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Polycrystalline Cd1−xZnxTe films were grown on glass substrates over the full range of compositions (0 < x < 1) by metal–organic chemical vapour deposition at 480 °C. The films (∼5 µm thick) showed uniform texture oriented along the ⟨1 1 1⟩ direction, perpendicular to the substrate, independent of the film composition. The dependence of the lattice parameter of cubic Cd1−xZnxTe on the composition followed Vegard's law. The thick Cd1−xZnxTe films were shown to be of a single phase and structurally stable. The average grain size in the thick films was in the range 3–5 µm. The dominant imperfections in the films were twins (mostly Σ = 3) and dislocations. The x-ray diffraction (XRD) FWHM parameter reached a maximum at x = 0.5. Transmission electron microscopy (TEM) in situ heating in the range 200–400 °C caused plastic deformation in the grains without causing ordering effects. Optical absorption and low-temperature photoluminescence measurements confirmed the XRD and TEM results.

The real refractive index n and power absorption coefficient alpha of high resistivity GaAs and CdTe have been directly measured at 300 K and 8 K in the wavelength region from 12.5 micro to 300 micro. This spectral region contains the fundamental lattice resonance of both materials: 37.2 micro for GaAs and 71.4 micro for CdTe. This resonance causes large dispersion in the linear material properties. Single Drude-type oscillators have been visually fit to the measured n data with the results that for GaAs, epsilon(dc)' = 12.8 +/- 0.5 at 300 K and 12.6 +/- 0.5 at 8 K, and epsilonalpha(') = 10.9 +/- 0.4 at 300 K and 8 K ; for CdTe, epsilon(dc)' = 9.4 +/- 0.4 at 300 K and 9.0 +/- 0.4 at 8 K, and epsilon(alpha)' = 6.7 +/- 0.3 at 300 K and 8 K. The GaAs data clarifies the role of dispersion in n in the 5-20 micro region where previous results differ considerably. For both materials the n and alpha data in the region past 30 micro are the first to be reported.

2014 On présente un calcul exact de la réflexion de la lumière par un échantillon orienté de cristal liquide hélicoïdal (SmC* ou cholestérique) en utilisant la formulation matricielle 4 x 4 des équations de Maxwell pour les milieux anisotropes. On montre que la méthode approximative de Berreman et Scheffer est inadéquate, spécialement en ce qui concerne la région des faibles longueurs d'onde (nombre de pics, nombre de branches dans la bande de réflexion ainsi que leur dépendance avec les différents paramètres).Abstract 2014 The exact calculation of the reflection from single domain aligned samples of helicoidal liquid crystals (SmC* or cholesterics) is performed using the 4 x 4 matrix formulation of Maxwell equations in anisotropic media. We show that the expansion, approximation up to the 1st order of Berreman and Scheffer, is not adequate to describe the real situation, especially concerning the short wavelength region (heights of peaks, number of branches in the reflection band and their dependence on the different parameters). J. Physique 46 (1985) 815-825 MAI 1985, : Classification