Optical spectra of Zn1-xBexTe mixed crystals determined by IR–VIS–UV ellipsometry and photoluminescence measurements

Assessment of optical phonons in BeTe, BexZn1-xTe, p-BeTe epilayers and BeTe/ZnTe/GaAs (001) superlattices

“…By using Eqs. (1-2), we have carried out least square fit to the reflectivity of ZnTe, BeTe, Be0.5Zn0.5Te, and GaAs [21][22][23][24][25] by exploiting the CERN library MINUIT program based on Metropolis algorithm to obtain the necessary phonon mode parameters (see: Table 1). For thin epifilms and SLs the reflectance and transmission spectra in the s-and ppolarized configurations are obtained by using the interference matrix approach [19].…”

“…For bulk materials the appropriate dielectric dispersions are meticulously accomplished by using the Kramers-Krönig analyses to obtain the frequency dependent dielectric functions 𝜀(𝜔). Least square fit to the reflectivity spectra [21][22][23][24][25] of bulk ZnTe, BeTe, Be0.5Zn0.5Te, and GaAs materials are achieved by exploiting the CERN library MINUIT program based on Metropolis algorithm. The resulting standard deviation  has been achieved ≤ 5 x 10 -3 in all the fits of reflectivity spectra to accomplish the necessary phonon mode parameters (see: Table 1).…”