Abstract: Polycrystalline ZnO thin films were for the first time deposited on SiO2/Si (100)
substrate using 2-step deposition; atomic layer deposition (ALD) and RF magnetron sputtering, for
Film Bulk Acoustic Resonator (FBAR) applications. The film deposition performed in this study
was composed of following two procedures; the 1st deposition was using ALD method and 2nd
deposition was using RF magnetron sputtering. The ZnO buffer layer ALD films were deposited
using alternating diethylzinc (DEZn)/H2O exposures and ultrahigh purity argon gas for purging.
Exposure time of 1 sec and purge time of 23 sec yielded an ALD cycle time. Two-step deposited
ZnO films revealed stronger c-axis preferred-orientation than one-step deposited. Therefore, this
method could be applied to the FBAR applications, since FBAR devices require high quality of thin
Abstract: We have preformed holographic recording in congruent LiNbO3 doped with Tb and Fe
with a continuous-wave green laser at λ = 532 nm. This material exhibited a fast coloration upon
exposure to ultraviolet (UV) light. The recording sensitivity was improved from about 0.02 cm/J
to over 0.08 cm/J after UV pre-exposure, due to the increased visible absorption. Holograms
recorded from the colored state could be quickly erased by UV illumination and a sequence of
recording by green and erasure by UV could be continuously repeated without any noticeable
degradation in maximum diffraction efficiency or sensitivity. The overall performances of this
crystal relevant to holographic storage are here presented, in comparison to those obtained with
Abstract: [MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single
crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling
down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single
crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by
using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb
concentration were confirmed by the EPMA and observed defects by optical microscopy.
Abstract: Amorphous indium tin oxide (ITO) thin films were grown on plastic substrates, PES (polyethersulfone) using low temperature DC magnetron sputtering. Various post-annealing techniques are attempted to optimize conductivity, transmittance, and roughness: i) conventional thermal annealing, ii) excimer laser annealing, and iii) UV irradiation. The electrical/optical properties were measured using Hall-measurement, DC 4-point resistance measurement, and UV spectrometry along with micro-structural characterization. Optimized UV treatment exhibits enhanced conductivity and smooth surface, compared to those of conventional thermal annealing and excimer laser annealing.
Abstract: SnO2 thin films were prepared on SiO2/Si substrate by RF-Magentron Sputtering method,
varying the deposition time and Ar-to-O2 flow ratio. The post-annealing was conducted at 500 oC
and 700 oC in Ar and O2 atmosphere, respectively. Film characteristics were very sensitive to the
gas flow ratio during the deposition and the conditions of post-annealing. The Film thickness
decreased with decreasing of Ar flow ratio at a constant amount (50 sccm) of total gas flow.
Especially, the film deposited under Ar-O2 mixture gas (Ar-to-O2 ratio of 50%) showed clearly
aggregated morphology of small particles (cauliflower) in a wide range of area. In the annealed
films, these cauliflowers separated some small grains, decreasing the film thickness.
Abstract: Tin oxide thin films were deposited at 375 °C on α-alumina substrate by metal-organic
chemical vapor deposition (MOCVD) process. A number of hillocks on the film were formed after
air annealing at 500 °C for 30 min and few things in N2 annealing. The oxygen content and the
binding energy after air annealing came to close the stoichiometric SnO2. The cauliflower hillocks
of the film seem to be formed by the continuous migration of crystallites from a cauliflower grain
on the substrate to release the stress due to the increase of oxygen content and volume.
Abstract: One of obstacles hindering a realization of large area size twisted nematic liquid crystal
display (TN-LCD) flat panel (for example, 1100 x 1250 mm) is a slow response time. The slow
response time is due to the inverse proportionality of turn on time with the frame frequency and pixel
number (number of gate lines) in the twisted nematic liquid crystal system. It is known that the slow
response time in the active matrix system of LCD be solved by reducing the sheet resistance of color
filter electrodes. In this paper, we report on the processing details of the deposition of transparent ITO
films using a DC sputtering system. The thickness of ITO layer was set for high transmittance and
good conductivity and the films were characterized with respect to the transmittance and sheet
resistance. The deposited ITO films show a good uniformity across the whole area and the average
thickness of the ITO is about 1350 Å under the DC power of 10.7 kW. The transmittance is increased
from 72.5 to about 93 % as the oxygen content is increased to 2.5 sccm for the samples without
annealing. It was found that the transmittance is significantly improved by the annealing process at
220 oC for 40 min. up to 94 %. The sheet resistance is decreased with the DC power and exhibits
below 22 / after the samples were annealed.
Abstract: The chemical and electrical characteristics of HfO2 dielectric layers grown on the p-type Si
substrate by the metalorganic molecular beam epitaxy (MOMBE) technique were investigated. The
XPS spectra showed that the Hf 4f and O 1s peaks shifted to the higher level of binding energy due to
the charge 1transfer effect. Electrical properties were analyzed by C-V and I-V measurements. The
distortion of C-V curve at depletion region is attributed to the effect of deep trap levels existence.
Saturation capacitance and leakage current density were in the range of 207 ~ 249 pF and 0.52 ~ 0.58
A/cm2 respectively, and the flat band voltage shift to the higher voltage appeared as the oxygen flow
Abstract: We synthesized ZnO nanocrystal colloids adopting sol-gel method using zinc acetate
dehydrate as precursor, and prepared ZnO films on glass substrates by a spin-coating technique. The
effect of annealing temperature on the structure, optical and electrical properties has been studied.
The crystallinity and morphologies were improved by the annealing. All film samples show high
transmittance of above 80% in the wavelength ranging from 400nm to 1000nm. A minimum
resistivity of 5.5x10-3 cm was obtained for the film annealed at 500oC. The crystallinity, oxygen
vacancies, and nanocrystalline boundaries seems likely to be crucial factors for these properties
Abstract: With new models of AM1 solar spectra and Si refractive indices in the wavelength range
, effective absorption powers of Si solar cells coated with the single and
double AR layers were theoretically calculated for the first time. The SiO2, Si3N4 and
SiO2/Si3N4 easily obtainable in the standard Si process were used as the AR layers of Si solar
cell. Optimum thicknesses showing the maximum absorption power for AR layers of SiO2,
Si3N4 and SiO2/Si3N4 were as follows: d(SiO2)=10001, d(Si3N4)=7001 and d(SiO2/Si3N4) =500
1 /3001 . Effective absorption powers in the solar cells of SiO2-Si, Si3N4-Si and SiO2/Si3N4-Si were
520W/m2, 565W/m2 and 607W/m2 at AM1 in the optimum conditions of AR coating, respectively