ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (20)
  • 1
    Electronic Resource
    Electronic Resource
    Microstructures of (In,Ga)P alloys grown on GaAs by metalorganic vapor-phase epitaxy (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 3077-3087 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The microstructures of metalorganic vapor-phase epitaxy alloys of (In,Ga)P grown on GaAs substrates were examined using transmission electron microscopy. Alloys examined were grown at 600–775 °C on substrates at or near (001) or (113)A using growth rates of 0.69 and 0.17 nm/s. Two common semiconductor alloy phenomenon, ordering and phase separation, were studied over this range of growth conditions. The CuPt-type ordering reflections are sharpest for growth at 675 °C and more diffuse at 600 and 725 °C due to higher densities of antiphase boundaries. Order can be eliminated by growth at 750 °C or above to obtain the highest band gaps and optical emission energies. Detailed investigation of the microstructure for growth at 675 °C indicates that ordered domains are platelets consisting of thin (1–2 nm) lamella on (001) planes that alternate between the two {111}B ordering variants, in agreement with a model proposed by others. We have formed "unicompositional'' quantum wells with sharply defined ordered layers between disordered barrier layers by changing growth temperature, which demonstrates that ordering is determined to a great degree by the conditions during growth. Phase separation is seen for the entire range of growth parameters, independently of ordering; its contrast shows modulations with a variable spacing ranging from a few nanometers to ∼100 nm. Implications of the coexistence of phase separation and ordering for growth models describing these phenomena are discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358659
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Band gap of "completely disordered'' Ga0.52In0.48P (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3185-3187 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The phenomenon of ordering in Ga0.52In0.48P is well known to reduce the optical band gap; the amount of band gap reduction is often used to measure the degree of ordering. For such measurements to be meaningful, the band gap of the random ("completely disordered'') binary alloy must be known. Values of this fundamental material parameter appearing in the literature vary by up to 40 meV, while the largest band gap reduction reported to date is only about 120 meV, i.e., within a factor of 3 of the uncertainty in one endpoint. We report here a low temperature band gap of 2.010±0.007 eV for material lattice matched to GaAs as deduced from a broad spectrum of samples believed for different reasons to contain minimal ordering. The corresponding value at 295 K is 1.910±0.008 eV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113717
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Microstructure of laterally oxidized AlxGa1−xAs layers in vertical-cavity lasers (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 19-21 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the lateral oxidation of AlxGa1−xAs (x=0.98 and 0.92) layers contained in vertical-cavity lasers using cross-sectional transmission electron microscopy. We find a fine-grained (∼4 nm) cubic spinel phase of Al2O3 in both the 2% Ga- and 8% Ga-oxidized layers. The 8% Ga-oxidized layers contract vertically by 6.7% and not the expected 20% for a fully dense Al2O3 layer, with the 2% Ga-oxidized layers showing a similar contraction. We observe a ∼17-nm-thick amorphous interface between the oxidized and unoxidized AlxGa1−xAs layers, which may account for the excellent electrical properties of these devices. We also observe metastable amorphous cavities associated with the moving reaction front. We infer the reaction proceeds from an initial amorphous phase that then transforms to a porous γ-Al 2O3 layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Threshold investigation of oxide-confined vertical-cavity laser diodes (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3689-3691 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report an experimental and theoretical analysis of the threshold properties of infrared oxide-confined vertical-cavity surface emitting lasers. We find good agreement between experiment and theory on the wavelength dependencies of the threshold current density and intrinsic voltage. The threshold voltage is shown to equal the sum of the calculated quasi-Fermi energy separation and the ohmic drop arising from a record low 17 to 30 Ω series resistance in these vertical-cavity lasers. Our analysis provides two independent means for determining the material threshold gain. A threshold gain of 500 cm−1 is found for these oxide-confined lasers, which is half that estimated for ion-implanted lasers with inferior electrical and optical confinement. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115744
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Improved AlGaInP-based red (670–690 nm) surface-emitting lasers with novel C-doped short-cavity epitaxial design (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 329-331 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A modified epitaxial design leads to straightforward implementation of short (1λ) optical cavities and the use of C as the sole p-type dopant in AlGaInP/AlGaAs red vertical-cavity surface-emitting lasers (VCSELs). Red VCSELs fabricated into simple etched air posts operate continuous wave at room temperature at wavelengths between 670 and 690 nm, with a peak output power as high as 2.4 mW at 690 nm, threshold voltage of 2.2 V, and peak wallplug efficiency of 9%. These values are all significant improvements over previous results achieved in the same geometry with an extended optical cavity epitaxial design. The improved performance is due primarily to reduced optical losses and improved current constriction and dopant stability. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115434
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Modal analysis of a small surface emitting laser with a selectively oxidized waveguide (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2616-2618 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe studies of an index-guided ∼4×3 μm2 vertical cavity surface emitting laser with a cw, room temperature 133 μA threshold current and 53% slope efficiency fabricated using selective wet thermal oxidation to provide optical and electrical confinement. While the device operates strictly single mode, a large number of transverse modes are evident in the subthreshold luminescence observed in both vertical and lateral directions. Despite the lumped nature of the index region, the transverse mode wavelengths agree very well with those predicted for a conventional distributed waveguide structure. Waveguide dimensions and an effective index step of 2% between the active and cladding region are determined by fitting the modal data. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Cavity characteristics of selectively oxidized vertical-cavity lasers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3413-3415 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We show that a buried oxide layer forming a current aperture in an all epitaxial vertical-cavity surface emitting laser has a profound influence on the optical and electrical characteristics of the device. The lateral index variation formed around the oxide current aperture leads to a shift in the cavity resonance wavelength. The resonance wavelength under the oxide layer can thus be manipulated, independent of the as-grown cavity resonance, by adjusting the oxide layer thickness and its placement relative to the active region. In addition, the electrical confinement afforded by the oxide layer enables record low threshold current densities and threshold voltages in these lasers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113371
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Transient photoinduced absorption in (AlxGa1−x)0.5In0.5P fractal quantum well heterostructures (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 966-968 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Picosecond photoinduced absorption measurements have been performed on four different (AlxGa1−x)0.5In0.5P fractal quantum well heterostructures. The results of these measurements reveal that, at early times following pulsed excitation, the carriers remain near the surface layer in which they were photogenerated, and populate the higher lying branches of the V-shaped fractal structure. With increasing time, the carrier population relaxes toward the lowest energy, central wall. The rate at which the relaxation occurs is governed by the characteristic layer of widths of the fractal structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117097
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Uniparabolic mirror grading for vertical cavity surface emitting lasers (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 605-607 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report details of mirror grading profiles for high efficiency vertical cavity surface emitting lasers. The mirrors provide low vertical resistance in conjunction with improvements in optical reflectivity, thermal conductivity, and lateral electrical conductivity in comparison to earlier grading profiles. The enhancement of these properties is verified by a comparison of thermal resistance and total electrical resistance for lasers of varying size. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116482
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    facet.materialart.
    Unknown
    Transient photoinduced absorption in (AlxGa1−x)0.5In0.5P fractal quantum well heterostructures (1996)
    American Institute of Physics
    Details
    Publication Date: 1996-08-12
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...