Minoru Kusabiraki

Effects of gas impurities in the sputtering environment on the stoichiometry and crystallinity of ZnS:Mn electroluminescent-device active layers

ZnS:Mn electroluminescent (EL) device active layers were prepared using the RF magnetron sputtering method employing a powder target. The active layer was prepared under specified sputtering conditions, and in situ analysis was carried out by quadrupole mass spectroscopy (QMS) and optical emission spectroscopy (OES). The effects of gas impurities as a function of the sputtering environment on the active layer quality, and EL device characteristics were examined. Gas impurities in the sputtering environment were observed by QMS. Gases of mass numbers 18 (H2O), 28 (CO/N2), and 32 (O2) a.m.u. had unfavorable effects on the preparation of the active layer, which demonstrates the importance of reducing the concentration of these gases in the preparation of high quality active layers for EL devices. In the optical emission spectra in sputtering plasma, when the Ar (750.3 nm) peak intensity is normalized as unity, the inverse of emission intensity at 472.2 and 636.2 nm from Zn could be utilized as a quality factor of the sputtering environment.

Oxygen-Plasma Treatment of Indium–Tin Oxide in a Triode Glow Discharge

An indium–tin oxide (ITO) surface was treated with oxygen (O2) plasma in a triode glow discharge system. The processing time and the radio frequency (rf) voltage applied to the substrate electrode were changed. The contact angle, X-ray photoelectron spectroscopy (XPS) spectra and scanning electron microscopy (SEM) image of the O2-plasma-treated ITO surface, and the characteristics of organic electroluminescence (EL) devices fabricated on O2-plasma-treated ITO were investigated. By applying an rf voltage of 200 V, contact angle decreased from 35 to 11°, the concentration ratio of C 1s/In 3d decreased, that of O 1s/In 3d increased, and the operating voltage of the EL devices decreased.

Improvement of the partial discharge resistance of polymer films by coating with plasma-polymerized films

The surface of polytetrafluoroethylene (PTFE) and polyethylene terephthalate films was coated with plasma-polymerized hexamethyldisiloxane (PPHMDS) film in a triode glow discharge system. The dielectric properties of PPHMDS films and their durability, the partial discharge characteristics and the surface morphology of coated polymer films were investigated. The lifetime of the coated PTFE films was longer than that of the uncoated PTFE films and varied with the preparation conditions of PPHMDS films. The maximum electrical pulse of the coated polymer film in a partial discharge electrode system was smaller than that of the uncoated polymer film. From observation of the deteriorated surface scars, it was shown that the PPHMDS film is effective for improving the partial discharge resistance.

Correlation between Adhesion Strength of Plasma-Polymerized Hexamethyldisiloxane Films to Polytetrafluoroethylene and Partial Discharge Resistance

Polytetrafluoroethylene (PTFE) films were coated with plasma-polymerized hexamethyldisiloxane (PPHMDS) films in a dc glow discharge system. The correlation between the adhesion of the PPHMDS films to the PTFE films and the partial discharge resistance of the composite films was investigated. The voltage endurance of the composite films in the presence of partial discharges increased with the adhesion of the PPHMDS films. From an observation of the deteriorated surface scars, it was shown that the deterioration is affected by the formation of cracks in the PPHMDS film.