1. |
Optimization of stripe width for low‐threshold operation of quantum well laser diodes |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2487-2489
J. S. Osinski,
K. M. Dzurko,
S. G. Hummel,
P. D. Dapkus,
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摘要:
An experimentally verified model for threshold current in GaAs/AlGaAs quantum well laser diodes has been extended to calculate for the first time the dependence of threshold current on stripe width. The lowest possible threshold is shown to occur when the lateral confinement factor is in the range of 55–60% for typical devices, a value that is not affected by mirror reflectivity or lateral index step. A simple, generalized optimization scheme for obtaining the unique width/length combination that results in lowest threshold is presented, and predicts potential as‐cleaved threshold currents as low as 0.5 mA.
ISSN:0003-6951
DOI:10.1063/1.102887
出版商:AIP
年代:1990
数据来源: AIP
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2. |
Optical generation of picosecond electrical pulses in asymmetric quantum well structures placed in a transverse magnetic field |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2490-2492
J. Khurgin,
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摘要:
New technique for optical generation of ultrashort electrical pulses in semiconductor heterostructures is proposed. It is shown that in asymmetric quantum well structures placed in a transverse magnetic field, optically excited carriers have an asymmetrical distribution ink‐vector space, and therefore, they have finite drift velocity in the direction perpendicular to both growth direction and field direction. It results in photogenerated voltage along the quantum well plane. The temporal response and sensitivity of the proposed scheme are evaluated, and possible applications are suggested in ultrafast detectors or as a tool for generation and study of hot carriers.
ISSN:0003-6951
DOI:10.1063/1.102888
出版商:AIP
年代:1990
数据来源: AIP
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3. |
Precision AlGaAs Bragg reflectors fabricated by phase‐locked epitaxy |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2493-2495
J. D. Walker,
K. Malloy,
S. Wang,
J. S. Smith,
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摘要:
Extremely high quality AlGaAs Bragg reflectors have been fabricated by molecular beam epitaxy using advanced growth techniques including phase‐locked epitaxy, short‐period superlattices, and growth interruptions. These techniques are used to control the layer periodicity, interface flatness, and producibility of the structures. The experimental reflectance spectrum shows an extremely square stop band and very regular side lobes closely matching the theoretical spectrum. A comparison of experimental to theoretical reflectance spectra is used to show that the layer periodicity is maintained within 1% and the interface flatness controls the optical loss per interface to less than 0.1%. Experimental results show a maximum reflectance of 98.5% for a (AlAs)6(GaAs)3/(AlAs)1(GaAs)435.5‐period Bragg reflector.
ISSN:0003-6951
DOI:10.1063/1.102890
出版商:AIP
年代:1990
数据来源: AIP
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4. |
Drastic reduction of series resistance in doped semiconductor distributed Bragg reflectors for surface‐emitting lasers |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2496-2498
K. Tai,
L. Yang,
Y. H. Wang,
J. D. Wynn,
A. Y. Cho,
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摘要:
Modifications to reduce the series resistance inp‐type semiconductor distributed Bragg reflectors (DBR) consisting of ten pairs of quarter‐wavelength GaAs (high refractive index)/Al0.7Ga0.3As (low index) layers were made by inserting an intermediate Al0.35Ga0.65As layer or a 200 A˚ superlattice of GaAs(10 A˚)/Al0.7Ga0.3As (10 A˚) at the GaAs/Al0.7Ga0.3As heterointerfaces. The specific DBR series resistance was reduced by two orders of magnitude to about 6.2×10−5&OHgr; cm2. These modifications did not alter the optical reflectivity and nearly identical reflection spectra were measured.
ISSN:0003-6951
DOI:10.1063/1.102869
出版商:AIP
年代:1990
数据来源: AIP
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5. |
Low‐threshold GaAs/AlGaAs graded‐index separate confinement heterostructure lasers grown by molecular beam epitaxy on oxide‐masked Si substrates |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2499-2501
Geoffrey F. Burns,
Herve´ Blanck,
Clifton G. Fonstad,
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摘要:
Low‐threshold GaAs/AlGaAs lasers have, for the first time, been grown selectively on 10 &mgr;m stripe openings patterned in oxide on Si substrates. Lateral current confinement provided by side facets reduces edge leakage, and results in threshold currents as low as 75 mA for a 10 &mgr;m by 210 &mgr;m device, a nearly two‐fold improvement over comparable etched ridge waveguide lasers. Spectrum measurements show single longitudinal mode emission near 850 nm. This adaptation of selective heteroepitaxial growth for lateral current confinement of AlGaAs/GaAs lasers on Si substrates, adopted from similar work on GaAs substrates, offers potential for significant threshold current reductions of lasers integrable with Si.
ISSN:0003-6951
DOI:10.1063/1.102870
出版商:AIP
年代:1990
数据来源: AIP
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6. |
1.5 &mgr;m InGaAsP/InP buried crescent superluminescent diode on ap‐InP substrate |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2502-2503
T. R. Chen,
Y. H. Zhuang,
Y. J. Xu,
A. Yariv,
N. S. Kwong,
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摘要:
An InGaAsP/InP superluminescent diode (SLD) emitting at 1.54 &mgr;m has been fabricated. The device uses a buried crescent structure on ap‐InP substrate. The parameters were optimized for high output power, small spectral modulation, and smooth far‐field operation. The coherence function of the SLD emission was studied systematically. An output power of 5 mW, a coherence length of 41 &mgr;m, and a second coherence peak suppression ratio of 22 dB were obtained.
ISSN:0003-6951
DOI:10.1063/1.102871
出版商:AIP
年代:1990
数据来源: AIP
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7. |
Slow wave propagation in air‐filled porous materials and natural rocks |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2504-2506
Peter B. Nagy,
Laszlo Adler,
Brian P. Bonner,
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摘要:
Slow compressional waves in fluid‐saturated porous solids offer a unique acoustical means to study certain material properties, such as tortuosity and permeability. We present a novel experimental technique based on the transmission of airborne ultrasound through air‐filled porous samples. The suggested method can be used to measure the velocity and attenuation of the slow compressional wave in a wide frequency range from 30 to 500 kHz. More important, the technique is so sensitive that it provides irrefutable evidence of slow wave propagation in air‐saturated natural rocks and lends itself quite easily to tortuosity measurements in such materials, too.
ISSN:0003-6951
DOI:10.1063/1.102872
出版商:AIP
年代:1990
数据来源: AIP
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8. |
Schottky barrier contacts on defect‐free GaAs (110) |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2507-2509
Zuzanna Liliental‐Weber,
E. R. Weber,
J. Washburn,
J. H. Weaver,
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摘要:
High resolution transmission electron microscopy and analytical electron microscopy show direct evidence for defect‐free interfaces produced byinsitucluster deposition of Au, Ag, and Ti onto ultrahigh vacuum‐cleavedn‐GaAs. In contrast to interfaces produced by atom‐by‐atom deposition, no specific interface reconstruction or orientation relationship and no change of stoichiometry of the GaAs near the interface was observed. Schottky barrier heights correspond to unusual Fermi level pinning positions in the upper half of the GaAs band gap, in clear contrast to values obtained for atom deposition and for diodes prepared by standard technology on GaAs (100). These results give clear evidence that Fermi level pinning for metal/GaAs interfaces formed without defects does not follow the predictions of current metal‐induced gap‐state models.
ISSN:0003-6951
DOI:10.1063/1.102873
出版商:AIP
年代:1990
数据来源: AIP
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9. |
Production of highly oxidized As on GaAs (110) at 20 K |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2510-2512
Steven G. Anderson,
J. M. Seo,
T. Komeda,
C. Capasso,
J. H. Weaver,
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摘要:
High‐resolution synchrotron radiation photoemission results for O2physisorbed on GaAs (110) show Ga‐O and As‐O formation that is a direct result of photon‐induced reaction at 20 K. Spatially resolved studies show that the thickness and chemical composition of the semiconductor oxides vary in proporition to total beam irradiation. The extent of reaction can be controlled by varying the amount of oxygen present on the surface, and As5+‐like bonding configurations can be formed. These results can only be understood when competition between thermodynamic, kinetic, photon‐ and electron‐mediated processes are considered.
ISSN:0003-6951
DOI:10.1063/1.103259
出版商:AIP
年代:1990
数据来源: AIP
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10. |
Observation of silicon wafer emissivity in rapid thermal processing chambers for pyrometric temperature monitoring |
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Applied Physics Letters,
Volume 56,
Issue 25,
1990,
Page 2513-2515
J. Nulman,
S. Antonio,
W. Blonigan,
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摘要:
The emissivity of silicon wafers in a rapid thermal processing chamber has been measured as a function of the wafer temperature. Wafers with different surface roughness and layers have been studied. For transparent wafers, both sides of the wafer affect the emissivity. This emissivity is not only affected by surface roughness, but also by the layers deposited on the wafer. It has also been observed that while the emissivity increases rapidly as the temperature increases from its room value to 600 °C, the emissivity decreases with a slope of −8.89×10−5 °C−1for temperatures larger than 600 °C.
ISSN:0003-6951
DOI:10.1063/1.102874
出版商:AIP
年代:1990
数据来源: AIP
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