Estudo teórico de defeitos intrínsecos em nanofios de telureto de estanho
Semiconductors nanowires are structures with dimension in order of nanometers that present a small energy gap and have great potencial for application in eletronic area. Among the applications of semiconductor nanowires are thermoelectric devices, in which temperature differences are converted into...
| Autor principal: | Souza, Taina Matendal de |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2021
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/24429 |
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| Resumo: |
Semiconductors nanowires are structures with dimension in order of nanometers that present a small energy gap and have great potencial for application in eletronic area. Among the applications of semiconductor nanowires are thermoelectric devices, in which temperature differences are converted into electric current due to the Seebeck effect. One of the most widely used thermoelectric nanowires today is PbTe, however due to environmental concerns, substitute materials are sought. The purpose of this work was to replace lead with selenium, as the SnTe has the same crystal structure of rock salt of PbTe, and has shown to be a semiconductor nanowire with great potential. However, electronically, SnTe performs less than PbTe. Therefore, there is a need for an optimization in the thermal properties of the SnTe. t is known that defects can improve the properties of a material.This work evaluates the influence of defects (vacancies and antisites) in order to increase the thermoelectric efficiency of this material. Through computational calculations it was possible to define the most stable lattice parameters of the material, in both bulk and nanowire. After locating the site with the most stable energy for each defect, we performed simulations with and without the influence of spin orbit interaction in order to verify the changes that occurred in each one.We can conclude that the vacancy of Sn modifies the electronic properties in a similar way in bulk and nanowire, introducing defect levels inside the valence band, making this defect a good candidate for thermoeletric material. The other defects were not efficient because the TeSn antisite showed levels in the gap and the Te vacancy as well as the SnTe antisite did not show defect levels at the Fermi level, not very differentiating their electronic characteristics from the pristine semiconductor. |
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