Solid line:

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Solid line direct bandgap materials Dotted
line indirect bandgap materials
Matched system to reduce the strain effect and
epitaxial growth defects!
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III-V Material systems with important
optoelectronic applications
Materials substrate Lattice matched
Important strained Main optoelectronic system
members
members applications
AlGaAs GaAs GaAs
Ga1-xInxAs Emitter and modulators
AlxGa1-xAs
0 ? x ? 0.25 0.75 ?m ? ? ? 1.1
?m AlAs

Detectors

0.4 ?m ? ? ? 1.1 ?m GaInAsP InP
Ga0.47In0.53As Ga1-xInxAs
Optoelectronic devices /InP
GaxIn1-xAsyP1-y 0.4 ? x ? 0.6
at ? 1.3 ?m and
x0.47y 0 ?y? 1
InAsxP1-x ? 1.55
?m InP
0 ? x ? 0.2 AlGaInAs InP
Ga0.47In0.53As Ga1-xInxAs
Optoelectronic devices /InP
(AlxGa1-x)0.47In0.53As 0.4 ? x ? 0.6
at ? 1.3 ?m and
0 ? x ? 1
? 1.55 ?m
Al0.48In0.52As AlGaInP GaAs
GaAs Ga1-xInxAs
Red emitter
Ga0.5In0.5P 0 ? x ? 0.25
(AlxGa1-x)0.5In0.5P
Ga1-xInxP 0 ?
x ? 1 0.4 ? x ? 0.6
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III-V Material systems with important
optoelectronic applications
Materials substrate Lattice matched
Important strained Main optoelectronic system
members
members applications
AlGaAsSb GaSb GaSb
Emitter and
Detectors /GaInAsSb
AlxGa1-xAsySb1-y
? 2-3 ?m /GaSb x
12y 0? x ?1
AlxIn1-xAsySb1-y
x 1.1y 0? x ?1 GaAsP GaAs
GaAs GaAsP
Visible LEDs InP
GaP
? Quantum Wells and Strained Materials
The Optical properties of a semiconductor
are altered by quantum size effects at
least one of the dimensions of material
is on the order of De Broglies
wavelength of an electron ? h/p if p eV gt
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? AlGaAs Materials system
GaAs direct bandgap materials AlAs indirect
bandgap materials
E? direct bandgap EX indirect bandgap
For effective light emission the x lt 0.4in
GaxAl1-xAs
Refractive index of GaxAl1-xAs
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? AlGaInP Materials system main
application is red diode lasere
RT Eg, refractive index, and absorption
coefficient of (AlxGa1-x)0.52In0.48As (match GaAs)
EX indirect
E? direct
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? GaSb Materials system two quaternaries,
AlGaAsSb, GaInAsSb lattice matched to
GaSb substrate ? AlxGa1-xAsySb1-y
(GaSb)x(AlAs0.083Sb0.917)1-x ?
Ga1-xInxAsySb1-y (GaSb)1-x(InAs0.911Sb0.089)x
RT Eg of AlxGa1-xAsySb1-y and Ga1-xInxAsySb1-y a
t RT and x 0, EL (indirect) gt? E? gt GaSb is
barely a direct bandgap materials!
AlxGa1-xAsySb1-y is nearly indirect in the whole
range!
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? GaAsP Materials system
RT Eg of GaAsxP1-x Crossover of direct- indirect
is x 0.5
Absorption coefficient of GaAsxP1-x
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Energy gaps and lattice constants for cubic group
IV, III-V, and II-VI semiconductors.
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? SiC and GaN as optoelectronic Materials
? The need to operate devices at high temperature
gt studies of wide bandgap
semiconductors (SiC, GaN, and diamond)
? The need for denser optical storage (light
with shorter wavelength) gt blue laser
or even UV laser (AlGaN).
Zinc-blende and wurtzite SiC and GaN lattice
constants vs. the energy gap.
SiC 2H and SIC 6H polymorph
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