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Lithium doped (0–10 at. % Li) ZnO films were grown in the wurtzite structure on sapphire (001) substrates and investigated in the 200–1200 cm−1 frequency range at 300 K by far-infrared reflectivity spectroscopy using polarized oblique (45°) incidence. This technique has enabled us to determine the longitudinal optical phonon frequency E1(LO) at 576 cm−1 of the fundamental lattice vibration at the center of the Brillouin zone, as well as to investigate the LO phonon-plasmon coupling in the low carrier density (N⩽1018 cm−3) ZnO films. The energy shift and halfwidth broadening of the LO phonon band in comparison with the uncoupled mode in high-ohmic ZnO:0.8 at. % Li (ρdc=0.6×106 Ω cm) film have been analyzed to get the concentration and “optical” mobility of charge carriers in the Li doped ZnO films. The results of optical, x-ray diffraction and dc resistivity measurements are discussed.

We report far-infrared reflectivity spectra of the PbZr 0.52 Ti 0 . 48 O 3 and copper doped PbTiO 3 single-crystal films focusing on the electronic properties. The conductivity has been analyzed by the Drude-Lorentz model and in terms of dynamic interaction, which leads to a frequency dependent scattering rate and enhanced low-frequency carrier mass. Introduction of 0.5 mas.% Cu in PbTiO 3 decreases effective mass from 3.5 to 1.5 near 200 cm −1 and increases relaxation time compared with the undoped sample.

Both n-type and p-type ZnO will be required for development of homojunction light-emitting diodes and laser diodes. It is easy to obtain strong n-type ZnO, but very difficult to create consistent, reliable, high-conductivity p-type material. Here we present our investigations of p-type ZnO thin film preparation by sol-gel method using single Li doping and Ga(Al)+N codoping technique. ZnO thin films with c-axis orientation have been prepared on glass substrates. Zn acetate dihydrate, gallium nitrate and acetamide were used as zinc, gallium and nitrogen precursors respectively. SEM, X-ray diffraction, electric conductivity and Hall effect measurements were carried out. The results show that p-type conducting ZnO films with hole concentrations as high as 5x1017 cm-3 were obtained by this method.

Monocrystalline c-axis oriented thin films of PbTiO3 with various hole concentration were prepared by Cu doping with 0.1, 0.5, 1.0 mas.% and substituting Zr for Ti (Zr:Ti equals 52:48). We report concentration-dependent far- and mid- infrared reflectivity spectra of these compounds focusing on the electronic properties. Optical functions (e 1, e 2, σ , -Im e -1) have been analyzed by Kramers-Kronig transformation to reflectivity spectra measured in a frequency range of 200 - 10000 cm-1 at room temperature. Conductivity spectra show a complete semiconducting dependence that can be analyzed by Drude-Lorentz model and in the terms of dynamic interaction, which leads to a frequency dependent scattering rate and enhanced low-frequency carrier mass 0.5 mas.% Cu in PbTiO3 decreases effective mass from 3.5 to 1.5 near 200 cm-1 and increases relaxation time as compared with the undoped sample.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.