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Quantum-Dot Molecules for Potential Applications in Terahertz Devices

Published online by Cambridge University Press:  26 February 2011

Valeria Gabriela Stoleru
Affiliation:
Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, U.S.A.
Elias Towe
Affiliation:
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, U.S.A.
Chaoying Ni
Affiliation:
Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, U.S.A.
Debdas Pal
Affiliation:
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, U.S.A.
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Abstract

The experimental and theoretical results of the electronic and optical properties of quantum dot artificial molecules (AMs), formed by pairs of electronically coupled quantum dots (QDs), are presented here in order to identify the necessary conditions for the development of new types of terahertz (THz) injection lasers based on intraband carrier transitions. We have performed analytical calculations to obtain the spatial strain distribution in vertically aligned (In, Ga)As QDs grown on (001) GaAs substrates by molecular beam epitaxy. Electronic coupling of the dots, mainly governed by the thickness of the separating barrier between the dot layers, is allowed due to the strain field-assisted self-organization of the dots. The calculated strain field reproduces our cross sectional high-resolution transmission electron microscopy observations very well. We further take into account the microscopic effects of the spatial strain distribution on carrier confinement potentials, and compute the electronic structure of the AM. Our calculations of the peak luminescence energies are in good agreement with our experimental results and those of others. The growth of quantum dot molecules represents a major step in tailoring the electronic and optical properties of the nanostructures.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1. Faist, J., Capasso, F., Sivco, D.L., Sirtori, C., Hutchinson, A.L., and Cho, A.Y., Science 264, 553 (1994).Google Scholar
2. Sirtori, C., Kruck, P., Barbieri, S., Collot, P., Nagle, J., Beck, M., Faist, J., and Oesterle, U., Appl. Phys. Lett. 73, 3486 (1998).Google Scholar
3. Paiella, R., Capasso, F., Gmachl, C., Sivco, D.L., Baillargeon, J.N., Hutchinson, A.L., Cho, A.Y., and Liu, H.C., Science 290, 1739 (2000).Google Scholar
4. Gmachl, C., Ng, H.M., and Cho, A.Y., Appl. Phys. Lett. 77, 334 (2000).Google Scholar
5. Ulrich, J., Zobl, R., Schrenk, W., Strasser, G., Unterrainer, K., and Gornik, E., Appl. Phys. Lett. 77, 1928 (2000).Google Scholar
6. Sirtori, C., Faist, J., Capasso, F., Sivco, D.L., Hutchinson, A.L., and Cho, A.Y., IEEE Photonics Technol. Lett. 9, 294 (1997).Google Scholar
7. Faist, J., Capasso, F., Sirtori, C., Sivco, D.L., Baillargeon, J.N., Hutchinson, A.L., and Cho, A.Y., Appl. Phys. Lett. 68, 3680 (1996).Google Scholar
8. Suris, R.A., in “Future Trends in Microelectronics. Reflections on the Road to Nanotechnology,” edited by Luryi, S., Xu, J., Zaslavsky, A., Kluwer Acad. Publishers, 197208 (1996).Google Scholar
9. Wingreen, N. and Stafford, C.A., IEEE J. of Quantum Electronics 33, 1170 (1997).Google Scholar
10. Hsu, C.-F., J.-S. O., , Zory, P., and Botez, D., IEEE J. of Selected Topics in Quantum Electronics 6, 491 (2000).Google Scholar
11. Fang, W., Xu, J.Y., Yamilov, A., Cao, H., Ma, Y., Ho, S.T. and Solomon, G.S., Opt. Lett., 27, 948 (2002).Google Scholar
12. Stranski, I.N., Krastanow, L., Sitzungsberichte d. Akad. d. Wissenschaften in Wien, Abt. IIb, Band 146, 797 (1937).Google Scholar
13. Stoleru, V.G., Pal, D. and Towe, E., Phys. E: Low-dimens. syst. and nanostr. 15, 131 (2002).Google Scholar
14. Pal, D., Stoleru, V.G., Towe, E., and Firsov, D., Jpn. J. Appl. Phys. 41, 482 (2002).Google Scholar
15. Stier, O., Grundmann, M., and Bimberg, D., Phys. Rev. B 59, 5688 (1999).Google Scholar
16. Heitz, R., Kalburge, A., Xie, Q., Grundmann, M., Chen, P., Hoffmann, A., Madhukar, A., and Bimberg, D., Phys. Rev. B 57, 9050 (1998).Google Scholar
17. Boucaud, P., Williams, J.B., Gill, K.S., and Sherwin, M.S., Appl. Phys. Lett. 77, 4356 (2000).Google Scholar
18. Batke, E., Weimann, G., and Schlapp, W., Phys. Rev. B 39, 11171 (1989).Google Scholar