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Partially relaxed InP/InAlAs/InGaAs heterostructures, grown by molecular beam epitaxy under tensile and compressive misfit stress, have been investigated by means of high-resolution X-ray diffractometry and spectroscopic ellipsometry. Additionally, chemical etching was used to determine polarity of the crystals and threading dislocation densities in the epitaxial layers. The measurements revealed a distinct anisotropy of the strain relaxation along two orthogonal 〈110〉 directions in the (001) plane of the structures, which resulted from an asymmetry in the formation of two types of misfit dislocations at the interface. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Introduction Lattice-mismatched heterostructures of indium-based III–V compound semiconductors are of current interest owing to their applications in optoelectronic devices emitting in the infrared wavelength range. An important consequence of epitaxial growth of those heterostructures is a strain in the epitaxial layer that results from a difference in lattice parameters between the substrate and the layer. If the epitaxial layer is thin enough, the lattice misfit can be accommodated by elastic strain of the layer and the growth of the layer is pseudomorpfic. However, when the layer thickness exceeds a critical value the strain is relieved by the formation of misfit dislocations at the interface. The misfit dislocations are associated with threading dislocations which cross the epitaxial layer up to the surface. Both the strain and the dislocations in the epitaxial layers can often affect dramatically their optical and electronic properties. In semiconductor heterostructures with zinc-blende structure, epitaxially grown on (001) oriented substrates with a small lattice mismatch (less than about 1.5%), the dominant type of misfit dislocations are 60° dislocations [1]. Two types of 60° dislocations, referred to as α and β, lying along two orthogonal 〈110〉 crystallographic directions at the interface differ in their core structures. In the predominated glide set configuration the α and β dislocations consist of the extra half-planes terminated in a row of group V and group III atoms, respectively, in the dislocation core. At the interface of heterostructures grown under tensile stress the α and β misfit dislocations are oriented along the [110] and ] 10 1

We discuss several problems of optimisation of the MBE growth of thick (3.5 ÷ 9 μm) InAs epilayers on GaAs(100) substrates. Three types of layers were grown: undoped, Si-doped, and Be-doped. The whole growth process has been divided into two parts: the initial stage and the main stage. For each stage, the optimum growth conditions comprising the substrate temperature, the growth rate, and the flux ratio have been found. The crystal quality and the transport properties of the layers have been analysed by the transmission electron microscopy, the double-crystal X-ray diffraction, and the Hall effect measurements. It has been demonstrated that epilayers grown under the optimum conditions have good structural and electrical properties. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

(a) Institute of Physics, Polish Academy of Sciences, Al. Lotniko´w 32/46,PL-02-668 Warsaw, Poland(b) Institute of Experimental Physics, Warsaw University, Ul. Hoz˙a 69,PL-00-681 Warsaw, Poland(c) Institute of Electron Technology, Al. Lotniko´w 32/46, PL-02-668 Warsaw, Poland(Received October 1, 1998)An analysis of extended defects generated during annealing by pulsed excimer laser radiation in sili-con crystals implanted with Ge ions is presented. The investigation was performed by means of twocomplementary methods: the interference-polarizing microscopy and the Lang X-ray transmissiontopography. The existence of extended defects was revealed. It has been stated that the distributionof these defects depends on the distribution of the power density in the laser beam cross-section.

The purpose of the presented paper is to find out what kinds of information on surface layer structure of implanted silicon after rapid thermal annealing can be acquired by such non-destructive methods as X-ray diffractometry and its complementary RHEED technique. The experiments were performed on Si crystals implanted with Bi ions. The studies showed that using the anomalous X-ray transmission of the wavelength of 1.54 A we are able to determine the defect concentration introduced by ion implantation with different doses as well as the effects of defect annealing. It was also shown using the REED that the surface layer of ca. 50 A thick remains amorphous after RTA probably due to the oxidation. The measurements by using SIMS pointed also out that at the crystal surface there was a small amount of Bi atoms accumulated after RTA. Rontgenbeugung wie auch Elektronenbeugung in Reflexion wurden angewandt. um die Oberflachenschichtstruktur der Silizium-Einkristalle nach der Bi-Ionen-Implantation und nach der Impulsthermischen Ausheilung (ITA) kennenzulernen. Rocking-Kurven in Transmission wie auch Veranderungen in anomaler Transmission in Abhangigkeit von der Ionen-Dosis wurden gemessen. SIMS Technik wurde angewandt. um die Tiefenverteilung der Bi-Atome einzuschatzen. Es wird gezeigt, das der Logarithmus der anomalen Transmission eine lineare Funktion des Logarithmus der Dosis ist. Die Wirksamkeit der ITA wird gezeigt sowie festgestellt, das im Prozes der ITA die Bi-Atome die Knotenpunkte der Kristallgitter besetzen. Nur dicht an der Oberflache bildet sich eine sehr dunne amorphe Schicht (ca. 50 A), die kleine Mengen von Bi- und Sauerstoffatomen enthalt. (nr. 935/2/91).

In the experiment (111) oriented silicon plates were implanted with 80 keV Ge ions (dose 5 × 1015 cm−2) and with 150 keV Kr ions (dose 5 × 1015 cm−2). Then the samples were annealed with the pulsed excimer laser by using the sample scanning technique. The effectiveness of the annealing has been analyzed by means of double crystal X-ray spectrometry (DCXS) and reflection high energy electron diffraction (RHEED). The results of the experiment show that the applied technique of annealing considerably improves the perfection of the structure of the implanted silicon crystals. In dieser Arbeit wurden 111-orientierte Silizium-Plattchen mit 80 keV Germanium-Ionen (Dose 5 × 1015 cm−2) wie auch mit 150 keV Krypton-Ionen (Dose 5 × 1015 cm−2) implantiert und nachher mit einem Excimer Impulslaser bestrahlt. Wahrend der Bestrahlung bewegte sich der Kristall mit konstanter Geschwindigkeit. Die Wirksamkeit des Ausheilens wurde mit Hilfe der Doppel-Kristallspektrometrie wie auch der hochenergetischen Elektronenbeugung in Reflexion untersucht. Wie es aus diesen Experimenten folgte, fuhrte die angewandte Excimer-Laser Bestrahlungstechnik zu bedeutender Verbesserung des Perfektionszustandes der implantierten Kristalle.

The MBE growth of PbTe layers on GaAs (100) 2° off-oriented substrates belongs to hard heteroepitaxy, because the two materials differ strongly in their lattice constants and, in addition, they also exhibit different crystal structures. Consequently, phases with different surface orientations may occur in MBE-grown PbTe epilayers. Two crystallographic orientations, i.e. (100) and (111), have been found in the PbTe epilayers grown by MBE on these off-oriented substrates. X-ray diffraction and reflection high energy electron diffraction (RHEED) measurements applied as post growth characterization techniques allow to identify which orientation is prevailing in films grown at different MBE conditions. It has been shown that the occurrence of the (100) and (111) orientations in MBE-grown PbTe epilayers depends mainly on the GaAs substrate in situ preheating procedure. At higher preheating temperature and longer preheating time the (111) orientation prevails. This finding is in accordance with the theoretical model of hard heteroepitaxy of CdTe on GaAs (100) substrates by Griesche et al.

The operation in the 1020 nm wavelength range of strained-layer InGaAs/GaAs separate-confinement-heterostucture lasers grown by molecular beam epitaxy is reported. The active region is formed by a single 80 A thick InGaAs quantum well with an indium content of 25%, which is close to critical parameters. This paper provides the operating characteristics of broad-area uncoated Fabry–Perot structures with cavities of 700 μm length measured in the pulsed regime. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 75–77, 2001.

In the experiment a (111) oriented silicon plate was subjected to implantation by 80 keV Ge ions. Then the pulsed-laser annealing of this sample was carried out by using neodymium laser to form several areas irradiated with different light power. The effectiveness of the annealing has been analyzed by means of transmission X-ray topography, double crystal X-ray spectrometry, and reflection high energy electron diffraction. These three methods have appeared to be complementary and very effective in studying the spatial homogeneity of annealed areas, their state of annealing, and the damage in the surface layers. In dieser Arbeit wurden 111-orientierte Silizium-Plattchen mit 80 keV Germanium-Ionen implantiert und nachher mit einem Impulslaser bestrahlt. Zu diesem Zweck wurde ein Neodym-Laser verwendet. Die Bestrahlung erfolgte durch ein rundes Diaphragma. So konnte man einzelne Kristallgebiete mit verschiedener Strahlungsdosis ausheilen. Die Wirksamkeit des Ausheilens wurde mit Hilfe der Rontgenographie, Doppel-Kristallspektrometrie wie auch der hochenergetischen Elektronenbeugung in Reflexion untersucht. Diese drei sich gegenseitig erganzenden Methoden haben sich in den Untersuchungen der Raumhomogenitat der bestrahlten Gebiete, deren Ausheilungszustand und der Restdefekte in der Oberflachenschicht als sehr effektiv erwiesen.

A model of an ionic crystal is constructed ab initio in terms of moving charged particles interacting mutually with an electromagnetic field. On the basis of the model the equations of motion of the crystal are derived by means of the Lagrangian formalism. Special attention is given to a precise description of interactions between polarizable ions and the electromagnetic field. Retardation of electromagnetic interactions as well as the existence of an external electromagnetic field are taken into account. The system of equations obtained seems to be convenient for an analysis of electromagneto-optical processes in ionic crystals. [Russian Text Ignored]

The problem of propagation of phonon polaritons in the presence of an external magnetic field is investigated on the basis of equations of motion derived previously. First the dispersion relations for diatomic ionic crystals in the absence of a magnetic field are derived. Then the indices of refraction of right and left circularly polarized waves are found in the case of the Faraday configuration of the system. The Faraday rotation as a function of frequency is determined. Numerical calculations are performed for NaI. [Russian Text Ignored]