| Project/Area Number |
13650013
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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 |
Applied materials science/Crystal engineering
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| Research Institution | Shimane University |
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Principal Investigator |
FUJITA Yasuhisa Shimane University, Interdisciplinary Faculty of Science and Engineering, Associate Professor, 総合理工学部, 助教授 (10314618)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Zinc oxide / ZnO / Epitaxial Growth / MOCVD / p-type / photoluminescence / exciton / nitrogen doping / 吸収スペクトル |
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| Research Abstract |
II-VI compound semiconductor, ZnO is expected as a material for high efficiency uv semiconductor lasers. However, the growth of high quality p-type thin films is difficult. In this study, we have performed the characterization for the low temperature growth of ZnO films by MOCVD as shown below.
1. The decomposition of source materials
The decomposition temperature, premature reaction between Zn metal organics and oxygen sources in vapor phase and the difference of carrier gas (H_2, N_2) are investigated by in situ uv absorption measurements. The source materials with low decomposition temperature and low premature reactivity were selected using above results. It was found that t-butylamin is suitable for the source materials for nitrogen doping at the growth temperature around 400℃.
2. The growth of ZnO thin films
The growth of ZnO thin films with specula surface were grown by MOCVD at the growth temperature below 400℃ using dimethylzinc or di-isopropropylzinc and isopropylarchol or t-butylarchol. The photoluminescence spectra dominated by free exciton emission indicate that the high purity ZnO films were obtained. However, incorporation of n-type impurities of source materials became a problem by changing the source rot. By this problem, the electron concentration of the films were 10^<18>〜10^<19>cm^<-3>, and this value have not been improved. The effects of photo-irradiation to the substrate were not shown in these experiments.
3. Nitrogen doping
Nitrogen doping was carried out at low II/VI conditions. The characterizations by low temperature photoluminescence spectra, Raman spectra and Hall effect show that nitrogen incorporation of 10^<18>〜10^<19>cm^<-3> was obtained. However the best hole concentration was only the order of 10^<18>cm^<-3> because of high electron concentration of undoped films.
The improvement of purity of source materials and the effect of photo-irradiation for MOCVD should be investigated.
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