Structural and thermoelectric properties of HfNiSn half-Heusler thin films

Wang, Shuhui; Cheng, Hsin‐Ming; Wu, Ren-Jye; Chao, Wen-Hsuan

doi:10.1016/j.tsf.2010.05.080

Cited by 26 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…HH compounds XYZ usually form the cubic MgAgAs type of structure (space group F4 À 3m) [12,13]. Usually good TE materials are narrow-band-gap semiconductors.…”

Section: Introductionmentioning

confidence: 99%

A new n-type half-Heusler thermoelectric material NbCoSb

Huang

Chen

et al. 2015

Materials Research Bulletin

View full text Add to dashboard Cite

A B S T R A C TWe surprisingly made a new n-type thermoelectric compound NbCoSb with half-Heusler (HH) structure having valence electron count of 19, different from the traditional 18, which opens up a new route to develop new half-Heusler thermoelectric materials not following the traditional valence electron count of 18. The samples are made by arc melting followed by ball milling and hot pressing. The effect of hot pressing temperature on the thermoelectric properties of NbCoSb samples has been studied. A maximum thermoelectric figure-of-merit (ZT) of $0.4 is achieved at 700 C in NbCoSb sample that is hot pressed at 1000 C. This work add a new member to HH compounds for thermoelectric applications, although the peak ZT of $0.4 is still lower than that of the traditional HHs. Moreover, it is very interesting to see that a traditionally thought of valence electron counts of 18 is not required.

show abstract

“…HH compounds XYZ usually form the cubic MgAgAs type of structure (space group F4 À 3m) [12,13]. Usually good TE materials are narrow-band-gap semiconductors.…”

Section: Introductionmentioning

confidence: 99%

A new n-type half-Heusler thermoelectric material NbCoSb

Huang

Chen

et al. 2015

Materials Research Bulletin

View full text Add to dashboard Cite

show abstract

“…In general, r increases with increase of the sputtering power, and the sample deposited at 80 W has the smallest r. The electrical conductivity of our Zr-Ni-Sn films is larger than those of other M-Ni-Sn thin films. 21,22 32. Although the r of the sample prepared at 80 W is the smallest among the four samples, its power factor S 2 r becomes the largest when the temperature reaches 393 K owing to its maximum S, as shown in Fig.…”

Section: Resultsmentioning

confidence: 85%

“…The largest value of S 2 r is 2.66 mW K À2 m À1 at 393 K, which is larger than those of other M-Ni-Sn films because both S and r of this sample are enhanced. 21,22 In addition, for the samples deposited at 120 W and 140 W, the power factors decrease with increasing T due to the reduction of S.…”

Section: Resultsmentioning

confidence: 99%

“…[17][18][19] MNiSn-based HH thin films have also been synthesized by magnetron sputtering or electron beam deposition, exhibiting a largest Seebeck coefficient and power factor on the order of tens of lV K À1 and on the order of 0.1 mW K À2 m À1 , respectively. [20][21][22] The reliable ZT values of crystalline HH materials have been limited to around 1.0 so far, mainly due to the high thermal conductivity of HH compounds. 23 Provided that the microstructure of a thermoelectric material is amorphous, the lattice thermal conductivity j l of the material can be minimized and the total thermal conductivity j can be greatly reduced, which hence should enhance the ZT value.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermoelectric Properties of Amorphous Zr-Ni-Sn Thin Films Deposited by Magnetron Sputtering

Zhou

Tan

Zhu

et al. 2015

Journal of Elec Materi

View full text Add to dashboard Cite

n-Type Zr-Ni-Sn thermoelectric thin films with thickness of 60 nm to 400 nm were deposited by radiofrequency magnetron sputtering. The microstructure of the Zr-Ni-Sn thin films was examined by x-ray diffractometry and highresolution transmission electron microscopy, revealing an amorphous microstructure. The thermal conductivity of the amorphous films was measured by the ultrafast laser pump-probe thermoreflectance technique, revealing values of 1.4 W m À1 K À1 to 2.2 W m À1 K À1 , smaller than that of bulk material because of the amorphous microstructure of the films. The effects of the sputtering power on the composition, Seebeck coefficient, and electrical conductivity of the films were investigated. The largest Seebeck coefficient and power factor were achieved at 393 K, being À112.0 lV K À1 and 2.66 mW K À2 m À1 , respectively. The low thermal conductivity and high power factor indicate that amorphous Zr-Ni-Sn thin films could be a promising material for use in thermoelectric microdevices.

show abstract

“…[ 17 ] There are several examples of combinatorial methods being applied in the fi eld of thermoelectrics, ranging from bulk diffusion couples [ 18,19 ] over sol-gel prepared samples [ 20 ] to thin fi lms prepared by pulsed-laser deposition [ 21,22 ] and co-sputtering. [23][24][25][26][27] Compared to, e.g., the diffusion couple approach, combinatorial sputtering offers much shorter sample fabrication times. However, to obtain the power factor the highthroughput measurements of the Seebeck coeffi cient must often be carried out using custom-made setups [ 28 ] combined with either van der Pauw [ 29,30 ] or four-point probe setup [31][32][33][34] measurements of the resistivity.…”

Section: Introductionmentioning

confidence: 99%

Unraveling Self‐Doping Effects in Thermoelectric TiNiSn Half‐Heusler Compounds by Combined Theory and High‐Throughput Experiments

Wambach

Stern

Bhattacharya

et al. 2015

Adv Elect Materials

View full text Add to dashboard Cite

The control of the carrier concentration is a key topic in the optimization of the thermoelectric power factor. It depends intricately on the defect chemistry of a host phase (here: TiNiSn) and the boundary conditions set by competing phases. The large impact of a slight off‐stoichiometry in the intermetallic half‐Heusler phase TiNiSn makes combinatorial techniques ideally suited for systematic optimization of its thermoelectric performance. In this work, computational thermochemistry, combinatorial synthesis, and high‐throughput characterization are combined to obtain a complete map of the thermoelectric power factor for the Ti–Ni–Sn system. The role of the chemical potential of the constituents in determining the detailed nonstoichiometric composition of the intermetallic half‐Heusler phase TiNiSn is elucidated. This work not only confirms the assumption of a large phase‐width in terms of Ni surplus but also demonstrates that TiNiSn phases with a relatively large Ti surplus can be produced. This can serve as a new route for achieving high carrier concentrations by self‐doping in the ternary system Ti–Ni–Sn. The defect thermochemistry calculations for the carrier concentration are in excellent agreement with the experimental results. The findings of this work suggest new ways of improving the thermoelectric performance of half‐Heusler phases such as TiNiSn.

show abstract

Structural and thermoelectric properties of HfNiSn half-Heusler thin films

Cited by 26 publications

References 16 publications

A new n-type half-Heusler thermoelectric material NbCoSb

A new n-type half-Heusler thermoelectric material NbCoSb

Thermoelectric Properties of Amorphous Zr-Ni-Sn Thin Films Deposited by Magnetron Sputtering

Unraveling Self‐Doping Effects in Thermoelectric TiNiSn Half‐Heusler Compounds by Combined Theory and High‐Throughput Experiments

Contact Info

Product

Resources

About