We report the first successful room-temperature cw operations of a Ga0.25 In0.75 As0.5 P0.5 -InP buried ridge structure laser emitting at 1.3 μm grown by two-step low-pressure metalorganic chemical vapor deposition on a silicon substrate. An output power of 20 mW with an external quantum efficiency of 16% at room temperature has been obtained. A threshold current as low as 45 mA under cw operation at room temperature has been measured. The first cw aging test at room temperature, at 2 mW during 5 h, shows a very low degradation (ΔI/I≤5%).

The influence of dispersion-less quantum optical phonons on the phase diagram of a quarter-filled Hubbard chain is studied using the Density-matrix renormalization group technique. The ground state phase diagram is obtained for frequencies corresponding to the intramolecular vibrations in organic conductors. For high vibrational modes the system is only slightly affected by the electron-phonons coupling. It remains in a Lüttinger liquid phase as long as the electronic repulsion is larger than the polaronic binding energy. For low vibrational modes the phase diagram is very rich. A noticeable point is the existence of a 4kF CDW phase for small values of the correlation strength. For realistic values of the electron repulsion and of the electron-phonons coupling constant a large phonons-mediated reduction of the Lüttinger liquid parameter Kρ was found compared to the pure electronic model.

High concentration Zn doping in InP grown by lowpressure metalorganic chemical vapor depositionResidual acceptor impurities in undoped highpurity InP grown by metalorganic chemical vapor deposition An electron trap related to phosphorus deficiency in highpurity InP grown by metalorganic chemical vapor deposition

High-quality GaAs/GaInP single and multi-quantum-well structures have been grown by metal organic molecular beam epitaxy. Wells as thin as 10 Å have been grown exhibiting confinement energies exceeding 310 meV. The influence of growth interruption at both interfaces has been investigated by low-temperature photoluminescence. The critical role of the relative incorporation kinetics of arsenic and phosphorus atoms in determining the nature of the normal and inverted interfaces defining GaAs quantum wells is shown. An excitonic type recombination is evidenced by low-temperature-dependence photoluminescence measurements. Carrier capture is shown to be very efficient, even for the narrowest wells studied.