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Title: Magnetoresistance Technique for Determining Cross-Plane Mobility in Superlattice Devices

Abstract

The cross-plane mobility, in the direction perpendicular to the planes of a superlattice, is critical for the computation of the figure of merit (ZT) in a thermoelectric device. The measurement of cross-plane mobilities in thermoelectric superlattice structures cannot be performed by conventional techniques such as the van der Pauw method. Therefore, alternative techniques must be used to obtain this important parameter. Magnetoresistance is the increase in material resistivity due to a lengthened path for charge carriers in a perpendicular magnetic field. The magnetoresistance is related to the magnetic field strength as ({mu}B)2 in the standard configuration, but the field dependence is also influenced by device geometry. This work focuses on measuring superlattice samples of composition Bi2Te3/Sb2Te3 that are removed from their growth substrate and mounted on metal-coated substrates. This resulting mesa structure has a 100-mm-square contact metallization. Technical issues related to the sample preparation for the measurement are discussed. The magnetoresistance effect is expected to be small due to the anticipated low mobilities in Bi2Te3-based materials. Magnetoresistance studies with such superlattice thermo-elements were attempted using a dc magnetic field, but the sensitivity was insufficient. An ac magnetoresistance with lock-in detection can yield improved sensitivity.

Authors:
; ;  [1];  [2]
  1. National Renewable Energy Laboratory, Golden, CO (US)
  2. Research Triangle Institute, NC (US)
Publication Date:
Research Org.:
National Renewable Energy Lab., Golden, CO (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
12203
Report Number(s):
NREL/CP-520-27056
TRN: US200307%%186
DOE Contract Number:  
AC36-99GO10337
Resource Type:
Conference
Resource Relation:
Conference: 18th International Conference on Thermoelectrics, Baltimore, MD (US), 08/29/1999--09/02/1999; Other Information: Supercedes report DE00012203; PBD: 1 Sep 1999; PBD: 1 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; CHARGE CARRIERS; CONFIGURATION; DETECTION; GEOMETRY; MAGNETIC FIELDS; MAGNETORESISTANCE; PERFORMANCE; SAMPLE PREPARATION; SENSITIVITY; SUBSTRATES; SUPERLATTICES; VANS; SUPERLATTICE; THERMOELECTRIC DEVICE; VAN DER PAUW METHOD; DEVICE GEOMETRY; CROSS-PLANE MOBILITY

Citation Formats

Johnston, S. W., Ahrenkiel, R. K., Young, D., and Venkatasubramanian, R. Magnetoresistance Technique for Determining Cross-Plane Mobility in Superlattice Devices. United States: N. p., 1999. Web. doi:10.1109/ICT.1999.843477.
Johnston, S. W., Ahrenkiel, R. K., Young, D., & Venkatasubramanian, R. Magnetoresistance Technique for Determining Cross-Plane Mobility in Superlattice Devices. United States. doi:10.1109/ICT.1999.843477.
Johnston, S. W., Ahrenkiel, R. K., Young, D., and Venkatasubramanian, R. Wed . "Magnetoresistance Technique for Determining Cross-Plane Mobility in Superlattice Devices". United States. doi:10.1109/ICT.1999.843477. https://www.osti.gov/servlets/purl/12203.
@article{osti_12203,
title = {Magnetoresistance Technique for Determining Cross-Plane Mobility in Superlattice Devices},
author = {Johnston, S. W. and Ahrenkiel, R. K. and Young, D. and Venkatasubramanian, R.},
abstractNote = {The cross-plane mobility, in the direction perpendicular to the planes of a superlattice, is critical for the computation of the figure of merit (ZT) in a thermoelectric device. The measurement of cross-plane mobilities in thermoelectric superlattice structures cannot be performed by conventional techniques such as the van der Pauw method. Therefore, alternative techniques must be used to obtain this important parameter. Magnetoresistance is the increase in material resistivity due to a lengthened path for charge carriers in a perpendicular magnetic field. The magnetoresistance is related to the magnetic field strength as ({mu}B)2 in the standard configuration, but the field dependence is also influenced by device geometry. This work focuses on measuring superlattice samples of composition Bi2Te3/Sb2Te3 that are removed from their growth substrate and mounted on metal-coated substrates. This resulting mesa structure has a 100-mm-square contact metallization. Technical issues related to the sample preparation for the measurement are discussed. The magnetoresistance effect is expected to be small due to the anticipated low mobilities in Bi2Te3-based materials. Magnetoresistance studies with such superlattice thermo-elements were attempted using a dc magnetic field, but the sensitivity was insufficient. An ac magnetoresistance with lock-in detection can yield improved sensitivity.},
doi = {10.1109/ICT.1999.843477},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {9}
}

Conference:
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