Electric Field Effect Thermoelectric Transport in Individual Silicon and Germanium/Silicon Nanowire

Brovman, Yuri M.; Small, Joshua P.; Hu, Yongjie; Fang, Ying; Lieber, Charles M.; Kim, Philip

doi:10.48550/arxiv.1307.0249

Cited by 8 publications

(18 citation statements)

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“…1 Recently, combining these two approaches, phonon engineering is used in low-dimensional structures, like silicon nanowires, to boost their ZT . [10][11][12][13][14] A natural question then arises: Is it possible to do the opposite, utilizing low-dimensional electrical transport in bulk phonon-glass crystals? To show this is indeed possible, we need to start from bulk materials with low thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Kai-Lun

et al. 2015

Nano Lett.

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Low-dimensional electronic and glassy phononic transport are two important ingredients of highly efficient thermoelectric materials, from which two branches of thermoelectric research have emerged. One focuses on controlling electronic transport in the low dimension, while the other focuses on multiscale phonon engineering in the bulk. Recent work has benefited much from combining these two approaches, e.g., phonon engineering in low-dimensional materials. Here we propose to employ the low-dimensional electronic structure in bulk phonon-glass crystals as an alternative way to increase the thermoelectric efficiency. Through first-principles electronic structure calculations and classical molecular dynamics simulations, we show that the π-π-stacking bis(dithienothiophene) molecular crystal is a natural candidate for such an approach. This is determined by the nature of its chemical bonding. Without any optimization of the material parameters, we obtained a maximum room-temperature figure of merit, ZT, of 1.48 at optimal doping, thus validating our idea.

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Section: Introductionmentioning

confidence: 99%

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Kai-Lun

et al. 2015

Nano Lett.

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“…Whereas the former requirement is necessary to increase efficiency, the latter is needed for enough electric (cooling) power to be extracted from a heat engine (Peltier refrigerator). From this perspective, semiconductor nanowires appear as very promising central building blocks of flexible, efficient and environmentally friendly thermoelectric converters [2,3,4,5,6,7,8]. Whereas their thermoelectric properties can be easily tuned by gates [5,8], the phononic contribution to thermal transport Ξ ph is suppressed due to the reduced dimensionality [3,4], and a good power output could be achieved by stacking them in parallel [9,3,6].…”

Section: Introductionmentioning

confidence: 99%

Gate-modulated thermopower of disordered nanowires: II. Variable-range hopping regime

et al. 2014

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We study the thermopower of a disordered nanowire in the field effect transistor configuration. After a first paper devoted to the elastic coherent regime (Bosisio, Fleury and Pichard 2014 New J. Phys. 16 035004), we consider here the inelastic activated regime taking place at higher temperatures. In the case where the charge transport is thermally assisted by phonons (Mott Variable Range Hopping regime), we use the Miller-Abrahams random resistor network model as recently adapted by Jiang et al for thermoelectric transport. This approach, previously used to study the bulk of the nanowire impurity band, is extended for studying its edges. In this limit, we show that the typical thermopower is largely enhanced, attaining values larger than ∼ − k e 10 1 mV K B 1 and exhibiting a non-trivial behaviour as a function of the temperature. A percolation theory by Zvyagin extended to disordered nanowires allows us to account for the main observed edge behaviours of the thermopower. efficiency is controlled by its dimensionless figure of merit, with T the temperature, S the Seebeck coefficient or thermopower and Ξ G, respectively the electrical and thermal conductances. As ZT increases, the efficiency moves closer to the Carnot limit. The stronger the particle-hole asymmetry in a system is, the higher S will be. An ideal thermoelectric device should then exploit to the maximum such asymmetry, while at the same time ensuring a poor thermal and a good electrical conductance [2]. Whereas the former requirement is necessary to increase efficiency, the latter is needed for enough electric (cooling) power to be extracted from a heat engine (Peltier refrigerator). From this perspective, semiconductor nanowires appear as very promising central building blocks of flexible, efficient and environmentally friendly thermoelectric converters [3][4][5][6][7][8][9]. Whereas their thermoelectric properties can be easily tuned by gates [6,9], the phononic contribution to thermal transport Ξ ph is suppressed due to the reduced dimensionality [4,5], and a good power output could be achieved by stacking them in parallel [4,7,10]. Furthermore Si-based devices, already under intense investigation [4,5,7,[10][11][12][13][14][15][16], exploit an abundant and non-polluting resource.Most existing works concentrate either on highly doped samples [4,7,8,10,11,13] or on the thermal conductivity of undoped wires [5,12,[15][16][17]. On the other hand, recent studies by Jiang et al [18,19] have rekindled the interest for systems in which electronic transport takes place via phonon-assisted hopping between localised states, of which disordered nanowires with low carrier density are a paradigmatic realization. Whereas in our first paper [1] we focused on the low-temperature coherent regime, in this work we extend the approach reviewed in [18,19] in order to investigate band-edge transport in the (activated) hopping regime. Two simple physical mechanisms have in this regime a synergy which is ideal for thermoelectric conversion [20,21]: (i) a strongly broken...

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“…At the same time, the amount of electrons conducting through the material goes towards zero at the insulating state. In this regime (region I), the TEP measurement is limited by the measurement setup due to high device resistance (30) and the V TEP signal decreases very quickly and exhibiting unreliable values once MoS2 goes to this 'off' state.…”

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confidence: 99%

Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-Layer MoS₂

et al. 2014

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Ultrathin layers of semiconducting molybdenum disulfide (MoS2) offer significant prospects in future electronic and optoelectronic applications. Although an increasing number of experiments bring light into the electronic transport properties of these crystals, their thermoelectric properties are much less known. In particular, thermoelectricity in chemical vapor deposition grown MoS2, which is more practical for wafer-scale applications, still remains unexplored. Here, for the first time, we investigate these properties in grown single layer MoS2. Microfabricated heaters and thermometers are used to measure both electrical conductivity and thermopower. Large values of up to ∼30 mV/K at room temperature are observed, which are much larger than those observed in other two-dimensional crystals and bulk MoS2. The thermopower is strongly dependent on temperature and applied gate voltage with a large enhancement at the vicinity of the conduction band edge. We also show that the Seebeck coefficient follows S ∼ T(1/3), suggesting a two-dimensional variable range hopping mechanism in the system, which is consistent with electrical transport measurements. Our results help to understand the physics behind the electrical and thermal transports in MoS2 and the high thermopower value is of interest to future thermoelectronic research and application.

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Electric Field Effect Thermoelectric Transport in Individual Silicon and Germanium/Silicon Nanowire

Cited by 8 publications

References 0 publications

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Gate-modulated thermopower of disordered nanowires: II. Variable-range hopping regime

Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-Layer MoS₂

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Electric Field Effect Thermoelectric Transport in Individual Silicon and Germanium/Silicon Nanowire

Cited by 8 publications

References 0 publications

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Enhancing the Thermoelectric Figure of Merit by Low-Dimensional Electrical Transport in Phonon-Glass Crystals

Gate-modulated thermopower of disordered nanowires: II. Variable-range hopping regime

Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-Layer MoS2

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Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-Layer MoS₂