Raman scattering of InAsSb

The InAs1–xSbx ternary alloy band gap nonlinearly depends on the composition, which gives the opportunity to use this material in devices operating in a wide range of infrared radiation. We present experimental results for InAs1–xSbx samples for Sb composition from 0.1 to 0.8. Raman spectrum of InAs and InSb in the range of 20 - 250 cm-1 exhibits two main peaks: LO peak and 2TA peak. On the other hand in the same range for InAsSb in Raman spectra two additional peaks (round 44 cm-1 and round 130 cm-1) appear, while they are not existing neither in pure InAs nor in InSb. Energies of 44 cm-1 and 130 cm-1 are close to phonon energy for momentum equals K and L for InAs. This type of peaks are usually called DALA and DATA and it is commonly accepted that they come from disorder in crystal field. We propose other explanation-existence of zone folding in phonon dispersion curves as a result of CuPt unit cell of InAsSb being twice larger than typical ZB unit cell.