Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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
Times Cited Count：8 Percentile：37.11(Chemistry, Physical)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.
Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro; Nath, K. G.
Journal of Electron Spectroscopy and Related Phenomena, 137-140, p.573 - 578, 2004/07
Times Cited Count：27 Percentile：72.98(Spectroscopy)Hexagonal boron nitride (h-BN) thin film has been epitaxially formed on Ni(111) by chemical vapor deposition using borazine gas. The electronic structure of this system is studied by near edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS). The thickness of the h-BN is estimated to be about two-layers from XPS. B K-edge NEXAFS spectra show new 
* peak which is not observed in the spectrum for bulk h-BN. From a polarization dependence analysis of NEXAFS, we propose this new * peak originates from the interaction between the h-BN and Ni(111). This new * peak clearly proves that conduction band of h-BN/Ni(111) is different from that of bulk h-BN.
Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro; Nath, K. G.; Sasaki, Masayoshi*; Okuno, Kenji*
Journal of Vacuum Science and Technology A, 21(6), p.1843 - 1848, 2003/11
Times Cited Count：6 Percentile：28.18(Materials Science, Coatings & Films)Ion implantation method is applied to synthesize B-C-N hybrids and their electronic structures are characterized by X-ray photoelectron spectroscopy. A boron nitride film is deposited on a graphite target by borazine plasma implantation. At the interface between the BN film and the graphite, variety of bonding combinations including B-N, B-C, and C-N are observed. This proved that B-C-N hybrids is formed by this method.
Muramatsu, Yasuji; Kaneyoshi, Takahiro*; Gullikson, E. M.*; Perera, R. C. C.*
Spectrochimica Acta, Part A, 59(9), p.1951 - 1957, 2003/07
Angle-resolved soft X-ray emission and absorption spectra in the BK and NK regions of hexagonal BN were measured using polarized synchrotron radiation. The take-off/incident-angle-dependence on the spectral features in both X-ray emission and absorption is clearly observed. The configuration of the s and p orbitals, which were calculated using discrete variaional (DV) -Xa molecular orbital calculations, explains the angle-resolved soft X-ray emission and absorption spectra. The relative peak intensity of the 394-eV peak in the NK X-ray emission provides useful information about the BN layer ordering.
/
peak intensity ratio in soft X-ray emission and absorption spectra of graphite and hexagonal boron nitrideMuramatsu, Yasuji; Gullikson, E. M.*; Perera, R. C. C.*
Advances in X-Ray Chemical Analysis, Japan, 34, p.153 - 163, 2003/00
Take-off/incident-angle-resolved soft X-ray emission and absorption spectra of highly oriented pyrolytic graphite (HOPG) and hexagonal boron nitride (h-BN) are measured by using polarized synchrotron radiation. The angle-dependent / peak intensity ratio can be explained by the configuration of - and -orbitals, which provides the information of layer ordering in the graphite-like layered materials.
coated by 2D materialsOgawa, Shuichi*; Yusa, Ryunosuke*; Wang, G.*; Pettes, M. T.*; Liu, F.*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Abukawa, Tadashi*; Moody, N. A.*; Yamaguchi, Hisato*
no journal, ,
Lanthanum hexaboride (LaB) has a low work-function and is widely used as a thermionic cathode. For practical application, further reduction of its work-function and high durability have been required. In this study, the effect of 2D material coating materials (graphene and hexagonal boron nitride (hBN)) prepared by a wet-transfer method on the work-function of LaB(100) was studied by using photoelectron emission microscopy (PEEM), synchrotron radiation photoemission spectroscopy, Raman spectroscopy, atomic force microscopy and DFT calculations. PEEM images for samples after 905C heating clearly showed strong photoemission in the hBN coating region. DFT calculations indicated that the work-function increases in graphene due to the inward dipole formation, while the work function decreases in hBN due to the outward dipole forming at the interface.
