Orientation of CuInS2 nanowires and estimation method of Optical gap
| Project/Area Number |
15510106
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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 |
Nanomaterials/Nanobioscience
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
WAKITA Kazuki Osaka Prefecture University, School of Engineering, Associate Professor, 工学研究科, 助教授 (80201151)
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| Co-Investigator(Kenkyū-buntansha) |
MAMEDOV Nazim Osaka Prefecture University, School of Engineering, Associate Professor, 工学研究科, 助教授 (60305654)
ASHIDA Atushi Osaka Prefecture University, School of Engineering, Research Associate, 工学研究科, 助手 (60231908)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2003: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Nanowires / CuInS_2 / Optical gap / Spectral Ellipsometry / TlInSe_2 / 配向 |
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| Research Abstract |
For synthesis of CuInS_2 nanowires using chemical treatment method, it is found that the synthesis temperature is key parameter to form nanostructure of thread type or belt type. In order to harden CuInS_2 nanowires, we tried to anneal treatment of CuInS_2 nanowires. CuInS_2 nanowires remain after anneal treatment at 700℃.
For evaluation of optical bandgap of CuInS_2 nanowires, board photoluminescence emissions have been observed in the short wavelength range compared with the emission of bulk CuInS_2 crystals. We have established estimation of optical band gap by investigation of polarization degree using coherent ellipsometry analysis. However, our results applying to CuInS_2 nanowires includes unclear parts because the nanowire powders have mixture of other products and then it is considered that the polarization degree is affected by the products. The isolation of CuInS_2 nanowires from the other products would be important theme in the next stage.
The pseudodielectric function resto
… More
red from the spectroellipsometric data of CuInS_2 nanowires has been investigated for the first time. The electronic spectrum, as a whole, undergoes certain changes displayed by comparison of the pseudodielectric function of bulky CuInS_2 with that of the samples with belt-type and thread-type nanowires. One can notice that in both real and imaginary parts of pseudodielectric function of the samples populated with belt-type nanowires are enough of resemblance with bulky CuInS_2.
As analogous compound nanostructure, preparation of TlInSe_2 nanorodes and nanoparticles has been succeeded. LCAO (linear combination of atomic orbitals) analysis of the electronic band states has been completed for one-dimensional TlInSe_2 having rod-like ground state shape of bulky crystal. From the results, we obtained knowledge of the selection rule of optical transition in this material. The results agree well with polarization properties of dielectric functions and photoluminescence spectra.
Seebeck coefficient of TlInSe_2, known as a p-type conductor, has been measured in the temperature range 70℃ to 500℃ in vacuum by using four probe techniques. With temperature down to below 200℃, the coefficient is becoming positive and huge to a cutting-edge value of 10^7μV/℃. The obtained results are discussed in terms of an incommensurate superlattice phase, which might have taken place in TlInSe_2 at temperatures below 200℃, and led to the above unique thermoelectric properties of this material. It is expected that thermoelectric devices based on TlInSe_2 will have superior parameters. Less
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Report
(3 results)
Research Products
(17 results)
