RAMAN-SCATTERING IN QUATERNARY INAS0.7P0.2SB0.1 FILM

We report the first Raman experiments of the quaternary InAs0.7P0.2Sb0 .1 film. This film was grown by liquid phase epitaxy on InAs substrate to minimize the strain on the interface due to lattice mismatch. As p robed by various emission lines of both Ar+ and Kr+ ion lasers, we obs erved three immiscible bands that correspond to the InAs, InP and InSb substructures. The scattering intensity of each band is proportional to the composition ratios of 7:2:1 as expected that indicates rather h omogeneous alloying. Due to mixing of the group-V elements, the LO pho non softening of three bands is present with the red shifts of 5, 34, and 8 cm(-1), respectively. Low temperature measurements resolved more clear structures at low energy side of these bands. We also observed the resonance effect that occurs in the vicinity of E(1) transition of InAs at 2.6 eV.