ELLIPSOMETRIC INVESTIGATIONS AND LUMINESCENCE PROPERTIES OF SEMICONDUCTOR MICROCAVITIES

Luminescence investigations on MBE-grown AlAs/AlGaAs microcavities rev eal position-dependent spectra from embedded GaAs quantum wells and fr om the reflector material. Because of their uniform energetic shifts t hey should be connected with the spatial distribution of strain. The s pectra themselves are related to the radiative recombination of confin ement 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 typica l for a pure metal in the FIR. Analogous investigations between 2.5 an d 3.5 eV determined the critical points E(0) and E(1) of the energy ba nd structure of AlAs and AlGaAs, respectively.