Dislocation content and thermal stability are improved by codoping iron doped semi-insulating (SI) InP with isoelectronic impurities. By using 3d impurities (Ti or Cr) as deep compensating donors, new SI InP have been grown. The thermal stability of Ti doped InP will be shown to be superior to that of Fe or Cr doped InP.

Among the various physical approaches of wafer defect characterization, special attention is to be payed to the infra red techniques of inspection. In particular, transmission images and scattering tomography will be emphasized. The former leads to low resolution images attributed to EL2 absorption; this point will be critically reviewed. The latter gives highly resolved images of decorated dislocations. The state of the art in both techniques will be presented and compared.

Fast neutron irradiated InP substrate material reveals a new broad electron paramagnetic resonance singlet of 2750 G peak to peak linewidth, located at g = 2.28 ± 0.06, together with the expected anion antisite PIn spectrum. It is ascribed to a phosphorus vacancy Vp. Irradiated InP:Fe shows in addition a complex spectrum of Fe associated defects among which the Fe In-In i pairs aligned along 111 and 001 directions could be identified.

After a brief introduction to the basics of impurity induced disordering in AlAs(or AlxGa1-xAs)-GaAS super-lattices and quantum wells, a detailed review of different experimental methods presently empioyed to achieve intermixing are presented and discussed.

The growth of InP and GaInAsP by Molecular Beam Epitaxy has been highly improved by the use of gas sources : hydrides sources (GSMBE) and metalorganic sources (MOMBE or CBE). High purity materials, heterostructures with low threshold current density (1 kA/cm2), quantum wells with sharp interfaces have been grown either by GSMBE or by MOMBE. These techniques which offer many advantages as compared to other epitaxial techniques, especially regarding the compositional homogeneity, appear very promising for high yield production of high performance components and optoelectronic and microelectronic IC's.

In this paper, we first describe the molecular beam epitaxial (MBE) growth procedure of AlGaInAs lattice-matche to InP. Next, we present the electrical and optical properties of this system in the whole range of compositions. We then compare these results with those of the more familiar GaInAsP/InP system.

Photoluminescence spectra measured on angle lapped InGaAs/InP and InGaAsP/InP LPE grown heterostructures have been used to determine carrier concentration and composition profiles in the consecutive epitaxial layers. The results have been supported by the ones obtained by SIMS measurements. It was also found that the shape of the photoluminescence spectrum can give an information on the lattice mismatch between ternary and quaternary epitaxial layers and the InP substrate.

Focused ion beams (FIB) systems allow maskless processes as n, p doping, isolation of semiconductors and selective disordering of GaAs-AlGaAs superiattices at submicronic scale. UHV compatiblility of FIB makes MBE/FIB coupling very promissing to build lasers and integrated optoelectronic structures. FIB machining of optical structures as laser mirrors can replace classical processes, with better control and comparable performances.

A novel three-segmented large optical cavity GaA1As/GaAs laser with channeled twin-ridge substrate is presented. The lasers show CW threshold current 30-70 mA and highly stable transverse and longitudinal single-mode lasing.

Fundamental limitations in optical system performance are demonstrated to be caused by deficiencies in Si photodetector operation. Static electrical testing may identify groups of devices showing specific levels of digital optical line system performance. The mechanism is shown to be inherent in the Si-Si02 system, and sensitive to device structure.

Two basic parameters, the surface recombination velocity(S) and the diffusion length(Le), have been studied through investigating the responsivity of InGaAs p-i-n photodiodes without an InP window layer. The values of S and Le were found to be 10 4cm/s and 4μm, respectively. The high responsivity of 0.7A/W at λ=1.3μm was obtained without an antireflection coating due to the small surface recombination velocity.

The HF plasma enhanced sulphidation is used, as a low temperature alternative of passivation of the InP surface for the elaboration of the gate insulator in MISFET-InP. The species (atom, radical, ion) present in the H2S glow discharge and the potential repartition in a HF plasma, capacitive type with internal electrodes, are described. We comment models of the sulphide layers with composition and surface and interface roughness resulting of XPS Spectroscopy, Spectroscopic Ellipsometry ang Grazing X Ray Reflectrometry. We give a growth mechanism of the sulphide layer and we show the duality between the growth and ionic bombardment mechanisms of a growing layer in HF plasma.

For opto-electronic applications, materials are needed exhibiting considerable optically nonlinear effects and which are easy to process or shape into desired structures. In recent years, organic molecules have been synthesized, showing large nonlinear polarization properties. These molecules are the building blocks of organic optically nonlinear materials. Such materials can in principle be used to perform functions for optical data transmission and optical data processing. The potential properties and applications of optically nonlinear polymers in these fields are discussed.

A process has been developed, for the mechanical shaping of silica fibre preforms. Porous preforms are shaped from prefabricated powders and transfered, to glass rods by thermal treatment. Drawn fibers now have attenuations of 1 dB/km and an OH absorption. of 0.5 dB/km at 138o nm. Both single and multimode fibres have been produced.

This paper gives a review on the state-of-the-art of the application of plasma-impulse-CVD (PICVD) for the preparation of preforms for optical fibers. Besides the fundamentals of the technological process we will deal with some experimental results with respect to the reaction kinetics and with problems involved in the preparation of pure Si02 core fibers, e.g. radiation resistance and losses.

The Maier Saupe theory for liquid crystals is extended to calculate the degree of polar and axial order, obtained during poling by an electric field of π conjugated acceptor-donor molecules in a liquid crystalline phase. Applications of the theory are in the field of non-linear optical materials.

The photochemical method and technique by which a variety of optical structures such as channel waveguides, gratings and GRIN lenses, can be patterned in a porous glass host, have been extended to the stable formation of a number of semiconducting compounds of the III-V, II-VI, and IV-VI families, within the porous glass. The specific compounds prepared are CdS, CdSe, PbS ,PbSe, MoS2, and GaAs. In certain of these cases the reaction is optically initiated thus prescribed geometric structures are obtained. The unique microstructure provided by the porous glass, average pore diameter of 4nm with 30 percent pore volume, leads to small microcrystal size in the quantum confined regime. Optical absorption and photoluminescence data are shown to support this.

The aim of the experimental study reported here, was to investigate the possibilities offered by the DMPE technique for the fabrication of monomode optical waveguides, to be used for the realization of acousto-optic devices. It was found that the DMPE process induces an efficient coupling mechanism between the "TE" guided and the "TM" not guided optical radiation. A modified fabrication process is proposed to overcome this problem and produ-ces a very interesting monomode optical waveguide at 830 nm.

The possibility of using CVD techniques for fiber telecommunication is examined. The difficulties of applying a vapor phase process to fluoride materials are described and the viability of this approach is discussed. Current achievements are reported.

III-V double heterostructure laser diodes emitting at room temperature near 2.55 μm can be prepared using InAsSbP, GaInAsSb or InAlAsSb active zones and GaAlAsSb confinement layers. The limits of the solid phase miscibility gap of these quaternary solid solutions were determined at 530°C. A phenomenological model giving the threshold current density of double heterostructure injection lasers is presented, and applied to the 2.55 μm emitting InAsSbP/ GaAlAsSb and GaInAsSb/GaAlAsSb DH lasers. It is shown that threshold currents are mainly controlled by Auger recombination currents. Thq low value of the overall Auger recombination coefficient for GaInAsSb alloy (C = 1.0 x 10 -28 cm6/s at 2.2 μm) gives threshold current densities varying from 4.5 kA/cm2 to 3 kA/cm2 at room temperature for Ga 0.73 In 0.27 As 0.24 Sb 0.76/Ga 1-x Al x As y Sb 1-y /GaSb 2.55 μm DH lasers when x is varied from 0.4 to 0.7.

Gal-xInxAsySb1-y epitaxial layers were grown by atmospheric pressure metal organic chemical vapor deposition (MOCVD) on (100) GaSb substrates with a wide range of x and y values. Layer morphology evolution versus growth conditions is described. First results on I-V, C-V and spectral response of GaInAsSb/GaSb heterojunctions are promising for 2.5 μm photodetection.

CdxHg1_xTe layers have been grown by Liquid Phase Epitaxy in a wide composition range (0.5 < x < 1), covering the alloys adapted to detection at the optical communication wave-lengths (1.3 - 2.5 μm). Layers of thickness ranging from 2 to 20 μm and with high structural quality and composition uniformity are obtained thanks to a new determination of the phase diagram. Electrical measurements and exciton photoluminescence spectra confirm the general improvement reached for LPE layers compared to bulk crystals.

This paper presents an evaluation of the noise equivalent power (NEP) of 1.55 pm avalanche photodetectors based on Ga0.96 Al0.04 Sb, liquid phase epitaxy (LPE) grown junctions. Deduced from some measured photoelectrical parameters and from others publicated ones an optimum NEP of 3.5 x 10 -12 W/ √Hz is calculated for a doping level of 3 x 10 21 m-3.

Due to the new applications of mercury cadmium telluride as a material for optoelectronic devices, it's important to have flexibles epitaxyal methods allowing growth of any composition. Working from Te-solutions in a two zones reactor, we present a method to prepare the growth solutions completely in-situ, controlling the compositional parameters by the zones temperatures.

Hgl-x Cdx Te is a good candidate for signal transmission through fiber optics for it has an adjustable direct band gap (x ~ 0.7 for silica glass and x~ 0.4 for fluorine glass). Photovoltaic detectors can be made by implantation on a p-type substrate. However the physical nature of the junction is not yet clearly understood. We implanted various ions (Al, Xe, Kr) at different energies, (60 3 keV to 320 keV) and temperatures (15 K, 300 K) in p-type bulk Hg 0.3 Cd 0.7 Te (p~ 1.5 x 10 16/cm3). From E.B.I.C. and differential Hall measurements, we conclude that Hg inferstitials should be the most realistic candidates as doping defects.

Cd0,7Hg0.3Te has been grown by MOCVD on GaAs in part of an optical fibre communication device study. Auto-doping from the substrate is contained in a suitable buffer layer and a thin HgTe layer has been used as the p-type contact. Preliminary device results are presented and are encouraging for future developments.