2000 Fiscal Year Annual Research Report
| Project/Area Number |
11450007
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
川崎 雅司 東京工業大学, 大学院・総合理工学研究科, 助教授 (90211862)
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| Keywords | 酸化亜鉛薄膜 / エピタキシャル成長 / レーザーMBE / 格子整合基板 / 酸化亜鉛超格子薄膜 / エキシトン発光 / エキシトン誘導放出 / p型酸化亜鉛 |
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| Research Abstract |
酸化亜鉛薄膜を原子レベルで平坦なサファイア基板c面上にレーザーMBEで成膜することによって、エピタキシャル成長を行うことができ、面内の配向や表面の極性の制御も実現した[I.Ohkubo et al.,Surf.Sci.Lett.443,L1043(1999)]。その結果、化合物半導体超格子と同レベルの品質を持つZnO/MgZnO超格子が作製でき、量子効果によるギャップのブルーシフトが観察された[A.Ohtomo et al.,Appl.Phys.Lett.75,980(1999);75,4088(1999)]。一般に半導体の価電子制御を行うためには薄膜の品質向上が不可欠であるため、さらに結晶性向上を目指し、酸化亜鉛薄膜と非常に格子整合性が良いScAlMgO4基板を採用することによって、単結晶レベルの結晶性を有する薄膜を実現した[A.Ohtomo et al.,Appl.Phys.Lett.75,2635(1999)]。その結果、エキシトン発光特性が向上し[T.Makino et al.,Appl.Phys.Lett.76,3549(2000)]、同じく高品質のZnO/MgZnO超格子とCdZnO/MgZnO超格子の室温エキシトン発光が明瞭に観測され[T.Makino et al.,Appl.Phys.Lett.77,975(2000);77,1632(2000);H.D.Sun et al.,Appl.Phys.Lett.77,4250(2000)]、ZnO/MgZnO超格子において室温でエキシトンの誘導放出が観測された[A.Ohtomo et al.,Appl.Phys.Lett.77,2204(2000)]。以上のように、p型酸化亜鉛の作製に関しては当初の目的を達していないが、酸化亜鉛薄膜のバンドエンジニアリングは大幅に進歩した。
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[Publications] Y.Matsumoto: "Room-Temperature Ferromagnetism in Transparent Transition Metal-Doped Titanium Dioxide"Science. 291. 854-856 (2001)
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[Publications] Y.-Z.Yoo: "High temperature growth of ZnS films on bare Si and transformation of ZnS to ZnO by thermal oxidation"Appl.Phys.Lett.. 78. 616-618 (2001)
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[Publications] T.Fukumura: "Magnetic properties of Mn doped ZnO"Appl.Phys.Lett.. 78. 958-960 (2001)
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[Publications] T.Makino: "Exciton spectra of ZnO thin film on lattice-matched substrates grown with laser MBE method"Appl.Phys.Lett.. 76. 3549-3551 (2000)
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[Publications] T.Makino: "Room-temperature luminescence of excitons in ZnO/ (Mg, Zn) O multiple quantum wells on lattice-matched substrates"Appl.Phys.Lett.. 77. 975-977 (2000)
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[Publications] T.Makino: "Radiative and nonradiative recombination processes in lattice-matched (Cd, Zn) O /(Mg, Zn) O multi-quantum wells"Appl.Phys.Lett.. 77. 1632-1634 (2000)
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[Publications] A.Ohtomo: "Room-temperature simulated-emission of exciton in ZnO/ (Mg, Zn) O superlattices"Appl.Phys.Lett.. 77. 2204-2206 (2000)
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[Publications] H.D.Sun: "Stimulated emission induced by inelastic exciton-exciton scattering in ZnO/ZnMgO multi-quantum wells"Appl.Phys.Lett.. 77. 4250-4252 (2000)
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[Publications] J.W.Tomm: "Optical and Photoelectrical properties of oriented ZnO films"J.Appl.Phys.. 87. 1844-1848 (2000)
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[Publications] F.Siah: "In-plane anisotropic strain of ZnO closely packed microcrystallites grown on tilted (0001) sapphire"J.Appl.Phys.. 88. 2480-2483 (2000)
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[Publications] M.Kubo: "Homoepitaxial growth mechanism of Zno (0001) : Molecular-dynamics simulations"Phys.Rev.B. 61. 16187-16192 (2000)
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[Publications] I.Ohkubo: "Investigation of ZnO/sapphire interface and formation of ZnO nanocrystalline by laser MBE"Appl.Surf.Sci. 159-160. 514-519 (2000)
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[Publications] K.Tamura: "Epitaxial growth of ZnO films on lattice-matched ScAlMgO_4(0001) substrates"J.Cryst.Growth. 214/215. 59-62 (2000)
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[Publications] A.Ohtomo: "Lateral grain size and electron mobility in ZnO epitaxial films grown on sapphire substrates"J.Cryst.Growth. 214/215. 284-288 (2000)
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[Publications] T.Makino: "Optical spectra in ZnO thin films on lattice-matched substrates grown with Laser-MBE method"J.Cryst.Growth. 214/215. 289-293 (2000)
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[Publications] T.Makino: "Temperature dependence of four-wave-mixing spectra in ZnO thin films on ssapphire substrates grown with laser MBE"J.Lumin.. 87-89. 210-212 (2000)
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[Publications] A.Ohtomo: "Novel Semiconductor Technologies of ZnO Films towards Ultraviolet LEDs and Invisible FETs"IEICE Trans.Electron. E83-C. 1614-1617 (2000)
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[Publications] T.Makino: "Optical characterization for combinatorial system based on semiconductor ZnO"SPIE Proc.. 3491. 28-35 (2000)
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[Publications] A.Ohtomo: "High throughput optimizations of alloy and doped films based on ZnO and parallel synthesis of ZnO/Mg_xZn_<1-x>O quantum wells using combinatorial laser MBE towards ultraviolet laser"SPIE Proc.. 3491. 70-83 (2000)
