Optical characterization of self-organized PbSe/BP1-xEuxTe quantum dot superlattices

Photoluminescence (PL) experiments have been performed on self-organized Pb Se/Pb1-xEuxTe (x = 0.05 to 0.1) quantum dot superlattices grown by molecula r beam epitaxy (MBE). At a temperature of 1.7 K, several PL lines were obse rved in the spectral range from 200 to 230 meV with a relatively narrow wid th of typically 1 to 2 meV. These lines emerge on top of a weak, broader ba nd. Comparison of the luminescence photon energy with that of bulk PbSe (14 6 meV) shows the strong influence of carrier confinement. Studies of the te mperature and magnetic field dependence demonstrate that the narrow lines a re not significantly shifted up to 50 K and 7 T, respectively. whereas the broader band exhibits a shift comparable to that of bulk PbSe material. Stu dies of the PL intensity as a function of excitation power and the preferre d emission of radiation from the sample edge indicate stimulated emission.