Optical characterization of Si-doped InAs1−xSbx grown on GaAs and GaAs-coated Si by molecular-beam epitaxy

Epitaxial layers of Si-doped InAs1−xSbx have been grown by molecular-beam epitaxy on GaAs and GaAs-coated Si substrates. The absorption coefficient was measured in the 3–12 μm wavelength range and the experimental data was fit using an analytical expression that was derived from the Kane band model. The fitted value of the Fermi level was used to calculate the electron concentration and the results were compared with doping levels obtained from secondary ion mass spectroscopy and Hall measurements.