Building a more complex molecule C 2 Isolated impurities From E. A. Moore: “Molecular Modelling and bonding”, Royal Soc. Chem.

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

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

Isolated atoms Condensed Phase Conduction Band Valence Band Available States No States available 1/R E Building a Semiconductor Valence band Conduction band Isolated impurities 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. Localized states near impurities; These control the properties of the semiconductor

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=(  o /  ) 2 (m*/m o )E H 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.

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

Nano Technology/Materials Why interesting? Technological Applications (7 responses) How do we make things that small? (8 responses) Interface between quantum and classical realms. (3) Confinement energy becomes important (DVB) What would you like to hear more about? Quantum computing (7 responses) Applications in general (5 responses) life sciences (2) How to make them? (4 responses)

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

Lecture 32 Semiconductor Laser

The Field-Effect Transistor

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

Integer Quantum Hall Effect 1985 Nobel Prize Von Klitzing

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

Vorlesung Quantum Computing SS ‘08 15 ENIAC Electronic Numerical Integrator And Computer vacuum tubes weight 20 t, power consumption 150 kW 1946

Vorlesung Quantum Computing SS ‘08 16 Moore’s law

Vorlesung Quantum Computing SS ‘08 17 breaking the barrier? minimum size of chip components (nm) source: quantum effects in silicon technology barrier silicon year proteins, macro-molecules size of viruses and DNA semiconductor industry exponential extrapolation

Gold Nano-particles Color varies with particle size (red stained glass From the middle ages uses gold nano-particles)

Gold Nano-particles Color varies with particle size (red stained glass From the middle ages uses gold nano-particles)

Self-Assembly routes to nanomaterials

Discovery of the Neutron T&R Figure 12.1

Size of Nuclei T&R Figure 12.2 R = r o A 1/3

Closing a shell-> Stable atom

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

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

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

Trends in Nuclear Stability T&R Figure 12.5 See also Nudat2 at:

S-Process

Trends in Nuclear Stability T&R Fig. 12.6