Modeling study of thermoelectric SiGe nanocomposites
Nanocomposite thermoelectric materials have attracted much attention recently due to experimental demonstrations of improved thermoelectric properties over those of the corresponding bulk material. In order to better understand the reported data and to gain insight into transport in nanocomposites,...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/52461 https://orcid.org/0000-0001-8492-2261 https://orcid.org/0000-0002-3968-8530 |
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| author | Minnich, Austin Jerome Lee, H. Wang, X. W. Joshi, G. Dresselhaus, Mildred Ren, Z. F. Chen, Gang Vashaee, D. |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Minnich, Austin Jerome Lee, H. Wang, X. W. Joshi, G. Dresselhaus, Mildred Ren, Z. F. Chen, Gang Vashaee, D. |
| author_sort | Minnich, Austin Jerome |
| collection | MIT |
| description | Nanocomposite thermoelectric materials have attracted much attention recently due to experimental demonstrations of improved thermoelectric properties over those of the corresponding bulk material. In order to better understand the reported data and to gain insight into transport in nanocomposites, we use the Boltzmann transport equation under the relaxation-time approximation to calculate the thermoelectric properties of n-type and p-type SiGe nanocomposites. We account for the strong grain-boundary scattering mechanism in nanocomposites using phonon and electron grain-boundary scattering models. The results from this analysis are in excellent agreement with recently reported measurements for the n-type nanocomposite but the experimental Seebeck coefficient for the p-type nanocomposite is approximately 25% higher than the model’s prediction. The reason for this discrepancy is not clear at the present time and warrants further investigation. Using new mobility measurements and the model, we find that dopant precipitation is an important process in both n-type and p-type nanocomposites, in contrast to bulk SiGe, where dopant precipitation is most significant only in n-type materials. The model also shows that the potential barrier at the grain boundary required to explain the data is several times larger than the value estimated using the Poisson equation, indicating the presence of crystal defects in the material. This suggests that an improvement in mobility is possible by reducing the number of defects or reducing the number of trapping states at the grain boundaries. |
| first_indexed | 2024-09-23T15:58:22Z |
| format | Article |
| id | mit-1721.1/52461 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:58:22Z |
| publishDate | 2010 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/524612022-10-02T05:26:15Z Modeling study of thermoelectric SiGe nanocomposites Minnich, Austin Jerome Lee, H. Wang, X. W. Joshi, G. Dresselhaus, Mildred Ren, Z. F. Chen, Gang Vashaee, D. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Department of Mechanical Engineering Massachusetts Institute of Technology. Department of Physics Dresselhaus, Mildred Minnich, Austin Jerome Lee, H. Dresselhaus, Mildred Chen, Gang Nanocomposite thermoelectric materials have attracted much attention recently due to experimental demonstrations of improved thermoelectric properties over those of the corresponding bulk material. In order to better understand the reported data and to gain insight into transport in nanocomposites, we use the Boltzmann transport equation under the relaxation-time approximation to calculate the thermoelectric properties of n-type and p-type SiGe nanocomposites. We account for the strong grain-boundary scattering mechanism in nanocomposites using phonon and electron grain-boundary scattering models. The results from this analysis are in excellent agreement with recently reported measurements for the n-type nanocomposite but the experimental Seebeck coefficient for the p-type nanocomposite is approximately 25% higher than the model’s prediction. The reason for this discrepancy is not clear at the present time and warrants further investigation. Using new mobility measurements and the model, we find that dopant precipitation is an important process in both n-type and p-type nanocomposites, in contrast to bulk SiGe, where dopant precipitation is most significant only in n-type materials. The model also shows that the potential barrier at the grain boundary required to explain the data is several times larger than the value estimated using the Poisson equation, indicating the presence of crystal defects in the material. This suggests that an improvement in mobility is possible by reducing the number of defects or reducing the number of trapping states at the grain boundaries. 2010-03-10T15:57:06Z 2010-03-10T15:57:06Z 2009-10 2009-08 Article http://purl.org/eprint/type/JournalArticle 1550-235X 1098-0121 http://hdl.handle.net/1721.1/52461 Minnich, A. J. et al. “Modeling study of thermoelectric SiGe nanocomposites.” Physical Review B 80.15 (2009): 155327. © 2009 The American Physical Society https://orcid.org/0000-0001-8492-2261 https://orcid.org/0000-0002-3968-8530 en_US http://dx.doi.org/10.1103/PhysRevB.80.155327 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Minnich, Austin Jerome Lee, H. Wang, X. W. Joshi, G. Dresselhaus, Mildred Ren, Z. F. Chen, Gang Vashaee, D. Modeling study of thermoelectric SiGe nanocomposites |
| title | Modeling study of thermoelectric SiGe nanocomposites |
| title_full | Modeling study of thermoelectric SiGe nanocomposites |
| title_fullStr | Modeling study of thermoelectric SiGe nanocomposites |
| title_full_unstemmed | Modeling study of thermoelectric SiGe nanocomposites |
| title_short | Modeling study of thermoelectric SiGe nanocomposites |
| title_sort | modeling study of thermoelectric sige nanocomposites |
| url | http://hdl.handle.net/1721.1/52461 https://orcid.org/0000-0001-8492-2261 https://orcid.org/0000-0002-3968-8530 |
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