Investigation of the Temperature Dependence of the Spectra of Optical Constants of Hg 1 – x Cd х Te Films Grown Using Molecular Beam Epitaxy

Based on in situ and ex situ ellipsometric measurements, the spectral dependences of the temperature sensitivity of the optical constants Hg 1 – x Cd х Te— dn (λ) and dk (λ) have been found for a series of samples of different compositions in the range from 0.160 to 0.327. The experiments were performed during cooling of the grown samples in a vacuum chamber. It has been found that the obtained dn and dk dependences can be well approximated by the sum of three Lorentz oscillators with the addition of the dispersion terms of the Cauchy formula. A parametric model that describes the sensitivities dn (λ) and dk (λ) for an arbitrary composition x in the specified range near the growth temperature has been proposed. Ex situ temperature measurements performed near room temperature correlate with the data of the high-temperature measurements. The results obtained are relevant for the development of ellipsometric control methods in situ of Hg 1 – x Cd х Te layer growth processes.