ITO/Au/ITO trilayers with varying gold spacer layer thicknesses were deposited on glass substrates by pulsed laser deposition. Transmission electron microscopy measurements demonstrated the continuous nature of the Au layer down to 2.4 nm. XRD patterns clearly showed an enhanced crystallinity of the ITO films promoted by the insertion of the gold layer. Compared with a single layer of ITO with a carrier concentration of 7.12 × 1020 cm–3, the ITO/Au/ITO structure achieved an effective carrier concentration as high as 3.26 × 1022 cm–3. Transmittance and ellipsometry measurements showed that the optical properties of ITO/Au/ITO films were greatly influenced by the thickness of the inserted gold layer. The cross-point wavelength of the trilayer samples was reduced with increasing gold layer thickness. Importantly, the trilayer structure exhibited a reduced loss (compared with plain Au) in the near-infrared region, suggesting its potential for plasmonic applications in the near-infrared range.Keywords: electrical and optical properties; ITO/Au/ITO; plasma frequency; pulsed laser deposition; transparent conductive oxide

Sr0.75Ba0.25Nb2O6 (SBN75) thin films were deposited on silicon substrate with MgO (100) or TiN (100) buffer layer by radio-frequency magnetron sputtering technique. X-ray diffraction confirmed that a 900 °C annealed SBN self-buffer layer introduced before SBN deposition can lead to the highly c-axis orientation of SBN75 thin film on MgO buffer layer. Energy-dispersive spectrometry analysis showed that the SBN75 films had target-film composition transfer and the TiN buffer layer was partially oxidized during SBN growth. The refractive index of SBN films on both MgO/Si and TiN/Si substrates was determined by fitting the measured reflectance curves with Sellmeier dispersion model in the visible region and the micro-structures were studied by scanning electron microscopy. In this paper, the conditions for SBN/MgO/Si treated as waveguide structure were also discussed.

This paper describes the preparation and characterization of unimorph actuators for deformable mirrors, based on Pb(Zr0.52Ti0.48)O3 (PZT52) thin film. As comparison, two different designs, where the PZT layer in the unimorph actuators was driven by either interdigitated electrodes (IDT-mode) or parallel plate electrodes (d31-mode), were investigated. The actuators utilize a unimorph membrane (diaphragm) structure consisting of an active PZT piezoelectric layer and a passive SiO2/Si composite layer. To fabricate the diaphragm structures, n-type (1 0 0) silicon-on-insulator (SOI) wafers with 1 μm thermal SiO2 were used as substrates (for d31-mode actuators, the upper Si part of SOI need to be heavily doped and used as bottom electrodes simultaneously). Sol–gel derived PZT piezoelectric layers with PbTiO3 (PT) bufferlayer in total of 0.86 μm were then fabricated on them, and 0.15 μm Al reflective layers were deposited and patterned into top electrode geometries, subsequently. The diaphragms were released using orientation-dependent wet etching (ODE) with 5–10 μm residual silicon layers. The complete unimorph actuators comprise 4 × 4 discrete units (4 mm2 in size) with patterned PZT films for parallel plate configuration or 3 × 3 individual pixels (2 mm in IDT diameter) with continuous PZT films in graphic region for IDT configuration. The measurement results indicated that both of the two configurations can generate considerable deflections at low voltage. The measured maximum central deflections at 15 V were approximately 2.5 μm and 2.8 μm, respectively. The intrinsic strain conditions shaping the deflection profiles for the diaphragm actuators were also analyzed. In this paper, the behaviors of clamped parallel plate configuration without a diaphragm were also evaluated.