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Hideo Hosono - One of the best experts on this subject based on the ideXlab platform.
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Electronic defects in Amorphous Oxide semiconductor and recent development
2020 27th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2020Co-Authors: Keisuke Ide, Hideo Hosono, Toshio KamiyaAbstract:Amorphous Oxide semiconductors (AOSs) represented by Amorphous In-Ga-Zn-O have been applied for state-of-the-art flat panel displays as thin-film transistor backplane since 2012. Understanding defects in AOS is critically important for controlling the instability of TFTs. It is found in the past decades that many AOS defects are related to oxygen and hydrogen impurities, though oxygen is the major constituent of AOS and hydrogen is not intentionally incorporated.
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Amorphous Oxide Semiconductor Thin-Film Transistors
Novel Structured Metallic and Inorganic Materials, 2019Co-Authors: Toshio Kamiya, Kenji Nomura, Keisuke Ide, Jungwhan Kim, Hidenori Hiramatsu, Hideya Kumomi, Hideo HosonoAbstract:Amorphous Oxide semiconductor (AOS) is now commercialized in many flat-panel displays. On the other hand, its electronic structures and defects are largely different from conventional covalent semiconductors such as Si. This chapter explains their origins and reviews the defects that have been known to date. Finally, we will discuss how to fabricate high-quality, stabile AOS.
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Transparent Amorphous Oxide semiconductors: Materials design, electronic structure, and device applications
2017 75th Annual Device Research Conference (DRC), 2017Co-Authors: Hideo HosonoAbstract:In 1995, I presented a materials design concept for transparent Amorphous Oxide semiconductors with a large electron mobility (TAOS) at the 16'h International conference on Amorphous semiconductors along with concrete example materials of TAOS and the paper was published in 1996 [1[. The basic concept of TAOS is that large electron mobility should be retained even in Amorphous materials if the conduction band minimum is mainly composed of spatially large spread of metal ns-orbitals.1 The validity of this design concept was demonstrated by analysis of electronic structure using photoemission experiments combined with calculations based on X-ray structural analysis[2].
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Ultrawide band gap Amorphous Oxide semiconductor, Ga–Zn–O
Thin Solid Films, 2016Co-Authors: Junghwan Kim, Hideo Hosono, Keisuke Ide, Hidenori Hiramatsu, Norihiko Miyokawa, Takumi Sekiya, Yoshitake Toda, Toshio KamiyaAbstract:Abstract We fabricated Amorphous Oxide semiconductor films, a-(Ga1–xZnx)Oy, at room temperature on glass, which have widely tunable band gaps (Eg) ranging from 3.47–4.12 eV. The highest electron Hall mobility ~ 7 cm2 V− 1 s− 1 was obtained for Eg = ~ 3.8 eV. Ultraviolet photoemission spectroscopy revealed that the increase in Eg with increasing the Ga content comes mostly from the deepening of the valence band maximum level while the conduction band minimum level remains almost unchanged. These characteristics are explained by their electronic structures. As these films can be fabricated at room temperature on plastic, this achievement extends the applications of flexible electronics to opto-electronic integrated circuits associated with deep ultraviolet region.
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4.1: Invited Paper: Electronic Structure, Carrier Transport, Defects and Impurities in Amorphous Oxide Semiconductor
SID Symposium Digest of Technical Papers, 2013Co-Authors: Toshio Kamiya, Kenji Nomura, Hideo HosonoAbstract:This review paper provides the present status of Amorphous Oxide semiconductor technology along with knowledge obtained to date on their carrier transport, defects and impurities in relation to their stability issues.
Toshio Kamiya - One of the best experts on this subject based on the ideXlab platform.
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Electronic defects in Amorphous Oxide semiconductor and recent development
2020 27th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD), 2020Co-Authors: Keisuke Ide, Hideo Hosono, Toshio KamiyaAbstract:Amorphous Oxide semiconductors (AOSs) represented by Amorphous In-Ga-Zn-O have been applied for state-of-the-art flat panel displays as thin-film transistor backplane since 2012. Understanding defects in AOS is critically important for controlling the instability of TFTs. It is found in the past decades that many AOS defects are related to oxygen and hydrogen impurities, though oxygen is the major constituent of AOS and hydrogen is not intentionally incorporated.
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Amorphous Oxide Semiconductor Thin-Film Transistors
Novel Structured Metallic and Inorganic Materials, 2019Co-Authors: Toshio Kamiya, Kenji Nomura, Keisuke Ide, Jungwhan Kim, Hidenori Hiramatsu, Hideya Kumomi, Hideo HosonoAbstract:Amorphous Oxide semiconductor (AOS) is now commercialized in many flat-panel displays. On the other hand, its electronic structures and defects are largely different from conventional covalent semiconductors such as Si. This chapter explains their origins and reviews the defects that have been known to date. Finally, we will discuss how to fabricate high-quality, stabile AOS.
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Ultrawide band gap Amorphous Oxide semiconductor, Ga–Zn–O
Thin Solid Films, 2016Co-Authors: Junghwan Kim, Hideo Hosono, Keisuke Ide, Hidenori Hiramatsu, Norihiko Miyokawa, Takumi Sekiya, Yoshitake Toda, Toshio KamiyaAbstract:Abstract We fabricated Amorphous Oxide semiconductor films, a-(Ga1–xZnx)Oy, at room temperature on glass, which have widely tunable band gaps (Eg) ranging from 3.47–4.12 eV. The highest electron Hall mobility ~ 7 cm2 V− 1 s− 1 was obtained for Eg = ~ 3.8 eV. Ultraviolet photoemission spectroscopy revealed that the increase in Eg with increasing the Ga content comes mostly from the deepening of the valence band maximum level while the conduction band minimum level remains almost unchanged. These characteristics are explained by their electronic structures. As these films can be fabricated at room temperature on plastic, this achievement extends the applications of flexible electronics to opto-electronic integrated circuits associated with deep ultraviolet region.
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4.1: Invited Paper: Electronic Structure, Carrier Transport, Defects and Impurities in Amorphous Oxide Semiconductor
SID Symposium Digest of Technical Papers, 2013Co-Authors: Toshio Kamiya, Kenji Nomura, Hideo HosonoAbstract:This review paper provides the present status of Amorphous Oxide semiconductor technology along with knowledge obtained to date on their carrier transport, defects and impurities in relation to their stability issues.
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Invited) Roles of Hydrogen in Amorphous Oxide Semiconductor
ECS Transactions, 2013Co-Authors: Toshio Kamiya, Hideo HosonoAbstract:Amorphous Oxide semiconductor represented by a-In-Ga-Zn-O is now used for thin-film transistors in some of current flat-panel displays due to its high mobility and good stability. Recently, it has been recognized that a-In-Ga-Zn-O films include some types of oxygen working as electron traps and that high-density impurity hydrogens. This paper reviews the recent findings on their roles.
Kenji Nomura - One of the best experts on this subject based on the ideXlab platform.
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Amorphous Oxide Semiconductor Thin-Film Transistors
Novel Structured Metallic and Inorganic Materials, 2019Co-Authors: Toshio Kamiya, Kenji Nomura, Keisuke Ide, Jungwhan Kim, Hidenori Hiramatsu, Hideya Kumomi, Hideo HosonoAbstract:Amorphous Oxide semiconductor (AOS) is now commercialized in many flat-panel displays. On the other hand, its electronic structures and defects are largely different from conventional covalent semiconductors such as Si. This chapter explains their origins and reviews the defects that have been known to date. Finally, we will discuss how to fabricate high-quality, stabile AOS.
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4.1: Invited Paper: Electronic Structure, Carrier Transport, Defects and Impurities in Amorphous Oxide Semiconductor
SID Symposium Digest of Technical Papers, 2013Co-Authors: Toshio Kamiya, Kenji Nomura, Hideo HosonoAbstract:This review paper provides the present status of Amorphous Oxide semiconductor technology along with knowledge obtained to date on their carrier transport, defects and impurities in relation to their stability issues.
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Present status and open issues of Amorphous Oxide semiconductor TFT technology
2013 IEEE Photonics Conference, 2013Co-Authors: Kenji NomuraAbstract:We review the progress made to date on Amorphous Oxide semiconductor TFT technology. In addition, we discuss some remaining issues for manufacturing with the focus on the role of hydrogen impurity in Amorphous Oxide semiconductors.
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effects of diffusion of hydrogen and oxygen on electrical properties of Amorphous Oxide semiconductor in ga zn o
ECS Journal of Solid State Science and Technology, 2013Co-Authors: Kenji Nomura, Toshio Kamiya, Hideo HosonoAbstract:We found that device-quality thin films of Amorphous Oxide semiconductor, a-In-Ga-Zn-O, unintentionally include high-density hydrogens over 1020 cm−3 but the electron concentration remains low at ~1015 cm−3 in as-deposited states. The hydrogens exist in the form of hydroxyl group –OH, but most of them are inactive as an electron donor, which is explained by charge compensation due to incorporation of excess oxygens. Although their diffusions are fast compared with those in crystalline ZnO, but oxygen can diffuse only 20 nm even at 400°C. Hydrogen diffusion is much faster, and easily hydrogenizes a thin channel of a thin-film transistor.
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three dimensionally stacked flexible integrated circuit Amorphous Oxide polymer hybrid complementary inverter using n type a in ga zn o and p type poly 9 9 dioctylfluorene co bithiophene thin film transistors
Applied Physics Letters, 2010Co-Authors: Kenji Nomura, Toshio Kamiya, Masahiro Hirano, Mutsumi Kimura, Takashi Aoki, Kiyoshi Nakamura, Takashi Nakanishi, Takayuki Hasegawa, Takeo Kawase, Hideo HosonoAbstract:A three-dimensional vertically-stacked flexible integrated circuit is demonstrated based on hybrid complementary inverters made of n-type In–Ga–Zn–O (a-IGZO) Amorphous Oxide thin-film transistors (TFTs) and p-type poly-(9,9-dioctylfluorene-co-bithiophene) (F8T2) polymer TFTs, where all the fabrication processes were performed at temperatures ≤120 °C. Saturation mobilities of the a-IGZO TFT and the F8T2 TFT are ∼3.2 and ∼1.7×10−3 cm2 V−1 s−1, respectively, from which we chose the appropriate dimensions of the TFTs so as to obtain a good balance for the inverter operation. The maximum voltage gain is ∼67, which is better than those reported for organic/Oxide hybrid complementary inverters.
Hyang Kim - One of the best experts on this subject based on the ideXlab platform.
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High thermal stability of the Amorphous Oxide in Ti44.5Cu44.5Zr7Be4 metallic glass
AIP Advances, 2015Co-Authors: Sung Hyun Park, Kang Cheol Kim, Ka Ram Lim, Won Tae Kim, Hyang KimAbstract:The oxidation behavior of Ti44.5Cu44.5Zr7Be4 metallic glass has been investigated. The Oxide layer with a fully Amorphous structure forms when heated up to the SCL temperature region, indicating that the presence of Be in the Oxide layer improves the thermal stability of the Amorphous Oxide. The Amorphous Oxide is stable even when heated above the crystallization onset temperature. The thickness of the Amorphous Oxide layer reaches to ∼160 nm when heated up to 773 K. The Oxide layer grows in both inward and outward directions, leaving Cu-enriched crystalline particles at the middle section of the Oxide layer.
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Formation of Amorphous Oxide in Al82Ni13Zr5 and Al88Ni7Ca5 alloys
Corrosion Science, 2014Co-Authors: Kang Cheol Kim, Ka Ram Lim, Sung Hyun Park, Won Tae Kim, Hyang KimAbstract:Formation and thermal stability of Amorphous Oxide in Al82Ni13Zr5 and Al88Ni7Ca5 alloys during holding at 873 K have been investigated. The thickness of Amorphous Oxide layer upon heating up to 873 K is ∼8 nm in Al82Ni13Zr5, while ∼15 nm in Al88Ni7Ca5. After exposure for 15 h, the Amorphous Oxide still remains in Al88Ni7Ca5, indicating that the thermal stability of the Amorphous Oxide in Al88Ni7Ca5 is higher than that in Al82Ni13Zr5. Such a phenomenon is discussed from the points of view of structural stability and oxygen ion mobility in the crystalline and Amorphous Oxide phases.
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Thermal stability of Amorphous Oxide in Al87Ni3Y10 metallic glass
Corrosion Science, 2013Co-Authors: Kang Cheol Kim, Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Hyang KimAbstract:Abstract The oxidation behavior of melt-spun Al 87 Ni 3 Y 10 metallic glass at 873 K is investigated in the present study. The simultaneous presence of aluminum and yttrium in the Oxide markedly promotes the thermal stability of the Amorphous Oxide phase, enabling the growth of the Amorphous Oxide layer up to ∼100 nm thickness. The stability of the Amorphous Oxide can be enhanced by suppressing the nucleation of the crystalline Oxide at the Oxide/matrix interface. The dense structure of aluminum–yttrium Oxide due to large difference in ionic radius between aluminum and yttrium ions disturbs the diffusion of oxygen ions through the Amorphous Oxide layer.
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Enhancement of oxidation resistance of the supercooled liquid in Cu–Zr-based metallic glass by forming an Amorphous Oxide layer with high thermal stability
Corrosion Science, 2013Co-Authors: Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Jin Man Park, Suk Jun Kim, Hyang KimAbstract:Abstract In the present study, we propose that the formation of Amorphous Oxide layers with an enhanced thermal stability can significantly improve the oxidation resistance of metallic glass in the supercooled liquid (SCL) state. Addition of a small amount of Be (2 at.%) in Cu 46 Zr 46 Al 8 widens the SCL region and simultaneously improves the oxidation resistance of the SCL. For Cu 46 Zr 46 Al 8 , the initial Amorphous Oxide completely transforms into the crystalline Oxide far below the glass transition temperature during continuous heating, while for Cu 45 Zr 45 Al 8 Be 2 , the Amorphous Oxide remains after heating up to the SCL region, thus significantly improving the oxidation resistance of the SCL.
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Effect of thermal stability of the Amorphous substrate on the Amorphous Oxide growth on Zr–Al–(Cu,Ni) metallic glass surfaces
Corrosion Science, 2013Co-Authors: Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Jin Man Park, Suk Jun Kim, Sang Soo Jee, Yun Kim, Hyang KimAbstract:Abstract In the present study, we propose that the glass stability of an Amorphous Oxide film is highly dependent on the interface stability between the Amorphous Oxide and the Amorphous substrate. The interface stability is closely linked to the thermal stability of the Amorphous substrate, which is changed by the chemical composition shift during formation of the Oxide layer. Therefore, significant improvement of the oxidation resistance in metallic glass systems can be achieved by controlling the compositional changes underneath the Oxide layer.
Ka Ram Lim - One of the best experts on this subject based on the ideXlab platform.
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High thermal stability of the Amorphous Oxide in Ti44.5Cu44.5Zr7Be4 metallic glass
AIP Advances, 2015Co-Authors: Sung Hyun Park, Kang Cheol Kim, Ka Ram Lim, Won Tae Kim, Hyang KimAbstract:The oxidation behavior of Ti44.5Cu44.5Zr7Be4 metallic glass has been investigated. The Oxide layer with a fully Amorphous structure forms when heated up to the SCL temperature region, indicating that the presence of Be in the Oxide layer improves the thermal stability of the Amorphous Oxide. The Amorphous Oxide is stable even when heated above the crystallization onset temperature. The thickness of the Amorphous Oxide layer reaches to ∼160 nm when heated up to 773 K. The Oxide layer grows in both inward and outward directions, leaving Cu-enriched crystalline particles at the middle section of the Oxide layer.
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Formation of Amorphous Oxide in Al82Ni13Zr5 and Al88Ni7Ca5 alloys
Corrosion Science, 2014Co-Authors: Kang Cheol Kim, Ka Ram Lim, Sung Hyun Park, Won Tae Kim, Hyang KimAbstract:Formation and thermal stability of Amorphous Oxide in Al82Ni13Zr5 and Al88Ni7Ca5 alloys during holding at 873 K have been investigated. The thickness of Amorphous Oxide layer upon heating up to 873 K is ∼8 nm in Al82Ni13Zr5, while ∼15 nm in Al88Ni7Ca5. After exposure for 15 h, the Amorphous Oxide still remains in Al88Ni7Ca5, indicating that the thermal stability of the Amorphous Oxide in Al88Ni7Ca5 is higher than that in Al82Ni13Zr5. Such a phenomenon is discussed from the points of view of structural stability and oxygen ion mobility in the crystalline and Amorphous Oxide phases.
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effect of thermal stability of the Amorphous substrate on the Amorphous Oxide growth on zr al cu ni metallic glass surfaces
Corrosion Science, 2013Co-Authors: Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Jin Man Park, Suk Jun Kim, Sang Soo Jee, Se Yun Kim, Do Hyang KimAbstract:Abstract In the present study, we propose that the glass stability of an Amorphous Oxide film is highly dependent on the interface stability between the Amorphous Oxide and the Amorphous substrate. The interface stability is closely linked to the thermal stability of the Amorphous substrate, which is changed by the chemical composition shift during formation of the Oxide layer. Therefore, significant improvement of the oxidation resistance in metallic glass systems can be achieved by controlling the compositional changes underneath the Oxide layer.
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Thermal stability of Amorphous Oxide in Al87Ni3Y10 metallic glass
Corrosion Science, 2013Co-Authors: Kang Cheol Kim, Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Hyang KimAbstract:Abstract The oxidation behavior of melt-spun Al 87 Ni 3 Y 10 metallic glass at 873 K is investigated in the present study. The simultaneous presence of aluminum and yttrium in the Oxide markedly promotes the thermal stability of the Amorphous Oxide phase, enabling the growth of the Amorphous Oxide layer up to ∼100 nm thickness. The stability of the Amorphous Oxide can be enhanced by suppressing the nucleation of the crystalline Oxide at the Oxide/matrix interface. The dense structure of aluminum–yttrium Oxide due to large difference in ionic radius between aluminum and yttrium ions disturbs the diffusion of oxygen ions through the Amorphous Oxide layer.
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Enhancement of oxidation resistance of the supercooled liquid in Cu–Zr-based metallic glass by forming an Amorphous Oxide layer with high thermal stability
Corrosion Science, 2013Co-Authors: Ka Ram Lim, Won Tae Kim, Eun-sung Lee, Annett Gebert, Jürgen Eckert, Jin Man Park, Suk Jun Kim, Hyang KimAbstract:Abstract In the present study, we propose that the formation of Amorphous Oxide layers with an enhanced thermal stability can significantly improve the oxidation resistance of metallic glass in the supercooled liquid (SCL) state. Addition of a small amount of Be (2 at.%) in Cu 46 Zr 46 Al 8 widens the SCL region and simultaneously improves the oxidation resistance of the SCL. For Cu 46 Zr 46 Al 8 , the initial Amorphous Oxide completely transforms into the crystalline Oxide far below the glass transition temperature during continuous heating, while for Cu 45 Zr 45 Al 8 Be 2 , the Amorphous Oxide remains after heating up to the SCL region, thus significantly improving the oxidation resistance of the SCL.