Picosecond Raman studies of the optical phonons in the AlxGa1-xAs layers of GaAs-AlxGa1-xAs multiple-quantum-well structures

Picosecond time-resolved Raman scattering has been used to investigate the properties of the GaAs-like and AlAs-like longitudinal-optical phonons in the AlxGa1-xAs layers of GaAs-AlxGa1-xAs multiple-quantum-well structures. The experimental results have shown that the phonon lifetimes are the same as in bulk AlxGa1-xAs and therefore have demonstrated that phonon zone folding caused by the additional periodicity of the lattice has little effect on the lifetimes of these barrier-confined LO phonons. The generation efficiency of these LO phonons in the AlxGa1-xAs layers of GaAs-AlxGa1-xAs multiple-quantum-well structures has been shown to be the same as in bulk AlxGa1-xAs.