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  • 2010-2014  (7)
  • 1995-1999  (27)
  • 1965-1969  (2)
  • 1
    Electronic Resource
    Electronic Resource
    The temperature dependence of threshold current of chemical beam epitaxy grown InGaAs–InP lasers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1804-1807 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of threshold current between 130 and 310 K of 1.65 μm In0.53Ga0.47As–InP bulk lasers grown by chemical beam epitaxy has been measured. Comparison with a calculation of the spontaneous recombination current at threshold allows one to determine the proportion of current loss over this temperature range. It is found that the loss can be described using an Auger recombination component of the form Rauger=C'n3 exp(−Ea/kBT) where n is the carrier population density in the undoped active region. The activation energy Ea is found to be 39±5 meV which is in excellent agreement with the theoretical value for the conduction to heavy hole band/split-off to heavy hole band Auger process. The values obtained for the Auger coefficient C over the temperature range are in close agreement with published values obtained by time resolved photoluminescence. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360212
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  • 2
    Electronic Resource
    Electronic Resource
    Optical and electrical properties of selectively delta-doped strained InxGa1−xAs/GaAs quantum wells (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 2627-2632 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report here an investigation of selectively delta-doped strained InGaAs/GaAs quantum wells. Electronic structures of the systems were calculated by self-consistently solving the Schrödinger and Poisson equations and the calculations revealed a systematic variation of the band structure as the delta sheet moved away from the center of the well to the edge and finally to the barrier. The results were found to be in agreement with our photoluminescence (PL) measurements. For center-doped samples, band-gap renormalization was found to be strong from the PL data, and our realistic random-phase approximation calculation for the heavily doped sample is in excellent agreement with the PL data. The radiative lifetimes were measured to be around 450 ps for all the samples, and surprisingly they vary very little from sample to sample although the wave-function overlap was considerably different for some samples. We also report Shubnikov–de Haas (SdH) measurements on the two barrier doped cases. For the heavily doped sample (A12132), two oscillation signals were detected and they were identified as two upper subbands. The measured electron densities were in very good agreement with the self-consistent calculation. Illumination did not make any difference to the measured densities. For the low-doped sample (A12025), however, the measured electron density before illumination is much smaller than the calculated, and illumination was found to make a large difference. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361133
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  • 3
    Electronic Resource
    Electronic Resource
    On the determination of internal optical mode loss of semiconductor lasers (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2365-2367 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Use is made of a numerical simulation of the light—current characteristic to examine the errors which may arise in the determination of the optical mode loss (αi) from the cavity length dependence of the external differential efficiency (ηextd). In particular, we focus on the effects of incomplete Fermi level pinning and carrier leakage, and show that αi can only be determined correctly if ηextd is determined under conditions where it is invariant both with current level and temperature. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118875
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  • 4
    Electronic Resource
    Electronic Resource
    Threshold current temperature dependence of GaInP/(AlyGa1−y)InP 670 nm quantum well lasers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1265-1267 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of threshold current of (AlyGa1−y)InP/GaInP quantum well lasers (y=0.3, 0.4, and 0.5) has been investigated and used to characterize thermally activated loss mechanisms above room temperature. We show good agreement between activation energies measured by Arrhenius analysis and those expected for the loss of electrons from the well to the X-conduction band minima in the barrier. Our analysis uses measured band gaps of the actual structures, avoiding assumptions about the alloy compositions, spontaneous emission data to subtract radiative and other direct gap processes, and recent band gap data for this alloy system. This provides convincing experimental confirmation of the loss of electrons from the indirect minima as the preferred process causing the rise in current at high temperature in these lasers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114392
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  • 5
    Electronic Resource
    Electronic Resource
    Piezoelectric field effects in InGaAs (111)B quantum wells (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1393-1395 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strained In0.21Ga0.79As/GaAs quantum well structures have been grown by molecular beam epitaxy on (111)B GaAs substrates. Well widths between 20 and 160 A(ring), separated by 500 A(ring) barriers were grown sequentially on the same substrate and subsequently characterized by low-temperature (10 K) photoluminescence. The variation of the e-hh transition energy with well width is markedly different for samples grown simultaneously on (100) and (111)B substrates due to the strain induced piezoelectric field. Using the envelope function approximation, the dependence of n=1 e-hh transitions of (111)B samples on well width can be interpreted by the presence of a built-in electric field of magnitude of 1.45×107 V/m. In contrast to the (100) sample, exciton lifetimes in the (111)B sample depend strongly on well width because of spatial separation of electrons and holes in the triangular wells. In the 160 A(ring) well, the exciton lifetime increases to 755 ns corresponding to a reduction of about three orders of magnitude in the electron-hole wave function overlap integral. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115544
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  • 6
    Electronic Resource
    Electronic Resource
    Edge-emitting quantum well laser with Bragg reflectors (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2949-2951 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have fabricated edge-emitting GaAs/AlGaAs quantum well lasers in which the outer cladding layers have been replaced by multilayer Bragg reflectors. The reflectance peak spans the intrinsic spontaneous emission spectrum of the wells and there are no allowed vertical cavity modes within this spectrum. Compared with an equivalent alloy structure the threshold current of these lasers is reduced by 25%. This is due to a reduction in the spontaneous recombination current rather than an increase in internal efficiency. Studies of spontaneous emission normal to the sample surface show that the emission intensity is significantly reduced. We suggest that the threshold current is reduced by reduction in the spontaneous recombination rate due to a combination of inhibition of the emission and photon recycling. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114239
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  • 7
    Electronic Resource
    Electronic Resource
    Measurement of optical mode loss in visible emitting lasers (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 1975-1977 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe a technique for direct measurement of the passive optical mode loss of a semiconductor laser or similar semiconductor waveguide structure, based upon measurement of the attenuation of optically excited luminescence in the guided mode as a function of distance traveled along the passive guide. A spectrometer is used to select luminescence in the low energy tail of the spectrum which is subject to very little reabsorption. We have applied the method to a series of highly strained GaInP quantum well laser structures and observe an increase in the mode loss from 9.9 cm−1 for 1% strain to 46 cm−1 for 1.7% strain. This correlates with the appearance of clustered regions in the highly strained wells observed by transmission electron microscopy (TEM). © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.119759
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  • 8
    Electronic Resource
    Electronic Resource
    Direct monitoring of thermally activated leakage current in AlGaInP laser diodes (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2540-2542 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using specially prepared structures, we have observed emission from a layer of direct-gap "monitor" material placed between the p-contact layer and p-cladding layer of a conventional 670 nm GaInP laser diode at room temperature. This observation provides direct evidence for electron leakage through the p-cladding layer in these devices. Furthermore, although emission from the quantum well and waveguide core both pin above threshold, indicating that the Fermi levels clamp throughout the active region, the monitor emission continues to rise above threshold. This is characteristic of a drift component to the leakage current, which we have confirmed by a simulation of the carrier transport processes through the cladding layer with and without drift. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123891
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  • 9
    Electronic Resource
    Electronic Resource
    Fermi level pinning and differential efficiency in GaInP quantum well laser diodes (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1073-1075 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Analysis of spontaneous emission spectra of GaInP quantum well laser diodes above and below threshold show that the quasi-Fermi level separation pins within the quantum wells but not throughout the whole device structure. By reproducing the temperature and cavity length dependence of the external differential efficiency using these measurements it is shown that a value of internal differential efficiency which is nonunity is due to current spreading and incomplete carrier injection and that the temperature dependence is due to the temperature dependence of the efficiency with which carriers are injected into the quantum well.© 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118488
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of single-pass optical gain and internal loss using a multisection device (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 2527-2529 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe a technique for the measurement of optical gain and loss in semiconductor lasers using a single, multisection device. The method provides a complete description of the gain spectrum in absolute units and over a wide current range. Comparison of the transverse electric and transverse magnetic polarized spectra also provides the quasi-Fermi-level energy separation. Measurements on AlGaInP quantum well laser structures with emission wavelengths close to 670 nm show an internal loss of 10 cm−1 and peak gain values up to 4000 cm−1 for current densities up to 4 kA cm−2. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125066
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