Determination and modeling of the optical constants of direct band gap BexZn1−xTe grown by molecular beam epitaxy
The optical constants ε(E) of direct band gap BexZn1−xTe have been measured at 300 K using spectral ellipsometry (0.73–6.45 eV). The ε(E) spectra displayed distinct structures associated with critical points at E0, E0+Δ0, E1, E1+Δ1, 1+Δ1 and E2. The experimental data over the entire measured spectral range has been fit using the Holden-Muñoz model dielectric function, which is based on the electronic energy-band structure near critical points plus excitonic and band-to-band Coulomb-enhancement effects at E0, E0+Δ0 and the E1, E1+Δ1, doublet. In addition to evaluate the energies of these various band-to-band critical points, information about the binding energy (R1) of the two-dimensional exciton related to the E1, E1+Δ1 critical points was obtained. The value of R1 was in good agreement with effective mass theory. The ability to evaluate R1 has important ramifications for first-principles band-structure calculations that include exciton effects at E0, E1, and E2.
Muñoz, M., Maksimov, O., Tamargo, M. C., Buckley, M. R. and Peiris, F. C. (2004), Determination and modeling of the optical constants of direct band gap BexZn1−xTe grown by molecular beam epitaxy. phys. stat. sol. (c), 1: 706–709. doi:10.1002/pssc.200304298.
physica status solidi (c)
11th International Conference on II–VI Compounds