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Effective Dielectric Function of Porous Silicon: the Transverse Component

Published online by Cambridge University Press:  28 February 2011

G. Gumbs
G. Gumbs*
Affiliation:
Department of Physics and Astronomy, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10021
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Abstract

A self-consistent many-body theory is developed to study the effect of temperature and electron density on the interband absorption coefficient and the frequency-dependent refractive index for an array of isolated quantum wires. The peaks in the absorption coefficient correspond to interband transitions resulting in the resonant absorption of light. The oscillations in the derivative spectrum are due to the quantization of the energy levels related to the in-plane confining potential for such reduced dimensional systems. There are appreciable changes in the absorption spectrum when the electron density or temperature is increased. One interband transition peak is suppressed in the high electron density limit and the thermal depopulation effect on the electron subbands can be easily seen when the temperature is high. We also find that the exciton coupling weakens the shoulder features in the absorption spectrum. This study is relevant to optical characterization of the confining potential and the areal density of electrons using photoreflectance. By using incident light with tunable frequencies in the interband excitation regime, contactless photoreflectance measurements may be carried out and the data compared with our calculations. By fitting the numerical results to the peak positions of the photoreflectance spectrum, the number of electrons in each wire may be extracted.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 358: Symposium F – Microcrystalline and Nanocrystalline Semiconductors , 1994 , 49
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

1 Optical Phenomena in Semiconductor Structures of Reduced Dimensionality, Vol. 248 of NATO Advanced Study Institute, Series 5, edited by Lockwood, D. J. and Pinczuk, A. (Kluwer Academic, Dordrecht, 1993).Google Scholar
2 Nanostructure Physics and Fabrication, edited by Reed, M. A. and Kirk, W. R. (Academic, San Diego, 1989).Google Scholar
3 Wegscheider, W., Pfeiffer, L., Dignam, M., Pinczuk, A., and West, K., in Growth, Processing, and Characterization of Semiconductor Heterostructures, edited by Gumbs, G., Luryi, S., Weiss, B., and Wicks, G. W., Mat. Res. Soc. Proc. 326, 401 (1994).Google Scholar
4 Gumbs, G., Huang, D. H., and Heitmann, D., Phys. Rev. B 44, 8084 (1991).Google Scholar
5 Wendler, L. and Grigoryan, V. G., Phys. Stat, Sol. B 181, 133 (1994).Google Scholar
6 Park, P. W., MacDonald, A. H., and Schaich, W. L., Phys. Rev. B 46, 12635 (1992).Google Scholar
7 Plaut, A. S., Lage, H., Grambow, P., Heitmann, D., von Klitzing, K., and Ploog, K., Phys. Rev. Lett. 67, 1642 (1991).Google Scholar
8 Bryant, G. W., Comments Cond. Mat. Phys. 14, 277 (1989).Google Scholar
9 A recent photoreflectance experiment on a GaAs/GaAlAs modulation doped quantum dot array shows that at 77 K the "2C - 2H" interband transition develops a series of evenly spaced oscillations, subbands. No fine structure is observed for the "1C - 1H"/"1C - lL", transitions since the first electron subband is occupied. F. H. Pollak, et al. (unpublished).Google Scholar
10 Callaway, J., Energy Band Theory, (Academic, New York, 1964), p. 287.Google Scholar
11 Huang, D. H., Gumbs, G., and Horing, N. J. M., Phys. Rev. B 49, 11463 (1994).Google Scholar
12 Gumbs, G., Huang, D., Yin, Y., Qiang, H., Yan, D., Pollak, F. H., and Noble, T. F., Phys. Rev. B 48, 18328 (1993).Google Scholar