The infrared spectroscopic ellipsometry (IRSE) of n-alkylthiol (CH3(CH2)xSH, x ) 4, 6, 7, 8, 10, 13, 15, and 17, self-assembled monolayers (SAMs), with 5-18 carbon atoms (C5-C18), grown on gold-coated Si(100) substrates) was investigated at room temperature. The C-H stretching vibrations could be resolved even for pentathiol, the shortest chain studied. The symmetric and asymmetric stretching vibrations of the CH2 groups are located at about 2850 and 2920 cm-1, and those of CH3 are at about 2877 and 2962 cm-1, respectively; they show a slight shift with the number of CH2 units. In addition, Fermi resonance of the symmetric CH3 stretching vibration at 2940 cm-1 appears with decreasing chain length due to weak coupling with the asymmetric CH2 stretching vibration. The "odd-even effect" of the n-alkylthiol SAMs with varying CH2 units could be distinguished by the two interactive IRSE parameters. The relative ellipsometric spectra for the four longest chains could be reproduced quite well by using a Lorentz multioscillator model with a threephase optical model (air/SAMs/gold). On the basis of the theoretical calculations, the vibrational strength of these oscillators is very weak, its magnitude being 10-4-10-5. The full width at half-maximum (fwhm) of the peaks varies from 7 to 33 cm-1. Moreover, the intensity of the C-H vibrations increases with the number of methylene units, due to strong lateral interactions and ordering effects occurring for longer chains.

The refractive index and absorption index of nanocrystalline diamond NCD films were investigated using spectroscopic ellipsometry between 30 and 500℃. Due to their high transparency the experimental spectra could be well fitted in the subgap region using a single-oscillator model with a four-phase layered structure. The single-oscillator model yields a small optical absorption in the band gap region. The temperature dependence of dispersion of the refractive index over the photon energy range of 1.15-4.75V was determined. Based on the Bose-Einstein model, a thermo-optic coefficient of 1/n n/T=6.5 10−6 K−1 at 300 K was obtained for the NCD film in the near-infrared region.

Optical anisotropy of hexagonal Ga1−xMnxN(x from 0.0% to 1.5%) epitaxial films grown on c-plane sapphire substrates has been investigated using far- and mid-infrared s- and p-polarized reflectance spectra at oblique incidence at 10, 22, and 32, respectively. The experimental data at room temperature can be well reproduced simultaneously in the measured frequency region of 200-2000 cm−15-50 m, which was based on a four-phase layered system using a 4×4 matrix method M. Schubert, Phys. Rev. B53, 4265(1996). The lattice vibrations perpendicular and parallel to the optic c axis(E1 and A1 modes) were expressed by Lorentz oscillator dielectric function model. There was a striking absorption dip at the A1 phonon frequency in p-polarized reflectance spectra due to the optical anisotropy. These infrared-active phonon parameters were obtained with uniaxial dielectric tensor. It was found that the A1 longitudinal-optical phonon frequency linearly increases with the Mn composition for the diluted magnetic semiconductor epilayers. The broadening values of the A1 phonon changed from 3.6±1.3 to 9.0±1.6 cm−1, showing the high film crystal quality. Moreover, the ordinary and extraordinary dielectric functions ε⊥ and ε‖ of the epilayers were determined. It indicated that was larger than ε⊥ for the Ga1−xMn x N films in the reststrahlen region, which can be ascribed to slight structural degradation of the wurtzite lattice.

Optical properties of ferroelectric Bi3.25La0.75Ti3O12 BLT films on quartz have been investigated using ultraviolet-infrared transmittance spectra in the temperature range of 77-500 K. The spectra can be divided into three distinctive photon regions between 1.1 and 6.5V. It is found that the band gap Eg decreases from 3.88 to 3.77V with the temperature. The parameters aB and B of the Bose-Einstein model are 30.3V and 218.7K, respectively. The band narrowing coefficient dEg/dT is −2.65 10−4V/K at room temperature. The present results can be crucial for future application of ferroelectric BLT-based electro-optic and high temperature optoelectronic devices.

The 70%Pb Mg1/3, Nb2/3O3-30%PbTiO3 PMNT films have been fabricated on LaNiO3 LNO coated silicon substrate. The conductive LNO films act as a seed layer for the growth of PMNT films, which depresses the formation of pyrochlore phase and induces the high 100 preferred orientation of perovskite PMNT films. Compared with the PMNT films grown on platinum bottom electrode, the ferroelectric properties of PMNT films grown on LNO are enhanced. The frequency dependence of complex permittivity from PMNT films on LNO is the conjunct result of polarization relaxation and movement of oxygen vacancy, which can be fitted by the function containing Debye and universal dielectric response models, respectively.