摘要:

The first cw operation of an AlGaAs/GaAs distributed Bragg reflector laser was achieved at room temperature with a threshold current as low as 38 mA. Surface emission exceeding 4 mW was obtained with an external differential quantum efficiency of 9% and a beam divergence of 0.17°×10°. A two‐dimensional laser array with 3×4 gratings was also fabricated and an output power exceeding 500 mW was obtained under pulsed condition.

ISSN:0003-6951    

DOI:10.1063/1.97721

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The passive mode locking of a continuous wave dye laser operating in the blue‐green spectral region is reported for the first time. In a simple linear configuration with no optimization of the intracavity dispersion, coumarin 102, excited by the ultraviolet lines of an argon ion laser, has been mode locked using 3,3’‐diethyl oxacarbocyanine iodide over the spectral range 487–508 nm, yielding pulses as short as 580 fs duration at 498 nm.

ISSN:0003-6951    

DOI:10.1063/1.97722

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We propose and analyze a new class of multichannel optical waveguide junctions. These junctions consist of a multimode channel waveguide that branches into several single‐mode channels. We show that such waveguide junctions, when properly designed, can route each of the spatial modes of the multimode waveguide into a different single‐mode channel. These waveguide junctions should be useful in selective mode excitation, routing, switching, modulation, and wavelength multiplexing/demultiplexing of guided waves, as well as for mode control in semiconductor lasers.

ISSN:0003-6951    

DOI:10.1063/1.97723

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Near‐diffraction‐limited (0.13° wide) single‐lobe operation of a 40‐element AlGaAs array emitting 510 mW cw is obtained by external injection locking, with 11.0 mW of injected power incident on the array. The injected and the array output beams were tilted relative to the facet normal to allow for spatial separation of the two beams and efficient coupling into a single‐mode fiber; 150 mW was coupled into a 5‐&mgr;m core, polarization holding fiber.

ISSN:0003-6951    

DOI:10.1063/1.97724

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

High rotational velocity and centrifugal isotopic separation of carbon in a vacuum‐arc plasma centrifuge are presented. Enrichments of up to 390% for13C are measured at 6 cm radius with angular rotation frequencies in excess of 1.0×105rad/s in an axial magnetic field of 0.12 T.

ISSN:0003-6951    

DOI:10.1063/1.97725

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Direct evidence, using reflection high‐energy electron diffraction, is found for a transition, at a specific thickness, from an amorphous to a crystalline state in Sb deposited on GaAs(110). After crystallization, Sb exists as small, 30–40 A˚ crystallites with a (0001) contact plane but randomly azimuthally oriented. A new surface phase, GaAs(110)p(3×2)‐Sb, is found and appears to be a consequence of the crystallization transition.

ISSN:0003-6951    

DOI:10.1063/1.97726

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Amorphous Ta93Cu7and Ta80Cu20alloy films are prepared by co‐sputtering of pure Ta and pure Cu targets with a rotating sample holder table. To investigate the possible application of these materials as diffusion barriers for the Au‐GaAs system, vacuum annealings are made in the temperature range from 200 to 800 °C. Resistivity change, x‐ray diffraction, and Auger electron spectroscopy measurements are performed to find the chemical and metallurgical stabilities of these materials in this system. The reaction temperature for TaxCu1−xin contact with GaAs lies between 500 and 700 °C. For Au in contact with TaxCu1−xthe reaction occurs at about 600 °C. Amorphous Ta93Cu7shows different interdiffusion characteristics with surrounding elements than does Ta80Cu20.

ISSN:0003-6951    

DOI:10.1063/1.97727

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Heteroepitaxial growth of InP on Si by low pressure metalorganic chemical vapor deposition is reported. The trimethylindium‐trimethylphosphine adduct was used as the In source in this study and PH3as the source of P. From x‐ray and scanning electron microscopy examinations, good crystallinity InP epilayers with mirrorlike surfaces can be grown directly on (100) and (111) Si substrates. The carrier concentration profile shows that the carrier distribution in the InP epilayer is very uniform. The efficient photoluminescence compared with that of InP homoepitaxy shows that the InP/Si epilayers are of good quality.

ISSN:0003-6951    

DOI:10.1063/1.97728

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Oscillatory structure is observed in thedI/dVandd2I/dV2characteristics of conventional GaAs/GaAlAs high electron mobility transistor samples at liquid‐helium temperature, which can be explained using a Fowler–Nordheim tunneling theory. The position of the oscillations allows a determination of the conduction‐band discontinuity, and the depth of the deep donor levels in the GaAlAs for high aluminum concentrations. The fit of the data gives a value of &Dgr;Ec/&Dgr;Eg=0.61±0.04 for aluminum concentration 30, 36, and 40%. The deep donor level in the GaAlAs was determined to be 130 meV below the conduction band.

ISSN:0003-6951    

DOI:10.1063/1.97729

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The accumulation of oxygen at GaAs/AlGaAs interfaces grown by molecular beam epitaxy has been established by secondary ion mass spectrometry profiling of GaAs/AlGaAs multilayer structures. An enhanced oxygen peak was observed at the boundary between GaAs and AlxGa1−xAs layers withx=0.35 andx=1 when the binary layer is deposited on top of the ternary layer. The segregation of oxygen may be a contributing factor responsible for the lower luminescence reported in the first GaAs well of multilayer quantum well structures and for the difference between normal and inverted interface high electron mobility devices.

ISSN:0003-6951    

DOI:10.1063/1.97730

出版商:AIP    

年代:1987

数据来源: AIP