Hee-Soo Moon

Characterization of protective-layer-coated LiMn2O4 cathode thin films

We introduced a post-annealing process for the preparation of spinet-phase LiMn 2 O 4 . The annealed films had proper crystallinity and surface roughness. In order to reduce the interfacereaction during operation, we introduced a diamond-like carbon (DLC) film. The DLC films were deposited on LiMn 2 O 4 films by using electron cyclotron resonance chemical vapor deposition (ECRCVD). A DLC-coated LiMn 2 O 4 film was more stable during the charging -discharging reaction and showed higher discharge capacity over a wide voltage window than the uncoated LiMn 2 O 4 film.

Ionic conductivity of LixB1−x/3PO4 ceramic electrolyte based on defect models

Abstract The ionic conductivity of LixB1−x/3PO4 is investigated in terms of defect models with a lithium doping level of 0

Dielectric Constant Stability and Thermal Stability of Cu/Ta/SiOF/Si Multilayer Films

The effects of post plasma treatment on the dielectric properties and reliability of fluorine-doped silicon oxide (SiOF) films deposited by electron cyclotron resonance chemical vapor deposition (ECRCVD) are studied. Also, the thermal stability of an electrodeposited Cu/sputtered Ta interconnect system with SiOF intermetal dielectrics was examined by annealing in a vacuum furnace. The stability of the dielectric constant of SiOF films was found to be improved by O2 post plasma treatment. Surface modification by the plasma treatment was effective for the prevention of water absorption and stabilization of the dielectric constant. The Cu/Ta/SiOF/Si system was thermally stable up to 500°C for 3 h. For the Cu/Ta/SiOF/Si multilayer structure, the plasma treatment seemed to play a significant role in suppressing the interdiffusion between SiOF and metal interconnects. By C–V measurement, the electrical stability of the Cu/Ta/SiOF/Si multilayer structure was found to be stable up to 500°C for 3 h.

Conditioning effects on La1-xSrxMnO3-Yttria stabilized Zirconia electrodes for thin-film solid oxide fuel cells

Composite cathodes of 50/50 vol percent LSM-YSZ (La1-xSrxMnO3-yttria stabilized zirconia) were deposited onto dense YSZ electrolytes by a colloidal deposition technique. The cathode characteristics were then examined by scanning electron microscopy (SEM) and studied by an impedance spectroscopy (IS). Conditioning effects of the LSM-YSZ cathodes were seen, and remedies for these effects were proposed for improving the performance of a solid oxide fuel cell (SOFC). LSM surface contamination and modification, cathode bonding to the YSZ electrolyte, changing Pt electrode and bonding paste, and curvature of sintered YSZ electrolytes led to some changes in microstructure and variability in cell performances.