Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films
Bismuth telluride (Bi2Te3) based alloys are preferred thermoelectric materials for room temperature thermoelectric applications. Electrical transport and thermopower properties of n-type nanostructured BixSb2-xTe3 films were tuned by post-growth heat treatment. We report that annealing of sputter-de...
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| Format: | Article |
| Language: | English |
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Elsevier
2019-02-01
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| Series: | Materials & Design |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127518309055 |
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| author | Peter P. Murmu John Kennedy Sidharth Suman Shen V. Chong Jérôme Leveneur James Storey Sergey Rubanov Ganpati Ramanath |
| author_facet | Peter P. Murmu John Kennedy Sidharth Suman Shen V. Chong Jérôme Leveneur James Storey Sergey Rubanov Ganpati Ramanath |
| author_sort | Peter P. Murmu |
| collection | DOAJ |
| description | Bismuth telluride (Bi2Te3) based alloys are preferred thermoelectric materials for room temperature thermoelectric applications. Electrical transport and thermopower properties of n-type nanostructured BixSb2-xTe3 films were tuned by post-growth heat treatment. We report that annealing of sputter-deposited nanostructured Bi0.7Sb1.3Te3 films lead to several-fold increases in thermoelectric power factor α2σ, where σ is electronic conductivity and α is Seebeck coefficient. Annealing at Tanneal = 200 °C nearly quadruples the power factor to α2σ = 3.1 μW cm−1 K−2. Spectroscopy and microscopy analyses indicate that the power factor increase is attributable to ~50% decrease in the Bi/Sb ratio, and grain growth, which increase the charge carrier concentration and mobility. The observed Bi depletion is contrary to annealing-induced Te depletion reported in p-type films. For Tanneal > 200 °C, although continued Bi depletion increases σ, a precipitous decrease in α sharply lowers the power factor, yielding tenfold lower α2σ for Tanneal = 400 °C than the as-deposited films. Our findings indicate that post-deposition annealing is a potent way to tune the thermoelectric properties of n-type Bi2Te3-based alloy films to fabricate devices for high-efficiency solid-state refrigeration and power harvesting from waste heat. Keywords: Thermoelectric, Bismuth antimony telluride, N-type, Power factor, Thin film |
| first_indexed | 2024-12-19T08:26:27Z |
| format | Article |
| id | doaj.art-8000b4b614f2423d89c15b4f88025dba |
| institution | Directory Open Access Journal |
| issn | 0264-1275 |
| language | English |
| last_indexed | 2024-12-19T08:26:27Z |
| publishDate | 2019-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj.art-8000b4b614f2423d89c15b4f88025dba2022-12-21T20:29:17ZengElsevierMaterials & Design0264-12752019-02-01163Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin filmsPeter P. Murmu0John Kennedy1Sidharth Suman2Shen V. Chong3Jérôme Leveneur4James Storey5Sergey Rubanov6Ganpati Ramanath7National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010, New ZealandNational Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand; Department of Physics and Nanotechnology, SRM University, Kattankulathur, Chennai 603203, India; Corresponding author at: National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010, New Zealand.National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010, New ZealandThe MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand; Robinson Research Institute, Victoria University of Wellington, PO Box 33436, Lower Hutt 5046, New ZealandNational Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010, New ZealandThe MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand; Robinson Research Institute, Victoria University of Wellington, PO Box 33436, Lower Hutt 5046, New ZealandUniversity of Melbourne, Bio21 Institute, Melbourne, Victoria 3010, AustraliaMaterials Science & Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180, USABismuth telluride (Bi2Te3) based alloys are preferred thermoelectric materials for room temperature thermoelectric applications. Electrical transport and thermopower properties of n-type nanostructured BixSb2-xTe3 films were tuned by post-growth heat treatment. We report that annealing of sputter-deposited nanostructured Bi0.7Sb1.3Te3 films lead to several-fold increases in thermoelectric power factor α2σ, where σ is electronic conductivity and α is Seebeck coefficient. Annealing at Tanneal = 200 °C nearly quadruples the power factor to α2σ = 3.1 μW cm−1 K−2. Spectroscopy and microscopy analyses indicate that the power factor increase is attributable to ~50% decrease in the Bi/Sb ratio, and grain growth, which increase the charge carrier concentration and mobility. The observed Bi depletion is contrary to annealing-induced Te depletion reported in p-type films. For Tanneal > 200 °C, although continued Bi depletion increases σ, a precipitous decrease in α sharply lowers the power factor, yielding tenfold lower α2σ for Tanneal = 400 °C than the as-deposited films. Our findings indicate that post-deposition annealing is a potent way to tune the thermoelectric properties of n-type Bi2Te3-based alloy films to fabricate devices for high-efficiency solid-state refrigeration and power harvesting from waste heat. Keywords: Thermoelectric, Bismuth antimony telluride, N-type, Power factor, Thin filmhttp://www.sciencedirect.com/science/article/pii/S0264127518309055 |
| spellingShingle | Peter P. Murmu John Kennedy Sidharth Suman Shen V. Chong Jérôme Leveneur James Storey Sergey Rubanov Ganpati Ramanath Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films Materials & Design |
| title | Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films |
| title_full | Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films |
| title_fullStr | Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films |
| title_full_unstemmed | Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films |
| title_short | Multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n-type bismuth antimony telluride thin films |
| title_sort | multifold improvement of thermoelectric power factor by tuning bismuth and antimony in nanostructured n type bismuth antimony telluride thin films |
| url | http://www.sciencedirect.com/science/article/pii/S0264127518309055 |
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