Atom probe tomography of a Cu-doped TiNiSn thermoelectric material: nanoscale structure and optimization of analysis conditions

He, H., Halpin, J. E., Popuri, S. R., Daly, L. , Bos, J.-W. G., Moody, M. P., MacLaren, D. A. and Bagot, P. A.J. (2022) Atom probe tomography of a Cu-doped TiNiSn thermoelectric material: nanoscale structure and optimization of analysis conditions. Microscopy and Microanalysis, 28(4), pp. 1340-1347. (doi: 10.1017/S1431927621012162) (PMID:34315548)

Abstract

Cu-doping and crystallographic site occupations within the half-Heusler (HH) TiNiSn, a promising thermoelectric material, have been examined by atom probe tomography. In particular, this investigation aims to better understand the influence of atom probe analysis conditions on the measured chemical composition. Under a voltage-pulsing mode, atomic planes are clearly resolved and suggest an arrangement of elements in-line with the expected HH (F-43m space group) crystal structure. The Cu dopant is also distributed uniformly throughout the bulk material. For operation under laser-pulsed modes, the returned composition is highly dependent on the selected laser energy, with high energies resulting in the measurement of excessively high absolute Ti counts at the expense of Sn and in particular Ni. High laser energies also appear to be correlated with the detection of a high fraction of partial hits, indicating nonideal evaporation behavior. The possible mechanisms for these trends are discussed, along with suggestions for optimal analysis conditions for these and similar thermoelectric materials.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Daly, Dr Luke and Halpin, Dr John and MacLaren, Professor Donald
• Authors: He, H., Halpin, J. E., Popuri, S. R., Daly, L., Bos, J.-W. G., Moody, M. P., MacLaren, D. A., and Bagot, P. A.J.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences; College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Microscopy and Microanalysis
• Publisher: Cambridge University Press
• ISSN: 1431-9276
• ISSN (Online): 1435-8115
• Published Online: 28 July 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Microscopy and Microanalysis 28(4): 1340-1347
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
172181		Nanostructured half-Heuslers for thermoelectric waste heat recovery	Donald Maclaren	Engineering and Physical Sciences Research Council (EPSRC)	EP/N017218/1	P&S - Physics & Astronomy
172958		A Focused Noble Gas Ion Beam Facility for Materials and Device Nanoanalysis - EQUIPMENT GRANT	Ian MacLaren	Engineering and Physical Sciences Research Council (EPSRC)	EP/P001483/1	P&S - Physics & Astronomy