This paper is studied for the improvement of the characteristics of gate oxide with 3-nm-thick gate oxide by deuterium ion implantation methode. Deuterium ions were implanted to account for the topography of the overlaying layers and placing the D peak at the top of gate oxide. A short anneal at forming gas to nitrogen was performed to remove the damage of D-implantation. We simulated the deuterium ion implantation to find the optimum condition by SRIM (stopping and range of ions in matter) tool. We got the optimum condition by the results of simulation. We compare the electrical characteristics of the optimum condition with others terms. We also analyzed the electrical characteristics to change the annealing conditions after deuterium ion implantation. The results of the analysis, the breakdown time of the gate oxide was prolonged in the optimum condition. And a variety of annealing, we realized the dielectric property that annealing is good at longer time. However, the high temperature is bad because of thermal stress.

In this paper, CdS thin films, which were widely used window layer of the CdTe and the Cu(In,Ga)Se2 thin film solar cell, were grown by chemical bath deposition, and effects of pH of reaction solution on the structural and optical properties were investigated. For pH<10.5, as the pH of reaction solution was higher, the deposition rate of CdS films was increased by improving ion-by-ion reaction in the substrate surface and the crystallinity of the films was improved. However, when the pH was higher than 10.5, the deposition rate was decreased because of smaller Cd2+ ion concentration in the reaction solution. Also, the crystallinity of the films were deteriorated. The CdS films deposited at lower pH showed poor optical transmittance due to adsorbed colloidal particles, while the transmittance was improved for higher pH.

Lead-free piezoelectric ceramics with the composition of (Na0.54K0.46)0.96Li0.04(Nb1-0.10-xTa0.10Sbx)O3 (x= 0∼8 mol%) were fabricated by nomal sintering at 1,090℃ for 5 h. the phase structure, microstructure and electrical properties were investigated with a emphasis on the influence of the Sb content. All samples exhibit a single perovskite phase over the whole compositional range. For the ceramics with x= 4 [mol%], two phase transitions are observed at 75℃ and 366℃, corresponding to the phase transitions of orthorhombic to tetragonal (To-t) and tetragonal to cubic (Tc), respectively. high electrical properties of d33= 210.83 pC/N, kp= 40%, εr= 1,091.35, ρ= 4.54 g/㎠ were obtained from the specimen with x= 4 [mol%], which suggests that the composition ceramics is a promising lead-free piezoelectric material.

[Li0.04(Na0.54K0.46)0.96](Nb1-0.04-XTaXSb0.04)O3 lead-free piezoelectric ceramics have been prepared by normal sintering at 1,100℃ for 5 h. X-ray diffraction analysis indicated that specimens demonstrate orthorhombic symmetry when Ta≤5 mol%. While transforming into tetragonal symmetry when x ≥ 20 mol%. These suggest that the orthorhombic and tetragonal phases co-exist in the ceramics with 5 mol% < Ta < 20 mol% at room temperature. All samples have high density, ranging from 4.46 to 4.79 g/cm3. As the result of SEM images, the grain growth was decreased with the increase of Ta substitution. The ceramics become ``softening``, leading to improvements in kp, ε r and d33, but a decrease in Qm. Excellent properties of kp= 0.46, d33= 293 pC/N, εr= 1,583 and Tc= 340℃ were obtained when Ta= 15 mol%

Additions (ZnO, CuO) doped 0.98(Na0.5K0.5)NbO3-0.02Li(Sb0.17Ta0.83)O3 (0.98NKN-0.02LST-x) lead free piezoelectric ceramics have been fabricated by ordinary sintering technique. The effects of additions doping on the dielectric, piezoelectric, and ferroelectric properties of the ceramics were mainly investigated. X-ray diffraction of the sample appeared orthorhombic phase. The specimen doped with additions exhibits enhanced electrical properties (d33= 153 pC/N). These results indicate that the 0.98NKN-0.02LST-x ceramics is a promising candidate for lead-free piezoelectric ceramics for applications such as piezoelectric actuators, harmonic oscillator and so on.

The lead-free 0.98(Na0.5,K0.5)NbO3-0.02Ba(Zr0.52,Ti0.48)O3-(hereafter NKN-BZT) CuO, ZnO-doped ceramics were prepared using a conventional mixed oxide method. NKN-BZT ceramics doped CuO, ZnO have superior structural and electrical properties than pure NKN-BZT ceramics. For the NKN-BZT-ZnO ceramics sintered at 1,120℃, piezoelectric constant (d33) of sample showed the optimum values of 172 pC/N. The 0.98(Na0.5,K0.5)NbO3-0.02Ba(Zr0.52,Ti0.48)O3-ZnO ceramics are a promising candidate for lead-free piezoelectric materials.

Ga-doped ZnO-SnO2 (ZSGO) films were deposited by rf magnetron sputtering and their structural and electrical properties were investigated. In order to fabricate the target for sputtering, the mixture of ZnO, SnO2 (1:1 weight ratio) and Ga2O3 (3.0 wt%) powder was calcined at 800℃ for 1 h. The substrate temperature was varied from room temperature to 300℃. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The optical transmittances of the films were measured and the optical energy band gaps were obtained from the absorption coefficients. The resistivity variation with substrate temperature was measured. Auger electron spectroscopy was employed to find the atomic ratio of Zn, Sn, Ga and O in the film deposited at room temperature. ZSGO films exhibited the optical transmittance in the visible region of more than 80% and resistivity higher than 10 Ωcm.

In this study, a method to measure the thickness of thin film by EDS (energy dispersive spectroscopy) is suggested. We have developed a model which calculates the thickness of thin film from the characteristic x-ray intensity ratio of the elements in thin film and substrate by considering incident electron beam energy, x-ray generation curve, backscattering and absorption of x-ray, take-off angle of x-ray and tilt angle of the sample. We obtained the relation curve between the film thickness measured experimentally and the x-ray intensity ratio of elements. The film thicknesses calculated from the model agrees quite well with those measured experimentally. Therefore, the thin film thickness can be measured rapidly and accurately by using the model developed in this study and the x-ray intensity ratio obtained in EDS analysis.

This paper was investigated the electrical properties for optimal operating conditions of monocrystalline silicon solar cell. The output of electricity for monocrystalline solar cell was investigated according to the distances between solar cell and halogen lamp and to the resistances by the variable resistor.

Y1-xBO3:Tbx 3+ ceramic phosphors were synthesized with changing the concentration of Tb3+ at a sintering temperature of 1,100℃ and a reduction temperature of 950℃ by using a solid-state reaction method. The crystal structure, surface morphology, and photoluminescence properties of the phosphors were investigated as a function of Tb3+ ion concentration by using XRD (x-ray diffractometer), scanning electron microscopy, and photoluminescence spectrophotometry, respectively. The XRD results showed that the main peak of the phosphor powders occurs at (101) plane. As for the photoluminescence properties, the excitation spectra showed the broad band centered at 306 nm and the emission intensity of the spectra peaked at 543 nm indicated a significant decrease as the concentration of Tb3+ ion is increased.

In this study, we have fabricated the red OLED (organic light emitting diode). The basic device structure is ITO/hole transporting layer, TPD(500 Å)/red emitting layer, Alq3 doped with DCM2:rubrene(20 Å)/electron transporting layer, Alq3(M) (500 Å-M Å)/LiF(15 Å)/Al(1,000 Å). The thickness of electron transporting layer(500 Å-M Å) changed 0, 20, 40, 60 Å. Turn on voltage of the red OLED was 5 V, 6 V, 6.5 V and 7.5 V , respectively with electron transfer layer changed ratio. Luminance of red OLED was 4,504, 1,840, 1,490 and 1,130 cd/m2, respectively. Optimized electron transfer layer position changed ratio of the red OLED was 0 Å.

The charged particle type display is a kind of the reflectivity type display and shows an image by absorption and reflection of external light source, which has keep an image without additional electric power because of bistability. In this paper, we made a device whose cell gap is 56 ㎛ and also analyzed driving and memory characteristics by applied driving voltages. As a result, we found that the driving voltage and memory effect depend on q/m(charge to mass ratio) of charged particle. In this case of breakdown voltage, the devices showed degradation of reflectivity and memory effect due to irregular movement of overcharged particles. In addition, contrast ratio of the device varies with memory effect. Thus, we consider that device needs uniform q/m for improvement of electric and optical properties and memory effect.

The dependency of sputtering power on the electrical performances in amorphous HIZO-TFT (hafnium-indium-zinc-oxide thin film transistors) has been investigated. The HIZO channel layers were prepared by using radio frequency (RF) magnetron sputtering method with different sputtering power at room temperature. TOF-SIMS (time of flight secondary ion mass spectrometry) was performed to confirm doping of hafnium atom in IZO film. The field effect mobility (μFE) increased and threshold voltage (Vth) shifted to negative direction with increasing sputtering power. This result can be attributed to the high energy particles knocking-out oxygen atoms. As a result, oxygen vacancies generated in HIZO channel layer with increasing sputtering power resulted in negative shift in Vth and increase in on-current.

We have investigated the effect of organic thin film on the driving voltage of OLED (organic light emitting diode) by inserting a 5 nm thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) or triphenylphosphineoxide (Ph3PO) between tris-(8-hydroxyquinoline)aluminum (Alq3) electron transport layer and 4,4``-bis(2,2``-diphyenylvinyl)-1,1``-biphenyl (DPVBi) emission layer. The device with 5 nm thick Ph3PO layer exhibited higher maximum current efficiency and lower driving voltage than the device with BCP layer, resulting from better electron injection from Alq3 to DPVBi in the device with Ph3PO layer.

An engine oil sensor based on multiwall carbon nanotubes was fabricated with screen printing method. Since carbon nanotubes are generally intertwined, dispersion of the carbon nanotubes in the binding agent (ethyl cellulose, a-terpineol, frit) is a key factor for large yield of engine oil sensor. By conventional dispersion method, a hand-mill method, the maximum yield was 80% at most. However, we used the hand ultrasonic, in order to increase the yield of the sensors. As a results, our engine oil sensor fabricated by the screen printing method shows excellent yield rate of 97%, when we dispersed a paste by the hand ultrasonic method.