Papers by Author: Kazuaki Kurihara

Abstract: Piezoelectric films using d15 shear-mode can be applied to many useful MEMS devices. The small displacement derived from the d15 shear-mode was directly observed by a SPM measurement. An isolated PZT(52/48) active part having a pair of driving Cu electrodes was processed in a 5 m-thick sputtering film. The displacement measurement of the active part and its FEM analysis suggested that the estimated d15 piezoelectric constant of the film was 590 pm/V. And, the d31 value of the film was -120 pm/V measured by a conventional cantilever method. The obtained piezoelectric constants of the PZT film are near those of bulk.

Abstract: Lanthanum-modified lead zirconate titanate and lead zirconate titanate epitaxial films with (100) and (111) orientations were grown respectively on (100) and (111) niobium, lending conductivity to strontium titanate through chemical solution deposition. This study investigated changes in the ordinary and extraordinary refractive index
no and
ne induced in these films by an electric field using the prism-coupling method. In the (100) epitaxial PZT 30/70 film, anisotropic electro-optic effects arise from the Pockels effect. The isotropic electro-optic effect, which is
no =
ne , was achieved on (100) epitaxial PLZT 8/65/35 and PZT 70/30 films.

Abstract: The influence of a rare earth oxide/yttria-stabilized zirconia (YSZ) double buffer layer structure on the orientation of a perovskite thin film was investigated on (100) silicon substrates. A calcium titanate perovskite film with a mixture of (110) and (100) orientation was grown epitaxially on a YSZ buffer layer. Since rare earth oxides have almost the same chemical nature and different lattice parameters, it is anticipated that the lattice parameter of the buffer layer can be controlled by changing the rare earth element. An (100) oriented epitaxial calcium titanate film was obtained by changing the composition of rare earth oxides on the YSZ/Si substrate.

Abstract: Epitaxial Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films for electrooptic applications were fabricated on a Si substrate using buffer layers. The PMN-PT/SrRuO3/SrTiO3/(La,Sr)CoO3/CeO2 /YSZ/Si hetrostructure was fabricated by pulsed laser deposition. A PMN-PT thin film with a thickness of 2μm was successfully deposited. The optical characteristics of PMN-PT epitaxial film were measured by prism coupling method. The morphology of the PMN-PT films was drastically improved by introducing a mask between the target and substrate during the deposition. The PMN-PT thin film showed a columnar structure, where the width of each column was approximately 180nm. A refractive index of 2.48 with zero bias voltage was obtained for the epitaxial PMN-PT thin film using the prism coupler method.

Abstract: Two-dimensional Pb0.865La0.09Zr0.65Ti0.35O3 (PLZT) photonic crystals with hexagonal arrays of air holes on (001) Pt-sputtered magnesium oxide substrates were fabricated using a sol-gel process with resist molds. The PLZT photonic crystals have a thickness of 200 nm, and the period of hexagonal array and the radius of air holes were 400 or 450 nm and 135 or 165 nm, respectively. The PLZT photonic crystals were primarily orientated along the c-axis. The strain hysteresis loop of the photonic crystals suggested that the photonic crystals are ferroelectric. Several peaks within range of wavelength between 500 nm and 1000 nm appeared in the optical reflection spectra from the cleaved facet of the photonic crystals. The peaks have polarization dependence and the frequency bands of the each peak were close to that of photonic band gaps (PBGs) expected by the calculations.