Germanium is a semiconducting metalloid element found in Group IV A. Germanium is used in the field of electronics, infrared optics, and in the fields of gamma ray spectroscopy, catalysis, and fiber optics. This article discusses the sources, manufacturing, and processing of germanium, and focuses on the chemical properties of various germanium compounds, including germanium halides, germanates, germanides, germanes, inorganic, and organogermanium compounds. It also tabulates the physical, thermal, electronic, and optical properties of germanium, and explains the economical aspects and specifications of germanium. The article describes the analytical and test methods of germanium, including gravimetric method, titrimetric method, and spectral method. It provides a short note on toxicology, and concludes with the uses of germanium in different fields.

This article is a compilation of binary alloy phase diagrams for which molybdenum (Mo) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

Pure metals normally solidify into polycrystalline masses, but it is relatively easy to produce single crystals by directional solidification from the melt. This article illustrates the dislocations present in a metal crystal, which is often polygonized into sub-boundaries during grain growth after solidification. It provides a description of small-angle and large-angle grain boundaries of polycrystalline metals.

This article is a compilation of binary alloy phase diagrams for which manganese (Mn) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

Soldering involves heating a joint to a suitable temperature and using a filler metal (solder) that melts below 450 deg C (840 deg F). Beginning with an overview of the specification and standards and applications, this article discusses the principal levels and effects of the most common impurity elements in tin-lead solders. It describes the various processes involved in the successful soldering of joints, including shaping the parts to fit closely together; cleaning and preparing the surfaces to be joined; applying a flux; assembling the parts; and applying the heat and solder.

This article provides a detailed account of extended x-ray absorption fine structure (EXAFS). It begins with a description of the fundamentals of EXAFS, providing information on the physical mechanism, single-scattering approximation, and multiple-scattering effects. This is followed by a discussion on the use of synchrotron radiation as an X-ray source for EXAFS. Data-reduction procedures used to extract EXAFS signals are then described. The article also provides information on the analysis of x-ray absorption near-edge structure spectrum and ends with a discussion on the unique features and applications of EXAFS.

This article provides an introduction to extended x-ray absorption fine structure (EXAFS). It describes the fundamentals of EXAFS with an emphasis on the physical mechanism, the single-scattering approximation, and multiple-scattering effects. The article discusses the use of synchrotron radiation as the x-ray source for EXAFS experiments. It also describes the typical EXAFS data analysis of pure nickel at 90 K, and explains the near-edge structure analysis of vanadium. The article presents a discussion on the unique features and applications of EXAFS.

This article focuses on precision and ultraprecision finish machining techniques that make use of defined cutting edges, such as polycrystalline diamond and cubic boron nitride compacts. The techniques are finish turning, finish broaching, finish milling, and finish drilling.

This article reviews the phase diagrams, alloy with third element additions, layer growth, critical current density, and matrix materials of A15 superconductors. It describes the production methods of tape conductors (chloride deposition, and surface diffusion) and multifilamentary wires (rod process, modified jelly roll process, niobium tube process, in-situ process, powder metallurgy process, and jelly roll method). The article focuses on reaction heat treatment, which is required at the end of wire processing to convert the ductile components to the desired, but brittle, superconductor. Finally, it discusses the applications of A15 superconductors in commercial magnets, power generation, power transmission, high-energy physics, and fusion.

Gallium-base components can be found in a variety of products ranging from compact disk players to advanced military electronic warfare systems, owing to the factor that it can emit light, has a greater resistance to radiation and operates at faster speeds and higher temperatures. This article discusses the uses of gallium in optoelectronic devices and integrated circuits and applications of gallium. The article discusses the properties and grades of gallium arsenide and also provides information on resources of gallium. The article talks about the recovery techniques, including recovery from bauxite, zinc ore and secondary recovery process and purification. The article briefly describes the fabrication process of gallium arsenide crystals. Furthermore, the article gives a short note on world supply and demand of gallium and concludes with research and development on gallium arsenide integrated circuits.

This article introduces various techniques commonly used in the characterization of semiconductors, namely single-crystal, polycrystalline, amorphous, oxide, organic, and low-dimensional semiconductors and semiconductor devices. The discussion covers material classification, fabrication methods, sample preparation, bulk/elemental characterization methods, microstructural characterization methods, surface characterization methods, and electronic characterization methods.

This article focuses on the use of indium and bismuth in low-melting-temperature solders and fusible alloys. It describes how the two elements typically occur in nature and how they are recovered and processed for commercial use. It also provides information on designations, classification, composition, properties (including temperatures ranges), and some of the other ways in which indium and bismuth alloys are used.

Infrared (IR) spectra have been produced by transmission, that is, transmitting light through the sample, measuring the light intensity at the detector, and comparing it to the intensity obtained with no sample in the beam, all as a function of the infrared wavelength. This article discusses the sampling techniques and applications of IR spectra as well as the molecular structure information it can provide. The discussion begins with a description of the general principle of IR spectroscopy. This is followed by a section on commercial IR instruments. Sampling techniques and accessories necessary in obtaining the infrared spectrum of a material are then discussed. The article presents various techniques and methods involved in IR qualitative analysis and quantitative analysis. It ends with a few examples of the applications of IR spectroscopy.

Infrared (IR) spectroscopy is a useful technique for characterizing materials and providing information on the molecular structure, dynamics, and environment of a compound. This article provides the basic principles and instrumentation of IR spectroscopy. It discusses the sampling techniques of IR spectroscopy, namely, attenuated total reflectance spectroscopy, diffuse reflectance spectroscopy, infrared reflection-absorption spectroscopy, emission spectroscopy, and photoacoustic spectroscopy, and chromatographic techniques. Explaining the qualitative analysis of IR spectroscopy, the article provides information on spectral absorbance-subtraction, analysis of components in spectral matrix mixture, and determination of exact peak location of broad profiles. It discusses the quantitative analysis that mainly includes Beer's law for single compound in single wave number. The article also exemplifies the applications of IR spectroscopy.

This article provides information on basic chemical equilibria, wet analytical chemistry, and the appropriateness of classical wet methods. It focuses on nonoxidizing acids and oxidizing acids. The article includes information on the qualitative methods used to identify materials by wet chemical reaction. Gravimetry, in which a chemical species is weighed; titrimetry, which involves volume measurement of a liquid reactant; and a host of separation techniques, which require diverse forms of laboratory manipulation, are discussed. The article briefly describes the partitioning of oxidation states as well as those applications in surface studies and rapid material identification in which chemical techniques have proved useful.

This article is a compilation of binary alloy phase diagrams for which gallium (Ga) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

This article describes the vapor-phase growth techniques applied to the epitaxial deposition of semiconductor films and discusses the fundamental processes involved in metal-organic chemical vapor deposition (MOCVD). It reviews the thermodynamics that determine the driving force behind the overall growth process and the kinetics that define the rates at which the various processes occur. The article provides information on the reactor systems and hardware, MOCVD starting materials, engineering considerations that optimize growth, and the growth parameters for a variety of Group III-V, II-VI, and IV semiconductors.

Ordered intermetallic compounds based on aluminides and silicides constitute a unique class of metallic materials that have promising physical and mechanical properties for structural applications at elevated temperatures. This article provides useful information on mechanical and metallurgical properties, material processing and fabrication, structural applications, mechanical behavior, environmental embrittlement, alloying effects, and crystal structure of aluminides of nickel, iron, titanium, and silicides. It describes the cleavage and intergranular fracture in trialuminides.

This article focuses on the electrodeposition of indium and its alloys, such as indium-antimony, indium-gallium, and indium-bismuth, in nonaqueous indium plating baths. It also provides information on the stripping of indium plate from plated components and presents an overview of the specifications, standards, and hazards of indium plating.

This article provides a detailed account of the principles, instrumentation,and applications of x-ray photoelectron spectroscopy (XPS), a technique used for elemental and compositional analysis of surfaces and thin films. It reviews the nomenclature of energy states and sensitivity of electrons at the surface that are capable of producing peaks in XPS. Additionally, it presents information on the instrumentation and the preparation and mounting of samples for XPS analysis. The article explains qualitative analysis, namely, measuring of shifts in the binding energy of core electrons, multiplet splitting, and the Auger parameter; and quantitative analysis such as depth analysis carried out using XPS. It also discusses the applications of XPS with examples.