Physical Review B - CMMP

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 x 1016≤n≤3.9x 1019 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 Thermphotovoltaic 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 ≥ 1019 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 (1999)] plus possible band- gap-reduction effects.