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Raman and Ellipsometric Studies of Delta-Doped GaAs

Published online by Cambridge University Press:  21 February 2011

H. Yao
Affiliation:
University of Nebraska, Center for Microelectronic and Optical Materials Research, and Department of Electrical Engineering, Lincoln, NE 68588
E. F. Schubert
Affiliation:
AT&T Bell Laboratories, Murray Hill, NJ 07974
R. F. Kopf
Affiliation:
AT&T Bell Laboratories, Murray Hill, NJ 07974
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Abstract

GaAs (100) samples with multiple δ-doped layers (N2D=∼2×1013/cm2) were studied by Raman scattering (RS) and spectroscopic ellipsometry (SE). A quasithree- dimensional (3D) plasmon-phonon coupled mode (L+), probed at λ= 514.5 nm, from a 9-layer δ-doped GaAs with layer-spacing of 100 Å, was observed at ∼895 cm−1. At similar frequency, a plasmon mode was also detected from another GaAs sample with the same δ-doping periods but doubled layer-spacing (200 Å). This provides evidence of spatial quantization of the electron distributions in δ-doped GaAs. The equivalent 3D electron concentration, estimated from the Raman plasmon mode, is ∼1.1×1019/cm3. The presence of the 3D plasmon mode from a quasi-two-dimensional (2D) electron gas is possibly contributed by the electrons in the high energy subbands in the V-shaped potential well of the δ-doped GaAs. The pseudodielectric function <ε>= <ε1>+i<ε2> of this δ-doped GaAs sample was measured by spectroscopic ellipsometry (SE), from an unoxidized surface in an ultrahigh vacuum (UHV) chamber, in the range of 1.5 to 5.0 eV. Compared with uniformly doped GaAs, our SE data indicates a reduced broadening of the optical transitions between the E1 and E11, energies due to the δ-doping.

Type
Research Article
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

1. Schubert, E.F., Cunningham, J.E., Tsang, W.T., and Chiu, T.H., Appl. Phys. Lett. 49, 292 (1986).Google Scholar
2. Ploog, K., Hauser, M., and Fischer, A., Appl. Phys. A 45, 233 (1988).Google Scholar
3. Malik, R.J., Aucoin, T.R., Ross, R.L., Board, K, Wood, C.E.C. and Eastman, L.F., Electron. Lett. 16, 836 (1980).Google Scholar
4. Schubert, E.F., Cunningham, J.E., Tsang, W.T., Appl. Phys. Lett. 51, 817 (1987).CrossRefGoogle Scholar
5. Baillargeon, J.N., Cheng, K.Y., Laskar, J., and Kolodzey, J., Appl. Phys. Lett. 55, 663 (1989).CrossRefGoogle Scholar
6. Zrenner, A., Reisinger, H., Koch, F., Ploog, K., Proc. 17th Int'l Conf. Phys Semicond., ed. by Chadi, J.D. and Harrison, W.A. (Springer, New York 1985) p. 325.CrossRefGoogle Scholar
7. See, for example Pinczuk, A. and Burstein, E., in Light Scattering in Solids I (Springer Topics in Applied Physics, Vol.8) (Springer, New York, 1983).Google Scholar
8. Abstreiter, G., Cardona, M. and Pinczuk, A., in Light Scattering in Solids IV(Springer Topics in Applied Physics, Vol.54) (Springer, New York, 1984).Google Scholar
9. Yao, H., Compaan, A. and Hale, E.B., Sol. St. Commun. 56, 677 (1985).CrossRefGoogle Scholar
10. Stern, F., Phys. Rev. Lett. 18, 546 (1967).Google Scholar
11. Azzam, R.M.A. and Bashara, N.M., Ellipsometry and Polarized Light, (North-Holland, Amsterdam, 1977).Google Scholar
12. Yao, H., Snyder, P.G., and Woollam, J.A., J. Appl. Phys. 70, 3261 (1991).Google Scholar
13. Erman, M., Theeten, J.B., Vodjdani, N., and Demay, Y., J. Vac. Sci. Technol. B1, 328 (1983).Google Scholar