Band to band optical absorption in LPE-growth InAs0.94Sb0.06 film

InAs1−xSbx films with x = 0.06 were grown on InAs (1 0 0) substrates by liquid phase epitaxy (LPE). Different purification procedures were applied to get InAsSb samples with different carrier concentration. The complete optical absorption spectra including absorption edge and intrinsic absorption region of InAsSb samples were extracted from the room temperature transmission spectra. The energy band gaps of InAsSb samples were obtained by fitting the intrinsic absorption spectra, giving rise to the values of 303.4-305.1 meV. The reciprocal slope (Eo) of the absorption edge related to the carrier concentration was also determined. The Eo value decreases with decrease of InAsSb epilayer carrier concentration.