Font Size: a A A

Analysis of thermoelectric properties of thin films

Posted on:2011-09-03Degree:M.SType:Thesis
University:Lehigh UniversityCandidate:Coull, Timothy WFull Text:PDF
GTID:2441390002454005Subject:Engineering
Abstract/Summary:
Today's trends in energy consumption pose a threat to the global climate and to long-term economic sustainability. In order to address these issues, it is essential to develop clean, more efficient and sustainable means of energy production. In recent years, developments in thermoelectric materials, particularly thin films and superlattices, for power generation have shown potential for effectively converting waste heat to improve overall energy efficiency. Given the scales in size of these materials -- on the micro- and nano-level -- accurate measurement of their thermoelectric properties can be difficult and has been a bottleneck in the development of thermoelectric devices for power generation.In this work, the validity of methods used to determine the thermoelectric properties of thin films and superlattices are investigated. More specifically, experimental setups used for measuring thermal conductivity and Seebeck coefficient, with particular emphasis on InN thin films, are analyzed using finite element analysis (FEA) techniques. It is found that pure-ac and two-dimensional models typically used are reasonably accurate for the determination of thermal conductivity. Differential techniques are found to be inadequate for thermoelectric property measurement because of undesired heat spreading, and it is currently necessary to couple computational modeling and experimentation. For the measurement of Seebeck coefficient, one-dimensional methods can be useful, though Seebeck effect is not exactly a one-dimensional phenomenon. Finally, this work proposes a finite element method for determining Seebeck coefficient once thermal conductivity is established.
Keywords/Search Tags:Thermoelectric properties, Thin films, Thermal conductivity, Seebeck coefficient
Related items