Orientation of CuInS2 nanowires and estimation method of Optical gap

对于化学处理法制备CuInS_2纳米线，发现合成温度是形成线状或带状纳米结构的关键参数。为了使CuInS_2纳米线硬化，我们尝试对CuInS_2纳米线进行退火处理。CuInS_2纳米线经700℃退火处理后仍保留下来，与块状CuInS_2晶体相比，在短波长范围内观察到了宽的光致发光，并对CuInS_2纳米线的光学带隙进行了评价。我们已经建立了估计的光学带隙的偏振度的调查，使用相干椭圆偏振分析。但是，我们的结果适用于CuInS_2纳米线，包括不明确的部分，因为纳米线粉末中有其他产品的混合物，然后认为极化程度受产品的影响。CuInS_2纳米线与其它产物的分离将是下一阶段的重要课题。 ...更多信息 本文首次研究了CuInS_2纳米线的椭圆偏振光谱数据中的红色。通过对块状CuInS_2与带状和线状纳米线样品的赝介电函数的比较，发现其电子光谱总体上发生了一定的变化。可以发现，在赝介电函数的真实的部分和虚部，填充有带状纳米线的样品与块状CuInS_2有足够的相似性。作为类似的复合纳米结构，TlInSe_2纳米棒和纳米颗粒的制备已经成功。本文对具有棒状基态形状的大块晶体一维TlInSe_2的电子带态进行了LCAO（Linear Combination of Atomic Orbitals）分析。从这些结果中，我们得到了该材料中光学跃迁的选择规律的认识。用四探针技术测量了TlInSe_2（p型导体）在70 ~ 500℃温度范围内的Seebeck系数。随着温度降低到200℃以下，该系数变得正且巨大，达到10^7μV/℃的尖端值。本文从TlInSe_2在低于200℃温度下可能发生的无公度超晶格相的角度讨论了上述结果，并认为这种无公度超晶格相是导致这种材料具有上述独特热电性能的原因。预期基于TlInSe_2的热电器件将具有优越的上级参数。少

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