Phonon sideband of quasi-two-dimensional excitons in GaAs quantum wells

We present an investigation of the absorption edge in quasi-two-dimensional GaAs quantum-well heterostructures. We find that the excition--longitudinal-optic-phonon interaction plays an important role in determining the spectral characteristics and magnitude of the low-temperature absorption. A calculation of the absorption coefficient based on the two-dimensional Fr\"ohlich interaction shows excellent agreement with the data.