We observed simultaneously two types of Raman spectra in a GaAs/AlGaAs superlattice under high magnetic field: a folded longitudinal acoustic phonon, IFA, and a structureless background, IB. The temperature dependence of the intensities in both spectra was studied in the range 2-100K and it was established that the background spectrum is due to the first-order Raman scattering from acoustic phonons with a wide range of wave vectors. We obtained the expression for the intensities ratio IB/IFA. It depends on the relationship between the homogeneous and the inhomogeneous broadening of the intermediate state of the photoexcited e-h pair. A rapid decrease of IB observed at T 30K is thought to be due to the increase of the homogeneous width with temperature.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry