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

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

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