J. A. Rossi

LPE In1−xGaxP1−zAsz (x∼0.12, z∼0.26) DH laser with multiple thin‐layer (<500 Å) active region

A liquid‐phase‐epitaxial (LPE) double‐heterojunction (DH) laser structure with an ∼1‐μm ’’active region’’ consisting of ≳20 In1−xGaxP1−zAsz and InP lattice‐matched thin layers is described. The thin‐layer dimensions are small enough (<500 A) to make quantum size effects relevant.

Multiple liquid phase epitaxy of In1−xGaxP1−zAsz double‐heterojunction lasers: The problem of lattice matching

Multiple liquid phase epitaxy of In1−xGaxP1−z Asz‐InP double heterojunctions, from a single set of In‐rich melts, is demonstrated, and is shown to be a useful technique for the study of the problem of lattice matching at heterojunction interfaces and for growing large numbers of low‐threshold (’’defect‐free’’) DH laser wafers (λ∼1 μm).

Single thin‐active‐layer visible‐spectrum In1−xGaxP1−zAsz heterostructure lasers

Single active‐layer visible‐spectrum In1−xGaxP1−zAsz heterostructure lasers are described that exhibit quantum size effects (QSE) in photoluminescence and by means of diode injection (λ<6300 A). Liquid‐phase epitaxial (LPE) quaternary layers as thin as ∼300 A have been realized. It is demonstrated that single thin‐layer recombination wells (Lz<1000 A) are very effective in the capture and recombination of carriers, even if injection occurs at some distance (a<1 μm) from the thin layer. On the other hand, optical confinement and absorption are weak in diodes with single active layers thin enough to exhibit QSE. This behavior indicates that the type of thin‐active‐layer diodes described here are not optimum as lasers, but may lead to improved light emitters.

Defect density reduction in epitaxial silicon

We present results establishing a relationship between epitaxial layer defect density and starting substrate perfection for silicon p/p+ epitaxy. Using these results we demonstrate that control of the layer defect density at a level <20/cm2 is reproducibly accomplished. At this level, the defects are primarily S pits. The density of stacking faults and dislocations is kept at <1/cm2.

In1−xGaxP1−zAsz double‐heterojunction‐laser operation (77 °K, yellow) in an external grating cavity

In1−xGaxP1−zAsz double‐heterojunction lasers fabricated by liquid‐phase epitaxy are operated at λ ≲6000 A (77 °K) in an external grating cavity to provide wavelength‐selective optical feedback. Diodes with and without antireflecting coatings and with heterobarrier heights of ∼20, ∼65, and ∼90 meV are examined. With external grating feedback, laser operation occurs at reduced threshold current densities and narrower linewidths and, depending upon heterobarrier height, can be tuned over an appreciable wavelength range. Within certain tuning limits on either side of line center, the carrier recombination is drawn to the grating wavelength and, as in earlier work, laser operation on a homogeneously broadened line is observed. Beyond these limits, particularly for excitation just above the threshold of stimulated emission, laser operation on an inhomogeneously broadened line can be distinguished. These observations showing that homogeneous and inhomogeneous line broadening occur in a semiconductor laser are ac...

In/sub 1-x/Ga/sub x/P/sub 1-z/As/sub z double-heterojunction-laser operation (77/sup 0/ K, yellow) in an external grating cavity

In1−xGaxP1−zAsz double‐heterojunction lasers fabricated by liquid‐phase epitaxy are operated at λ ≲6000 A (77 °K) in an external grating cavity to provide wavelength‐selective optical feedback. Diodes with and without antireflecting coatings and with heterobarrier heights of ∼20, ∼65, and ∼90 meV are examined. With external grating feedback, laser operation occurs at reduced threshold current densities and narrower linewidths and, depending upon heterobarrier height, can be tuned over an appreciable wavelength range. Within certain tuning limits on either side of line center, the carrier recombination is drawn to the grating wavelength and, as in earlier work, laser operation on a homogeneously broadened line is observed. Beyond these limits, particularly for excitation just above the threshold of stimulated emission, laser operation on an inhomogeneously broadened line can be distinguished. These observations showing that homogeneous and inhomogeneous line broadening occur in a semiconductor laser are ac...

GaAs1−yPy heterojunction lasers

Data are presented showing that low‐threshold (300 °K) visible‐spectrum GaAs1−yPy and In1−xGaxP1−zAsz DH laser diodes can be grown on GaAs1−yPy substrates of composition at least as high as y=0.41, which corresponds to a short‐wavelength limit of ∼6420 A for the ternary and ∼6180 A for the quaternary.The growth and laser properties of In/sub 1-x/Ga/sub x/P/sub 1-z/As/sub z//GaAs/sub 1-y/P/sub y/ single heterojunction laser diodes are described. High- quality p-type In/sub 1-x/Ga/sub x/P/sub 1-z/As/sub z/ layers are grown by liquid phase epitaxy (LPE) on n-type VPE GaAs/sub 1-y/P/sub y/ substrates of composition y = 0.32 - 0.40. Laser operation (77

GaAs/sub 1-y/P/sub y/ heterojunction lasers

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Continuous room-temperature photopumped laser operation of visible-spectrum LPE In 1-x Ga x P 1-z As z (&#955; ~ 6700 &#197;)

K) of these quaternary-ternary heterojunctions is demonstrated at shorter wavelengths (less than 6300 A) and lower thresholds (J/sub th/ greater than or equal to 6.2 x 10

GaAs/1-y/P/y/ heterojunction lasers

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