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Abstract: The optical properties of thin films based on unsubstituted and tetrafluoro-substituted zinc phthalocyanines synthesized by physical vapor deposition are studied within the wavelength range of 250-1000 nm. Spectroscopic ellipsometry shows that films based on zinc phthalocyanines have uniform thicknesses and optical parameters, strongly absorb visible light, and have characteristic absorption peaks corresponding to electronic transitions in the system of conjugated double bonds of phthalocyanine rings. Introduction of fluorine substituents into peripheral positions of the zinc phthalocyanine molecule leads to an increase in light absorption and a shift of the main absorption maximum to longer wavelengths (bathochromic shift). The absorption spectra are described using the Lorentz-Drude dispersion model. It is shown that the films based on a mixture of phthalocyanines can be well described using the Bruggeman effective medium model. [ABSTRACT FROM AUTHOR]

Amorphous nonstoichiometric ZrO films of different composition have been synthesized by the method of ion-beam sputtering deposition of metallic zirconium in the presence of oxygen at different partial oxygen pressures in the growth zone, and their optical properties have been studied in the spectral range of 1.12-4.96 eV. It is found that light-absorbing films with metallic conductivity are formed at the partial oxygen pressure below 1.04 × 10 Pa and transparent films with dielectric conductivity are formed at the pressure above 1.50 × 10 Pa. It is shown that the spectral dependences of optical constants of ZrO films are described well by the corresponding dispersion models: the Cauchy polynomial model for films with dielectric conductivity and the Lorentz-Drude oscillator model for films with metallic conductivity. [ABSTRACT FROM AUTHOR]

The optical properties of the highly-textured VO thin-films grown on Si(100) by sputter-deposition at various oxygen reactive-pressures were investigated in detail. The profiles of the optical constants, namely the refractive index and extinction coefficient, of VO films were evaluated in the photon-energy range of 1-5 eV. At photon-energy above 2.5 eV, the dispersion behavior in optical constants is explained based on Lorentz-Drude model. The refractive index dispersion fits to a Cauchy's relation at photon-energy below 2.5 eV, where the VO-film is mostly transparent. The optical transitions across the bandgap occur at energy ∼2.5-3.2 eV depending on the VO growth conditions and film-microstructure. The highly-textured and c-axis oriented VO-films, fabricated under optimum conditions of temperature and oxygen partial pressure, exhibit excellent optical characteristics similar to VO single crystals. [ABSTRACT FROM AUTHOR]

To date, the complex evaluation of physical and dispersive optical characteristics of the ZrON/Si film system has yet been reported. Hence, ZrON thin films have been formed on Si(100) substrates through oxidation/nitridation of sputtered metallic Zr in NO environment at 500, 700, and 900 C. Physical properties of the deposited films have been characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, reflection high-energy electron diffraction (RHEED), and spectroscopic ellipsometry (SE). It has been shown that ZrON/Si thin films without optical absorption can be prepared by oxidation/nitridation reaction in NO environment at 700-900 C. [ABSTRACT FROM AUTHOR]

Lanthanum oxide (La2O3) films were grown by the reactive dc magnetron sputtering and studied their structural, chemical and optical parameters. La2O3 films were deposited onto Si substrates by sputtering La-metal in a reactive gas (Ar+O2) mixture at a substrate temperature of 200 °C. Reflection high-energy electron diffraction measurements confirm the amorphous state of La2O3 films. Chemical analysis of the top-surface layers evaluated with x-ray photoelectron spectroscopy indicates the presence of a layer modified by hydroxylation due to interaction with atmosphere. Optical parameters of a-La2O3 were determined with spectroscopic ellipsometry (SE). There is no optical absorption over spectral range λ=250-1100 nm. Dispersion of refractive index of a-La2O3 was defined by fitting of SE parameters over λ=250-1100 nm. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y2O3) films with an average crystallite-size (L) ranging from 5 to 40 nm were grown by sputter-deposition onto Si(100) substrates. The optical properties of grown Y2O3 films were evaluated using spectroscopic ellipsometry measurements. The size-effects were significant on the optical constants and their dispersion profiles of Y2O3 films. A significant enhancement in the index of refraction (n) is observed in well-defined Y2O3 nanocrystalline films compared to that of amorphous Y2O3. A direct, linear L-n relationship found for Y2O3 films suggests that tuning optical properties for desired applications can be achieved by controlling the size at the nanoscale dimensions. [ABSTRACT FROM AUTHOR]

The optical properties, interface structure, and thermal stability of the ZrO2 films grown on Si(100) were investigated in detail. A 2 nm thick interfacial layer (IL) is formed at the ZrO2–Si interface for the as-grown ZrO2. The optical constants of ZrO2 films and IL correspond to amorphous-ZrO2 and amorphous-SiO2, respectively. The oxidation and IL growth at 900 °C, as a function of annealing time, exhibit a two-step behavior with a slow and a fast growth-rate zones. The transition from a zone of slow to fast rate is attributed to structurally modified ZrO2 facilitating the faster oxygen transport to the ZrO2/Si interface. [ABSTRACT FROM AUTHOR]