ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

You have 0 saved results.
Mark results and click the "Add To Watchlist" link in order to add them to this list.
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Chemical Physics Letters 75 (1980), S. 239-242 
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 8 (1978), S. 135-179 
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1265-1267 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe a convenient method utilizing chemical reduction of SiO2 by Al (from AlxGa1−xAs) to generate Si and O for impurity-induced layer disordering (IILD) of AlxGa1−xAs-GaAs quantum well heterostructures (QWHs). Experimental data show that Si-O diffusion (from SiO2) is an effective source of Si for Si-IILD and of O that compensates the Si donor, thus resulting in higher resistivity layer-disordered crystal. The usefulness of the Si-O IILD source for fabricating low-threshold disorder-defined buried-heterostructure AlxGa1−xAs-GaAs QWH lasers is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2015-2018 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Process conditions for fabricating Si-O impurity-induced layer disorder defined AlxGa1−xAs-GaAs buried heterostructure quantum well lasers utilizing a fully self-aligned planar process and conventional As free open-tube-furnace annealing are presented. An SiO2 layer, deposited by sputtering, was used as a diffusion source for Si and O impurities as well as a source for Ga vacancies that enhance impurity diffusion and allow for a reduction in the required annealing temperature and time. A self-aligned native oxide of the AlxGa1−xAs cladding layer was used to form a Zn diffusion mask and dielectric layer. Lasers fabricated using this process exhibited threshold currents as low as 2.72 mA and external differential quantum efficiencies of 79% at room temperature in continuous operation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2235-2238 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data describing the deterioration of AlxGa1−xAs-GaAs heterostructures in long-term exposure (2–12 years) to normal room environmental conditions (∼20–25 °C, varying humidity) are presented. Optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron dispersion x-ray spectroscopy are used to examine AlxGa1−xAs-GaAs quantum-well heterostructure material that has hydrolyzed at cleaved edges, cracks, and fissures, and at pinholes in cap layers. The hydrolysis is found to be significant for thicker (〉0.1 μm) AlxGa1−xAs layers of higher composition (x〉0.85).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experiments are described determining the critical parameters for vacancy- and impurity-induced layer disordering of AlxGa1−xAs-GaAs quantum-well heterostructure (QWH) crystals that utilize SiO2 and Si3N4 diffusion source layers. The SiO2- or Si3N4-capped QWH crystal surface reaches equilibrium with the external annealing ambient by diffusion of Ga and As through the encapsulant layer, thus determining the crystal-surface deviation from stoichiometry and the column III vacancy concentration for layer disordering. By proper design of the QWH crystal, encapsulant layer thickness, and annealing ambient, the SiO2 (Si3N4) can be employed as a column III vacancy source (or mask) or as a Si and O (or N) diffusion source to effect impurity-induced layer disordering.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Extensive data are presented on impurity-induced layer disordering (IILD) of AlxGa1−xAs-GaAs quantum-well heterostructures and superlattices that are Si implanted and annealed (Si+-IILD) at three different implant doses. We show that impurity activation is not critical to the layer disordering process and that Si diffusion from the implanted profile initiates Si+-IILD. When the implant dose is as high as φ≥5×1013/cm2 (nSi ≥2×1018/cm3), Si interstitial loops (Si-ILs) form by diffusion and agglomeration of the implanted Si atoms during the initial stages of annealing. If a source of Ga vacancies is provided (e.g., via an As overpressure or SiO2 encapsulation), the Si-ILs dissociate and supply Si atoms for diffusion and hence Si+-IILD during the latter stages of annealing. If a Si3N4 encapsulant is employed, however, fewer Si-ILs form and Si diffusion is inhibited. For an implantation dose as low as φ=1×1012/cm2 (nSi =3×1016/cm3), extensive Si+-IILD is realized via capless annealing and Si-ILs are not observed. It is significant for device applications that the layer-disordered material operates as a cw 77 K photopumped laser, which indicates that the layer averaging (IILD) does not damage the crystal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 4662-4665 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Cryobaric (11–100 K and 300 K, 0–65 kbar) measurements of photoluminescence in GaAs/AlxGa1−xAs multiquantum well structures are described. Results on a narrow-well (38 A(ring) wide) structure exhibiting both quantum well and bulk GaAs emission (from a thick buffer region) allow direct comparison of the two for the first time. We find that transitions between Γ-derived n=1 confined levels have the same pressure coefficient, within ±0.2 meV/kbar, as the bulk E0 gap, 11.4 meV/kbar. An interaction between n=1 electron states and a state 35–40 meV below the X-conduction minima is observed within the pressure-induced Γ-X crossover region for our narrow-well sample. The proposed origin of the latter state is residual interface impurities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 4515-4520 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two different quantum well heterostructure wafers are used to fabricate buried-heterostructure AlxGa1−xAs-GaAs quantum well lasers using Si-induced layer disordering (via Si diffusion). In contrast to the first wafer (QWH1), the second quantum well wafer (QWH2) utilizes Zn instead of Mg as the p-type dopant in the top AlxGa1−xAs confining layer and yields, because of concentration mismatch in acceptor and donor doping in the confining layers (nZn〉nSe), inferior laser diodes owing to Zn diffusion from the p-type to the n-type confining layer during high temperature processing (850 °C Si diffusion). The first quantum well heterostructure, however, employs a lower concentration Mg doping for its p-type confining layer (nMg〈nSe) and yields high performance devices when used with the Si-induced layer-disordering process. For QWH1 the p-n junction and injection is not displaced (as for QWH2) from the QW active region during Si-induced layer disordering (850 °C annealing). A fabrication process is presented in which quantum well laser diodes are built with active regions as narrow in width as 0.6 μm, cw room-temperature laser threshold currents as low as 3 mA, and pulsed current thresholds as low as 1.5 mA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 1489-1494 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The far-field supermode patterns of a phase-locked multiple-stripe quantum-well heterostructure (QWH) laser diode are described as a function of injection current and emission wavelength, the latter controlled by an external grating. The external-grating cavity is used to isolate single or multiple supermodes of the multiple-stripe QWH laser (Pout〉170 mW cw, λ∼7400 A(ring)). The progression of supermode patterns consists of a discrete set of mode configurations for each longitudinal mode of the spectrum. The progression is cyclic with a ∼2.8-A(ring) period which corresponds to the longitudinal mode spacing of the diode. Under high gain conditions, i.e., near the center of the recombination-radiation spectrum or at higher current levels, continuous tunability is observed with gradual transitions between supermode eigenstates. As the gain is reduced (low current), the number of supermodes observed decreases until only the in-phase pattern, i.e., each emitter at the same phase, remains above threshold. The far-field patterns range from a double-lobe pattern with a 10° peak separation (5 μm between emitter phase reversals) to a narrow (〈2° full angle half power) single-lobe in-phase pattern. The experimental data are compared to the results of coupled-mode analysis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...