References
T. Koda, T. Murahashi, T. Mitani, T. Sakoda and Y. Onodera, Phys. Rev. B 5(1972) 705.
S. Ves, D. Glotzel, M. Overhof and M. Cardona, ibid. 24(1981) 3073.
A. Blacha, S. Ves and M. Cardona, ibid. 27(1983) 6346.
A. Blacha, N. E. Christensen and M. Cardona, ibid. 33(1986) 2413.
K. Reimann and S. R ¨ubenacke, ibid. 46(1994) 11021.
D. Fr ¨ohlich, W. Nieswand and S. R ¨ubenacke, J. Lumin 60(1994) 627.
C. Wecker, PhD thesis, University of Strasbourg, 1984.
H. Erguig, PhD thesis, University of Metz, 1990.
M. Certier, H. Erguig, M. Soltani and T. Sauder, Phys. Status. Solidi B 168(1991) 361.
B. H¨onerlage, U. R¨ossler, V. D. Phach, A. Bivas and J. B. Grun, Phys. Rev. B 22(1980) 797.
M. Cardona, "Modulated Spectroscopy," edited by F. Seitz, D. Turnbull and H. Ehrenreich (Academic Press, New York, 1969).
R. C. Hanson, J. R. Hallberg and C. Schwab, Appl. Phys. Lett. 21(1970) 490.
O. V. Gogolin, J. L. Deiss and E. G. Tsitsichvili, Nuovo Cimento 11D(1989) 1525.