Structural modulations in Bi2Te3
Structural modulations in Bi2Te3
复制标题
DOI：
10.1063/1.2837043
复制
发表时间：
2008-01
影响因子：
3.2
通讯作者：
N. Peranio;O. Eibl
中科院分区：
文献类型：
--
作者：
N. Peranio;O. Eibl
Bi2Te3以其热功率大，导热系数低而闻名，因此在室温下具有较大的热电性能ZT。特别是，低导热系数是由于高结构无序。采用电子探针显微分析、透射电镜（TEM）和透射电镜能谱法对n型Bi2(Te,Se)3和p型（Bi,Sb）2Te3块状材料进行了结构和化学分析。在微米尺度上发现了化学计量学的显著变化。块状材料的织构为1 ~ 10 μm，基面位错密度为109 cm−2，室温下具有较高的迁移率。在纳米尺度上发现了结构调制[天然纳米结构（nns）]。在Bi2Te3薄膜和Bi2Te3/Bi2(Te,Se)3超晶格中也观察到这种nns，并证明了这种nns具有Bi2Te3材料的一般特征。用TEM体视显微镜和图像分析了nns的结构。
Bi2Te3 is known for its large thermopower, a low thermal conductivity, and thereby a large thermoelectric figure of merit ZT at room temperature. Particularly, the low thermal conductivity is attributed to a high structural disorder. Electron probe microanalysis, transmission electron microscopy (TEM), and energy dispersive x-ray spectrometry in the TEM were applied on n-type Bi2(Te,Se)3 and p-type (Bi,Sb)2Te3 bulk materials for structural and chemical analysis. Significant variations in stoichiometry were found on the micrometer scale. Bulk materials showed a texture, grain sizes of 1−10 μm, and dislocations in the basal plane with a density of 109 cm−2 having a high mobility at room temperature. A structural modulation [natural nanostructure (nns)] was found on the nanometer scale. This nns was also observed in Bi2Te3 thin films and Bi2Te3/Bi2(Te,Se)3 superlattices and turned out to be of general character for Bi2Te3 materials. The nns was analyzed in detail by stereomicroscopy in the TEM and by image s...