Control of polarization and mode mapping of small volume high Q micropillars

We show that the polarization of the emission of a single quantum dot embedded within a microcavity pillar of elliptical cross section can be completely controlled and even switched between two orthogonal linear polarizations by changing the coupling of the dot emission with the polarized photonic modes. We also measure the spatial profle of the emission of a series of pillars with different ellipticities and show that the results can be well described by simple theoretical modeling of the modes of an infinite length elliptical cylinder

Ac Stark Effects and Harmonic Generation in Periodic Potentials

The ac Stark effect can shift initially nonresonant minibands in semiconductor superlattices into multiphoton resonances. This effect can result in strongly enhanced generation of a particular desired harmonic of the driving laser frequency, at isolated values of the amplitude.Comment: RevTeX, 10 pages (4 figures available on request), Preprint UCSBTH-93-2

Electrical and optical studies of n+nn+GaAs and GaAs/(AlGa)As structures and of GaAs:Cr/Si

SIGLEAvailable from British Library Document Supply Centre- DSC:D68609/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Hot Electrons In Delta-doped Gaas(si) Layers

Low temperature (2K) photoluminescence measurements have been performed in delta-doped GaAs(Si) layers, with carrier sheet concentrations Ns ranging from 1012 to 1013cm-2. Under the same excitation intensity, the luminescence spectra of all samples show a high energy tail which becomes more pronounced as Ns increases. Well defined electron temperatures, higher than the lattice temperature, are obtained, characterizing the electron heating effect in this system. The architecture of the delta-doping allows to observe hot electrons even at relatively low laser pumping intensities. © 1990.759707710Shah, Leite, (1969) Phys. Rev. Lett., 22, p. 1304Shah, (1978) Solid State Electron., 21, p. 43Meneses, Jannuzzi, Leite, (1973) Solid State Commun., 13, p. 245Shah, (1989) Superlattices and Microstructures, 6, p. 293. , See for example, and references thereinShah, Pinczuk, Gossard, Wiegmann, (1985) Phys. Rev. Lett., 54, p. 2045Kash, Shah, Block, Gossard, Wiegmann, (1985) Physica, 134 B, p. 189Yang, Carlson-Swindle, Lyon, Worlock, (1985) Phys. Rev. Lett., 55, p. 2359Tatham, Taylor, Ryan, Wang, Foxon, (1988) Solid State Electron., 31, p. 459Oberli̧, Wake, Klein, Henderson, Morkoç, Intersubband relaxation of photoexcited hot carriers in quantum wells (1988) Solid-State Electronics, 31, p. 413Leo, Rühle, Ploog, (1988) Phys. Rev. B, 38, p. 1947Ploog, Hauser, Fischer, Fundamental studies and device application of ?-doping in GaAs Layers and in AlxGa1?xAs/GaAs heterostructures (1988) Applied Physics A Solids and Surfaces, 45 A, p. 233Eisele, (1989) Superlattices and Microstructures, 6, p. 123Zrenner, Reisinger, Koch, Ploog, (1985) Proc. 17th Intern. Conf. on the Physics of Semiconductors, p. 325. , J.P. Chadi, W.A. Harrison, San Francisco, 1984, Springer, New YorkZrenner, Koch, Ploog, (1988) Surf. Sci., 196, p. 671Perry, Lee, Zhou, Worlock, Zrenner, Koch, Ploog, (1988) Surf. Sci., 196, p. 677Schwarz, Müller, Tempel, Koch, Weimann, (1989) Semicond. Sci. Technol., 4, p. 571Scolfaro, Mendonça, Meneses, Martins, Leite, (1990) Int. J. Quant. Chem., , accepted for publication i

Broadening Of The Si Doping Layer In Planar-doped Gaas In The Limit Of High Concentrations

A series of samples of GaAs planar doped with Si, grown by MBE at low substrate temperatures and with different doping concentrations, is investigated. A comparison of Shubnikov-de Haas measurements and self-consistent numerical calculations shows that a broadening of the doped region occurs in spite of the low growth temperature. The broadening occurs via segregation of the Si impurities with the growth surface when the solid solubility limit of Si in GaAs is exceeded. For the growth conditions used this limit is determined to be (2.1 ± 0.2) × 1019 cm-3. At high doping densities an intrinsic compensation mechanism becomes active, limiting the concentration of conduction electrons. © 1991.789793796Zrenner, Reisinger, Koch and K. Ploog, 17th ICPS, Koch and K. Ploog, 17th ICPS,, p. 325. , Springer, New YorkYamada, Makimoto, (1990) Appl. Phys. Lett., 57, p. 1022Santos, Sajoto, Zrenner, Shayegan, (1988) Appl. Phys. Lett., 53, p. 2504Santos, Sajoto, Lanzillotto, Zrenner, Shayegan, Migration of Si IN δ-doped GaAs and AlxGa1 − x As: Effect of substrate temperature (1990) Surface Science, 228, p. 55Zrenner, Koch, (1988) Inst. Phys. Conf. Series, 95, p. 1Gillman, Vinter, Barbier, Tardella, (1988) Appl. Phys. Lett., 52, p. 972Zrenner, Koch, Ploog, (1988) Surface Science, 196, p. 671Sasa, Muto, Kondo, Ishikawa, Hiyamizu, Si Atomic-Planar-Doping in GaAs Made by Molecular Beam Epitaxy (1985) Japanese Journal of Applied Physics, 24, p. L602Maguire, Murray, Newman, Beall, Harris, (1987) Appl. Phys. Lett., 50, p. 51