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Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Japanese Journal of Applied Physics, 58(SI), p.SIIC04_1 - SIIC04_4, 2019/08
Times Cited Count：0 Percentile：0(Physics, Applied)The electronic structure of the unoccupied conduction band of polycrystalline chloroaluminum phthalocyanine was investigated by X-ray absorption spectroscopy (XAS) near the Cl K-edge. XAS spectra were recorded in total electron yield (TEY) and partial Auger electron yield (AEY) modes. Partial AEY spectra were measured using normal and spectator Cl KL
L Auger yields as a function of photon energy. Although the TEY spectrum showed a broad shape; that was difficult to deconvolute curve fitting, the normal and spectator AEY spectra clearly showed that 
*(Cl-Al) transition splits into two competitive peaks attributed to the core excitons (localized with a core hole) and conduction band (delocalized without a core hole). The existence of a band-like peak in the Cl K-edge XAS is evidence that the Cl axial ligand participates in forming the conduction band. Thus, band-like electron transport is expected to occur in the oligomer-like (-Al-Cl-Al-) site.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Molecular Crystals and Liquid Crystals, 622(1), p.50 - 54, 2015/12
Times Cited Count：0 Percentile：0.01(Chemistry, Multidisciplinary)Organic electrically conducting 
-stacked molecules are widely regarded as promising materials for future application of nanoelectronics. Direct measurements of electronic structures of unoccupied states in organic semiconductors lead to better understanding of mechanism of electron conduction. For probing unoccupied partial density of states (DOS), X-ray absorption spectroscopy (XAS) is commonly used, where selective excitation of the 1s core electron to the unoccupied conduction band is possible. However, XAS cannot distinguish localized and delocalized features without comparing any theoretical approach. In this work, the core-hole-clock method in resonant Auger spectroscopy (RAS) has been applied to probe electron delocalization through the empty conduction band in the attosecond domain for the purpose of exploring electronic materials with high-speed electron transport. We will discuss some organic molecules such as pentacenes.
Ogawa, Hiroshi*; Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
Molecular Crystals and Liquid Crystals, 622(1), p.164 - 169, 2015/11
Times Cited Count：0 Percentile：0.01(Chemistry, Multidisciplinary)Unoccupied electronic states near the Fermi level of poly(dimethylsilane) were probed using Si 1s X-ray absorption spectroscopy (XAS) and Si KLL resonant Auger spectroscopy (RAS). The measured resonance peaks of XAS spectra near Si K-edge have been assigned in comparison with the discrete variational (DV)-X
molecular orbital calculations. The rapid delocalization of Si 1s core-excited electron through the empty conduction band was observed along the polymer chain with the energy dependent RAS measurement, and the electron delocalization time was estimated based on the core-hole clock method.
Esaka, Fumitaka
Ekisupato Oyo Kagaku Sirizu; Kiki Bunseki, p.119 - 135, 2015/09
Bulk analysis has been conventionally used for measuring solid materials. In contrast, surface analysis is extensively used for analyzing chemical compositions and chemical states of solid surface. The surface compositions often differ from those of bulk materials. Recently, doping of impurity elements and deposition of thin films on the surface of the materials are key techniques to fabricate functional materials. Therefore, surface analysis becomes important to characterize such materials. In this paper, the principle and feature of some surface analytical techniques are described.
Ioka, Ikuo; Onuki, Kaoru; Futakawa, Masatoshi; Kuriki, Yoshiro*; Nagoshi, Masayasu*; Nakajima, Hayato; Shimizu, Saburo
Ryusan To Kogyo, 52(4), p.1 - 6, 1999/04
no abstracts in English
Sasaki, Teikichi; Baba, Yuji; Yoshii, Kenji; Yamamoto, Hiroyuki
Hyomen Kagaku, 17(7), p.370 - 374, 1996/07
no abstracts in English
and O ion-implanted Si(100)Yamamoto, Hiroyuki; Baba, Yuji; Sasaki, Teikichi
Surface and Interface Analysis, 23, p.381 - 385, 1995/00
Times Cited Count：17 Percentile：53.78(Chemistry, Physical)no abstracts in English
Sasaki, Teikichi
Hyomen, 30(11), p.915 - 927, 1992/00
no abstracts in English
I.Kadar*; H.Altevogt*; R.Koehrbrueck*; V.Montemayor*; A.Mattis*; G.Schiwietz*; B.Skogvall*; K.Sommer*; N.Stolterfoht*; Kawatsura, Kiyoshi*; et al.
Physical Review A, 44(5), p.2900 - 2912, 1991/09
Times Cited Count：5 Percentile：39.01(Optics)no abstracts in English
, N, CO
, and CO ion bombardmentNagai, Shiro
Nuclear Instruments and Methods in Physics Research B, 59-60, p.936 - 939, 1991/00
Times Cited Count：3 Percentile：50.31(Instruments & Instrumentation)no abstracts in English
, CO, O and DONagai, Shiro
Journal of Nuclear Materials, 151, p.275 - 280, 1988/00
no abstracts in English
Matsuzaki, Yoshimi; ; ; ; ; ; ;
Journal of Nuclear Materials, 145-147, p.704 - 708, 1987/00
Times Cited Count：9 Percentile：66.62(Materials Science, Multidisciplinary)no abstracts in English
; ;
Japanese Journal of Applied Physics, 25(3), p.L209 - L211, 1986/00
Times Cited Count：9 Percentile：46.67(Physics, Applied)no abstracts in English
Proc.9th Symp.on ISIAT 85, p.551 - 552, 1985/00
no abstracts in English
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
no journal, ,
Femo and atto second electron dynamics through unoccupied conduction band in organic electronic materials can be probed by Auger spectroscopy (RAS). In this method, RAS spectra are interpreted based on two competing decay channels: core-hole decay and core-excited resonant electron delocalization. Recent progress in our understanding of previous data, we found that maximum energies in P K-edge X-ray absorption spectra (XAS) measured by Auger electron yields are different between spectator Auger (SA) and normal Auger (NA) for phosphate groups in DNA and nucleotides. This can be explained by core excitation binding energy shifts for the localized state corresponding to SA.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
no journal, ,
Many peaks are observed in X-ray absorption fine structure near the inner-shall edges. Such fine structures are called near-edge X-rays absorption fine structure or abbreviated as NEXAFS. NEXAFS spectra provide us with information on property of electronic states concerning partial density of states of unoccupied conduction band for materials. In this work, we have investigated several sulfur-containing thiophene derivative polymers using NEXAFS spectroscopy. We have recorded the S K-edge NEXAFS spectra of film samples of these electronic materials and tried to interpret the origin of electronic transition seen in NEXAFS on the basis of molecular orbital theory. Furthermore, we discuss whether there is a potential relation between the observed spectra and charge-transfer property of the materials.
Ikeura, Hiromi*; Sekiguchi, Tetsuhiro
no journal, ,
A metal complex having dithiolene as a ligand, which is known as a non-inocentric ligand, is a complex electronic system composed of p-electrons of a ligand and d-electrons of a central metal ion. Since it shows unique properties, a huge number of researches on such complexes have been carried out. Complex electron systems are attracting strong attention in aiming at practical use such as functional materials. In this study, to investigate the electronic state of the dithiolene type ligand, experiments were conducted using sulfur K-shell X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy, and resonant Auger electron spectroscopy (RAS). In XAS, in some systems a broadened peak is observed and can not be separated by the XAS method alone. It was found that peak separation may be possible by assist of RAS result. We discuss the assignment on the transition of XAS process of materials on the basis of both XAS and RAS.
Hata, Kuniki; Nagai, Yasuyoshi*; Nishiyama, Yutaka
no journal, ,
no abstracts in English
Hata, Kuniki
no journal, ,
no abstracts in English
