Materials World Network: Quantum Size Effects in Semiconducting V2VI3 and IV-VI- based Thin Film and Bulk Structures and Control of their Thermoelectric Properties

这项与乌克兰卡尔霍夫理工学院的合作研究集中在V2VI3和IV-VI半导体中能谱尺寸量子化对热电输运的影响的实验和理论研究。V2VI3和IV-VI半导体是热电发电机和制冷装置的两类潜在材料。这项研究包括：1)详细系统地研究了V2VI3量子阱(QW)的热电性质与量子阱宽度、载流子浓度和温度的关系；2)类似地研究了生长在(111)BaF2衬底上的IV-VI量子阱；3)研究了含有纳米夹杂物的IV-VI基复合材料的热电性质；以及4)发展了介观系统和纳米系统中电子和声子输运的新理论模型。由此得到的实验和理论结果对于理解电子和声子转移现象起主要作用的各种效应是有意义的。将详细研究与电子和声子谱的尺寸量子化有关的效应，建立表面态的作用和经典的尺寸效应，并将建议应用这些效应来控制和优化V2VI3和IV-VI基体和薄膜结构的热电性能，并创造新的高效热电材料。在现代电力工程中，特别关注直接能量转换方法的发展，因为它们关系到全球能源的可持续性。这项工作强调了纳米技术在直接能量转换中的作用不断增加，特别是在热电材料科学中。学生的积极参与促进了他们学习纳米材料科学中使用的许多基本实验和理论方法。

This collaborative research with Karkhov Polytechnic Institute in Ukraine focuses on an experimental and theoretical investigation of the influence of size quantization of the energy spectra on the thermoelectric transport in V2VI3 and IV-VI semiconductors which are two categories of prospective materials for thermoelectric generators and cooling devices. The research includes: 1) a detailed systematic investigation of the thermoelectric properties of V2VI3 quantum wells (QWs) as a function of the QW width, charge carrier concentration and temperature; 2) an analogous investigation of the IV-VI QWs grown on (111)BaF2 substrates; 3) an investigation of the thermoelectric properties of bulk IV-VI-based composites with nanometer-scale inclusions as a function of the size of the inclusions and the distance between inclusions; and 4) the development of new theoretical models for electron and phonon transport in mesoscopic systems and nanosystems. The experimental and theoretical results thus obtained are of interest for understanding a wide range of effects where electron and phonon transfer phenomena play a major role. Effects connected with size quantization of the electron and phonon spectra will be studied in detail, the role of surface states and the classical size effect will be established, and recommendations will be made for applying these effects to control and optimize the thermoelectric properties of V2VI3- and IV-VI-based bulk and thin film structures and to create new high-efficiency thermoelectric materials. In modern power engineering, special attention is given to the development of methods of direct energy conversion, as they relate to global energy sustainability. The work emphasizes the constantly increasing role of nanotechnologies in direct energy conversion, particularly in thermoelectric materials science. The active participation of students in the project promotes their learning the many basic experimental and theoretical methods used in nanomaterials science