TY - JOUR
T1 - Three-Dimensional Atom-Probe Tomographic Analyses of Lead-Telluride Based Thermoelectric Materials
AU - Kim, Yoon Jun
AU - Blum, Ivan D.
AU - He, Jiaqing
AU - Kanatzidis, Mercouri G.
AU - Dravid, Vinayak P.
AU - Seidman, David N.
N1 - Funding Information:
This research was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, through the Energy Frontier Research Center ‘‘Revolutionary Materials for Solid State Energy Conversion’’, Award Number DE-SC0001054. The three-dimensional atom-probe tomographic measurements were performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The local-electrode atom-probe (LEAP) tomograph was purchased and upgraded with funding from NSF-MRI (DMR-0420532) and ONR-DURIP (N00014-0400798, N00014-0610539, N00014-0910781) grants. We also gratefully acknowledge the Initiative for Sustainability and Energy at North-western (ISEN) for grants to upgrade the capabilities of NUCAPT. The microscopy and analysis was performed at the Electron Probe Instrumentation Center (EPIC) facility of the Northwestern University’s Atomic and Nanoscale Characterization Experimental (NUANCE) Center. The NUANCE Center is partially supported by NSF-MRSEC, NU-IIN, State of Illinois and Northwestern University.
PY - 2014/11
Y1 - 2014/11
N2 - Precipitates in bulk p-type thermoelectric materials, PbTe-SrTe and PbTe-PbS, are studied using three-dimensional (3-D) atom-probe tomography (APT). APT is capable of characterizing chemically materials in 3-D with subnano-scale spatial resolution on an atom-by-atom basis, which enables us to characterize secondary phases in the PbTe matrix as well as the dopant distributions at different imperfections. We demonstrate that APT provides accurate information about the compositions and morphologies of nanoprecipitates. In the PbTe-SrTe system, different morphology of precipitates is observed and the SrTe composition is confirmed. Also, segregation of Na dopants at mesoscale imperfections, dislocations and grain boundaries, and at matrix/precipitate interfaces is observed. In the PbTe-PbS system, PbS precipitates are observed. The PbS precipitates exhibit faceting, and have a morphology that depends on the bulk Na concentration. A predominance of {100} faceted precipitates is observed for 2 mol.% Na. Using 3-D APT, we demonstrate that Na segregation at matrix/precipitate interfaces is most likely responsible for the change in their morphologies, which occurs by reducing the interfacial free energy of {100} facets.
AB - Precipitates in bulk p-type thermoelectric materials, PbTe-SrTe and PbTe-PbS, are studied using three-dimensional (3-D) atom-probe tomography (APT). APT is capable of characterizing chemically materials in 3-D with subnano-scale spatial resolution on an atom-by-atom basis, which enables us to characterize secondary phases in the PbTe matrix as well as the dopant distributions at different imperfections. We demonstrate that APT provides accurate information about the compositions and morphologies of nanoprecipitates. In the PbTe-SrTe system, different morphology of precipitates is observed and the SrTe composition is confirmed. Also, segregation of Na dopants at mesoscale imperfections, dislocations and grain boundaries, and at matrix/precipitate interfaces is observed. In the PbTe-PbS system, PbS precipitates are observed. The PbS precipitates exhibit faceting, and have a morphology that depends on the bulk Na concentration. A predominance of {100} faceted precipitates is observed for 2 mol.% Na. Using 3-D APT, we demonstrate that Na segregation at matrix/precipitate interfaces is most likely responsible for the change in their morphologies, which occurs by reducing the interfacial free energy of {100} facets.
UR - http://www.scopus.com/inward/record.url?scp=84925541267&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84925541267&partnerID=8YFLogxK
U2 - 10.1007/s11837-014-1155-0
DO - 10.1007/s11837-014-1155-0
M3 - Article
AN - SCOPUS:84925541267
VL - 66
SP - 2288
EP - 2297
JO - JOM
JF - JOM
SN - 1047-4838
IS - 11
ER -