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Titanium-vanadium dioxide or TixV1−xO2 films for 0 ≤ x ≤ 1 were examined using ellipsometry, and their optical constants (n and k) at visible and near-infrared wavelengths were determined at temperatures (T) below, at, and above the semiconductive-to-metallic phase transition (SMT) temperature (TSM). Ellipsometric analysis was performed for each x at each T using a wavelength dispersion model, i.e., a combination of Lorentz oscillators and a Drude free electron model. The ellipsometric analyses provided information on the electronic band transition caused by the SMT and the influence of cationic replacement (Ti↔V) on the SMT. The results revealed that when x ≤ 0.05, close to the SMT, the energy gap of the interband transition O2p→V3d varied from ≈3.5 eV to ≈3.1 eV, and the quantity of electrons in the interband transition decreased by half. In addition, the energy gap monotonically increased to 4.2 eV when x was increased to 1. Moreover, the energy gap of the split V3d intraband transition varied from ≈1.4 eV to zero, and the quantity of electrons in the intraband transition increased by a factor of four. Furthermore, when x ≥ 0.2, close to the SMT, the energy gap of the intraband transition varied from ≈1.4 eV to a constant positive value, with the generation of a small number of conductive electrons, depending on x. [ABSTRACT FROM AUTHOR]

Ellipsometric memory which is optical memory based on the ellipsometric principle has been proposed in 1994 for the first time and was examined by preliminary experiments using multilayer thin film structures. Though this idea has a great potential for new high capacity optical memory, oblique angle incidence was inevitable and needed rather big sized cells because of the large incident angle. To overcome this difficulty we propose the transparent type ellipsometric memory with thin film multilayer structures. In the transparent ellipsometric memory, the ellipsometric parameters of transmitted light through thin film multilayer structures, instead of reflected light, are measured. This modification makes the normal incident light useful and the cell size small. We carried out model calculations and preliminary experiments using Mg–Mo two-layered thin film structures to confirm the feasibility of the transparent type ellipsometric memory. [Copyright &y& Elsevier]

Abstract: Vanadium dioxide () is a promising candidate for various thermochromic devices. Layering film with amorphous silicon suboxide () is an effective approach for controlling the thermochromic spectrum efficiently, since possesses an easily adjustable refractive index over a wide range. However, the crystalline quality of is so sensitive to under- and/or over-coated materials that the coatings may be disadvantageous with respect to material suitability. In this study, the controllability of the thermochromic spectrum of by employing layer was evaluated under several fabrication conditions and, as a result, it was found that an layer can control thermochromism well without any decline in the stability of crystalline growth, which strongly suggests the possibility of expansion in the optical design for efficient thermochromic control. [Copyright &y& Elsevier]

Abstract: Composite films of titanium and vanadium oxides (TVO) with various compositional ratios were prepared by sputtering deposition. The optical properties, crystalline structure and film morphology were investigated as a function of the composition. The results of thermochromism and X-ray diffraction suggest that the TVO films at any compositional ratios form substitutional solid solution of Ti and V, that is, Ti x V1−x O2, where 0≤ x ≤1. Dielectric constants of the TVO films at any compositions were consistently determined at photon energies between 0.75 to 3 eV by employing the Lorentz-oscillator formula. With wide variation in x, the dielectric constants at visible and near-infrared wavelengths monotonically decrease down to the values of TiO2, which suggests that dielectric constants of the TVO film can be precisely controlled by adjusting rf power in co-sputtering deposition. [Copyright &y& Elsevier]