EEE 537
Semiconductor Optoelectronics
Cun-Zheng Ning, Professor
School of Electrical, Computer and Energy
Engineering (ECEE)
Arizona State University
State University
Office: GWC 614
Tel: 480-965-7421
Email: [email protected]
Group Webpage: http:/nanophotonic
Band Structure Engineering by Heterostructuring:
Quantum Wells
aGaAs = 5.65 A
a AlAs = 5.66 A
Mismatch parameter < 0.2%
AlAs / GaAs / AlAs
Could be more general:
Al x Ga1 x As / Al y Ga1 y As / Al xGa1 x As
y<x
1
Bandgap can be engineered
through x and y
Electronic States of Semiconductors
Vacuum level
e
Eg
Ek
k
Valence band: Top most, fully filled band at T=0
Conduction band: Bottom most empty band at T=0
Affinity: from vacuum level to the bottom of
conduction band
valence band can be filled up? Due t
Brief Review of Quantum Mechanics
Wave-particle duality
Schroedinger equation for free particles, in a periodic lattice
equation for free particles in periodic lattice
Effective masses
Bandstructure examples
examples
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EEE537 Fall 2010 ECEE ASU C.Z. Ning
Waveguide Theory Based on Wave Optics
Waveguides were discussed in terms of geometric optics
or ray optics (Snell law total reflection etc)
or ray optics (Snells law, total reflection etc)
Geometric or ray optics fails to describe certain optical
phenom
Chapter 3 Light Propagation in Waveguides
From infinitely large space to finite, restricted geometry;
fi
Guide (restrict) wave in one or two directions, while propagating
in the rest of direction (s): waveguides
Planar Waveguide/
Plasmonic slab waveguid
Wave Propagation Across
Wave Propagation Across
Interfaces
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EEE537 2010 Fall C.Z. Ning ECEE ASU
Boundary Conditions
r
D1
n
medium 1
r
D2
medium 2
S
h 0
r
r
S D dS = V dV
rr
B dS = 0
S
rr
n ( D1 D2 ) = s
rr
n ( B1 B2 ) = 0
s = lim(h )
Normal component o
Chapter 2: Light Propagation in Media
What is light has been evolving, in general EM wave propagation
Entire EM spectrum is described by the Maxwell equations
Semiconductors have been used to generate light (semiconductor
lasers and LEDs) in the wavele
Defects
Anything that breaks the original symmetry
Unavoidable
Affect electrical and optical properties (how?)
(h
Point defects involve isolated atoms in localized
defects
isolated atoms in localized
regions of a host crystal.
Line defects involve rows
Chapter 1: Materials for Optoelectronics
Anything
else ?
c2
Order in all ranges
Flow like a liquid
But with
orientational order
c1
SRO, and LRO in a
LRO
domain
No center
No center-of-mass order
order
Order (Symmetry) determines/dictates properties!
Galliu
El
Electrons and Holes in
Semiconductors
Semiconductors
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EEE537_Fall 2010 C.Z. Ning EECE ASU
Carrier Distributions: Fermi-Dirac Distribution
F-D Distribution: (Fermi and Dirac 1926, Jordan 1925):
Probability that a state of energy E is occupied by a Ferm