Electrical and Optical Properties of Unrelaxed InAs_{1 –x}Sb_x Heteroepitaxial Structures

The electrical and galvanomagnetic properties of unrelaxed heteroepitaxial InAs_{1 –x}Sb_x structures (x = 0.43 and 0.38) in a wide temperature range of 5–300 K and magnetic fields up to 8 T are studied. From the thermal-activation dependence of the electrical conductivity, the band gap of the composition InAs_0.57Sb_0.43 is estimated as 120 meV. The electron concentration in InAs_{1 –x}Sb_x (6 × 10¹⁶ cm^–3 for InAs_0.62Sb_0.38 and 5 × 10¹⁶ cm^–3 for InAs_0.57Sb_0.43) determined from the Hall effect agrees well with the electron concentration calculated from the Shubnikov–de-Haas oscillations. We also carry out the spectral ellipsometric studies of unrelaxed heteroepitaxial structures of InAs_{1 –x}Sb_x (x = 0.43 and 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 index and the extinction coefficient are calculated and presented.