Loading...
Defect driven transport in thermoelectric semiconductors and their alloys
Adamczyk, Jesse Min-Tze
Adamczyk, Jesse Min-Tze
Citations
Altmetric:
Advisor
Editor
Date
Date Issued
2022
Date Submitted
Keywords
Collections
Research Projects
Organizational Units
Journal Issue
Embargo Expires
Abstract
Thermoelectric materials are semiconducting materials that convert heat to electricity, and vice versa,
through solid state electronic transport processes. Traditional thermoelectric studies typically focus on
optimizing a single compound to achieve high thermoelectric performance; however, improvement of
thermoelectric performance is challenged by the interrelated properties in the thermoelectric figure of
merit. While computation has overcome deficiencies in understanding electronic transport of single
compounds, models are only so accurate when it comes to experimental behavior. Further, computational
approaches to modeling the thermoelectric behavior of alloys shows even worse performance. Alloying
between single compounds will expand the space in which high performance thermoelectric materials can
be identified. Using alloys, continuous property control enables fine tuning of individual properties that
make up the thermoelectric figure of merit. There are some issues with alloy studies however; uncontrolled
defect concentrations in alloy studies lead to property-composition trends that may be undecipherable. To
mitigate this, studying alloys requires foundational studies on the native defects and transport properties
of endmembers prior to entering the increased complexity of the alloy space.
The first study in this work focuses on the PbTe-SnTe system and motivates much of the future work
on understanding native defects and alloy behavior. The next study focuses on controlling native defects
and their impacts on transport properties using CuInTe2 as a model material. Further understanding of
the transport properties are obtained by doping CuInTe2 with Zn and Cd and examining how the
electronic transport differs from the native doped material. Alloying in the Ge1−xMnxTe system, a space
without major defect concentrations, shows how alloy endmembers that strongly differ from one another
can lead to unpredictable transport properties, even for high symmetry materials. Finally, alloying in the
SnTe-SnSe-GeSe space shows how simultaneous alloying and control of native defects enables high quality
invariant point driven data that ultimately leads to increased thermoelectric performance.
Associated Publications
Rights
Copyright of the original work is retained by the author.