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Improving the thermal efficiency of micro and nanostructured semiconductor materials and nanocomposites based on bismuth alloys for miniature thermoelectric energy converters

Code: 13.820.05.12/BF
Title: Improving the thermal efficiency of micro and nanostructured semiconductor materials and nanocomposites based on bismuth alloys for miniature thermoelectric energy converters
Programme: Bilateral project Moldova – Belarus
Execution period: 2013-2014
Coordinating institutions: Ghitu Institute of Electronic Engineering and Nanotechnologies
Belarusian State University, Minsk, Republic of Belarus
Project Leader: Nikolaeva Albina, dr. hab., associated professor (docent)
Participants: Laboratory of Electronics of Low Dimensional Structuress
Keywords: Nanotechnology, nanostructured semiconductor, thermoelectricity, size quantization, anisotropy, thermoelectric cooling


Abstract:

The project focuses on finding methods to improve the efficiency of thermoelectric efficiency (TE) of nanostructures and nanostructured materials using both the physical principles that lead to an increase in TE and the development of new technologies for producing nanostructures and nanostructured materials based on Bi and its semiconductor alloys. A few methods for producing high-performance TE materials will be used. One of the methods for improving the thermoelectric properties will be the preparation of nanostructures and nanowires in a glass envelope with different crystallographic orientation on the basis of semiconductor alloys. Crystallographic orientation plays an important role both in the occurrence of the quantum size effect, which leads an increase in TE, and in the improvement and optimization of the anisotropy of thermoelectric properties for anisotropic TE energy converters. The compression and tensile strain methods will be used for nanostructures to study the effect of the Fermi surface cross section and the gap value on the thermoelectric properties and their anisotropy.

The team from Belarus will develop a method for producing foil-coated spatially heterogeneous materials the heterogeneities of which have sizes comparable to the characteristic wavelengths of electrons or phonons, i.e., lie in a nanometer range. For these purposes, the method of foil-coating of heterogeneous materials at a rapid rate of solidification and formation of micrograin inclusions (to nanometer sizes), which lead to a decrease in heat conduction during their preparation in the form of a foil of semiconductor materials, will be used. The thermoelectric properties of semiconductor wires of different lengths, diameters, and compositions will be studied in a temperature range of 4.2300 K. Weak magnetic fields will be used to improve the magnetothermoelectric efficiency of devices based on micro and nanostructures. It should be noted that wires in a glass envelope exhibit higher mechanical strength and are safely protected from external influences and mechanical damage both during installation and in practical use; along with a low consumption of the initial material, this feature is a great advantage for using the objects under study as highly sensitive thermoelectric modules in practice.

A breadboard model of a multistage microcooler will be prepared on the basis of foil-coated nanostructured materials