In this study, chemical bath deposition method was used to grow Zinc sulfide(ZnS) thin filmsfrom NH3/SC(NH2)2/ZnSO4 solutions at 90℃. ZnS thin films have been prepared onto ITO glass. Theconcentrations of ZnSO4 and NH were varied while the concentration of Thiourea was fixed in 0.52 M. Structural, optical, electrical characteristic of ZnS thin films were measured. The physical and opticalproperties of different ZnS thin films were influenced severely by the concentration of the two reactingchemicals. The optimal concentration of ZnSO4 and NH3 was 0.085 M and 1.6 M, respectively.

A high-responsive Schottky device has been achieved by forming a thin metal deposition on aSi substrate. Two-different metals of Ni and Ag were used as a Schottky metal contact with a thicknessabout 10 nm. The barrier height formation between metal and Si determines the rectifying currentprofiles. Ag-embedding Schottky device gave an extremely high response of 17,881 at a wavelength of900 nm. An efficient design of Schottky device may applied for photoelectric devices, includingphotodetectors and solar cells.

We have investigated the structural and electrical properties of Si-Zn-Sn-O (SZTO) thin filmsdeposited by RF magnetron sputtering at various deposition temperatures from RT to 350℃. All theSZTO thin fims are amorphous structure. The mobility of SZTO thin film has been changed dependingon the deposition temperature. SZTO thin film transistor shows mobility of 8.715 ㎠/Vs at roomtemperature. We performed the electrical stress test by applying gate and drain voltage. SZTO thin filmtransistor shows good stability deposited at room temperature while showing poor stability deposited at350℃. As a result, the electrical performance and stability have been changed depending on depositiontemperature mainly because high deposition temperature loosened the amorphous structure generatingmore oxygen vacancies.

In this study, novel ultrasonic rotary motor of hexadecagon shape stator was proposed. Statorof the hexadecagon ultrasonic motor was composed of an elastic ring and ceramics. The elastic ring hadsixteen sides and sixteen angular points. Eight ceramics were attached on the outer surface of the eightsides of the ring. When rotor of cylindrical shaft was inserted inside of the ring stator, central lines of thesixteen sides of the stator hold the shaft by the slight pressures(frictions). This slight pressure was apreload of the motor and it could be controlled by radius and thickness of the ring. When two sinusoidalvoltages which have 90 degree phase difference were applied to each four ceramics, elliptical displacementsof inner surface of the ring were obtained. These elliptical displacements of the inner surface rotated theshaft rotor through the frictions. The proposed hexadecagon ultrasonic motor was designed and analyzedby using the finite element method (FEM), depending on materials of the elastic ring. Based on the FEMresults, one model of motor which showed maximum displacement at contact points was chosen andfabricated. And characteristics of the motor were compared with simulated results. When the motor wasfabricated with these results, EL20ET0.5CT0.5CW2 model showed 115[rpm] speed about input voltage of60[Vrms] at 65.6[kHz]. And the maximum torque of 6[gfcm] was obtained. From these results, thehexadecagon shaped ultrasonic motor can be used to actuator for optical device which needs detailedposition control. Also it can be used to medical and portable device by reducing size and weight.

We investigated the effect of Ta doping on the dielectric and piezoelectric properties oflead-free (K0.5Na0.5)NbO3 ceramics prepared using a conventional ceramic processing. X-ray diffractionanalysis revealed that Ta was perfectly substituted into Nb-sites in the range of 0 to 20 at%. As Tacontent in the KNN increased, the sinterability of KNN ceramics was significantly degraded while the Tadoping enhanced the piezoelectric constant d33, planar mode piezoelectric coupling coefficient (kp), andelectromechanical quality factor (Qm). The highest values for d33, kp, and Qm was found to be 156 pC/N,0.37, and 155, respectively.

l.ao.5Sro5CoO₃ (LSCO) electrode thin films with a resistivity of ~ 1,600 μΩcm were grown on c-Al₂O₃ (0001) substrates. ZnsnO₃ (ZTO) thin films with different thicknesses were directly grown on LSCO/c-Al₂O₃ (0001) substrates at a substrate temperature that ranged from 550 to 750 ℃ using Pulsed Laser Deposition (PLD). The secondary phase Zn₂SnO₄ occurred during the growth of ZTO films and it became more significant with further increasing substrate temperature. Polarization-electrc-field (P-E) hysteresis characteristics. with a remnant polarization and coercive field of 0.05 μC/㎠ and 48 kv/cm, respectively, were obtained in the ZTO film grown at 700℃ in 200 mTorr.

In this paper, by using a dual frequency liquid crystal material, we propose a liquid crystaldevice with a fast response characteristics. The dual frequency liquid crystal material has a positivedielectric anisotropy value at a low frequency. With a high frequency, the dielectric anisotropy becomesnegative. Therefore, the relaxation process is governed by not only the elastic deformation, but also thedielectric interaction. The measured decay time and rise time were 0.88 ms and 0.33 ms, respectively.

Because of a waveguiding effect and total internal reflection caused by a difference inrefractive indices, only 20% of generated light is emitted to the air and the rest is trapped or absorbed inthe device. An improvement of outcoupled efficiency of organic light-emitting diodes was studied using amicrolens array. Mold of microlens array was fabricated by using photo-lithography with the AZ9260photoresist, and the microlens array was formed onto the glass substrate using the UV curing agentnamed ZPU13-440. Device structure consists of microlens/glass/ITO/TPD/Alq3/LiF/Al. It was found thatthere is an improvement of external quantum efficiency by about 20% at the same current density for thedevice with the microlens array compared to that of the reference one. Simulated outcoupled efficiencyshows the improvement by about 20% for the device with the microlens array compared to that of thereference one. These results are consistent with the experimental ones

Photoemission is a process in which photons are converted into free electrons. Photocathodesare the typical materials for the process. They emit electrons when a light is irradiated upon. Thetraditional method of manufacturing photocathodes is complicated, requires specialized equipment, and islimited very small sized samples. Cs3Sb photocathode was formed on a substrate in   atmosphericconditions. The photocathode formation was a gas phase reaction with the substrate. Vacuum deviceswere made to test electron emission characteristics of the formed photocathode. Visible light ofwavelength 475 nm was used for the primary light source. The results showed high current density andlong term stability of the photoelectron emission.

Hydrothermal synthesis technique could be carried out for growth of ZnO nanowires atrelatively low process temperature, and it could be freely utilized with various substrates for fabricationprocess of functional electronic devices. However, it has also a demerit of relatively slow growthcharacteristics of the resulting ZnO nanowires. In this paper, an external DC bias of positive and negative0.5 [V] was applied in the hydrothermal synthesis process for 2∼8 [h] to prepare ZnO nanowires on aseed layer of AZO with high electrical conductivity. Growth characteristics of the synthesized ZnOnanowires were analyzed by FE-SEM. Material property of the grown ZnO nanowires was examined byPL analysis. The ZnO nanowires grown with positive bias revealed distinctively enhanced growthcharacteristics, and they showed a typical material property of ZnO.

nternal corrosion of the distribution line can be detected in order to develop techniques ofnon-destructive inspection methods that operate only on the metal track eddy current diagnosis ispossible by applying the technique investigated. Sensor for the production of a finite element methodmodeled by using an eddy current sensor, a distribution line by using an accelerated aging samples ofsodium hydroxide was prepared. Sheathed cables for internal corrosion studies detected using an eddycurrent sensor is considered to be possible.

The object of this paper is to develop optimal optical filter, which can be used to identify thefinancial account and read the information. The five factors which affect the performance of the opticalfilter are identified as optical glass type, existence of Fe, Photo pic coating type, and coating form. Inthis study we seek to determine the optimal combination for the best design of the optical filter. For eachcombination, the performances of optical filter are investigated using the proper experimental equipmentsand methods. White-state voltage, black-state voltage, and black-state error rate are used for theperformance measures. Through the statistical analysis of the performance data collected, we havedetermined the optimal design of the optical filter.