Acoustic phonon dephasing in shallow GaAs/Ga1-xAlxAs single quantum wells

The intermediate dimensionality regime is studied on a set of shallow GaAs/Ga(1-x)A(x)As single quantum wells. Such heterostructures exhibit 2D strong excitonic electroabsorption together with near 3D fast transport properties. We report dephasing time measurements (T-2) Of the heavy-hole exciton and we show that the acoustic phonon contribution decreases with x to a value in good agreement with theoretical predictions for GaAs bulk.