| Project/Area Number |
16560270
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Niigata University |
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Principal Investigator |
TSUBOI Nozomu Niigata University, Institute of Science and Technology, Associate Professor, 自然科学系, 助教授 (70217371)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Satoshi Niigata University, Institute of Science and Technology, Professor, 自然科学系, 教授 (30018626)
UCHIKI Hisao Nagaoka Univ.of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50142237)
TANAKA Kunihiko Nagaoka Univ.of Technology, Faculty of Engineering, Assistant, 工学部, 助手 (30334692)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | delafossite / CuAlO_2 / transparent conductive oxide / p-type oxide / thin films / reactive sputtering / sputtering / oxide electronics / レーザアニール |
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| Research Abstract |
Cu-Al-O films were prepared on quarts substrates at 500〜700℃ by sputtering alternately the Cu and the Al targets on atomic-layer-scale under Ar-diluted O_2(5〜20%) gas atmosphere, and then annealed at 1050℃ under the nitrogen atmosphere. The [Cu]/[Al] ratio was controlled by changing Cu and Al deposition periods. Composition of as-deposited films corresponded to the slightly oxygen-rich region of the CuO-CuAl_2O_4-Al_2O_3 system. Films as-deposited at 500℃ had amorphous structure, while films as-deposited at 700℃ had CuAl_2O_4 and CuO phases. After thermal annealing, the film composition approached to the Cu_2O-CuAlO_2-Al_2O_3 system line, causing noticeable appearance of CuAlO_2 delafossite phase along with absences of the CuAl_2O_4 and CuO phases. Cu-rich and Al-rich annealed films had additionally Cu_2O phase and amorphous Al_2O_3 phase, respectively. All annealed films exhibited p-type conductivity. The annealed films with [Cu]/[Al]【approximately equal】1 had the absorption edge corresponding to the energy gap of CuAlO_2. These results indicate the change of Cu ion from di-valence to mono-valence through the annealing process, which results the preparation of transparent conductive films dominated by CuAlO_2. We also tried to irradiate the as-deposited films in order to crystallize the amorphous structure to CuAlO_2 delafossite structure by using a KrF laser in the power range of 10〜10^3 mJcm^<-2>. However, we observed no changes of the amorphous structure. At the power more than about 10^2 mJcm^<-2>, laser ablation of the films was observed.
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