Back to 460 Home
Calendar
Previous Lecture
Next Lecture

Phys 460 Lecture 21

( pdf version - 6 slides/page )
Wednesday, November 8, 2006
Lecturers: R. Martin and Prof. M. Nayfeh 		No new homework today

Reading:
Kittel, ch. 18, added material

Added Slides for presentation by M. Nayfeh
Semiconductor Nanostructures
Outline

  1. From previous lectures:
    • Part I: Crystal Structures, Diffraction, Reciprocal Lattice, Crystal binding
      Phonons, Dispersion curves, Thermal properties
    • Part II: Free electron gas, Energy bands for electrons in crystals Ekn, gaps, metals vs. insulators
    • Semiconductors
      • Effective mass, negative electrons and positive holes, doping
      • Semiconductor devices - inhomogeneous semiconductors
        • Variations of band energies, p-n junctions
        • Rectification; Light-emitting diodes; Solar cells
        • Bipolar Transistor n-p-n p-n-p
      • Semiconductor structures
        • Control semiconductor properties by voltages or material growth
        • Heterostructure formed of different semiconductor materials
  2. Today: Semiconductor nanostructures
    • Structures that confine electrons
    • "Electron in a box" - confined in all directions
  3. How small do structures need to be to exhibit quantum size effects
    • Estimate in terms of the effective mass
    • Typical energies
    • Experimentally made systems have important effects
  4. Special addition - Presentation by Prof. M. Nayfeh
    • Si nanoclusters - as small as Si29H36
    • Strong dependence on size - Very large changes in the gap compared to bulk Si
    • Typical energies
    • Absorption and emission of light - demonstration
    • Use in biological applications
Email clarification questions and corrections to rmartin@uiuc.edu
Email questions on solving problems to xin2@.uiuc.edu