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3,873 results on '"YOSHIDA, Hiroyuki"'

1. Complementary Speckle STED Microscopy

Author

Arjmand, Payvand, Thodika, Samlan Chandran, Bivas, Elsa, Li, Haoyang, Oheim, Martin, Yoshida, Hiroyuki, Brasselet, Etienne, and Guillon, Marc

Subjects
Physics - Optics
Abstract

Stimulated Emission Depletion (STED) microscopy has emerged as a powerful technique providing visualization of biological structures at the molecular level in living samples. In this technique, the diffraction limit is broken by selectively depleting the fluorophore's excited state by stimulated emission, typically using a donut-shaped optical vortex beam. STED microscopy performs unrivalably well in degraded optical conditions such as living tissues. Nevertheless, photo-bleaching and acquisition time are among the main challenges for imaging large volumetric field of views. In this regard, random light beams like speckle patterns have proved to be especially promising for three-dimensional imaging in compressed sensing schemes. Taking advantage of the high spatial density of intrisic optical vortices in speckles -- the most commonly used beam spatial structure used in STED microscopy -- we propose here a novel scheme consisting in performing STED microscopy using speckles. Two speckle patterns are generated at the excitation and the depletion wavelengths, respectively, exhibiting inverted intensity contrasts. We illustrate spatial resolution enhancement using complementary speckles as excitation and depletion beam on both fluorescent beads and biological samples. Our results establish a robust method for super-resolved three-dimensional imaging with promising perspectives in terms of temporal resolution and photobleaching.

Published
2024

7. Anti-integrin αvβ6 autoantibodies are a potential biomarker for ulcerative colitis-like immune checkpoint inhibitor-induced colitis

Author

Yokode, Masataka, Shiokawa, Masahiro, Kawakami, Hisato, Kuwada, Takeshi, Nishikawa, Yoshihiro, Muramoto, Yuya, Kitamoto, Hiroki, Okabe, Makoto, Yamazaki, Hajime, Okamoto, Norihiro, Morita, Toshihiro, Ohno, Kazuya, Nakanishi, Risa, Takimoto, Ikuhisa, Yasuda, Muneji, Chikugo, Koki, Matsumoto, Shimpei, Yoshida, Hiroyuki, Ota, Sakiko, Nakamura, Takeharu, Okada, Hirokazu, Hirano, Tomonori, Kakiuchi, Nobuyuki, Matsumori, Tomoaki, Yamamoto, Shuji, Uza, Norimitsu, Ooi, Makoto, Kodama, Yuzo, Chiba, Tsutomu, Hayashi, Hidetoshi, and Seno, Hiroshi

Published
2024
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9. Efficacy of subsequent therapies in patients with advanced ovarian cancer who relapse after first-line olaparib maintenance: results of the PAOLA-1/ENGOT-ov25 trial

Author

Bogner, Gerhard, Marth, Christian, Petru, Edgar, Reinthaller, Alexander, Schauer, Christian, Sevelda, Paul, D’Hondt, Lionel, Vergote, Ignace, Vuylsteke, Peter, Hietanen, Sakari, Lindahl, Gabriel, Mäenpää, Johanna, Nøttrup, Trine Jakobi, Puistola, Ulla, Abadie-Lacourtoisie, Sophie, Alexandre, Jérôme, Berton-Rigaud, Dominique, Boissier, Emilie, Bourgeois, Hugues, Chevalier-Place, Annick, Combe, Pierre, Costan, Cristina, Dauba, Jérôme, De Cock, Laure, Desauw, Christophe, Despax, Raymond, Dohollou, Nadine, Dubot, Coraline, Fabbro, Michel, Favier, Laure, Floquet, Anne, Follana, Philippe, Tixidre, Claire Garnier, Garnier, Georges, Gladieff, Laurence, Grenier, Julien, Guillemet, Cécile, Hardy-Bessard, Anne-Claire, Joly, Florence, Kalbacher, Elsa, Kaminsky, Marie-Christine, Kurtz, Jean-Emmanuel, Largillier, Rémy, Lefeuvre-Plesse, Claudia, Lesoin, Anne, Levache, Charles Briac, L’Haridon, Tifenn, Lortholary, Alain, Lotz, Jean-Pierre, Medioni, Jacques, Meunier, Jérôme, Mousseau, Mirerille, Mouret-Reynier, Marie-Ange, Pautier, Patricia, Petit, Thierry, Provansal, Magali, Pujade-Lauraine, Eric, Raban, Nadia, Ray-Coquard, Isabelle, Rodrigues, Manuel, Selle, Frédéric, Sverdlin, Robert, Tazi, Youssef, You, Benoît, Aktas, Bahriye, Olaf Bauerschlag, Dirk, Beck, Thomas, Belau, Antje, Bronger, Holger, Buchholz, Stefan, Buderath, Paul, Burges, Alexander, Canzler, Ulrich, de Gregorio, Nikolaus, Denschlag, Dominik, Dieterich, Max, Eichbaum, Michael, El-Balat, Ahmed, Emons, Günter, Fasching, Peter, Feisel-Schwickardi, Gabriele, Frank, Matthias, Friedrich, Michael, Grischke, Eva-Maria, Gropp-Meier, Martina, Hanker, Lars, Hannig, Carla, Harter, Philipp, Hasenburg, Annette, Hellriegel, Martin, Herwig, Uwe, Heubner, Martin, Hulde, Joachim, Jackisch, Christian, Kögel, Matthias, Krieger, Peter, Kühn, Thorsten, Liebrich, Clemens, Lück, HansJoachim, Mallmann, Peter, Marmé, Frederik, Meier, Werner, Möbus, Voker, Mohamed, Omar Farag, Nestle-Krämling, Carolin, Neunhöffer, Tanja, Oskay-Özcelik, Gülten, Park-Simon, Tjoung-Won, Rautenberg, Beate, Rein, Daniel, Ruhwedel, Wencke, Runnebaum, Ingo, Sagasser, Jacqueline, Schmalfeldt, Barbara, Schneeweiss, Andreas, Schnelzer, Andreas, Scholz, Heinz, Sehouli, Jalid, Sperfeld, Antje, Steckkönig, Annette, Strauß, Hans-Georg, Tomé, Oliver, Treustedt, Jörn, Voß, Hermann, Wischnik, Arthur, Witteler, Ralf, Wöckel, Achim, Woeltjen, Hans-Heinrich, Zorr, Andreas, Bologna, Alessandra, Colombo, Nicoletta, Tognon, Germana, Cinieri, Saverio, Lorusso, Domenica, Mosconi, Anna Maria, Pignata, Sandro, Savarese, Antonella, Scambia, Giovanni, Sorio, Roberto, Zamagni, Claudio, Fujiwara, Keiichi, Fujiwara, Hiroyuki, Kobayashi, Hiroaki, Matsumoto, Takashi, Nagao, Shoji, Satoh, Toyomi, Yonemori, Kan, Yoshida, Hiroyuki, Bratos, Raquel, Caballero, Cristina, Garica, Yolanda, González-Martín, Antonio, Guerra-Alía, Eva Maria, Hernando, Susana, Herrero, Ana, Lainez, Nuria, Manso, Luis, Martin, Cristina, Murata, Eleonor, Ortega, Eugenia, Palacio, Isabel, Poveda, Andres, Romero, Ignacio, Rubio-Pérez, María Jesús, Harter, P., Marth, C., Mouret-Reynier, M.-A., Cropet, C., Lorusso, D., Guerra-Alía, E.M., Matsumoto, T., Vergote, I., Colombo, N., Mäenpää, J., Lebreton, C., de Gregorio, N., Mosconi, A.M., Rubio-Pérez, M.J., Bourgeois, H., Fasching, P.A., Cecere, S.C., Hardy-Bessard, A.-C., Denschlag, D., de Percin, S., Hanker, L., Favier, L., Bauerschlag, D., Desauw, C., Hillemanns, P., Largillier, R., Sehouli, J., Grenier, J., Pujade-Lauraine, E., and Ray-Coquard, I.

Published
2025
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10. How long is long enough? An international survey exploring practice variations on the recommended duration of maintenance therapy with PARP inhibitors in patients with platinum sensitive recurrent ovarian cancer and long-term outcomes

Author

Haggstrom, Lucy, Lee, Yeh Chen, Scott, Clare, Harter, Philipp, Woelber, Linn, Ledermann, Jonathan, Gourley, Charlie, McNeish, Iain A, Amant, Frédéric, Ray-Coquard, Isabelle, Leary, Alexandra, Oza, Amit M, Tinker, Anna, González Martin, Antonio, Cecere, Sabrina Chiara, Pignata, Sandro, Colombo, Nicoletta, Yoshida, Hiroyuki, Marth, Christian, Rosengarten, Ora, Moore, Kathleen Nadine, Gómez-García, Eva María, Tan, David, and Friedlander, Michael L

Published
2024
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13. Magnetic properties of the Shastry-Sutherland lattice material BaNd$_2$ZnO$_5$

Author

Ishii, Yuto, Sala, G., Stone, M. B., Garlea, V. O., Calder, S., Chen, Jie, Yoshida, Hiroyuki K., Fukuoka, Shuhei, Yan, Jiaqiang, Cruz, Clarina dela, Du, Mao-Hua, Parker, DavidS., Zhang, Hao, Batista, C., Yamaura, Kazunari, and Christianson, A. D.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We investigate the physical properties of the Shastry-Sutherland lattice material BaNd$_2$ZnO$_5$. Neutron diffraction, magnetic susceptibility, and specific heat measurements reveal antiferromagnetic order below 1.65 K. The magnetic order is found to be a 2-$\boldsymbol{Q}$ magnetic structure with the magnetic moments lying in the Shastry-Sutherland lattice planes comprising the tetragonal crystal structure of BaNd$_2$ZnO$_5$. The ordered moment for this structure is 1.9(1) $\mu_B$ per Nd ion. Inelastic neutron scattering measurements reveal that the crystal field ground state doublet is well separated from the first excited state at 8 meV. The crystal field Hamiltonian is determined through simultaneous refinement of models with both the LS coupling and intermediate coupling approximations to the inelastic neutron scattering and magnetic susceptibility data. The ground state doublet indicates that the magnetic moments lie primarily in the basal plane with magnitude consistent with the size of the determined ordered moment., Comment: 13 pages, 8 figures

Published
2021
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14. Emergence of Frustrated Short-Range Order above Long-Range Order in the $S=1/2$ Kagome Antiferromagnet CaCu$_3$(OD)$_6$Cl$_2\cdot0.6$D$_2$O

Author

Ihara, Yoshihiko, Matsui, Kazuki, Kohama, Yoshimitsu, Luther, Sven, Opherden, Daryna, Wosnitza, Jochen, Kühne, Hannes, and Yoshida, Hiroyuki K.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We report on the low-energy dynamics in the kagome antiferromagnet CaCu$_3$(OD)$_6$Cl$_2\cdot0.6$D$_2$O (Ca-kapellasite) as studied by use of $^2$D-NMR measurements. Previous $^{35}$Cl-NMR measurements revealed that the nuclear spin-lattice relaxation rate ($1/T_1$) shows two peaks at temperatures, $T^{\ast} = 7.2$ K and $T_s \simeq 25$ K. While the low-temperature peak at $T^{\ast}$ is ascribed to the critical fluctuations near the long-range magnetic ordering, the origin of the high-temperature peak has not been fully understood. From the $1/T_1$ measurements on the D sites at the OD groups (D$_{\rm OD}$), we find no peak at $T_s$, evidencing that the high-temperature peak is not related to the molecular dynamics of the OD groups. We discuss the possibility of a frustration-induced short-range ordered state below $T_s$ before the long-range order is stabilized by the Dzyaloshinskii-Moriya interaction. We also observed static internal fields at the D$_{\rm OD}$ site in the long-range ordered state below $T^{\ast}$, and confirm the previously proposed negative-chirality $q=0$ magnetic structure., Comment: 5 pages, 4 figures

Published
2021
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15. Anti-integrin αvβ6 autoantibodies in patients with primary sclerosing cholangitis

Author

Yoshida, Hiroyuki, Shiokawa, Masahiro, Kuwada, Takeshi, Muramoto, Yuya, Ota, Sakiko, Nishikawa, Yoshihiro, Maeda, Hirona, Kakiuchi, Nobuyuki, Okamoto, Kanako, Yamazaki, Hajime, Yokode, Masataka, Nakamura, Takeharu, Matsumoto, Shimpei, Hirano, Tomonori, Okada, Hirokazu, Marui, Saiko, Sogabe, Yuko, Matsumori, Tomoaki, Mima, Atsushi, Uza, Norimitsu, Eso, Yuji, Takai, Atsushi, Takahashi, Ken, Ueda, Yoshihide, Kodama, Yuzo, Chiba, Tsutomu, and Seno, Hiroshi

Published
2023
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17. Accessing the conduction band dispersion in CH3NH3PbI3 single crystals

Author

Yang, Jinpeng, Sato, Haruki, Orio, Hibiki, Liu, Xianjie, Fahlman, Mats, Ueno, Nobuo, Yoshida, Hiroyuki, Yamada, Takashi, and Kera, Satoshi

Subjects
Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

The conduction band structure in methylammonium lead iodide (CH3NH3PbI3) was studied both by angle-resolved two-photon photoemission spectroscopy (AR-2PPE) with low-photon intensity and angle-resolved low-energy inverse photoelectron spectroscopy (AR-LEIPS). Clear energy dispersion of the conduction band along the {\Gamma}M direction was observed by these independent methods under different temperatures, and the dispersion was found to be consistent with band calculations under the cubic phase. The effective mass of the electrons at the {\Gamma} point was estimated to be (0.20+-0.05)m0 at 90 K. The observed energy position was largely different between the AR-LEIPS and AR-2PPE, demonstrating the electron correlation effects on the band structures. The present results also indicate that the surface structure in CH3NH3PbI3 provides the cubic-dominated electronic property even at lower temperatures., Comment: 23pages, 3figures

Published
2020

18. Butterfly-shaped magnetoresistance in triangular-lattice antiferromagnet Ag$_2$CrO$_2$

Author

Taniguchi, Hiroki, Watanabe, Mori, Tokuda, Masashi, Suzuki, Shota, Imada, Eria, Ibe, Takashi, Arakawa, Tomonori, Yoshida, Hiroyuki, Ishizuka, Hiroaki, Kobayashi, Kensuke, and Niimi, Yasuhiro

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Spintronic devices using antiferromagnets (AFMs) are promising candidates for future applications. Recently, many interesting physical properties have been reported with AFM-based devices. Here we report a butterfly-shaped magnetoresistance (MR) in a micrometer-sized triangular-lattice antiferromagnet Ag$_2$CrO$_2$. The material consists of two-dimensional triangular-lattice CrO$_2$ layers with antiferromagnetically coupled $S$ = 3/2 spins and Ag$_2$ layers with high electrical conductivity. The butterfly-shaped MR appears only when the magnetic field is applied perpendicularly to the CrO$_2$ plane with the maximum MR ratio ($\approx$ 15%) at the magnetic ordering temperature. These features are distinct from those observed in conventional magnetic materials. We propose a theoretical model where fluctuations of partially disordered spins with the Ising anisotropy play an essential role in the butterfly-shaped MR in Ag$_2$CrO$_2$., Comment: 25 pages, 6 figures

Published
2020
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19. Surface geometry determined temperature-dependent band structure evolutions in organic halide perovskite single crystals

Author

Yang, Jinpeng, Meissner, Matthias, Yamaguchi, Takuma, Xi, Bin, Takahashi, Keishi, Abdullah, Shed, Liu, Xianjie, Yoshida, Hiroyuki, Fahlman, Mats, and Kera, Satoshi

Subjects
Condensed Matter - Materials Science
Abstract

In this study, different electronic structure evolutions of perovskite single crystals are found via angle-resolved photoelectron spectroscopy (ARPES): (i) unchanged top valence band (VB) dispersions under different temperatures can be found in the CH3NH3PbI3, (ii) phase transitions induced the evolution of top VB dispersions, and even a top VB splitting with Rashba effects can be observed in the CH3NH3PbBr3. Combined with low-energy electron diffraction (LEED), metastable atom electron spectroscopy (MAES), and DFT calculation, we confirm different band structure evolutions observed in these two perovskite single crystals are originated from the cleaved top surface layers, where the different surface geometries with CH3NH3+-I in CH3NH3PbI3 and Pb-Br in CH3NH3PbBr3 are responsible for finding band dispersion change and appearing of the Rashba-type splitting. Such findings suggest that the top surface layer in organic halide perovskites should be carefully considered to create functional interfaces for developing perovskite devices., Comment: 4 figures

Published
2020

20. Observation of domain wall bimerons in chiral magnets

Author

Nagase, Tomoki, So, Yeong-Gi, Yasui, Hayata, Ishida, Takafumi, Yoshida, Hiroyuki K., Tanaka, Yukio, Saitoh, Koh, Ikarashi, Nobuyuki, Kawaguchi, Yuki, Kuwahara, Makoto, and Nagao, Masahiro

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Topological defects embedded in or combined with domain walls have been proposed in various systems, some of which are referred to as domain wall skyrmions or domain wall bimerons. However, the experimental observation of such topological defects remains an ongoing challenge. Here, using Lorentz transmission electron microscopy, we report the experimental discovery of domain wall bimerons in chiral magnet Co-Zn-Mn(110) thin films. By applying a magnetic field, multidomain structures develop, and simultaneously, chained and isolated bimerons arise as the localized state between the domains with the opposite in-plane components of net magnetization. The multidomain formation is attributed to magnetic anisotropy and dipolar interaction, and domain wall bimerons are stabilized by the Dzyaloshinskii-Moriya interaction. In addition, micromagnetic simulations show that domain wall bimerons appear for a wide range of conditions in chiral magnets with cubic magnetic anisotropy. Our results promote further study in various fields of physics., Comment: 30 pages, 10 figures (including Supplementary Materials)

Published
2020
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30. Efficacy and safety of maintenance olaparib and bevacizumab in ovarian cancer patients aged ≥65 years from the PAOLA-1/ENGOT-ov25 trial

Author

Sabatier, Renaud, Rousseau, Frédérique, Joly, Florence, Cropet, Claire, Montégut, Coline, Frindte, Johanna, Cinieri, Saverio, Guerra Alía, Eva M., Polterauer, Stephan, Yoshida, Hiroyuki, Vergote, Ignace, Colombo, Nicoletta, Hietanen, Sakari, Largillier, Rémi, Canzler, Ulrich, Gratet, Alain, Marmé, Frederik, Favier, Laure, Pujade-Lauraine, Eric, and Ray-Coquard, Isabelle

Published
2023
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32. Spin Thermal Hall Conductivity of a Kagom\'e Antiferromagnet

Author

Doki, Hayato, Akazawa, Masatoshi, Lee, Hyun-Yong, Han, Jung Hoon, Sugii, Kaori, Shimozawa, Masaaki, Kawashima, Naoki, Oda, Migaku, Yoshida, Hiroyuki, and Yamashita, Minoru

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

A clear thermal Hall signal ($\kappa_{xy}$) was observed in the spin liquid phase of the $S=1/2$ kagom\'e antiferromagnet Ca kapellasite (CaCu$_3$(OH)$_6$Cl$_2\cdot 0.6$H$_2$O). We found that $\kappa_{xy}$ is well reproduced, both qualitatively and quantitatively, using the Schwinger-boson mean-field theory with the Dzyaloshinskii--Moriya interaction of $D/J \sim 0.1$. In particular, $\kappa_{xy}$ values of Ca kapellasite and those of another kagom\'e antiferromagnet, volborthite, converge to one single curve in simulations modeled using Schwinger bosons, indicating a common temperature dependence of $\kappa_{xy}$ for the spins of a kagom\'e antiferromagnet., Comment: 5 pages, 4 figures + Supplemental Material(9 pages, 6 figures)

Published
2018
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33. Hyaluronan Degradation by Cemip Regulates Host Defense against Staphylococcus aureus Skin Infection

Author

Dokoshi, Tatsuya, Zhang, Ling-juan, Li, Fengwu, Nakatsuji, Teruaki, Butcher, Anna, Yoshida, Hiroyuki, Shimoda, Masayuki, Okada, Yasunori, and Gallo, Richard L

Subjects
Microbiology, Biological Sciences, Biodefense, Infectious Diseases, Emerging Infectious Diseases, 2.1 Biological and endogenous factors, Infection, Adipogenesis, Animals, Dermis, Host-Pathogen Interactions, Hyaluronic Acid, Hyaluronoglucosaminidase, Inflammation, Mice, Inbred C57BL, Mice, Knockout, Staphylococcal Infections, Staphylococcus aureus, antimicrobial peptides, cathelicidin, dermis, glycosaminoglycans, hyaluronan, innate immunity, skin, Biochemistry and Cell Biology, Medical Physiology, Biological sciences
Abstract

Staphylococcus aureus is a major human bacterial pathogen responsible for deep tissue skin infections. Recent observations have suggested that rapid, localized digestion of hyaluronic acid in the extracellular matrix (ECM) of the dermis may influence bacterial invasion and tissue inflammation. In this study we find that cell migration-inducing protein (Cemip) is the major inducible gene responsible for hyaluronan catabolism in mice. Cemip-/- mice failed to digest hyaluronan and had significantly less evidence of infection after intradermal bacterial challenge by S. aureus. Stabilization of large-molecular-weight hyaluronan enabled increased expression of cathelicidin antimicrobial peptide (Camp) that was due in part to enhanced differentiation of preadipocytes to adipocytes, as seen histologically and by increased expression of Pref1, PPARg, and Adipoq. Cemip-/- mice challenged with S. aureus also had greater IL-6 expression and neutrophil infiltration. These observations describe a mechanism for hyaluronan in the dermal ECM to regulate tissue inflammation and host antimicrobial defense.

Published
2020

34. Evaluation of electronic state of Cs-adsorbed clay minerals by NEXAFS analysis using DFT calculations

Author

Suzuki, Chikashi, Yaita, Tsuyoshi, Suzuki, Shinichi, Pacold, Joseph, Altman, Alison B, Minasian, Stefan G, Tyliszczak, Tolek, Shuh, David K, Yoshida, Hiroyuki, and Osaka, Masahiko

Subjects
Chemical Sciences, Physical Chemistry, Cesium, NEXAFS, Clay mineral, DFT calculation, Electronic state, Condensed Matter Physics, Physical Chemistry (incl. Structural), Materials Engineering, Inorganic chemistry, Macromolecular and materials chemistry, Condensed matter physics
Abstract

A combined analytical method of NEXAFS measurement and DFT-calculation was employed for the evaluation of Cs states in clay minerals. The measured Cs M4,5 NEXAFS spectra of Cs halides were analyzed using the DFT-calculations in order to establish the analytical methods. The NEXAFS spectra of the Cs halides were well reproduced by incorporating the core-hole strength. The Cs M4,5 NEXAFS spectrum of the clay minerals was well reproduced by the DFT-calculations including the major transitions and tail structures with the established method. Further evaluation of this spectrum by charge density analysis suggested that these major transitions and the tail structures likely reflect the bonding state and the local environment around the Cs atoms. Comparison of electronic states of Cs in the clay mineral with those in the Cs halides by DFT-calculations has shown that the interaction between Cs and the nearest-neighbor atom is largest in the clay mineral, which differs from those of Cs halides. This happened due to the energy level of Cs-5s and 5p, which was closer to that of O-2s and 2p than the s and p orbitals of other alkali metal and alkali earth metal elements.

Published
2019

36. Reliable measurement of the density of states including occupied in-gap states of an amorphous In–Ga–Zn–O thin film via photoemission spectroscopies: Direct observation of light-induced in-gap states.

Author

Nakazawa, Ryotaro, Matsuzaki, Atsushi, Shimizu, Kohei, Nakamura, Ikuko, Kawashima, Emi, Makita, Seiji, Tanaka, Kiyohisa, Yasuno, Satoshi, Sato, Haruki, Yoshida, Hiroyuki, Abdi-Jalebi, Mojtaba, Stranks, Samuel D., Tadano, Shohei, Krüger, Peter, Tanaka, Yuya, Tokairin, Hiroshi, and Ishii, Hisao

Subjects
PHOTOELECTRON spectroscopy, THIN films, DENSITY of states, PHOTOEMISSION, SYNCHROTRON radiation, ULTRAVIOLET spectroscopy
Abstract

Illumination stress (IS) and negative bias under illumination stress (NBIS) cause considerable device instability in thin-film transistors based on amorphous In–Ga–Zn–O (a-IGZO). Models using in-gap states are suggested to explain device instability. Therefore, to provide reliably their density of states (DOS), this study investigated the valence band, conduction band, and in-gap states of an a-IGZO thin film. The DOS of in-gap states was directly determined in a dynamic range of six orders of magnitude through constant final state yield spectroscopy (CFS-YS) using low-energy and low-flux photons. Furthermore, light irradiation irreversibly induced extra in-gap states near the Fermi level and shifted the Fermi level to the vacuum level side, which should be related to the device instability due to IS and NBIS. Hard x-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy using synchrotron radiation observed the large DOS of in-gap states near the Fermi level as in previous works. Here, we reveal that they are not intrinsic electronic states of undamaged a-IGZO, but induced by the intense measurement light of synchrotron radiation. This study demonstrates that CFS-YS is useful for determining the reliable DOS of the in-gap states for samples that are sensitive to light irradiation. The absorption spectrum measured through photothermal deflection spectroscopy is interpreted based on DOS directly determined via photoemission spectroscopies. This indicates that the line shape in the energy region below the region assigned to the Urbach tail in previous works actually roughly reflects the DOS of occupied in-gap states. [ABSTRACT FROM AUTHOR]

Published
2024
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