Bulk-like d band of SrVO3 under a self-protective cap layer (2008)
Takizawa, M., Minohara, M., Kumigashira, H., Toyota, D., Oshima, M., Wadati, H., ...
We have performed a detailed angel-resolved photoemission spectroscopy study of in-situ prepared SrVO3 thin films. Naturally capped by a ``transparent'' protective layer, contributions from surface...
Wadati, H., Maniwa, A., Chikamatsu, A., Ohkubo, I., Kumigashira, H., Oshima, M., ...
We have performed an {\it in-situ} photoemission study of Pr_{1-x}Ca_xMnO_3 (PCMO) thin films grown on LaAlO_3 (001) substrates and observed the effect of epitaxial strain on the electronic...
Chikamatsu, A., Wadati, H., Kumigashira, H., Oshima, M., Fujimori, A., Lippmaa, M., ...
We report the first observation of changes in the electronic structure of La$_{1-x}$Sr$_{x}$MnO$_{3}$ (LSMO) across the filling-control metal-insulator (MI) transition by means of in situ...
Shifting donor-acceptor photoluminescence in N-doped ZnO (2006)
Makino, Takayuki, Tsukazaki, A., Ohtomo, A., Kawasaki, M., Koinuma, H.
We have grown nitrogen-doped ZnO films grown by two kinds of epitaxial methods on lattice-matched ScAlMgO$_4$ substrates. We measured the photoluminescence (PL) of the two kinds of ZnO:N layers in...
Hole Transport in p-Type ZnO (2006)
Makino, Takayuki, Ohtomo, Akira, Tsukazaki, A., Kawasaki, M., Koinuma, H.
A two-band model involving the A- and B-valence bands was adopted to analyze the temperature dependent Hall effect measured on N-doped \textit{p}-type ZnO. The hole transport characteristics...
Photoemission from buried interfaces in SrTiO3/LaTiO3 superlattices (2006)
Takizawa, M., Wadati, H., Tanaka, K., Hashimoto, M., Yoshida, T., Fujimori, A., ...
We have measured photoemission spectra of SrTiO3/LaTiO3 superlattices with a topmost SrTiO3 layer of variable thickness. Finite coherent spectral weight with a clear Fermi cut-off was observed at...
Wadati, H., Chikamatsu, A., Takizawa, M., Hashimoto, R., Kumigashira, H., Yoshida, T., ...
We have performed an angle-resolved photoemission spectroscopy study of La$_{0.6}$Sr$_{0.4}$FeO$_3$ using {\it in situ} prepared thin films and determined its band structure. The experimental band...
Robust Ti4+ states in SrTiO3 layers of La0.6Sr0.4MnO3/SrTiO3/ La0.6Sr0.4MnO3 junctions (2005)
Kumigashira, H., Chikamatsu, A., Hashimoto, R., Oshima, M., Ohnishi, T., Lippmaa, M., ...
We have investigated the interfacial electronic structure of La0.6Sr0.4MnO3 (LSMO)/ SrTiO3 (STO)/ LSMO heterojunctions utilizing the elemental selectivity of photoemission spectroscopy. The Ti 2p...
Spectral shape analysis of ultraviolet luminescence in \textit{n}-type ZnO:Ga (2005)
Makino, T., Segawa, Y., Yoshida, S., Tsukazaki, A., Ohtomo, A., Kawasaki, M., ...
Thin films of laser molecular-beam epitaxy grown \textit{n}-type Ga-doped ZnO were investigated with respect to their optical properties. Intense room-temperature photoluminescence (PL) in the...
Chikamatsu, A., Wadati, H., Kumigashira, H., Oshima, M., Fujimori, A., Hamada, N., ...
We have performed an in situ angle-resolved photoemission spectroscopy (ARPES) on single-crystal surfaces of La$_{0.6}$Sr$_{0.4}$MnO$_{3}$ (LSMO) thin films grown on SrTiO$_{3}$ (001) substrates by...
Manifestation of Correlation Effects in the photoemission spectra of Ca$_{1-x}$Sr$_x$RuO$_3$ (2004)
Takizawa, M., Toyota, D., Wadati, H., Chikamatsu, A., Kumigashira, H., Fujimori, A., ...
We have measured soft x-ray photoemission and O 1{\it s} x-ray absorption spectra of Ca$_{1-x}$Sr$_x$RuO$_3$ thin films prepared {\it in situ}. The coherent and incoherent parts have been identified...
Makino, T., Segawa, Y., Kawasaki, M., Koinuma, H.
The optical properties of ZnO quantum wells, which have potential application of short-wavelength semiconductor laser utilizing a high-density excitonic effect, were investigated. Stimulated emission...
Wadati, H., Chikamatsu, A., Hashimoto, R., Takizawa, M., Kumigashira, H., Fujimori, A., ...
We have measured the temperature dependence of the photoemission and x-ray absorption spectra of La$_{1-x}$Sr$_x$FeO$_3$ (LSFO) epitaxial thin films with $x=0.67$, where charge disproportionation...
Optical Properties of Excitons in ZnO-based Quantum Well Heterostructures (2004)
Makino, T., Segawa, Y., Kawasaki, M., Koinuma, H.
Recently the developments in the field of II-VI-oxides have been spectacular. Various epitaxial methods has been used to grow epitaxial ZnO layers. Not only epilayers but also sufficiently...
Horiba, K., Chikamatsu, A., Kumigashira, H., Oshima, M., Nakagawa, N., Lippmaa, M., ...
We have investigated change in the electronic structures of atomically-controlled La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films as a function of hole-doping level ($x$) in terms of {\it in situ}...
Horiba, K., Taguchi, M., Chainani, A., Takata, Y., Ikenaga, E., Namatame, H., ...
Using hard x-ray (HX ; $h\nu$ = 5.95 keV) synchrotron photoemission spectroscopy (PES), we study the intrinsic electronic structure of La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films. Comparison of Mn 2$p$...
Wadati, H., Kobayashi, D., Kumigashira, H., Okazaki, K., Mizokawa, T., Fujimori, A., ...
We have studied the electronic structure of epitaxially grown thin films of La$_{1-x}$Sr$_x$FeO$_3$ by {\it in-situ} photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS)...
Elements of informatics for combinatorial solid-state materials science (2004)
S Meguro, T Ohnishi, H Koinuma
The main purpose of using combinatorial techniques for materials science studies is to achieve higher experimental throughput than what is possible when samples are synthesized and characterized one...
Modeling and simulation of polycrystalline ZnO thin-film transistors (2003)
Hossain, Faruque M., Nishii, J., Takagi, S., Ohtomo, A., Fukumura, T., Fujioka, H., ...
Thin film transistors (TFTs) made of transparent channel semiconductors such as ZnO are of great technological importance, because their insensitivity to visible light makes device structures simple....
Resonant exciton second-harmonic generation in self-assembled ZnO microcrystallite thin films (2003)
Zhang, X. Q., Tang, Zi-Kang, Kawasaki, M., Ohtomo, A., Koinuma, H.
Second-harmonic generation has been studied for fundamental wavelengths from 720 to 1100 nm on high-quality ZnO thin films deposited on sapphire substrates by laser molecular beam epitaxy. The...
Toyosaki, H., Fukumura, T., Yamada, Y., Nakajima, K., Chikyow, T., Hasegawa, T., ...
A ferromagnetic semiconductor, rutile (Ti,Co)O2, exhibits anomalous Hall effect at room temperature. Strong dependence of the anomalous Hall effect, as well as the magneto-optic response, on the...
Exploration of oxide-based diluted magnetic semiconductors toward transparent spintronics (2003)
Fukumura, T., Yamada, Y., Toyosaki, H., Hasegawa, T., Koinuma, H., Kawasaki, M.
A review is given for the recent progress of research in the field of oxide-based diluted magnetic semiconductor (DMS), which was triggered by combinatorial discovery of transparent ferromagnet. The...
Terajima, T., Chaudhary, K. A., Inomata, K., Koinuma, H.
We have developed new plasma generators to make low temperature material processing possible in open air conditions. The torch-type generator is a cylindrical plasma generator which is composed of a...
Magneto-Optical Spectroscopy of Anatase TiO2 Doped with Co (2002)
Fukumura, T., Yamada, Y., Tamura, K., Nakajima, K., Aoyama, T., Tsukazaki, A., ...
Magneto-optical spectroscopy of a transparent ferromagnetic semiconductor, anatase TiO2 doped with Co, is carried out at room temperature. A large magneto-optical response with ferromagnetic field...
Phonon replicas in ZnO/ZnMgO multi-quantum wells. (2002)
Sun, H. D., Segawa, Y., Kawasaki, M., Ohtomo, A., Tamura, K., Koinuma, H.
The photoluminescence properties of ZnO/ZnMgO multiquantum wells have been investigated by continuous and time-resolved photoluminescence spectra at various temperatures. Strong first-order and...
Enhancement of exciton binding energies in ZnO/ZnMgO multi-quantum wells. (2002)
Makino, T., Segawa, Y., Kawasaki, M., Ohtomo, A., Tamura, K., Koinuma, H., ...
The effect of confinement on the exciton binding energies has been systematically investigated for two series of ZnO/ZnMgO multiquantum wells with various well widths and barrier heights. The exciton...
Makino, T., Tuan, N. T., Sun, H. D., Chia, C. H., Segawa, Y., Kawasaki, M., ...
We report on temperature dependence of excitonic photoluminescence (PL) from ZnO/(Mg, Zn)O multiple quantum wells (MQWs). Two kinds of MQWs having different barrier heights grown by laser...
Biexciton emission from ZnO/Zn0.74Mg0.26O multi-quantum wells. (2001)
Sun, H. D., Makino, T., Tuan, N. T., Segawa, Y., Kawasaki, M., Ohtomo, A., ...
Luminescence due to the radiative recombination of localized biexcitons has been observed at low temperature (5 K) in ZnO/Zn0.74Mg0.26O multiquantum wells grown by laser-molecular-beam epilaxy on a...
Sun, H. D., Makino, T., Tuan, N. T., Segawa, Y., Kawasaki, M., Ohtomo, A., ...
The excitonic properties of high-quality ZnO/Zn0.88Mg0.12O multiquantum wells grown by laser-molecular-beam epitaxy were investigated using temperature-dependent optical absorption spectra from 5 K...
Makino, T., Tuan, N. T., Sun, H. D., Chia, C. H., Segawa, Y., Kawasaki, M., ...
We report on temperature dependence of excitonic photoluminescence (PL) from ZnO/(Mg, Zn)O multiple quantum wells (MQWs). Two kinds of MQWs having different barrier heights grown by laser...
Makino, T., Chia, C. H., Tuan, N. T., Sun, H. D., Segawa, Y., Kawasaki, M., ...
We report on the optical properties of ZnO/(Mg, Zn)O multiple quantum wells (MQWs) on lattice-matched ScAlMgO4 substrates fabricated by laser molecular-beam epitaxy. As the well layer thickness...
Sun, H. D., Makino, T., Tuan, N. T., Segawa, Y., Tang, Z. K., Wong, G. K. L., ...
The mechanism of ultraviolet stimulated emission was investigated in ZnO/ZnMgO multiquantum wells. Stimulated emission induced by exciton–exciton scattering occurred throughout a range of...