Enhanced thermoelectric efficiency in topological insulator Bi2Te3 nanoplates via atomic layer deposition-based surface passivation
- Univ. of Southern California, Los Angeles, CA (United States). Ming Hsieh Dept. of Electrical Engineering
- Univ. of Texas, Austin, TX (United States). Dept. of Mechanical Engineering. Texas Materials Inst.
- Univ. of Southern California, Los Angeles, CA (United States). Mork Family Dept. of Chemical Engineering and Materials Science
- Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry
- Univ. of Southern California, Los Angeles, CA (United States). Ming Hsieh Dept. of Electrical Engineering. Dept. of Chemistry. Dept. of Physics and Astronomy
We report in-plane thermoelectric measurements of Bi2Te3 nanoplates, a typical topological insulator with Dirac-like metallic surface states, grown by chemical vapor deposition. The as-grown flakes exposed to ambient conditions exhibit relatively small thermopowers around -34 μV/K due to unintentional surface doping (e.g., gas adsorption and surface oxidation). After removal of the unintentional surface doping and surface passivation by deposition of 30 nm of Al2O3 using atomic layer deposition (ALD), the Seebeck coefficient of these flakes increases by a factor of 5× to -169 μV/K. We believe that the ALD-based surface passivation can prevent the degradation of the thermoelectric properties caused by gas adsorption and surface oxidation processes, thus, reducing the unintentional doping in the Bi2Te3 and increasing the Seebeck coefficient. The high surface-to-volume ratio of these thin (~10 nm thick) nanoplates make them especially sensitive to surface doping, which is a common problem among nanomaterials in general. An increase in the sample resistance is also observed after the ALD process, which is consistent with the decrease in doping.
- Research Organization:
- Univ. of Southern California, Los Angeles, CA (United States); Univ. of Texas, Austin, TX (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- FG02-07ER46376; FG02-07ER46377; 1402906
- OSTI ID:
- 1510945
- Alternate ID(s):
- OSTI ID: 1465902
- Journal Information:
- Applied Physics Letters, Vol. 113, Issue 8; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Energy efficiency of thermoelectric materials: A three-dimensional study
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journal | August 2019 |
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