Mathematical modeling the thermal processes during cassette crystallization of chalcogenides
Open Access
- 19 January 2020
- journal article
- Published by National University of Science and Technology MISiS in Materials of Electronics Engineering
- Vol. 22 (3), 179-189
- https://doi.org/10.17073/1609-3577-2019-3-179-189
Abstract
An original modification of the directed crystallization method is considered as a multi-cassette process, which has comparative simplicity and high productivity. The basis of this research was domestic patents and technological research carried out at the National University of Science and Technology MISIS. As a result, mathematical models of the multi-cassette method were developed that allow both a three-dimensional radiative — conductive analysis of thermal processes in the entire volume of the hot zone and a two-dimensional analysis of convective — conductive heat transfer in a separate cassette. The parametric calculations carried out on their basis were aimed to the identifying an influence of locations and sizes of the hot zone components to a thermal field in the cassette unit; the establishing an influence of vertical heat supply equability to the cassette unit and an influence of heating power decrease during the plate crystallization, as well as to the determining an influence of small cassette design distortions and violation of cooling uniformity in its bottom part on the occurrence of convection and asymmetrical thermal field. By means of the conductive-radiative heat transfer model for the entire hot zone there were carried out parametric calculations and it was analyzed an influence of hot zone components (their locations and temperatures) on the heat exchange conditions at the cassette unit boundaries. By means of the conductive-convective model for a cassette it was determined that the boundary thermal conditions asymmetry, as well as an unstable vertical temperature gradient, result in the convective vortices and a significant deviation of the crystallization front from a flat shape. The calculations with using the convective mass transfer model showed that an increase of the crystallization rate by an order significantly increases a tellurium flux into the crystal, thereby substantially changing a melt composition near crystallization front and, thus, being a potential cause of dendritic growth. The reliability of the calculation results was checked on a number of tests, in which the influence of heat and mass transfer on the crystallization front shape was analyzed at cassette cooling rates corresponding to the growth processes of bismuth telluride polycrystals.Keywords
This publication has 10 references indexed in Scilit:
- Exploring the Origin of Contact Destruction in Tetradymite-Like-Based Thermoelectric ElementsJournal of Electronic Materials, 2019
- Study of the Plastic Formation in the Production of Thermoelectric Material Based on Bismuth TellurideRussian Microelectronics, 2018
- Comparative analysis of methods of plastic forming and crystallization at the production of thermoelectric materials on the basis of halkogenidesPublished by Tambov State University - G.R. Derzhavin ,2018
- Structure of Bi2Se0.3Te2.7 alloy plates obtained by crystallization in a flat cavity by the Bridgman methodSemiconductors, 2017
- Electrical and structural properties of Bi2Te3 and Sb2Te3 thin films grown by the nanoalloying method with different deposition patterns and compositionsJournal of Materials Chemistry, 2012
- Thermoelectric and transport properties of nanostructured Bi2Te3 by spark plasma sinteringJournal of Materials Research, 2011
- Synthesis and Thermoelectric Characterization of Bi2Te3 NanoparticlesAdvanced Functional Materials, 2009
- Synthesis of nanocrystalline Bi2Te3 via mechanical alloyingJournal of the American Academy of Dermatology, 2009
- Numerical simulation of macrosegregation: a comparison between finite volume method and finite element method predictions and a confrontation with experimentsMetallurgical and Materials Transactions, 1998
- Study of the Bi-Sb-Te ternary phase diagramJournal of Physics and Chemistry of Solids, 1992