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  • 1
    Electronic Resource
    Electronic Resource
    Determining Absolute Configurations of Stereocenters in Annonaceous Acetogenins through Formaldehyde Acetal Derivatives and Mosher Ester Methodology (1994)
    s.l. : American Chemical Society
    The @journal of organic chemistry 59 (1994), S. 5162-5172 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00097a017
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  • 2
    Electronic Resource
    Electronic Resource
    Point defects in lithium triborate (LiB3O5) crystals (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 1114-1118 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron paramagnetic resonance (EPR), electron-nuclear double resonance, optical absorption, and thermoluminescence have been used to investigate radiation-induced point defects in a single crystal of lithium triborate (LiB3O5). Two prominent defects are observed after irradiation near liquid-nitrogen temperature with 60 kV x rays. A four-line EPR spectrum, with 12.2 G splittings, is assigned to a trapped-hole center, and another four-line EPR spectrum, with 120 G splittings, is assigned to a trapped-electron center. In each case, the nucleus responsible for the observed hyperfine is 11B. The trapped hole is localized on an oxygen ion and has a weak hyperfine interaction with one neighboring boron nucleus, whereas the trapped electron is localized primarily on a boron ion with a correspondingly larger hyperfine interaction. Both defects become thermally unstable near 125 K, and their decay (i.e., recombination) correlates with an intense thermoluminescence peak at this same temperature. An optical absorption peak at 300 nm is produced by the x rays and thermally decays at the same temperatures as the EPR spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353275
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  • 3
    Electronic Resource
    Electronic Resource
    Midinfrared photoluminescence from IV–VI semiconductors grown on silicon (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 3514-3516 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Above room temperature continuous wave midinfrared photoluminescence has been observed from PbSe/Pb1−xSrxSe multiple quantum well structures grown by molecular beam epitaxy on (111) silicon. Emission energy from a sample with 10-nm-thick quantum wells varied from 336.1 to 343.7 meV as sample temperature was increased from 15 to 35 °C. At a heat sink temperature of 25 °C the emission energy varied from 336.8 to 339.9 meV as the current in the near-infrared diode pump laser was increased from 300 to 800 mA indicating an additional 8.2 °C of epilayer heating due to increased photon flux from the pump laser. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1347950
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  • 4
    Electronic Resource
    Electronic Resource
    Microstructure and magnetic properties of as-quenched and heat-treated (Nd,Dy)FeB powders produced by high pressure gas atomization (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 5678-5680 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetic properties and microstructures of a series of as-quenched and heat-treated inert gas atomized (IGA) rare-earth rich (Nd,Dy)–Fe–B particles have been investigated. Heat treatment was found to substantially improve magnetic properties, with effects most pronounced in samples with higher Dy content and higher total rare earth (RE) content. The as-quenched particles consisted of an underquenched dendritic-like structure with the majority phase RE2Fe14B, and a fine network of RE-rich material between the grains. The heat-treated particles showed a change in microstructure which correlated with magnetic property changes. Particles which showed little change in magnetic properties showed no obvious change in microstructure. Particles which showed large changes in magnetic properties showed a large change in microstructure: most of the fine network of RE-rich interdendritic material disappeared, leaving behind only a few small isolated regions. This would seem to indicate that the predominant mechanism determining coercivity in these IGA RE-rich (Nd,Dy)–Fe–B powers is nucleation of reverse domains, rather than domain wall pinning at nonmagnetic intergranular material. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369838
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  • 5
    Electronic Resource
    Electronic Resource
    Pressure dependence of the intersubband transition in strained In0.15Ga0.85As/GaAs multiple quantum wells (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 475-477 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dependence of the intersubband transitions on pressure in strained In0.15Ga0.85As/GaAs multiple quantum wells has been studied in two samples with well widths of 8 and 15 nm, respectively, with photomodulated transmission spectroscopy by using a diamond anvil cell. The pressure coefficients of the energies for the intersubband transitions were found to depend significantly on the well widths and to be smaller than that of the band gap of constituents in bulk form. These results suggested that the critical thickness for strained In0.15Ga0.85As/GaAs layer should be smaller than 15 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.103670
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  • 6
    Electronic Resource
    Electronic Resource
    Reflection high-energy electron diffraction study of the molecular beam epitaxial growth of CaF2 on Si(110) (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1695-1697 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Molecular beam epitaxial growth of CaF2 on Si(110) was studied using reflection high-energy electron diffraction (RHEED) and scanning electron microscopy (SEM). An optimum substrate temperature range exists between 800 and 900 °C within which (110)-oriented epitaxy can be sustained. At the initial growth stage, long strips of CaF2 parallel to the [1¯10] direction are formed due to the growth anisotropy on the (110) surface. This is followed by the development of low-energy {111} facets, producing a ridged and grooved surface morphology. Growth then proceeds via the stacking of {111} planes on the sidewalls of the ridges. This surface morphology is believed to result from the combination of favorable energetics in exposing the low-energy {111} facets and the presence of twinned crystallographic domains. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115060
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  • 7
    Electronic Resource
    Electronic Resource
    Eu-doped CaF2 grown on Si(100) substrates by molecular beam epitaxy (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1891-1893 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Eu is incorporated into CaF2 films grown on Si(100) by molecular beam epitaxy using elemental Eu evaporation. Eu doping as high as 4.05 at. % does not significantly degrade the surface morphology, indicating a relatively high solubility of Eu in CaF2. Photoluminescence spectra from Eu-doped CaF2 show strong blue emissions from Eu2+ ions in cubic sites. The inhomogeneous broadening of the zero-phonon line near 24 190 cm−1 is reduced by ∼20% upon in situ annealing at 1100 °C. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114367
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  • 8
    Electronic Resource
    Electronic Resource
    Visible electroluminescence from Eu:CaF2 layers grown by molecular beam epitaxy on p-Si (100) (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 3610-3612 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Visible electroluminescence (EL) is observed at room temperature by current injection into Eu:CaF2 layers containing 7.5 and 8.0 at. % Eu grown by molecular beam epitaxy on lightly doped (100) p-type silicon. The EL spectra are broad with peaks near 700 and 600 nm, respectively. Room temperature photoluminescence spectra for the same samples exhibited peaks near 420 nm, with higher doped samples showing a more pronounced long wavelength tail. Although both metal and indium–tin–oxide (ITO) contacts were successfully used for current injection, the best EL intensity stability was achieved with contacts made of a 100 Å thick Al layer covered by a 2500 Å thick ITO layer. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120456
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  • 9
    Electronic Resource
    Electronic Resource
    Above-room-temperature continuous-wave mid-infrared photoluminescence from PbSe/PbSrSe quantum wells (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3608-3610 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strong photoluminescence between 3 and 4 μm was observed at temperatures as high as 55 °C from PbSe/PbSrSe multiple-quantum-well structures grown on BaF2 (111) substrates by molecular-beam epitaxy. Fabry–Perot interference fringes dominated the spectra, indicating that the luminescence was primarily due to stimulated emission processes. Peak emission energies were determined by fitting Gaussian functions to the spectra, and they showed that emission energies at 25 °C decreased from 402 to 312 meV as quantum-well thickness increased from 40 to 200 Å. The temperature tuning coefficient was also observed to decrease from 0.400 meV/K for a 200 Å multiple-quantum-well sample to 0.313 meV/K for a 40 Å multiple-quantum-well sample. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125403
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  • 10
    Electronic Resource
    Electronic Resource
    IV–VI compound midinfrared high-reflectivity mirrors and vertical-cavity surface-emitting lasers grown by molecular-beam epitaxy (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3688-3690 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Midinfrared broadband high-reflectivity Pb1−xSrxSe/BaF2 distributed Bragg reflectors and vertical-cavity surface-emitting lasers (VCSELs) with PbSe as the active material were grown by molecular-beam epitaxy. Because of an extremely high index contrast, mirrors with only three quarter-wave layer pairs had reflectivities exceeding 99%. For pulsed optical pumping, a lead salt VCSEL emitting at the cavity wavelength of 4.5–4.6 μm operated nearly to room temperature (289 K). © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126750
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