Knowlton
MSE 510
Part 3: Heterojunctions - Bandgap Engineering

Bandgap Energy –vs- Lattice Constant
Red 700-630 nm; 1.77-1.97eV
Orange 630-600 nm; 1.97-2.07eV
Yellow 600-570 nm; 2.07-2.18eV
Green 570-520 nm; 2.18-2.38eV
Cyan 520-480 nm; 2.38-2.58eV
Blue 480-430 nm; 2.58-2.88eV
Violet 430-400 nm; 2.88-3.10eV
Alloy Ternary or Quaternary III-V to Adjust E g
& a: e.g., Al x
Ga
1-x
As or Ga x
In
1-x
N or Al
1-x-y
In x
Ga y
P
Knowlton Dr. Rod Nave, HyperPhysics, Georgia State University
1
MSE 510
Part 3: Heterojunctions - Bandgap Engineering

Bandgap Energy –vs- Lattice Constant
Red 700-630 nm; 1.77-1.97eV
Orange 630-600 nm; 1.97-2.07eV
Yellow 600-570 nm; 2.07-2.18eV
Green 570-520 nm; 2.18-2.38eV
Cyan 520-480 nm; 2.38-2.58eV
Blue 480-430 nm; 2.58-2.88eV
Violet 430-400 nm; 2.88-3.10eV
Alloy Ternary or Quaternary III-V to Adjust E g
& a: e.g., Al x
Ga
1-x
As or Ga x
In
1-x
N or Al
1-x-y
In x
Ga y
P
Knowlton E.F. Schubert, Physical Foundations of Solid State Devices (2009)
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1

Knowlton
Knowlton
MSE 510
Part 3: Heterojunctions - Bandgap Engineering

Bandgap Energy –vs- Lattice Constant
Red 700-630 nm; 1.77-1.97eV
Orange 630-600 nm; 1.97-2.07eV
Yellow 600-570 nm; 2.07-2.18eV
Green 570-520 nm; 2.18-2.38eV
Cyan 520-480 nm; 2.38-2.58eV
Blue 480-430 nm; 2.58-2.88eV
Violet 430-400 nm; 2.88-3.10eV
Alloy Ternary or Quaternary III-V to Adjust E g
& a: e.g., Al x
Ga
1-x
As or Ga x
In
1-x
N or Al
1-x-y
In x
Ga y
P
Knowlton E.F. Schubert, Physical Foundations of Solid State Devices (2009)
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MSE 510
Part 3: Heterojunctions - Bandgap Engineering

Bandgap Energy –vs- Lattice Constant
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Knowlton
MSE 510
Heterojunctions - Bandgap Engineering
 III-V and II-VI Semiconductors
 Use for light emitting diodes, laser diodes and detectors (photon and other high energy particles)
II-VI
III-V
Knowlton
MSE 510
Bandgap Engineering Light Emitting Devices
Solid-state Semiconductor Lighting
The Gallium Nitride
Light Emitting Diode(LED):
200
 m
Knowlton
Completing the Visible
Spectrum from T. Sands, UC Berkeley
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MSE 510
Bandgap Engineering for Light Emitting Devices
 Bandgap Engineering: Quantum wells
 Note that the band offsets are not the same!
Knowlton V. Mitin, V. Kochelap, M. Stroscio, Quantum Heterostructures: Microelectronics and Optoelectronics , (Cambridge University Press, 2005) p. 412
7
MSE 510
Bandgap Engineering for Light Emitting Devices
 Bandgap Engineering: Three types
 Note that the band offsets are not the same!
Type 1 Type 2 Type 3
Knowlton
Knowlton
Herbert Kroemer, Nobel Lecture: Quasielectric fields and band offsets: teaching electrons new tricks*, REVIEWS OF MODERN PHYSICS,
VOLUME 73, JULY 2001, *The 2000 Nobel Prize in Physics was shared by Zhores I. Alferov, Jack S. Kilby, and Herbert Kroemer. This lecture is the text of Professor Kroemer’s address on the occasion of the award.
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Knowlton
MSE 510
Here we will assume the band offsets are equal.
This is not usually the case.
E c
E f
E v
Heterojunctions – Type I
E vacuum
Band offset
E c
E f
E c
E f
E v
Band offset
E v
(ex., GaAs)
(ex., AlN)
2DEG
(2d e e
-
-
Gas)
's
E c
E f
Band offset
E v
Knowlton
9
MSE 510
Heterojunctions – Type I
Here we will assume the band offsets are equal.
This is not usually the case.

E
C
= Conduction Band offset
E c
E f
E c
E v

E
V
= Valence Band offset
(ex., GaAs)
(ex., GaN)
E f
E v
E vacuum

E
C
E f
Band offset

E
V
Knowlton
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Knowlton
MSE 510
Other References
 Alfonso Franciosi and Chris G. Van de Walle, Heterojunction band offset engineering , Surface Science Reports 25 (1996) 1-140

Jasprit Singh, Electronic and Optoelectronic Properties of Semiconductor Structures
(Cambridge Press, 2003) Ch. 3 .2 p. 118
 V. Mitin, V. Kochelap, M. Stroscio, Quantum Heterostructures: Microelectronics and Optoelectronics , (Cambridge University Press, 2005)
 Anderson & Anderson, Fundamentals of Semiconductor Devices , (McGraw Hill,
2005) Ch. 6.3 p. 317-331

K.F. Brennan, The Physics of Semiconductors – with Applications to Optoelectronic
Devices , (Cambridge University Press, 1999) Ch. 11.2 p. 554
 Jasprit Sing, Physics of Semiconductors and Their Heterostructures, (McGraw Hill,
1993) Ch. 6

S.M. Sze, Physics of Semiconductor Devices , 2 nd Ed. (Wiley-Interscience, 1981)
 K.K. Ng, Complete Guide to Semiconductor Devices , 2 nd Ed. (Wiley-Interscience,
2002)
 Angus Rocket, , The Materials Science of Semiconductors , (Springer, 2007)
Knowlton
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