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Deep Levels in Superlattices

Published online by Cambridge University Press:  25 February 2011

John D. Dow
Affiliation:
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 U.S.A.
Shang Yuan Ren
Affiliation:
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 U.S.A.
Jun Shen
Affiliation:
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 U.S.A.
Min-Hsiung Tsai
Affiliation:
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 U.S.A.
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Abstract

The physics of deep levels in semiconductors is reviewed, with emphasis on the fact that all substitutional impurities produce deep levels - some of which may not lie within the fundamental band gap. The character of a dopant changes when one of the deep levels moves into or out of the fundamental gap in response to a perturbation such as pressure or change of host composition. For example, Si on a Ga site in GaAs is a shallow donor, but becomes a deep trap for x>0.3 in AℓxGa1-xAs. Such shallow-deep transitions can be induced in superlattices by changing the period-widths and quantum confinement. A good rule of thumb for deep levels in superlattices is that the energy levels with respect to vacuum are relatively insensitive (on a >0.1 eV scale) to superlattice period-widths, but that the band edges of the superlattices are sensitive to changes of period. Hence the deep level positions relative to the band edges are sensitive to the period-widths, and shallow-deep transitions can be induced by band-gap engineering the superlattice periods.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

1 Kohn, W., in Solid State Physics, edited by Seitz, F. and Turnbull, D., (Academic Press, New York, 1957), Vol. 5, P. 258321.Google Scholar
2 Hjalmarson, H. P., Vogl, P., Wolford, D. J., and Dow, J. D., Phys. Rev. Letters 44, 810 (1980); H. P. Hjalmarson, Ph.D. thesis, University of Illinois at Urbana-Champaign, 1979, unpublished. See also W. Y. Hsu, J. D. Dow, D. J. Wolford, and B. G. Streetman, Phys. Rev. B 16, 1597 (1977) for the concepts that form the foundation of this work.Google Scholar
3 Dow, J. D., Mater. Res. Soc. Symp. Proc. 46, 71 (1985).Google Scholar
4 Dow, J. D., in Highlights of Condensed Matter Theory (Proc. Intl. School of Phys. “Enrico Fermi” Course 89, Varenna, 1983) ed. by Bassani, F., Fumi, F., and Tosi, M. P. (Societa Italiana di Fisica, Bologna, Italy, and North Holland, Amsterdam, 1985), pp. 465 et seq.Google Scholar
5 Wolford, D. J., Hsu, W. Y., Dow, J. D., and Streetman, B. G., J. Lumin. 18/19, 863 (1979).Google Scholar
6 The hydrogenic potential, strictly speaking, can bind a second electron, since the ion H- is stable. However, this second-electron binding energy is so small compared with typical thermal energies that we neglect it.Google Scholar
7 Ren, S. Y., Dow, J. D., and Shen, J., Phys. Rev. B 38, 10677 (1988).Google Scholar
8 Ren, S. Y. and Dow, J. D., J. Appl. Phys. 65, 1987 (1989).Google Scholar
9 Hong, R.-D., Jenkins, D. W., Ren, S. Y., and Dow, J. D., Proc. Materials Research Soc. 77, 545 (1987), Interfaces, Superlattices, and Thin Films, ed. J. D. Dow and I. K. Schuller.Google Scholar
10 For a review of the physics of impurities in superlattices, see Properties of impurity states in superlattice semiconductors, ed. by Fong, C. Y., Batra, I. P., and Ciraci, S. (Plenum Publishing Corporation, 1988). See also Refs. [7], [8], [11], [12], [13], and [14].Google Scholar
11 Das Sarma, S. and Madhukar, A., J. Vac. Sci. Technol. 19, 447 (1981).Google Scholar
12 Maude, D. K., Portal, J. C., Dmowski, L., Foster, T., Eaves, L., Nathan, M., Heiblum, M., Harris, J. J., and Beall, R. B., Phys. Rev. Letters 59, 815 (1987).Google Scholar
13 Nelson, J. S., Fong, C. Y., Batra, I. P., Pickett, W. E., and Klein, B. M., unpublished.Google Scholar
14 Lannoo, M. and Bourgoin, J., to be published.Google Scholar
15 Hjalmarson, H. P. and Drummond, T. J., Appl. Phys. Letters 48, 657 (1986). A preliminary account was given by H. P. Hjalmarson, Bull. Amer. Phys. Soc. 32, 814 (1987).Google Scholar
16 Wolford, D. J., Kuech, T. F., Bradley, J. A., Grell, M. A., Ninno, D., and Jaros, M., J. Vac. Sci. Technol. B4, 1043 (1986).Google Scholar
17 Vogl, P., Hjalmarson, H. P., and Dow, J. D., J. Phys. Chem. Solids 44, 365 (1983).Google Scholar