Optical study of ZnSexTe1−x alloys using spectroscopic ellipsometry

1077-3118

AIP Digital Archive

Physics

We report pseudodielectric function data 〈ε〉=〈ε1〉+i〈ε2〉 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 〈ε〉. 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 monotonic 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. © 2000 American Institute of Physics.

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