| Summary: | Cu-doping and crystallographic site occupations within the half-Heusler TiNiSn, a promising
thermoelectric material, have been examined by Atom Probe Tomography (APT). In
particular, this investigation aims to better understand the influence of atom probe
analysis conditions on the measured chemical composition. Under voltage pulsing mode,
atomic planes are clearly resolved and suggest an arrangement of elements in-line within
the expected half-Heusler (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 non-ideal evaporation behaviour.
The possible mechanisms for these trends are discussed, along with suggestions for
optimal analysis conditions for these and similar thermoelectric materials.
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