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Title: Enhanced thermoelectric efficiency in topological insulator Bi2Te3 nanoplates via atomic layer deposition-based surface passivation

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.5030674· OSTI ID:1510945
 [1]; ORCiD logo [2];  [1];  [1]; ORCiD logo [3];  [4]; ORCiD logo [2]; ORCiD logo [5]
  1. Univ. of Southern California, Los Angeles, CA (United States). Ming Hsieh Dept. of Electrical Engineering
  2. Univ. of Texas, Austin, TX (United States). Dept. of Mechanical Engineering. Texas Materials Inst.
  3. Univ. of Southern California, Los Angeles, CA (United States). Mork Family Dept. of Chemical Engineering and Materials Science
  4. Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry
  5. 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
Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

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Cited By (1)

Energy efficiency of thermoelectric materials: A three-dimensional study journal August 2019