To observe the optical characteristic of oxide semiconductor depending on the degree of bonding structures, SiOC, ZnO and IGZO were prepared by the RF magnetron sputter system and chemical vapor deposition. Generally, crystal ZnO, amorphous SiOC and IGZO changed the optical characteristics in according to the electro-chemical behavior due to the oxygen vacancy at an interface between different groups. Transmittance of SiOC and IGZO with amorphous structures was higher than that of ZnO with crystal structure, because of lowering the carrier concentration due to the recombination of electron and holes carriers as oxygen vacancies. Besides, the energy gap of amorphous SiOC and IGZO was higher than the energy gap of crystal ZnO. The diffusion mobility of holes is higher than the drift mobility of electrons.

Dual-gate PCRAM which unify capacitor-less DRAM and NVM using a PCM instead of a typical SONOS flash memory is proposed as 1 transistor. VO2 changes its phase between insulator and metal states by temperature and field. The front-gate and back-gate control NVM and DRAM, respectively. The feasibility of URAM is investigated through simulation using c-interpreter and finite element analysis. Threshold voltage of NVM is 0.5 V that is based on measured results from previous fabricated 1TPCM with VO2. Current sensing margin of DRAM is 3 ㎂. PCM does not interfere with DRAM in the memory characteristics unlike SONOS NVM. This novel unified dual-gate PCRAM reported in this work has 1 transistor, a low RESET/SET voltage, a fast write/erase time and a small cell so that it could be suitable for future production of URAM.

The bipolar resistive switching characteristics of resistive random access memory (ReRAM) based on HfO2 thin films have been demonstrated by using Ag/HfO2/Pt structured ReRAM device. MIcrowave irradiation (MWI) treatment at low temperature was employed in device fabrication with HfO2thin films as a transition layer. Compared to the as-deposited Ag/HfO2/Pt device, highly improved uniformity characteristics of resistance values and operating voltages were obtained from the MWI treatment Ag/HfO2/Pt ReRAM device. In addition, a stable DC endurance (> 100 cycles) and a high data retention (> 104 sec) were achieved.

Ag paste has been used in the front electrode of the Si-solar cell. It is composed by Ag powder, glass frit, binder, solvent and dispersant. The role of the binder and the solvent is to make a flow and a printing property. However, it was not enough to report the printing properties with the variation of binder in the controled viscosity. In this study, we selected 3 kinds of typical binder which were used as binder for the paste in the industry, such as Ethyl cellulose, Hydroxypropyl cellulose and Acrylic. Ag pastes using these were prepared, controled viscosity and printed on the SiNx coated Si wafer. In the ‘A paste’ used Acrylicbinder, printed hight was highest and ‘H paste’ used Hydroxypropyl cellulose binder was lowest. Because ‘Hpaste’ was high viscosity due to the molecular weight, the solvent was added in the paste to control the viscosity. Therefore, the content of solid was lower in ‘H paste’. The relative pattern width which is related to the spreading of paste was the best in the case of ‘H paste’ and ’EH paste’ at 30℃. It is thought that the optimization of the relative pattern width is possible for a paste by the controling shear thinning phenomenon. In the case of ‘A paste’, though printing hight was best, the pattern width was dependant on the temperature.

Aspheric lenses used in the thermal imaging are typically fabricated using expensive single-crystal materials (Ge and ZnS, etc.) by the costly single point diamond turning (SPDT) process. As a potential solution to reduce cost, compression molding method using chalcogenide glass has been attracted to fabricate IR optic. Thermal deformation of a molded lens should be compensated to fabricate chalcogenide aspheric lens with form accuracy of the submicron-order. The thermal deformation phenomenon of molded lens was analyzed ant then compensation using mold iteration process is followed to fabricate the high accuracy optic. Consequently, it is obvious that compensation of thermal deformation is critical and useful enough to be adopted to fabricate the lens by molding method.

Phase transition properties of the copolymer films of polyvinylidene fluoride (PVDF) and trifluoroethylene(TrFE), P(VDF-TrFE), were studied with X-ray diffraction (XRD) and polarization modulated ellipsometry (PME). XRD studies on both Langmuir-Blodgett (LB) films and spin coated films exhibit conversions from ferroelectric phase to paraelectric phase at 108±2℃ on heating and paraelectric phase to ferroelectric phase at 78±2℃ on cooling. The presence of the ferroelectric-paraelectric phase transition is also confirmed by the PME technique for the first time in this study. PME was proved to be a very sensitive tool in the measurement of the structural changes at the nano-thickness films.

To operate organic light emitting device (OLED) with alternating current (AC) power source without AC/DC(direct current) converter, we fabricated the fluorescent OLED and measured the emission characteristics with AC and DC. The OLED operated by AC showed higher maximum current efficiency of 8.2 cd/A and maximum power efficiency of 8.3 lm/W. But current efficiency and power efficiency of AC driven OLED showed worse than DC driven OLED at high voltage above 10 V. This result can be explained by the peak voltage of AC was  times than DC, In case of low driving voltage the emission characteristics were improved by the peak voltage of AC, but in case of high driving voltage the emission efficiencies were decreased by the roll off phenomena. Finally, serial OLED arrays using twelve OLEDs driven by AC 110 V showed average voltage of 9.17 V, voltage uniformity of 99.0%, average luminance of 1,175 cd/㎡, luminance uniformity of 94.4%.

In this study, we report the doping effect of graphene quantum dots (QDs) in nematic liquid crystal (NLC) system on rubbed polyimide (PI) surface. The good LC alignment and high thermal stability in QD-LC cell system on rubbed PI surfaces can be measured. Also, the low threshold voltage of QD-TN cell was observed about 2.77 V. The fast response time of 13.2 ms for QD-TN cell can be achieved. Finally, the good voltage holding ratio of QD-TN cell on rubbed PI surface was measured.

Photo electrode is an important component for DSSC. DSSCs electrical characteristics and efficiencies fabricated with different TiO2 photo electrodes thickness and modified phoro electrode surface area were studied. 11 ㎛ TiO2 photo electrode shows a 4.956% efficiency. The highest short circuit current density was a 9.949 mA/cm2. Efficiencies and short circuit current density increased as tape casting thickness decreased. Modified surface area of the photo electrode by needle stamp processing were studied. 200 times needle stamp processing on photo electrodes shows a highest 5.168% efficiency. Also the short circuit current density was a 10.261 mA/cm2.

In this research, nanocomposite layers consisting of poly (3,4,-ethylene dioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) and CuO nanoparticles were investigated as hole transport layers in organic solar cells based on poly (3-hexylthiophene) (P3HT) as the electron donor and (6.6) phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor. The addition of CuO nanoparticles to PEDOT:PSS layer improved the solar cell performance with 0.5% CuO nanoparticle concentration. At optimized concentration, CuO mixed PEDOT:PSS films had good electrical (4.131 Ω?cm) and optical (transmittance > 90%) properties for using hole transporting layer. We investigated that improved solar cell performance with CuO nanoparticles mixed PEDOT:PSS films.

In this paper, plant crops used in the region to grow crops for the LED lighting area of a rectangle to fit the light distribution to maximize the efficiency of a rectangular distribution was made of LED lights. After the fabrication of LED lamps, light distribution, and in the area of 1.2 m × 3 m was the analysis of Illuminance chart. As a result of examining the performance light distribution for total Emin/Eav is 56%, and the target area of the light distribution compared to normal lamps Emin/Eav is improved by about 17%. In addition, plants grown in the area to minimize the outgoing light distribution can be focused on the cultivation area, according to the distance of the plants and be able to have the best luminous efficacy is judged.

The Sr based ceramic thin films were deposited on Si substrate by RF magnetron sputtering method. And Sr based thin films were annealed at 500～700℃ using RTA. The surface roughness showed about 2.4 nm in annealed thin film at 600℃. The capacitance density of Sr based thin films were increased with the increase of annealing temperature. The maximum capacitance density of 0.6 ㎌/㎠ was obtained by annealing temperature at 700℃. The voltage dependence of dielectric loss showed about 0.02 in voltage ranges of -10～＋10 V. The leakage current density of annealing temperature of 600℃ was the 4.0×10-6 A/㎠ at applied voltage of -5～＋5 V.