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