Lasers and LED's for optical communications using fibers

Kressel, H.

doi:10.1029/rs016i004p00445

Cited by 3 publications

(2 citation statements)

References 23 publications

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“…The failure to achieve uniform alloy composition leads to rapid deterioration of the material quantum efficiency (Holonyak and Lee 1979). It is essential that the number of non-radiative recombination centres (point and line defects) is small for high performance optoelectronic devices (Kressel 1981) and a substantial amount of research effort on alloys has been devoted to methods of controlling and characterising extrinsic phenomena (e.g. defects, junctions, interfaces, etc).…”

Section: Development Of Semiconductor Alloys As a Means Of Optimising...mentioning

confidence: 99%

“…Much of the interest in point defects has been fuelled by their role in the formation of non-radiative recombination centres identified as a major cause for degradation of the alloy materials (i.e. optoelectronic devices (Kressel 1981 and references therein)). In particular, the possibility that enough energy (of the order of E,,,) may be released in a single recombination event and supplied to the lattice to initiate defect motion and formation of a dislocation climb has been vigorously studied.…”

Section: Electronic Properties Of Deep Impurities and Lattice Defects...mentioning

confidence: 99%

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Electronic properties of semiconductor alloy systems

Jaroš¹

1985

Rep. Prog. Phys.

176

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Semiconductor alloys provide a natural means of tuning the magnitude of the forbidden gap and other material parameters so as to optimise and widen the application of semiconductor devices. With the advent of small-structure systems, such as quantum wells and superlattices, the effects of alloy composition, size, device geometry, doping and controlled lattice strain can be combined to achieve maximum tunability. In this article, the concepts and ideas peculiar to the description and modelling of semiconductor alloy systems are reviewed with a view to providing a link between electronic structure and optical and transport properties.The material parameters of intrinsic and extrinsic alloys are normally derived from those of the endpoint compounds in terms of a simple interpolation procedure. This model assumes that the material is a nearly perfect random alloy and that the electronic structure can be generated from suitably averaged parameters of the constituent compounds. Any deviation from this virtual crystal approximation (VCA) is treated separately as a perturbation. Consequently, the concepts and methods developed for compound semiconductors can be employed in a straightforward manner to describe alloys. However, recent experimental and theoretical studies on several semiconductor alloys (e.g. GaInAs, HgCdTe) indicate that the VCA breaks down whenever the mismatch between the electronic properties of the constituent atoms exceeds a certain critical value. The breakdown of the VCA is manifested by (i) the formation of ordered structures of lower symmetry, and (ii) the weakening of sp3 bonds on one sublattice which leads to selective localisation and charge transfer. In the case of defects, the position of deep levels and resonances reflects strong mixing by the short-range part of the potential of Bloch states spanning a range of many tens of volts. The relationship between the level depth and localisation as a function of alloy composition is non-linear and unrelated to the bowing of the alloy band gap. In the assessment of the electronic properties of submicron structures containing an alloy semiconductor, the bulk alloy properties and the effects of confinement, doping and strain must be treated on an equal footing. The bulk alloy states are mixed and the corresponding optical and transport parameters are changed. A certain degree of such mixing normally occurs in lattice-matched undoped systems as a result of the interaction between the states belonging to adjacent layers. This leads to the formation of well localised states which 0034-4885/85/081091+ 64$09.00 @ 1985 The Institute of Physics 10911092 M Jaros lie outside the confining barriers and which cannot be properly accounted for by the simple envelope function model. In narrow and medium-thick wells (< 100 A) the confinement effect is a sensitive function of the short-wavelength Fourier components of the potential. A breakdown of the vcA-which alters the description of alloy properties in a qualitative manner-has significant consequences for confine...

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Section: Development Of Semiconductor Alloys As a Means Of Optimising...mentioning

confidence: 99%

Section: Electronic Properties Of Deep Impurities and Lattice Defects...mentioning

confidence: 99%

Electronic properties of semiconductor alloy systems

Jaroš¹

1985

Rep. Prog. Phys.

176

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Sendeelemente

Kersten

1983

Einführung in Die Optische Nachrichtentechnik

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Improved Meltback Procedures for Liquid-Phase-Epitaxial Growth of Planar and Buried Heterostructures

Chin¹,

Chin²,

DiGiuseppe³

et al. 1982

MRS Proc.

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In the liquid phase epitaxy on indium phosphide, the substrate,just prior to the growth of the first epitaxial layer, is commonly etched back with an indium melt to remove any thermallydegraded surface and to ensure uniform and consistent wetting.This procedure, however, often produces defects which degrade both planar and buried heterostructure devices. For planar edgeemitters and lasers, the resulting rippled surface morphology degrades device performance by scattering light. For buried heterostructures, the meltback in the regrowth step leads to indium-rich inclusions. The effects of meltback on material quality are presented, and a new multiple meltback procedure which maintains flat surface morphology and eliminates inclusions is described.

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Lasers and LED's for optical communications using fibers

Cited by 3 publications

References 23 publications

Electronic properties of semiconductor alloy systems

Electronic properties of semiconductor alloy systems

Sendeelemente

Improved Meltback Procedures for Liquid-Phase-Epitaxial Growth of Planar and Buried Heterostructures

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