Electrical and optical properties of unrelaxed InAs$_{1-x}$Sb$_{x}$ heteroepitaxial structures

The electrical and galvanomagnetic properties of unrelaxed heteroepitaxial structures of InAs$_{1-x}$Sb$_{x}$ ($x$ = 0.43 and $x$ = 0.38) were studied in a wide temperature range of 5–300K and magnetic fields up to 8 T. The band gap of the composition InAs$_{0.57}$Sb$_{0.43}$ was estimated from the thermo-activation dependence of the electrical conductivity, and is equal to 120 meV. The electron concentration in InAs$_{1-x}$Sb$_{x}$ ($n$ = 6 $\times$ 10$^{16}$ cm$^{-3}$ for InAs$_{0.62}$Sb$_{0.38}$ and $n$=5 $\times$ 10$^{16}$ cm$^{-3}$ for InAs$_{0.57}$Sb$_{0.43}$) determined from the Hall effect and consistent with the electron concentration calculated from Shubnikov-de Haas oscillations. Also, implemented spectral ellipsometric studies of unrelaxed heteroepitaxial structures of InAs$_{1-x}$Sb$_{x}$ ($x$ = 0.43 and $x$ = 0.38) in the photon energy range of 1–6 eV. The spectral dependences of the imaginary and real parts of the dielectric constant are determined. The dispersion dependences of the refractive indices and extinction are calculated and given.