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Advanced Semiconductor Physics

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Presentation on theme: "Advanced Semiconductor Physics"— Presentation transcript:

1 Advanced Semiconductor Physics
EE 698D Fall 2004 SUMMARY

2 Topics Covered Semiconductor Bandstructure & Effective Mass Approximation Phonons/Lattice Vibrations Electronic Transport Optical Properties Quantum Confined Structures & Device Applications

3 Semiconductor Bandstructure
Silicon GaAs GaN

4 Bandstructure – k.p Most of the action happens very close to the CB & VB edges k.p theory ideal to handle such cases From Notes

5 Bandstructure – more accurate methods
Empirical Pseudopotential Method LCAO methods Silicon GaAs

6 Phonons / Lattice Vibrations
Phonon Dispersion of a typical semiconductor

7 Transport – Depends on Bandstructure, Phonons, Defects
Example : GaN

8 Transport – Scattering and Velocity – field curves
Low-field: Mobility High field – Velocity Saturation, Optical Phonon emission

9 Table of Scattering Processes

10 Theoretical Formalism

11 Theoretical Formalism – Contd…

12 Theoretical Formalism – Contd…

13 Theoretical Formalism – Contd…

14 Transport in a Silicon MOSFET
Electron Distribution in k-space Electron Distribution in Real-Space

15 Ballistic Transport – Electrons as waves
Electrons flow and “diffract” like Waves on surface of water…

16 Optical Properties

17 Light in periodic structures…
Photonic Bandgap Crystals

18 Bandgaps for light…

19 Quantum Confined Structures

20 Quantum Confined Structures
Nanotubes – 1D (Quantum Wires) Epitaxial 0-D (Quantum Dots) Nanowire Superlattices Nanowire “Combs”

21 Bulk Semiconductor – Device Applications
Today’s HBT The First Transistor (1947) Today’s MOSFET

22 Quantum – Well Devices GaN HEMTs High-electron Mobility Transistors
GaAs Laser Diodes

23 Quantum Well Devices – GaN Solid State Lighting
Blu-Ray DVD (GaN QW Laser) White LEDs - The New Bulbs!

24 Superlattices – Device Applications
Quantum Cascade Lasers

25 (Based on optical transitions in organic QW- structures)
Quantum Well Devices : Organic Semiconductors Flexible Displays (Based on optical transitions in organic QW- structures)

26 Quantum Wire Device Applications
Nanowire Laser Arrays Nanotube FETs

27 Quantum Dot Applications
Nanocrystal (Quantum-Dot) Luminescence Spectra Quantum confinement changes emission wavelengths!

28 Uses quantum-dot dispersion
Quantum Dot Applications Today’s Nanocrystals Bio-Applications Stained Glass – Uses quantum-dot dispersion In Glass (19th-century)!

29 And Finally… The NEW Christmas Lights!
Hope you take away from this class the Excitement of this field …

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