We report pseudodielectric function data 〈∈〉 = 〈∈1〉 + i〈∈2〉 of ZnSexTe1 - x samples grown on GaAs substrates. The data were obtained from 1.5 to 6.5 eV using spectroscopic ellipsometry. Critical-point parameters were obtained by fitting model line shapes to numerically calculated second-energy derivatives of 〈∈〉. The bowing parameters of E0, E1, and E1 + Δ1 were determined and were comparable to that of E0 quoted from the literature. We observed a monotonie increase of the linewidth of the E1 gap up to x = 0.85, whereas that of E1 + Δ1 showed a maximum value near x = 0.5. We attribute this anomalous broadening of the E1 gap to sample microstructures developed in the low-Te composition alloys.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)