Yuri Kato

Angle-Dependent Measurement of Near Edge X-ray Absorption Fine Structure of Annealing Effect on Local Structure of Focused-Ion-Beam Chemical Vapor Deposition Diamond-Like Carbon

The annealing effect on the local structure of diamond-like carbon (DLC) formed by Ga+ focused-ion-beam chemical vapor deposition (FIB-CVD) was investigated by the incidence angle-dependent measurement of the C K-edge near edge X-ray absorption fine structure (NEXAFS) from 0 to 60°. The peak intensity corresponding to the resonance transition of 1s →σ* originating from carbon–gallium bonding markedly increased with incidence angle in the spectra of a FIB-CVD DLC film annealed at 400 °C. This angle dependency was attributable to the movement of residual Ga atoms from the bottom to the neighboring surface of the FIB-CVD DLC film.

Etching of Poly(tetrafluoroethylene) Sheet by Synchrotron Radiation Exposure in Soft X-ray Region

The reaction mechanism for the direct photoetching of poly(tetrafluoroethylene) (PTFE) using synchrotron radiation (SR) in the soft X-ray region, which is important for the microfabrication of PTFE nanoparts, was investigated by varying the photon flux irradiated to a PTFE sheet by changing the electron current of the storage ring. The etching depth of the PTFE sheet by SR exposure at 100 mAh was measured at room temperature, 120 and 200 °C. Etching depth increased with photon flux despite of setting the SR exposure on the same quantity at each substrate temperature. It was found that the etching of PTFE proceeds not only via the first-order reaction but also via the second-order reaction whether substrate temperature was higher than glass transition temperature.

Synchrotron Radiation Effect in the Soft X-ray Region on the Surface Properties of Pyromellitic Dianhydride-Oxydianline Polyimide

The surface modification of a polyimide (PI) sheet using synchrotron radiation (SR) was carried out. The PI sheet was irradiated to white radiation ranging between 50–1000 eV in a vacuum chamber. The contact angle of the PI surface with a water droplet was found to decrease from 75° to 58° by the SR irradiation. The variation of chemical components of the PI surface was studied using X-ray photoelectron spectroscopy (XPS). The ratio of peak intensity from the O1s orbital to that from the C1s orbital increased remarkably by SR irradiation. The increase of wettability on the PI surface was ascribable to the production of an O-rich surface by SR irradiation in the soft X-ray region.

Surface Modification of Diamond-like Carbon by Synchrotron Radiation Exposure under the Perfluorohexane Gas Atmosphere

The control of wettability on a diamond-like carbon (DLC) surface was carried out by exposure to synchrotron radiation (SR) in the soft X-ray region under the perfluorohexane (C6F14) gas atmosphere. It was found that the contact angle of a water drop against the DLC surface increased with SR dose; in particular, it increased from 73 to 91° by the SR exposure of a 1 mAh dose. The formation of the hydrophobic DLC surface was attributable to the fluorine-functional groups that existed on the DLC surface after SR exposure under the C6F14 gas atmosphere.

Photoexcitation Process Leading to Modification on Poly(tetrafluoroethylene) Surface by Irradiation of Synchrotron Radiation in Soft X-ray Region

Photoexcitation process leading to a variation in the wettability of a poly(tetrafluoroethylene) (PTFE) surface induced by synchrotron radiation (SR) exposure in the soft X-ray region was investigated. It was found that two types of photoexcitation, that is, the formations of a hydrophobic surface and a hydrophilic surface, proceed on the PTFE surface with the exposure to SR. The formation rate of the hydrophobic surface strongly depended on substrate temperature.

The Gas Pressure‐dependent Contact Angle of Diamond‐like Carbon Surface by SR Exposure Under Perfluorohexane(C6F14) Gas Atmosphere

The contact angle on a diamond‐like carbon (DLC) surface was controlled by synchrotron radiation (SR) under perfluorohexane (C6F14) gas atmosphere. It was found that the fluorocarbon group bonded to the DLC surface in the modified hydrophobic area from the measurement of X‐ray photoelectron spectrum. The contact angle of a DLC surface was succeeded to increase from 73° to 116° by the SR irradiation with 400 mA⋅h at C6F14 gas pressure higher than 1.2 Pa.

NEXAFS Study of the Annealing Effect on the Local Structure of FIB‐CVD DLC

Annealing effect on the local structure of diamond like carbon (DLC) formed by focused ion beam‐chemical vapor deposition (FIB‐CVD) was investigated by the measurement of near edge x‐ray absorption fine structure (NEXAFS) and energy dispersive x‐ray (EDX) spectra. Carbon K edge absorption NEXAFS spectrum of FIB‐CVD DLC was measured in the energy range of 275–320 eV. In order to obtain the information on the location of the gallium in the depth direction, incidence angle dependence of NEXAFS spectrum was measured in the incident angle range from 0° to 60°. The peak intensity corresponding to the resonance transition of 1s→σ* originating from carbon‐gallium increased from the FIB‐CVD DLC annealed at 200°C to the FIB‐CVD DLC annealed at 400°C and decreased from that at 400°C to that at 600°C. Especially, the intensity of this peak remarkably enhanced in the NEXAFS spectrum of the FIB‐CVD DLC annealed at 400°C at the incident angle of 60°. On the contrary, the peak intensity corresponding to the resonance tra...

Surface Modification of Poly(tetrafluoroethylene) by Synchrotron Radiation Exposure under Several Kinds of Gas Atmosphere

The surface modification of poly(tetrafluoroethylene) (PTFE) sheet was carried out by exposing the sheet to synchrotron radiation (SR) ranging 50–1000 eV under O2, H2O and CH3OH gas atmospheres. The wettability of the PTFE surface was found to increase with SR dose under each gas atmosphere. The rate of increase in the wettability of the PTFE surface exposed to SR under the O2 gas atmosphere was higher than those of the PTFE surfaces exposed to SR under the other gas atmospheres. The decrease in the amount of –CF2 component and the presence of –C=O and –OH components were observed on a hydrophilic PTFE surface.

Confirmation and Readjustment of Bending Magnet Beam‐Line Optics Using SHADOW

Optical alignment of the NewSUBARU beam‐line 6 (BL6) is discussed by comparing the observed SR profiles with the calculated results of ray‐tracing using SHADOW. A new screen monitor was mounted downstream of the first mirror to observe the synchrotron radiation profile. The distorted profile downstream of the second mirror was attributed to the rotation of the first mirror along the vertical axis. The distortion was successfully improved by a re‐adjustment according to the calculations.