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Electron density distrubution and physical properties in chalcogenide ceramics semiconductors

硫族化物陶瓷半导体中的电子密度分布和物理性质

基本信息

批准号：
08455298
负责人：
ISHIZAWA Nobuo
金额：
$ 3.71万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455298/
关键词：
chalcogenide area detector pressure induced phase transition structure analysis single crystal X-ray diffraction electron density distribution diamond anvil cell 単結晶X線回析

项目摘要

Symmetry of AgGaS_2 high-pressure phase has been determined by the single crystal method using a diamond anvil pressure cell. The crystal was monoclinic with space group Cc. Intensity data of a specimen in the diamond anvil cell were collected at 5.5 GPa, using a horizontal-type four-circle diffractometer at the beam line 14A, Photon Factory, KEK, with synchrotron radiation of 0.5 * wavelength. The structure has been determined from the three-dimensional X-ray diffraction data. The phase transition at 4.2 GPa was reversible. A most conspicuous structural feature accompanying the phase transition was a characteristic compression of one of the octahedral large interstices formed by sulfur atoms. It was also found that the difference of bonding nature between the ionic Ag-S and the more covalent Ga-S plays an important roll in the high-pressure phase transition. Development of the software to control the diffractometer for the high-pressure measurement has been undertaken. The performance of the diffractometers, including the four-circle diffractometers with Ag rotating anode, that with synchrotron radiation, and the two-axis diffractometer with the CCD area detector, were compared using a CuInSe_2 crystal, for more accurate structural investigation under high pressures. The structure of Cu_2In_4Se_7, a key material to govern the development of solar device based on CuInSe_2 was first solved in this study.

用金刚石压腔单晶法测定了AgGaS_2高压相的对称性。晶体为单斜晶系，空间群为CC。在KEK光子工厂的14A光束线上，使用同步辐射0.5*波长的水平式四圆衍射仪，在5.5 GPA下收集了钻石顶压室中样品的强度数据。由三维X射线衍射数据确定了该化合物的结构。在4.2 GPa时相变是可逆的。伴随相变的一个最明显的结构特征是硫原子形成的一个八面体大空隙的特征压缩。研究还发现，离子Ag-S和共价较高的Ga-S之间的成键性质的差异在高压相变中起着重要的作用。开发了高压测量用衍射仪的控制软件。用CuInSe_2晶体比较了银阳极四轴衍射仪、同步辐射四轴衍射仪和面阵面阵探测器两轴衍射仪的性能，以便在高压下进行更准确的结构研究。本研究首次解决了控制CuInSe_2太阳能器件发展的关键材料Cu2In_4Se_7的结构。