2006 Fiscal Year Final Research Report Summary
Developments of newer oxysulfide semiconductors for magnetic and fluorescence materials
| Project/Area Number |
17540302
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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 |
Condensed matter physics I
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| Research Institution | Tokai University |
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Principal Investigator |
MATSUSHITA Hiroaki Tokai University, School of high-technology for human welfare, Assistant professor, 開発工学部, 助教授 (30256789)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Crystal growth / Sintering / Fluorescence / Optical properties / Lattice defects |
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| Research Abstract |
(1) Delafossite-type ternary oxides such as CuAlO_2 have received much attention as a material for thermoelectric application and transparent semiconductor. CuLaO_2 is one of delafossites and hence is expected to have valuable properties. The preparation of single-phase CuLaO_2 with delafossite-type structure by means of the solid-state reaction method was investigated. The results showed nearly single-phase CuLaO_2, although a trace amount of metallic copper was included, was obtained by using La(OH)_3, and firing the mixed powder with non-stoichiometric composition ratio of La(OH)_3 : Cu_20 =1 : 1.425 in a vacuum. The CuLaO_2 thus obtained was a p-type semiconductor and has the Seebeck coefficient of 70 μV/K. The single-phase CuLaO_2 was obtained by using La_20_3, and firing the mixed powder with stoichiometric composition ratio in Argon. The emission intensities of samples doped by Sr or Ca were higher of one order than that of non-doped CuLaO_2.[
(2)The layered oxysulfide LaCuOS is
… More
a wide-gap p-type semiconductor that exhibits exceptional properties compared to representative wide-gap semiconductors. We have attempted the process method for synthesizing a single phase of LaCuOS powders not using La_2S_3, and reported by the calcinations from the combination of two materials, La_2S_3 and 2CuO. These results of the samples prepared at the lower temperature of 600℃ under a vacuum showed to have the single phase of LaCuOS with a band gap of about 3.1eV. We have developed for synthesizing a single phase of In-or Y-doped LaCuOS by solid phase reaction method using La_2S_3, CuO and (In_2S_3 or Y_2S_3) powders. The results of X-ray diffraction and diffuse reflective spectroscopy of La_<1-x>In_xCuOS and La_<1-x>Y_xCuOS samples prepared from the combinations showed that the single phase of In-and Y-doped LaCuOS solid solutions below about x = 0.2. These photoluminescence spectra of In-doped (x < 0.3) and Y-doped (x < 0.15) LaCuOS showed to have higher emission intensities than that of non-doped LaCuOS. Less
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Research Products
(15 results)
