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Published in Zbigniew Galazka, Transparent Semiconducting Oxides, 2020
The availability of bulk single crystals and exploration of their optical and electrical properties may lead not only to a better understanding of the underlying physics, but also to an expansion of the area of applications through utilizing specific properties characteristic for each of the materials.
Electronic Materials and Properties
Published in Michael Pecht, Handbook of Electronic Package Design, 2018
Jillian Y. Evans, John W. Evans
Semiconductors are used primarily as single crystals. Unlike polycrystalline metals and ceramics, single-crystal semiconductor materials are generally not isotropic. The properties of the material will vary with the orientation of the crystal. Of particular importance to the packaging engineer are the elastic properties, which may be used to relate the stresses and strains induced in single-crystal semiconductors. Isotropic materials are simply described by the elastic modulus or Young’s modulus and Poisson’s ratio. However, in the general case, the elastic behavior of a solid is much more complex.
Physical Properties of Crystalline Infrared Optical Materials
Published in Paul Klocek, Handbook of Infrared Optical Materials, 2017
James Steve Browder, Stanley S. Ballard, Paul Klocek
Notes: Gallium arsenide finds broad use as an optical material. Single crystals can be grown from the melt by the Czochralski method. Semi-insulating polycrystalline gallium arsenide has been produced by a horizontal Bridgman process to sizes of 8 × 12 × 0.7 in. at Texas Instruments Inc. and is being studied as a material for windows and domes (Klocek et al., SPIE Proc. 929, 1988). Gallium arsenide is being studied for use in photonic switching and waveguides in integrated optics [Alferness and Leonberger, Optics News, 14(2), 46 (1988)].
Revisiting the experimental dielectric function datasets of gold in accordance with the Brendel-Bormann model
Published in Journal of Modern Optics, 2023
Farzad Firouzi, Sayed Khatiboleslam Sadrnezhaad
The validity of the ‘Babar’ and ‘Palik’ datasets according to the Brendel-Bormann model is attributed to their adopted experimental methodologies (Table 1). The fundamental similarity between the as-mentioned datasets is their utilization of gold samples with the lowest structural and surface imperfections. Babar et al. [26] prepared mechanically-polished single crystals that were chemically cleaned to remove any work damage. In general, single crystals exhibit the best structural quality due to minimum defects and, thus, might be known to be the most appropriate samples for optical measurements. This interpretation also applies to the ‘Olmon’ dataset series employing different gold samples through unique measurement strategies and experimental conditions [24]. Among its three different datasets and others, the ‘Olmon-SC’ one utilizing single crystal gold exhibits relatively better compatibility with the model. On the other hand, samples for extracting the ‘Palik’ dataset were annealed vacuum-evaporated semitransparent thin films [22]. In this context, it was claimed that the annealing process eliminates the sample defects affecting its optical response (e.g. surface roughness or grain boundaries) due to recrystallization and grains growth.
Effects of pressure-temperature protocols on the properties of crystals and ageing effects – an analogy with glasses
Published in Philosophical Magazine, 2022
A crystal contains defects as part of its structure. In a single crystal, these defects or imperfection in the regular geometrical arrangement of the atoms may be point defects such as vacancies, interstitials and substitutional atoms or molecules, may be line defects, e.g. dislocations and planar defects, e.g. stacking faults. In a polycrystalline solid there are additional defects of grain boundaries and grain junctions. All these defects affect the thermodynamic, transport, optical, and electrical properties of a crystal. The subjects of crystal defects, atomic diffusion and defects disorder is part of the university-level courses on electronic, mechanical and thermodynamic properties of materials [1–6]. Thermodynamics of their formation, the population-dependent consequences for their physical properties, interaction between various crystal defects and their practical use in controlling the mechanical, optical and electrical properties have been discussed in the proceedings of numerous conferences, and in review articles [7–18]. Change in the properties of metal-crystals during thermal quenching, and of their quenched state with time and the effect of pressure on their formation and diffusion have been studied since the 1950s [11–29] (We make no attempt to provide a complete list of citations here because such lists have appeared in review papers, and cite only the original and the relevant papers.) In a comprehensive review of the subject, Kraftmakher [18] has provided a detailed description of the defects equilibrium in metals. He listed the history of studies on crystal defects equilibrium and their thermodynamics and kinetics in Table 1 of his paper [18], and discussed the techniques used for studying crystal defects since Frenkel’s original studies in 1926 [30].
Optimization of SAW-type Surface Wave Ultrasonic Sensors for Ultrasonic SHM
Published in Research in Nondestructive Evaluation, 2018
R. Takpara, M. Duquennoy, M. Ouaftouh, C. Courtois, F. Jenot, M. Rguiti
According to the modeling results, PZT-type ceramics produce the highest displacements. Regarding 128° XY LiNbO3, displacements are more modest. However, this single crystal is conventionally used for making electronic filters. It should be noted that frequencies of several hundred MHz or several GHz are used in conventional applications with SAW sensors, and so it is preferable to consider single crystals rather than PZT-type ceramics. For the NDT applications referred to here, the frequency range is between 1 and 100 MHz.