CdS기관의 物性이 熱處理된 多結晶 CdTe 薄膜의 物理的 特性에 미치는 影響에 關한 硏究

이용혁 成均館大學校 1997 국내석사

Optical properties of rare-earth ternary compounds CePtSb and LaPtSb

김기회 成均館大學校 1997 국내석사

극소 전달자 계인 희토류 Ditellurides에 관한 물리적 특성 연구

정명화 成均館大學校 1997 국내석사

플라스틱 기판을 사용한 반사형 칼라 STN 액정표시소자의 설계 및 제작

민관식 成均館大學校 大學院 2001 국내석사

There is an increasing demand for color displays with light weight, thin thickness and low power consumption in the personal communication system. To satisfy the requests of the current display, various types of reflective color LCDs are proposed and it seems to be one of the most suitable displays because of its low power consumption and high performances. However, conventional reflective color LCDs have some problems related to the brightness and parallax. Front scattering film decreases the brightness with blurs image and outside reflector also induced parallax effect resulting in degrade of color purity. Therefore, many researchers have proposed various types reflective color LCDs with inner scattering reflectors to improve these blurred problems. In this paper, we present the results and discuss on the techniques related to reflector with high brightness and parallax free image and to optical design for reflective color STN LCD and contact characteristics of upper and lower plastic substrates. We designed and fabricated the SP reflective color plastic film STN LCD by invented low temperature stepped methods and materials. and obtained enhanced image quality.

誘電體 內部에서의 電氣場形成에 關한 統計力學的 硏究

최경영 忠南大學校 1985 국내석사

The dielectric polarization of the polarizable dipole fluids with highly directional attractive forces is studied by using linear graph theory assuming that the potential energy of a system of N molecules in an external field consists of three parts; 1) short-range repulsive interaction 2) short-range attractive interaction 3) Iong-range dipole-dipole interaction For a non-polarizable gas, the contribution of each potential terms to the dielectric constant is obtained. The contribution 'of the short range repulsive interaction term to the dielectric constant is proportional to (-μ² □²ND³). The long-range dipole -dipole interaction term has no contributions to the dielectric constant. The contribution of the short-range attractive interaction term to the dielectric constant can be calculated only by the electronic computer.

적층성장된 절연막 CeO2/YSZ/Si(111) 위에 성장한 Si 박막의 결정성 향상에 관한 연구

양재건 成均館大學校 大學院 2001 국내박사

强相關係 전기 및 자기적 특성의 압력 의존성 연구

조영훈 成均館大學校 大學院 2003 국내박사

In this study, we have investigated the electronic and magnetic properties of four systems with different ground state. In order to understand better the ground state, we have concentrated in pressure dependence of the bulk properties The superconducting transition point is strongly related to the frequency of phonon and the density of state of conduction electrons at the Fermi level. We have investigated the pressure dependence of the upper critical field of HoNi_(2)B_(2)C and DyNi_(2)B_(2)C. In HoNi_(2)B_(2)C, as increasing pressure the superconducting state near the antiferromagnetic transition point was easily suppressed when we applied the field. The reentrant behavior shown in the H_(c2)(T) of HoNi_(2)B_(2)C was suppressed as increasing pressure and eventually followed the H_(c2)(T) of DyNi_(2)B_(2)C at high pressure. Through the Ginzburg-Landau type analysis, we can find that the reentrant behavior in H_(c2)(T) of HoNi_(2)B_(2)C is due to the effects of the multi band nature of the supercon-ductivity . We investigated the thermodynamic and magnetic properties of pyrochlore molybdates, (Gd_(1-x)Dy_(x))_(2)Mo_(2)O_(7). It undergoes a ferromagnetic transition at x ≤0.2, and a spin-glass transition at x≥0.4. We have shown that there is a reentrant spin-glass phase at low temperature for the supposedly ferromagnetic phase through the dc and ac susceptibilities and the time de-pendence of magnetization studies. In addition to this, this spin-glass phase is enhanced when we applied pressure. We also found this spin-glass state is different from normal spin-glass state found in disordered system through the Cole-Cole analysis. This is caused by the coexistence of the ferromag-netic phase in this spin-glass phase of our samples. From these results, we suggest that the reason of the anomalous hall coeffcient as known before may as well be due to the coexistence between the ferromagnetic state and the spin-glass state. ZnCr_(2)O_(4) undergoes a first order transition at 12.5 K and also has a structural transition from cubic to tetragonal at the same temperature. In addition to this, the neutron scattering experiments have shown that it has a singlet-triplet spin gap. We have investigated the pressure and the field dependence of the gap energy with a home-made Be-Cu cell. As we increase the pressure, gap energy shows nonlinear behavior at low magnetic field, transition temperature shows linear behavior. We tried to explain with the microscopic model including the next nearest neighbor interaction. J_(eff) , the coeffcient of the effective coupling within the mean field scheme decrease as increasing pressure, which can explain the decrease of the gap energy. As increasing the external field, the gap energy decreases in the low field and increases in the high fleld. J_(eff) also increases in the high fleld region. We can find that the fleld more affects to the gap energy in the low fleld region, but J_(eff) is more effective to the gap energy in the high fleld region. We also find the nonlinearity shown in the fleld dependent magnetization increases as we applied the pressure. We have investigated the ground state properties of La_(1-x)Ca_(x)MnO_(3), one of the most famous manganites, as changing the concentration of Ca in the charge ordered phase. We can find why the transition point have a maximum at x = 0.625 through the DC magnetization. We find that there are always ferromagnetic components in the charge ordered phase and these ferromagnetic components are suppressed when the system goes through the antiferromagnetic transition point. These ferromagnetic components are in-creased when x becomes 0.5, the phase boundary between the ferromagnetic metal and the charge ordered antiferromagnetic phases. From the above results, we can find that the coexistence and competition between ferromag-netic component and antiferromagnetic component is a key in determining a maximum of the charge ordering transition point in the region of x > 0.5. In this paper, we have investigated the pressure effect strongly corre-lated electron system. In the case of the RNi_(2)B_(2)C superconductor, pressure enhances the electron-phonon coupling and increases the antiferromagnetic transition point. In pyrochlore system, the physical pressure plays the same role as the chemical pressure. We also found that the coeffcient of effective coupling of ZnCr_(2)O_(4) was suppressed as increasing pressure; in addition, this suppression plays a role in decreasing the gap energy. As shown above, pres-sure have been a good tool to probe the physical properties just like fleld and temperature.

Growth of carbon nanotubes on the AAO template using RTCVD

하병호 成均館大學校 大學院 2003 국내석사

There has been increasing interest in carbon nanotubes (CNTs) since they were discovered by Iijima. CNTs have been synthesized by arc discharge, laser ablation, or chemical vapor deposition methods. CNTs, which have structural characteristics of nanometer-size, one-dimensional (1D) shape, and are well crystallined, are attractive for the idealistic 1D system. Moreover, physical or chemical properties, such as high elasticity, chirality dependent electric property, thermal stability, etc.,have motivated the research of CNTs. Many applications of CNTs have been proposed, for example, electron emitters, probes in scanning probe microscopy, single electron transistors, quantum wires, and electrochemical probes. In this paper, we have fabricated CNTs on the AAO(Anodic Aluminum Oxide) template using RT-CVD(Rapid Thermal CVD) as changing Co or Fe deposition frequency. Co or Fe particles are deposited in the AAO bottom with electrodeposition method. Deposition frequency changed from 100Hz to 250Hz for Co particles and from 100Hz to 700Hz for Fe particles. For device application of AAO, we have fabricated through hole membrane.

HMDSO 단량체를 사용한 저유전상수 물질의 PECVD 증착 및 특성분석

최문규 成均館大學校 大學院 2003 국내석사

We have investigated the characteristics of low dielectric constant film deposited by plasma enhanced chemical vapor deposition (PECVD) using hexamethyldisiloxane (HMDSO, C_(6) H_(18) O_(1) S_(I2)) as a precursor with Ar or He carrier gas. The deposited film was called as plasma polymerized hexamethyldisiloxane (PPHMDSO). The pressure and power were fixed at 1 Torr and 30 W, respectively. The deposition temperature was varied from 50 °C to 200 °C and the PPHMDSO films were annealed at 400 °C in vacuum furnace for 8 hours. Fourier transform infrared (FTIR) absorption spectra were measured for investigating the chemical structures of the films. There was a common feature between Ar and He carrier gases, in the deposition temperature range, the decreasing trend of the deposition rate was increasing the deposition temperature. The range of the dielectric constant for as-deposited PPHMDSO films was 2.8-3.6, and the dielectric constant was reduced to 2.5-3.1 after annealing at 400 °C in vacuum furnace for 8 hours. There was no dependence on carrier gas in terms of the dielectric constant of the film. We could obtain the lowest dielectric constant of 2.5 for Ar carrier gas. It is thought that FTIR spectra peak intensity ratio's increase of -CH_(x) groups in PPHMDSO films contributes to the reduction of the k values.

異種에피成長法에 의한 Si/CeO2/Si의 形成

김종걸 성균관대학교 1999 국내박사