Progress in Crystal Growth and Characterization最新文献

A set of preferred numerical relations describing the cadmium-mercury-tellurium phase diagram is presented in the form of equations and tabulated data.

Al_xGa_1−xAs is an important III–V semiconductor for device applications in the optoelectronics field. Growth aspects, characterization and kinetics of Al_xGa_1−xAs by organometallic - CVD are reviewed. The review primarily covers the effect of growth parameters on material preparation and material quality, doping, electronic and optical properties, and applications to devices and associated problems with their performance. Current problems of PPC centers, D.X centers, and deep level characterization in relation to the basic chemistry of the material and implications on device performance are dealt with. Growth and characterizations of exotic multilayer structures (superlattices, cascades, multiple quantum well structures, etc.) are reported in terms of current specific problems. The future of crystal growth methods employing the organometallics is assessed in relation to the current and future technologies.

The magnetic properties of layer AB₂X₄ compounds, having a ZnIn₂S₄-type structure, are discussed considering them as possible models for two-dimensional magnetic systems. MnAL₂S₄, MnAL₂Se₄ and FeGa₂S₄ do not appear to be good model systems because the magnetic ions are distributed among tetrahedral as well as octahedral sites of the structure. Their magnetic properties are better understood in terms of short-range magnetic order arising from the presence of isolated clusters. The magnetic behaviour of Co _.46Zn _.54In₂S₄, crystallizing in space group R3m, can be explained in the same way.

Only in CrGa_1.67S₄ do the magnetic Cr³⁺ ions lie in a triangular planar lattice and, therefore, the magnetic properties are interpreted in terms of a 2-d magnetic system in the temperature range 80 ⩽ T ⩽ 300K.

X-ray topographic studies of crystal perfection over the past two decades in the People's Republic of China are outlined. Those papers published in Chinese Journals and in the Chinese language are reviewed and a summary of instrumentation and research groups presently active is presented.

Work on silicon molecular beam epitaxy (Si-MBE) is now growing on a worldwide scale and various aspects of this work are here reviewed. Basic studies on surface cleaning and defect evaluation have been conducted to improve epitaxy and homoepitaxy and doping have been certified to be comparable or exceed those of conventional CVB epitaxial layers. Formation of doping superlattices is a prime example demonstrating the potential of Si-MBE over conventional growth techniques. Heteroepitaxy including combinations such as silicon/insulator and silicon/metal (silicide) has become an active and growing field for both basic research and device development.

Semiconductor material to which has been added carefully controlled amounts of impurities (dopant) is the basis of modern electronics. A parameter which has to be taken into account when assessing the suitability of a semiconductor for a particular application is its thermal conductivity. This article has been written with the view to providing a convenient collective source of information on the preparation of doped semiconductors, the various techniques employed in the measurement of thermal conductivity and an update on the thernal conductivity behaviour of most of the established semiconductors.

A brief coverage of the main methods employed in the preparation of semiconductors and of doping techniques is presented in Section 1, while a comprehensive coverage of the measurement of thermal conductivity is given in Section 2. In Sections 3 and 4 are reported the thermal conductivity data on elemental and alloy semiconductors and on compound semiconductors respectively.