INDUCED ABSORPTION SPECTROSCOPIC DETERMINATION OF EXCITON BINDING-ENERGIES IN TYPE-II GAAS ALAS SUPERLATTICES

The binding energies of magnetoexcitons in a range of GaAs/AlAs type-II superlattices have been measured directly for the first time, using a novel induced far-infrared absorption technique. Zero-field binding energies in the range 13.2 17.4 meV are found, and these are in excellent agreement with recently published variational calculations. Good fits to the experimental data in the range B=0 8 T are obtained with a modified quasi-two-dimensional magnetoexciton theory, allowing exciton dimensionality parameters to be determined. © 1990 The American Physical Society.