Cavity-enhanced photoluminescence of SiGe/Si multiquantum wells grown on silicon-on-insulator substrate

Sharp and strong room-temperature photoluminescence (PL) of the Si0.59Ge0.41/Si multiquantum wells grown on the silicon-on-insulator substrate is investigated. The cavity formed by the mirrors at the surface and the buried SiO2 interface enhances the PL emission and has a wavelength-selective effect on the luminescence. The peak position is consistent with the simulation result and independent of the exciting power, which indicates a strong cavity effect on the room-temperature PL. (C) 2004 American Institute of Physics.

High structural and optical quality 1.3 mu m GaInNAs/GaAs quantum wells with higher indium content grown by molecular-beam expitaxy

High structural and optical quality 1.3 mu m GaInNAs/GaAs quantum well (QW) samples with higher (42.5%) indium content were successfully grown by molecular-beam epitaxy. The cross-sectional transmission electron microscopy measurements reveal that there are no structural defects in such high indium content QWs. The room-temperature photoluminescence peak intensity of the GaIn0.425NAs/GaAs (6 nm/20 nm) 3QW is higher than, and the full width at half maximum is comparable to, that of In0.425GaAs/GaAs 3QW, indicating improved optical quality caused by strain compensation effect of introducing N to the high indium content InGaAs epilayer. (C) 2005 American Institute of Physics.

Optical and magnetic properties of ZnS nanoparticles doped with Mn2+

ZnS:Mn nanoparticles of the cubic zinc blende structure with the average sizes of about 3 nm were synthesized using a coprecipitation method and their optical and magnetic properties were investigated. Two emission bands were observed in doped nanoparitcles and attributed to the defect-related emission of ZnS and the Mn2+ emission, respectively. With the increase of Mn2+ concentration, the luminescence intensities of these two emission bands increased and the ZnS emission band shifted to lower energy. Based on the luminescence excitation spectra of Mn2+, the 3d(5) level structure of Mn2+ in ZnS nanoparticles is similar to that in bulk ZnS:Mn, regardless of Mn2+ concentration. Magnetic measurements showed that all the samples exhibit paramagnetic behavior and no antiferromagnetic interaction between Mn2+ ions exists, which are in contrast to bulk ZnS:Mn. (c) 2005 Elsevier B.V. All rights reserved.