Orientation of one-dimensional silicon polymer films studied by X-ray absorption spectroscopy

Mannan, M. A.*; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Nagano, Masamitsu*; Noguchi, Hideyuki*

Journal of Nanomaterials, 2012, p.528256_1 - 528256_9, 2012/00

https://doi.org/10.1155/2012/528256

Molecular orientations for thin films of one-dimensional silicon polymers grown by vacuum evaporation have been assigned by X-ray absorption fine structure (XAFS) using linearly polarized synchrotron radiation. For XAFS spectra of polydimethlysilane (PDMS) films on highly oriented pyrolytic graphite (HOPG), the intensities of two peaks were found to be strongly polarization dependent. Quantitative evaluation of the polarization dependence of the XAFS spectra revealed that the polymers are oriented nearly parallel to the surface. The observed orientation is opposite to the previously observed results for PDMS on oxide (indium tin oxide) and metal (polycrystalline copper). The flat-lying feature of PDMS observed only on HOPG surface is attributed to the interaction between CH bonds in PDMS and orbitals in HOPG surface.

Self-ordering of silicon polymer thin film grown on indium tin oxide surface investigated by X-ray absorption spectroscopy

Mannan, M. A.*; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Narita, Ayumi; Nagano, Masamitsu*; Noguchi, Hideyuki*

Journal of Electron Spectroscopy and Related Phenomena, 181(2-3), p.242 - 248, 2010/08

https://doi.org/10.1016/j.elspec.2010.02.014

The ordering and molecular orientation of polydimethylsilane (PDMS) films grown on indium tin oxide (ITO) surface has been assigned. The orientation of the samples as well as that of the annealed sample was studied by Si K-edge near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy using linearly polarized synchrotron radiation. The Si K-edge NEXAFS spectra for the thick film have at least four resonance peaks of which two peaks are found to be strongly polarization dependent. On the basis of the polarization dependences of the peak intensities, it is revealed that the backbones of the PDMS films are perpendicularly oriented on the ITO surface. The angle between surface and the Si-Si bonds for multilayered film calculated from the helical structure of PDMS molecule was found to be 41.5 which was almost coincided with the experimentally obtained angle of 40 . It was concluded that PDMS molecules are highly self-ordered on ITO surface.

Preparation and characterization of B-C-N hybrid thin films

Uddin, M. N.*; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Nath, K. G.*; Baba, Yuji; Nagano, Masamitsu*

JAEA-Research 2006-034, 72 Pages, 2006/06

JAEA-Research-2006-034.pdf:4.05MB

no abstracts in English

Substitution effect on orientation of organosilicon compounds (CH)SiX (X = F, Cl, Br, I, NCO) as studied using NEXAFS spectroscopy

Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Nath, K. G.*; Uddin, M. N.*

Journal of Physics; Condensed Matter, 17(36), p.5453 - 5466, 2005/09

https://doi.org/10.1088/0953-8984/17/36/002

The orientation nature of multilayer organosilicon compounds has been investigated by measuring the dependence of the Si K-shell near-edge X-ray absorption fine structures (NEXAFS) on the polarization angle. Two approaches helped to elucidate the orientation mechanism: the substitution effect and the deposition-rate dependence. The orientation angles of Si-X bond axes were obtained for trimethylsilyl halides, (CH)SiX (X =F Cl Br I NCO, condensed on Cu(111) at a low (82 K) temperature: the angles are 60, 73, 61, 55, and 55 degrees with respect to the surface normal, for X =F, Cl, Br, I, and NCO, respectively. Chloride (X =Cl) produces the most parallel tilt angle. The specific orientation nature of chloride is attributed to its strong dipole moment as well as the regular tetrahedron shape of the molecule. The molecular volumes calculated verify this view. Furthermore, deposition rates are found to greatly influence the growth manner: namely, high deposition rates led to a slightly perpendicular orientation of Si-X bond axis.

B-C-N hybrid synthesis by high-temperature ion implantation

Uddin, M. N.; Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro; Nath, K. G.; Nagano, Masamitsu*

Applied Surface Science, 241(1-2), p.246 - 249, 2005/01

https://doi.org/10.1016/j.apsusc.2004.09.040

Recently, much attention has been given on the synthesis and characterization of graphite-like B-C-N hybrid. Since graphite-like B-C-N hybrid may have semiconducting property, this material is interesting for applications to electronic and luminescent devices. In order to synthesize this material, borazine ion plasma was implanted in graphite at room temperature (RT) and 600 C. An ultrahigh vacuum (UHV) chamber with base pressure 10 Pa was used for the experiment. The X-ray photoelectron spectroscopy (XPS) study suggested that B atoms in the deposited films are in a wide variety of atomic environment such as BC3, BN3 and B-C-N hybrid. The ratios of these coordinations strongly depend on the temperature during the ion implantation. It was found that the B-C-N hybrid is predominantly synthesized by the implantation at 600 C where the surface [B]/([B]+[C]+[N]) ratio ranges from 0.1 to 0.35. The results imply that it is possible to control the composition of B-C-N hybrid by changing the fluence of the ion plasma and the temperature of graphite during ion implantation.

Production of doubly excited He atoms in collisions of He ions with aklaline-earth atoms

Iemura, K.*; Suzuki, H.*; Otani, Shunsuke*; Takeda, Junichi*; Takayanagi, Toshinobu*; Wakiya, K.*; Sekiguchi, M.*; Kanai, Yasuyuki*; Kitazawa, Shinichi; Tong, X. M.*; et al.

Atomic Collision Research in Japan, No.25, p.42 - 43, 1999/11

no abstracts in English

Extremely high selectivity in fragmentation of (CHS) on Si(100) following excitation of adsorbate or substrate core level

Sekiguchi, Tetsuhiro; Baba, Yuji; Li, Y.; Ali, M.

Photon Factory Activity Report 1998, Part B, P. 67, 1999/11

http://ccdb5fs.kek.jp/cgi-bin/img/tiff2gif?199923003+00097

no abstracts in English

Electron spectra from singlet and triplet states of N(1s3l3l',1s3l4l') produced by low energy N+He, Ne and Ar collisions

Kitazawa, Shinichi; *; Machida, Shuichi*; Matsui, Y.*; Ida, H.*; *; Wakiya, K.*; *; F.Currell*; *; et al.

Journal of Physics B; Atomic, Molecular and Optical Physics, 31(14), p.3233 - 3243, 1998/00

https://doi.org/10.1088/0953-4075/31/14/019

no abstracts in English

Studies of ejected-electron spectra arising from O-He, Ne, Ar and N-He, Ne, Ar, collisions

Kitazawa, Shinichi; *; *; *; *; Sekiguchi, M.*; *; Wakiya, K.*; Machida, Shuichi*

Phys. Scr., T73, p.207 - 208, 1997/00

https://doi.org/10.1088/0031-8949/1997/T73/063

no abstracts in English

Ejected-electron spectroscopy in highly charged ion collisions

Kitazawa, Shinichi; *; *; Sekiguchi, M.*

INS-J-182, 0, p.274 - 276, 1995/09

no abstracts in English