The reflectance measurements of p-type GaSb: Zn epitaxial films with different hole concentrations, grown by metalorganic vapor-phase epitaxy, have been investigated in the 3-30-THz frequency region. The experimental spectra were fitted using a classical harmonic Lorentz oscillator and the Drude model, illustrating that the hole effective mass and the mobility change with the carrier concentration. The hole effective mass was found to vary from 0.22m to 0.41m as the carrier concentration changed from 3.5×1017 to 3.8×1018 cm−3. The mobility values derived from the reflectance measurements were slightly smaller than the values obtained from Hall-effect measurements. A sublinear relationship between the absorption coefficient and the hole concentration was found at a frequency of 3 THz. Those results can be used for designing GaSb-based terahertz detectors.

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.

(Pb1−xLax)Ti1−x/4O3 (PLT) ferroelectric thin films with various La concentrations have been grown on LaNiO3/Si(100) substrates by a modified sol-gel technique. X-ray-diffraction analyses show that the PLT and LaNiO3 thin films are polycrystalline and entirely perovskite phase. The infrared optical properties of the PLT thin films have been investigated using infrared spectroscopic ellipsometry in the wavelength range of 2.5-12.5 μm. By fitting the measured ellipsometric parameter (tanΨ and cos Δ) data with a four-phase model (air/PLT/LaNiO3/Si), and a derived dispersion relation for the PLT thin films, the optical constants and thicknesses of the thin films have been determined. The refractive index of the PLT thin films decreases with increasing wavelength; however, by a Kramers-Kronig analysis the extinction coefficient increases with increasing wavelength. Moreover, the refractive index and extinction coefficient of the PLT thin films increase with increasing La concentration. This indicates that the infrared optical constants of the PLT thin films are a function of the La concentration. It is believed that the increase in the infrared optical constants of the PLT thin films with increasing La concentration is mainly due to the crystallinity and the electronic band structure of the PLT thin films.

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.

Optical response of rutile TiO2 films grown under different laser energy by pulsed laser deposition has been investigated by Raman scattering and spectral transmittance. Dielectric functions in the photon energy range of 1.24-6.5V have been extracted by fitting the experimental data with the Adachi's model [S. Adachi, Phys. Rev. B35, 7454(1987)]. The refractive index dispersion in the transparent region is mainly ascribed to the higher A1-A2 electronic transitions for the rutile TiO2 films. Owing to slightly different crystalline structures and film densities, the optical band gap linearly increases with increasing packing density. The phenomena were confirmed by different theoretical evaluation methods.