Burstein-Moss Shift Of N-Doped In0.53ga0.47as/Inp

We have evaluated the Burstein-Moss (BM) shift at 300 K in seven samples of n-In0.53Ga0.47As (1.3 x10(16)less than or equal ton less than or equal to3.9x10(19)cm(-3)) lattice matched to InP using spectral ellipsometry in the range of 0.4-5.1 eV. The data have been fitted over the entire spectral range to a model reported by Holden et al. [in Thermphotovolmic Generation of Electricity, edited by T. J. Coutts, J. P. Brenner, and C. S. Allman, AIP Conf. Proc. No. 460 (AIP, Woodbury, NY, 1999), p. 39], based on the electronic energy-band structure near critical points plus relevant discrete and continuum excitonic effects. A Fermi-level filling factor in the region of the fundamental gap has been used to account for the BM effect. While our data exhibit nonparabolic effects, with a blueshift of 415 meV for the most highly doped sample, we did not observe the Fermi-level saturation at 130 meV for n greater than or equal to 10(19)cm(-3) reported by Tsukernik et al. [Proceedings of the 24th International Conference on the Physics of Semiconductors, Jerusalem, 1998; edited by D. Gershoni (World Scientific, Singapore, 1999)]. Our BM displacements are in agreement with a modified full-potential linearized augmented-plane-wave calculation [G. W. Charache et al., J. Appl. Phys. 86, 452 (1949)] plus possible band-gap-reduction effects.