Controlled improvement in specific contact resistivity for thermoelectric materials by ion implantation

Taylor, Patrick J.; Maddux, Jay R.; Meissner, Greg; Venkatasubramanian, R.; Bulman, G. E.; Pierce, Jonathan; Gupta, Rahul; Bierschenk, Jim; Caylor, Chris; D’Angelo, Jonathan; Ren, Zhifeng

doi:10.1063/1.4816054

Cited by 42 publications

(46 citation statements)

References 18 publications

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“…Their results, as shown in Fig. 13, are consistent with the theoretical analysis shown above [191]. This work demonstrates an easy way to reduce the specific contact resistivity without changing the contact material.…”

Section: Specific Contact Resistivitysupporting

confidence: 88%

Current progress and future challenges in thermoelectric power generation: From materials to devices

et al. 2015

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Thermoelectric power generation represents one of the cleanest methods of energy conversion available today. It can be used in applications ranging from the harvesting of waste heat to conversion of solar energy into useful electricity. Remarkable advances have been achieved in recent years for various thermoelectric (TE) material systems. The introduction of various nanostructures is used to tune the transport of phonons, and band structure engineering allows for the tailoring of electron transport. In this overview, top-down approaches for phonon engineering such as atomic construction of new materials will be reviewed. Bottom-up approaches for electron engineering such as the formation of ordered nanostructures will also be discussed. The assembly of Thermo-Electric power Generating (TEG) devices is still particularly challenging, and consequently, thermal-to-electric conversion utilizing these devices has been realized only in niche applications. In this review paper, we will discuss some of the challenges that must be overcome to enable widespread use of TE devices. These include: thermal stability at the material level, and reliable contact at the device level.

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Section: Specific Contact Resistivitysupporting

confidence: 88%

Current progress and future challenges in thermoelectric power generation: From materials to devices

et al. 2015

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“…6b). This is in agreement with well-known approaches widely used to optimize the interfacial transport properties of semiconductor-metal contacts [34][35][36]. The contributions from thermionic emission and tunneling are also apparent when considering the temperature dependence.…”

Section: Resultssupporting

confidence: 88%

Atomistic study of the electronic contact resistivity between the half-Heusler alloys (HfCoSb, HfZrCoSb, HfZrNiSn) and the metal Ag

Léonard

Spataru

2018

Phys. Rev. Materials

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Half-Heusler(HH) alloys have shown promising thermoelectric properties in the medium and high temperature range. To harness these material properties for thermoelectric applications, it is important to realize electrical contacts with low electrical contact resistivity. However, little is known about the detailed structural and electronic properties of such contacts, and the expected values of contact resistivity. Here, we employ atomistic ab initio calculations to study electrical contacts in a subclass of HH alloys consisting of the compounds HfCoSb, HfZrCoSb, and HfZrNiSn. By using Ag as a prototypical metal, we show that the termination of the HH material critically determines the presence or absence of strong deformations at the interface. Our study includes contacts to doped materials, and the results indicate that the p-type materials generally form ohmic contacts while the n-type materials have a small Schottky barrier. We calculate the temperature dependence of the contact resistivity in the low to medium temperature range and provide quantitative values that set lower limits for these systems. where h max =(T H -T C )/T H is the Carnot efficiency, T H and T C are the hot and cold side temperatures, and ZT is a dimensionless figure of merit that characterizes the TE performance of materials. For the efficiency of a TE device, ZT is an average of the ZT values for the n-type and p-type TE materials. The material ZT is given by ("#) %&' = * + ,#/. , where σ is the electrical conductivity, S the Seebeck coefficient, and κ the thermal conductivity. Equation 1 is valid in the ideal situation where the thermal and electrical contact resistivity at the hot and cold ends are negligible [2]. In reality, the finite electrical and thermal contact resistivities lead to both temperature and voltage drops at the hot and cold ends, hence reduce the overall device efficiency, which is proportional to the effective figure of merit (ZT) 233 = ZT * [1 + +r 8 9 : ; : ] => , where ZT is the device level figure of merit without contact effects, r C is the contact resistivity, r m and L m are the resistivity and length of the p-type and n-type TE materials for the legs in the TE module. Thus, for optimal device performance, the contact resistivity should be as small as possible; a rule of thumb is that a good module performance requires r C

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“…As reported in [12] , big cracks can be observed at the interface due to a local thermal-expansion difference at an M-S joint, when applying a big thermal shock (550°C). To increase the bonding strength, a surface cleaning approach was reported in [13][14][15] . Hot pressing [5] and thermal spray processes [16] were also reported to increase the bonding strength.…”

Section: Introductionmentioning

confidence: 99%

“…sputtering through a solid mask (made from a 100-µm thick stencil, Newbury Electronics Ltd.) with different dimensions, giving deposited TE strip lengths of13,20,30,40,50 mm and TE strip widths of 0.5, 1, 2, 3, 4 mm (see Figure 8 a). Unlike TEGs containing both n-& p-type semiconductors, single-type TEGs use metal contacts to connect in-series one side of the TE strip to the other side of an adjacent TE strip.…”

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confidence: 99%

Device Optimization and Large‐Scale Roll‐to‐Roll Manufacturability of Flexible Thin‐Film Thermoelectric Generators

et al. 2021

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The optimization of flexible thin-film thermoelectric generator suitable for large-area roll-toroll processing is investigated. The selection of suitable contact materials, in-line patterning of connections, and dimension of the thermoelectric strip are investigated. As a result, copper is selected for contacts because it possesses a similar performance to gold while being cheaper.Both in-series and in-parallel connected devices are found to work well and provide a voltagedominant and current-dominant power source, respectively. The Seebeck coefficient and internal resistance of a device are extracted from fits to the measured power data. The inparallel connected thermoelectric generator has a much smaller internal resistance and is thus suitable for wearable/portable devices with the small load resistance. A shorter and wider thermoelectric strip generates more power. To the authors' knowledge, this is the first study that experimentally proves a downward trend of power output with increasing the strip length.In addition, an industrially feasible/continuous process is proposed for large-scale manufacture of flexible thermoelectric generators, by roll-to-roll sputtering thermoelectric materials on polymer web, inkjet printing contacts, and segmenting using a laser. A segmented

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Controlled improvement in specific contact resistivity for thermoelectric materials by ion implantation

Cited by 42 publications

References 18 publications

Current progress and future challenges in thermoelectric power generation: From materials to devices

Current progress and future challenges in thermoelectric power generation: From materials to devices

Atomistic study of the electronic contact resistivity between the half-Heusler alloys (HfCoSb, HfZrCoSb, HfZrNiSn) and the metal Ag

Device Optimization and Large‐Scale Roll‐to‐Roll Manufacturability of Flexible Thin‐Film Thermoelectric Generators

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