Building a more complex molecule C 2

1. Building a more complex molecule C2 Isolated impurities From E. A. Moore: “Molecular Modelling and bonding”, Royal Soc. Chem.

2. Building a solid Graphite/Diamond Isolated impurities From W. A. Harrison: “Electron Structure” Royal Soc. Chem.

3. Building a metal (Copper) Isolated impurities From J. A. Burdick Phys. Rev. 129 138 (1963)

4. E 1/R Building a Semiconductor Fill up the states with electrons just like you fill up atomic or molecular states, fill from the lower energy up being careful to abide by Pauli. The material properties are dominated at by the highest energy states that are occupied. Isolated atoms Condensed Phase Conduction Band Available States No States available Valence Band Conduction band Localized states near impurities; These control the properties of the semiconductor Isolated impurities Valence band

5. Impurities in Semiconductors • “Electrons” in solids can behave as if they have a different mass and charge than free electrons. Why, the dynamics of the material are really determined by the “excitations” of the system (how it’s behaviour differs from the equilibrium state). • E.G. for Donors in Si you might expect E=(eo/e)2(m*/mo)EH • For Si this works out to be about 25meV, and this is in reasonable agreement with the experimental results for shallow donors (even though we have left out a lot of details that account for differences between elements like P and As etc.

6. Band structure and Impurties in Si and Ge From S. SM .Sze “Physics of Semiconductor devices”, Wiley (1969))

7. Nano Technology/Materials • Why interesting? • Technological Applications (7 responses) • How do we make things that small? (8 responses) • Confinement energy becomes important (DVB) • What would you like to hear more about? • Quantum computing (7 responses) • Applications in general (5 responses) life sciences (4) • Buckyballs/Carbon Nanotubes (5 responses) • How to make them? (4 responses)

8. Key Properties of Materials • Electrical Conductivity • Hall Effect (balance of Lorentz and Electric forces within a wire carrying a current in a magnetic field). • Useful for measuring carrier concentration and type (electrons vs. holes) • Ubiquitous for measuring magnetic fields • Thermo-electric Effects • Electrons carry both charge and energy, hence the two can be coupled. • Used widely for measuring temperature • Piezoelectric effects (strain<-> voltages) • Used in SPM’s, small sensors etc.

9. Lecture 32Semiconductor Laser http://www.explainthatstuff.com/laserdiode.png

10. The Field-Effect Transistor

11. Inside an Integrated Circuit Materials Science: Interdiffusion, anisotropic etching, electromigration, diff. therm. exp. From Mayer and Lau (1990) From T. N. Thies IBMJRD (2000) Condensed-matter Physics: Quantum Hall effects, quantum interference, non-local transport

12. Integer Quantum Hall Effect 1985 Nobel Prize Von Klitzing

13. Fractional QHE A very rich area of CMP for 2 decades, Anyons, Skyrmions, Coulomb drag … 1998 Nobel Prize Laughlin, Tsui, Stormer

14. Fractional QHE A very rich area of CMP for 2 decades, Anyons, Skyrmions, Coulomb drag … Take-home lesson: It’s the excitations (stupid!); the low-lying Excitations of a many- Particle system determine Its properties! 1998 Nobel Prize Laughlin, Tsui, Stormer

16. The Field-Effect Transistor

17. Photo-lithography (the birth of nano-tech) http://www.hitequest.com/Kiss/VLSI.htm

18. Inside an Integrated Circuit Materials Science: Interdiffusion, anisotropic etching, electromigration, diff. therm. exp. From Mayer and Lau (1990) From T. N. Thies IBMJRD (2000) Condensed-matter Physics: Quantum Hall effects, quantum interference, non-local transport

19. Fractional QHE A very rich area of CMP for 2 decades, Anyons, Skyrmions, Coulomb drag … Take-home lesson: It’s the excitations (stupid!); the low-lying Excitations of a many- Particle system determine Its properties! 1998 Nobel Prize Laughlin, Tsui, Stormer

20. ENIAC 1946 • Electronic Numerical Integrator And Computer • 17468 vacuum tubes • weight 20 t, power consumption 150 kW

21. Moore’s law http://www.intel.com/technology/mooreslaw/

22. size of viruses and DNA semiconductor industry exponential extrapolation minimum size of chip components (nm) ??e: proteins, macro-molecules quantum effects in silicon technology barrier silicon year source: breaking the barrier? We may be starting to see this flatten out, latest Intel processors are using a “32 nm” process, and they are planning for 22nm. Previous generations had used a “45nm” process. http://techreport.com/articles.x/18216

23. Gold Nano-particles Color varies with particle size (red stained glass From the middle ages uses gold nano-particles) http://www.meliorum.com/gold.htm?gclid=CObsuZfvlJ4CFQOdnAodoEl-qA

24. Gold Nano-particles Color varies with particle size (red stained glass From the middle ages uses gold nano-particles) http://www.nsec.ohio-state.edu/teacher_workshop/Gold_Nanoparticles.pdf For even more exciting applications see the Dragnea group site in IU Chem.: http://www.indiana.edu/~bdlab/research.html

25. Self-Assembly routes to nanomaterials

26. Nanostructures from Self-Assembly http://cae2k.com/photos-of-aloha-0/mcm-41.html http://igitur-archive.library.uu.nl/dissertations/2003-0325-143241/inhoud.htm This self-assembly can be used to make materials with molecular size control (e.g. MCM-41 and related silicates)

27. Discovery of the Neutron Chadwick (1932, building on earlier work by Both and Becker, and later I. Curie, and Joliot) demonstrated that the unknown radiation must have a mass of the same order as the proton by measuring the energy of recoil nuclei of various mass. T&R Figure 12.1

28. Size of Nuclei R = ro A1/3 T&R Figure 12.2

29. Trends in Nuclear Stability See also: T&R Fig. 12.6 Please note two things from this figure: The binding energy per nucleon peaks at 56Fe (CALM) Note the peaks at 4He 16O, and (to some extent) at 12C. http://www.tutorvista.com/physics/binding-energy-per-nucleon

30. 2 10 18 36 54 86 Closing a shell-> Stable atom, high ionization energy http://www.corrosionsource.com/handbook/periodic/periodic_table.gif

31. Magic numbers in Nuclei(protons) Note the sharp drop in separation energy at atomic numbers of 9, 21, 29,51, and 83 From E. Segre “Nuclei and Particles

32. Magic numbers in Nuclei(neutrons) From E. Segre “Nuclei and Particles

33. Shell model for Nuclei From E. Segre “Nuclei and Particles” Spherical Square well 3-D Harmonic Oscillator

34. Trends in Nuclear Stability T&R Figure 12.5 See also Nudat2 at: http://www.nndc.bnl.gov/nudat2/

35. Types of Radiation http://www.nndc.bnl.gov/nudat2/reColor.jsp?newColor=dm

36. Types of Radiation • Alpha (a): • 4He nucleus; very easy to stop (paper,etc.) • Beta (b) • Electrons or positions, relatively easy to stop • NOTE: you can also get high-energy electrons through “internal conversion” and the Auger process, but strictly speaking, these do not come from beta decay, and are therefore not, technically, “beta” particles (even though they behave exactly the same way). • Gamma (g) • High-energy photons (of nuclear origin) • X-rays • High-energy photons (of atomic origin) • Neutron (n) • Protons, ions

37. Types of Nuclear Decay • Alpha (a): • 4He nucleus; • Beta (b) • Electrons or positions, of nuclear origin • Electron Capture • Gamma (g) • (gamma, internal conversion do not change nucleons). • Spontaneous fission • proton • Neutron (n) http://library.thinkquest.org/3471/radiation_types.html

38. Examples • What is the binding energy per nucleon of 56Fe? • The mass of 12553I is 124.904624u and that of 12552Te is 124.904425 u. What decay mode is possible between these two nuclei?