Ellipsometric investigations and luminescence properties of semiconductor microcavities.

Luminescence investigations on MBE-grown AlAs/AlGaAs microcavities reveal position-dependent spectra from embedded GaAs quantum wells and from the reflector material. Because of their uniform energetic shifts they should be connected with the spatial distribution of strain. The spectra themselves are related to the radiative recombination of confinement shifted free-electron-hole pairs, free and bound excitons and to the intrinsic luminescence of AlGaAs. Ellipsometric investigations in the range of the resonator stop band around 1.5 eV accentuate the one-dimensional behaviour as a 1D singularity within the effective joint density of states. The resonator mode and the stop band are dependent on the angle of incidence. The effective dielectric function is metal-like with the maximum imaginary part above 10(3), i.e. as it is typical for a pure metal in the FIR. Analogous investigations between 2.5 and 3.5 eV determined the critical points E(0) and E(1) of the energy band structure of AlAs and AlGaAs, respectively.