Effect of substitution on the transport properties of the half-Heusler alloy ZrNiSn

Substituted semiconductor alloys exhibit effects due to doping and disorder. To focus on the effect of disorder on transport properties, we have investigated isoelectronic Zr/sub 1-x/Hf/sub x/NiSn (x=0.0-0.3) and heavily substituted Zr/sub 0.5/Hf/sub 0.5/Ni/sub 0.7/Pd/sub 0.3/Sn/sub 0.95/, half Heus...

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Published inEighteenth International Conference on Thermoelectrics. Proceedings, ICT'99 (Cat. No.99TH8407) pp. 340 - 343
Main Authors Ponnambalam, V., Pope, A.L., Xia, Y., Bhattacharya, S., Poon, S.J., Tritt, T.M.
Format Conference Proceeding
LanguageEnglish
Published IEEE 1999
Subjects
Charge carrier density
Hafnium
Nickel alloys
Semiconductor device doping
Semiconductor materials
Temperature distribution
Thermal conductivity
Thermal resistance
Tin
Zirconium
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Summary:Substituted semiconductor alloys exhibit effects due to doping and disorder. To focus on the effect of disorder on transport properties, we have investigated isoelectronic Zr/sub 1-x/Hf/sub x/NiSn (x=0.0-0.3) and heavily substituted Zr/sub 0.5/Hf/sub 0.5/Ni/sub 0.7/Pd/sub 0.3/Sn/sub 0.95/, half Heusler alloys. Upon substitution, Zr/sub 1-x/Hf/sub x/NiSn alloys exhibit resistivity ratios R=/spl rho//sub 4.2K///spl rho//sub 295K/ as large as /spl sim/300 and thermally activated conduction in the temperature range 100-295K. At 4.2K, the (Zr,Hf)NiSn alloys possess carrier densities of /spl sim/10/sup 16/ to 10/sup 18/ cm/sup -3/ and carrier mobilities in the range /spl sim/100-350 cm/sup 2//V-s. The opposite signs exhibited by the Hall coefficient and thermopower, along with the saturation of resistivity at low temperature in ZrNiSn and Zr/sub 0.5/Hf/sub 0.5/Ni/sub 0.7/Pd/sub 0.3/Sn/sub 0.95/ alloys indicate band overlapping. Various scenarios of bandgap structures are discussed.
ISBN:9780780354517
0780354516
ISSN:1094-2734
DOI:10.1109/ICT.1999.843399