Optical properties binary oxides

Tantalum and niobium are added, in the form of carbides, to cemented carbide compositions used in the production of cutting tools. Pure oxides are widely used in the optical industiy as additives and deposits, and in organic synthesis processes as catalysts and promoters [12, 13]. Binary and more complex oxide compounds based on tantalum and niobium form a huge family of ferroelectric materials that have high Curie temperatures, high dielectric permittivity, and piezoelectric, pyroelectric and non-linear optical properties [14-17]. Compounds of this class are used in the production of energy transformers, quantum electronics, piezoelectrics, acoustics, and so on. Two of... 

Binary Selenides. Most binary selenides are formed by heating selenium in the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts in aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH Se [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the tellurides. Selenides of the alkali, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are insoluble in water. Polyselenides form when selenium reacts with alkali metals dissolved in liquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

It is normally unnecessary for the electrochemist to be concerned with the mobility of carriers in most of the semiconductors whose properties have been studied, since the very low conductivity of "small polaron samples would normally preclude their measurement. However, a proviso must be entered here in the case of binary and, more especially, ternary samples. It may well be the case that the majority carriers in a particular material are indeed itinerant (i.e. have mobilities in excess of ca. 1 cm2 V 1s 1), but there is no guarantee that this will be true of the minority carriers generated by optical absorption. Thus, the oxide MnTi03 shows a marked optical charge transfer absorption from Mn(II) to Ti(IV), the latter being the CB. The resultant holes reside on localised sites in the Mn levels, presumably as local Mn(III) centres, and are comparatively immobile. The result is that there is... 

In the first half of this book, chemical stability, reactivity, structural features, and chemical bonding including band calculation of the rare earth oxides, have been examined from the viewpoints of the fundamental characterization and appearance mechanism of the properties. Particularly, further development of high resolution electron microscopy (HREM) and quantum band calculation will be of great aid for us to understand the unique characteristics of binary rare earth oxides from both the experimental and theoretical approaches. In addition, physical and chemical properties of the rare earth oxides such as electrical, magnetic, optical, and diffusion properties are also analyzed in details, leading to find relationships between basic science and applications in several functional materials. 

Another type of structures for metal-dielectric mirrors are metallodielectric multilayers. In this case alternating quarterwave or subwavelength stacks of metal and dielectric are deposited. Typical for such multilayers is alow reflection in visible, but large in infrared wavelength range. Thus they basically behave as low-pass optical filters. Such stmctures were denoted in literature as heat mirrors. First heat mirrors were fabricated as early as in 1950s [252]. The simplest heat mirrors consist of three layers only, dielectric-metal-dielectric or, alternatively, dielectric-transparent conductive oxide-dielectric [253]. Full multilayer metal-dielectric reflectors with binary but also ternary layers were also considered [254]. Because of their high reflectance in infrared, but also because of their plasmonic properties [255] metal-dielectric multilayer mirrors are of interest for cavity enhancement of infrared detectors. 

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