicine Applications and Opportunities Other Nanotemplate-based Applications: Superconductors Magnetic Nanowires Ferroelectrics Dielectric Nanostructures and Cloaking The Business of Nanotechnology
  • 9. Basis for Grade in the CourseYour grade in the course is based on 2 factors: 1) class attendance 2)grade earned on the paper assigned.
  • 10. A 1-2 page paper in English is to be turned in to Prof. Hermann by the end of the last lecture. Both a hard copy and a digital copy emailed to allen.hermann@colorado.edu are required. This paper should be in your own words.The paper could contain one or more figures and/or tables. The subject matter should be either 1) a tutorial explaining clearly one topic from thiscourse (in greater detail than given in the course), or 2) a clear description of your own research related to the subject of this course.
  • 11. Your grade will be calculated as follows:Attendance- 40% ( 5.71 % per class attended)Grade for paper- 60%
  • 12. Further References1. Charles Kittel, “Introduction to Solid State Physics”, Prentice Hall(1967 ff.)2. S.M. Sze, “Physics of Semiconducting Devices”, John Wiley (1969,ff.)3.Frank Larin, “Radiation Effects in Semiconducting Devices” (JohnWiley)4. H.Y. Tada and J.R. Carter, JPL Solar cell Radiation handbook, NASA(1977)5. Martin Green, “Solar Cells”, Prentice Hall (1982,ff.)6. H.J. Hovel, “Solar Cells”, in Semiconductors and Semimetals, Vol.11(edited by R. Richardson and A. Beer, Academic Press, 1975).7. J. Reynolds and A. Meulenberg, J.Appl. Phys. 45, 2582(1974)
  • 13. Lecture 1Course Introduction and Definitions
  • 14. Lecture 1. Course Introduction and Definitions History, and examples in nature and man-made Quantum nature- theory: quantum confinement Nanomaterials: Dimensionality Chemical varieties and shapes Synthesis Top-down: Lithography Bottom-up: Self-assembly Characterization and Handling Measurements Nanotemplates
  • 15. 10,000 Kilometers
  • 16. 1000 km
  • 17. Sliding scale universe:http://htwins.net/scale2/scale2.swf?bordercolor=white
  • 18. What is Nanotechnology?• Research and technology development at the atomic, molecular or macromolecular levels, in the length scale of approximately 1 - 100 nanometers.• Creating and using structures, devices and systems that have novel properties and functions because of their small and/or intermediate size.• Ability to control processes at a few nm-range for advanced material processing and manufacturing.
  • 19. The Scale of Things – Nanometers and More Things Natural Things Manmade 10-2 m 1 cm 10 mm Head of a pin 1-2 mm The Challenge Ant 1,000,000 nanometers = ~ 5 mm 10-3 m 1 millimeter (mm) Microwave MicroElectroMechanical Dust mite (MEMS) devices 10 -100 mm wide 200 mm 10-4 m 0.1 mm 100 mm Microworld Fly ash Human hair ~ 10-20 mm~ 60-120 mm wide O P O O -5 10 m 0.01 mm O O O O 10 mm O O O O O O O O Pollen grain Red blood cells O O O O O O O O Infrared S S S S S S S S Red blood cells (~7-8 mm) Zone plate x-ray “lens” 1,000 nanometers = 10-6 m 1 micrometer (mm) Outer ring spacing ~35 nm Visible Fabricate and combine nanoscale building blocks to make useful 10-7 m 0.1 mm devices, e.g., a 100 nm photosynthetic reaction Ultraviolet center with integral semiconductor storage. Nanoworld Self-assembled, 0.01 mm Nature-inspired structure 10-8 m Many 10s of nm ~10 nm diameter 10 nm Nanotube electrode ATP synthase 10-9 m 1 nanometer (nm) Carbon buckyball Soft x-ray ~1 nm diameter Carbon nanotube ~1.3 nm diameter DNA 10-10 m Quantum corral of 48 iron atoms on copper surface 0.1 nm ~2-1/2 nm diameter Atoms of silicon positioned one at a time with an STM tip spacing ~tenths of nm Corral diameter 14 nm
  • 20. My Personal Early Nanotechnology Motivation
  • 21. Li+Li PVP-I CT LiI complex
  • 22. 20 nm nanorods of MnO2 for positive electrodes in Li ion batteries
  • 23. • Quantum Confinement • One Dimension
  • 24. • Quantum Confinement • Three Dimensions
  • 25. For absorption, energy of photon absorbed goes as 1/L2, smaller particle absorbs larger energy photon, who’s wavelengthis smaller (toward blue), and longer wavelength photons (toward red) are transmitted.
  • 26. Figure 7.2. Solutions of quantum dots of varying size. Note the variation in color of each solution illustrating the particle size dependence of theoptical absorption for each sample. Note that the smaller particles are in the red solution (absorbs blue), and that the larger ones are in the blue (absorbs red).
  • 27. For light scattering, the photon wavelength must besmaller than the particle size, and the smaller particles tend to scatter only the shorterwavelength photons (toward blue)
  • 28. .Nanomaterials• C. Dimensionality• D. Chemical varieties• E. Shapes• F. Synthesis – 1. Lithography – 2. self-assembly
  • 29. • Synthesis1. Lithography
  • 30. Exposing Radiation Polymer Resist Thin Film Substrate Positive Negative Developing Resist Resist Etching and StrippingFigure 1.1. Schematic of positive and negative resists.
  • 31. Figure 1.6. Schematic of a focused ion beam system.
  • 32. Carbon Nanotubes/Nanocones with Various Catalyst Patterning Dimensionsby E-beam Lithography 30 0n 40 m 0n 1m 12 m1 0n m 60 m 20 60 nm 0n nm 80 m nm 10 0n m nm 100
  • 33. Figure 2.1. The process of forming a self-assembled monolayer. Asubstrate is immersed into a dilute solution of a surface-activematerial that adsorbs onto the surface and organizes via a self-assembly process. The result is a highly ordered and well-packedmolecular monolayer. (Adapted from Ref. 9 by permission ofAmerican Chemical Society.)
  • 34. .Characterization and Handling – a. Optical Tweezers – b. Electromagnetic tweezers – c. In nanotemplates – d. Structural Analysis by TEM, SEM, X-ray, etc.
  • 35. Ballistic Nanotube MOS Transistors (Chen,Hastings)Placement of Nanotubes by E-Field D Nanotube Field-Effect Transistor(FET) (The first-demo) Al-Gate SWNTL Drain Source d HfO2 W L Ti SiO2 L~20 nm E-Beam Lithography
  • 36. • Measurements
  • 37. Coarse approach mechanism Reference S c a feedback n n data - e r Signa l Sensor Sample Figur e 3.1. Schematic showing all major components of an SPM. In this example, feedback is used major components all to move the sensorFigure 3.1. Schematic showingmaintain a constant signa l. of an SPM. In vertically tothis example, feedback is used to movethe sensor is taken Vertical displacement of the sensor vertically to as topograph ical data.maintain a constant signal. Vertical displacement of the sensor istaken as topographical data
  • 38. Clean Room Major equipmentPhotolithography Plasma Enhanced • Focused Ion Beam System (FIB) (scheduled for installation in mid 2007) Chemical • Atomic Layer Deposition System (ALD) Vapor • Rapid Thermal Processing System (RTP) • Plasma Enhanced Chemical Vapor Deposition System (PECVD) Deposition • Standard Resolution Electron Beam Lithography (EBL) • Atomic Force Microscope for Nanopatterning, and Manipulation (AFM) • Atomic Force Microscope for Atomic Resolution Imaging (AFM) • Quartz Crystal Microbalance (QCM) • 4-furnace bank of 3-zone oxidation, dopant diffusion, and annealing furnaces • Class 100 Clean Room • Spin-Coating Station • Photolithography System • Surface Profiler Reactive Ion Etching • Chemical Treatment Station (cleaning, etching, and functionalization) • Ion Milling System • Plasma Cleaning/Oxidation System • Gas Cabinet Bank • Experimental Materials Thermal Evaporator • Standard Materials Thermal Evaporator • Electron-Beam Evaporator • Multi-target Sputtering System • Probe Station and Device Characterization System • Four-Point Resistance Measurement System Atomic • Ellipsometer Layer • Optical Microscopes Deposition • Dicing Saw Quartz MicroBalance • Equipment Cooling Systems (3) • Inductive Coupled Plasma (ICP) Etching System (scheduled for installation in Feb. 2006) • Experimental materials sputtering system (scheduled for installation in mid 2006) • Ultra-High Resolution EBL and SEM System Rapid Thermal Processing
  • 39. IV. Nanotemplates• G. Inorganic• H. Organic
  • 40. Fig.2 (a) Nanostructure of anodically formed Al2O3 template. (b) its cross-section,(c) catalyst deposited at the bottom of the pores, (e) vertically aligned nanotubes, and (f) TEM image of a nanotube.
  • 41. Nano-scale Material Research (Chen, Singh, DeLong, Saito, Yang, Bhattacharyya, and Sumanasekeras) The first vertically aligned nanotubes on silicon substrates using templates 200nm (b)200 nm (d) Nano-template Catalyst(a) (c) Hexagonal Cells SiO2 Al SiO2 Vertically aligned MWNTsHorizontallyaligned embedded in AAO insulator SiO2 Si substrate Carbon nanotubes
  • 42. • Fig. 3 Schematic representing the helix-coil transitions within the pore of a Poly-L-Glutamic Acid functionalized membrane (a) random-coil formation at PH > 5.5 , (b) helix formation at low pH ( <4 ).