 |
| Vertical
Cavity Surface-Emitting Laser
(VCSEL) (sideview). It is a sandwich
of high tech materials that traps
and uses electric current to generate
a laser beam. |
Stacks of ultrathin layers—each
less than one-thousandth the thickness
of a human hair—are the secret
to a class of artificially grown materials
that have enabled numerous advances
in technology over the past generation.
In 1981, scientists at Sandia National
Laboratories were the first to predict
the unique electronic and optical
properties of strained-layer semiconductor
(SLS) superlattices, and, a few years
later, the first to make devices from
them. These crystalline materials
got their name because the spacing
between the atoms in different layers
is mismatched initially, but the thinness
of the layers allows alignment by
elastic strain without causing dislocations
or other defects. Because the number,
composition, and thickness of the
layers can be varied over wide limits,
scientists can tailor the electrical
and optical properties to design materials
and devices with targeted properties.
This work has won a number of awards,
including the American Physical Society's
International Prize for New Materials
in 1993.
Scientific Impact:
This work established new areas of
materials science and electronics
as well as new research technologies;
for instance, SLS materials are used
to make transistors for high-frequency,
low-noise electronic amplifiers, such
as those found in radiotelescopes.
These materials made it possible for
scientists to tailor the wavelength
(or color) of light-emitting devices
(such as light-emitting diodes) and
increase the speed of electrons in
transistors.
Social Impact: The
SLS technology revolutionized the
multibillion-dollar field of opto-electronics
and is a key to wireless communications.
These materials enhance the performance
and efficiency of semiconductor lasers
and make possible new types of lasers
with applications in optical communications,
supermarket scanners, remote sensing,
and medical diagnostics.
Reference: "Laser
Gain and Threshold Properties in Compressive-Strained
and Lattice-Matched GaInNAs/GaAs Quantum
Wells", W. W. Chow, E. D. Jones, Appl.
Phys. Lett 75, pp. 2891-93 (1999).
"Pressure Dependence of the Bandgap
Energy and the Conduction-Band Mass
for an N-Type InGaAs/GaAs Single-Strained
Quantum Well", E. D. Jones, S. W.
Tozer, and T. Schmiedel, Physica
E 2, pp. 146-150 (1998).
"Study of Cyclotron Resonance and
Magneto-Photoluminescence of N-Type
Modulation-Doped In GaAs Quantum Well
Layers and Their Characterizations",
N. Kotera, E. D. Jones, K. Tanaka,
H. Arimoto, M. Ohno, N. Miura, T.
Mishima, edited by S. C. Shen, D.
Y. Tang, G. Z. Zheng, and G. Bauer
(World Scientific, Singapore,
199) pp. 591-598.
"Room-Temperature Continuous Wave
InGaAsN Quantum Well Vertical-Cavity
Lasers Emitting at 1.3 Microns", K.
D. Choquette, J. F. Klem, A. J. Fischer,
O. Blum, A. A. Allerman, I. J. Fritz,
S. R. Kurtz, W.G. Breiland, R. Sieg,
K. M. Electronics Letters
Vol. 36, 1388 (2000).
"GaAsSb/InGaAs Type-II Quantum Wells
for Long-Wavelength Lasers on GaAs
Substrates", J. F. Klem, O. Blum,
S. R. Kurtz, I. J. Fritz, and K. D.
Choquette, J. Vac. Sci. Technol.
B, Vol. 18, 1605 (2000). "Strained-layer
semconductor superlattices from lattice
mismatched materials." Osbourn, J.C.
J. Applied Physics (53) p1586
(1982).
"InGaAs strained-layer semiconductor
superlattices: A proposal for useful
new electronic materials." Osbourn,
J.C. Phy Rev. B. (27) p5126
(1983).
URL: http://www.sandia.gov/E&E/besms.html
http://www.sandia.gov/awards/images/Energy/Strained.pdf
Technical Contact:
Don Freeburn, Office of Basic Energy
Sciences, 301-903-3156
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of Basic Energy Sciences |
