Ellipsometric, photoluminescence and Auger electron spectroscopy studies of Zn1−xBexSe and Zn1−x−yBexMnySe crystals

Zn1−x−yBexMnySe and Zn1−xBexSe crystals, investigated in the present paper, were grown from the melt by the high pressure Bridgman method. Spectroscopic ellipsometry was used for determination of the complex dielectric function ε(ω) of Zn1−xBexSe and Zn1−x−yBexMnySe samples. On the basis of ε(ω) dependence, the energy gaps E0 of alloys containing different beryllium and manganese concentrations have been evaluated. It was found that for Zn1−xBexSe, the value E0 linearly increases with the beryllium content. Measurements of luminescence spectra allowed us to find the excitonic energy gap in the investigated alloys. The results were compared with E0 values obtained from ellipsometric investigations. Auger electron spectroscopy and argon ion sputtering were used for determination of composition of investigated samples in the sub-surface region. Surface concentrations were compared with the values obtained in the bulk.