Substantial local variation of the Seebeck coefficient in gold nanowires

Zolotavin, Pavlo; Evans, Charlotte; Natelson, Douglas

doi:10.1039/c7nr02678a

Cited by 27 publications

(54 citation statements)

References 56 publications

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“…4,20 We can explain this local variation of the Seebeck coefficient by a reduction in the EMFP, which is caused by the increased scattering from the edges. Compared to Au nanowires, where a similar effect has been observed previously, 15 graphene is a more suitable system for achieving control of the mean free path due to its lower dimensionality and also comparatively bigger electron mean free path. Furthermore, we observe an additional contribution to the Peltier effect by an “electron wind” resulting from the high drift velocity of charge carriers in the constriction.…”

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confidence: 62%

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Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions

et al. 2018

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The influence of nanostructuring and quantum confinement on the thermoelectric properties of materials has been extensively studied. While this has made possible multiple breakthroughs in the achievable figure of merit, classical confinement, and its effect on the local Seebeck coefficient has mostly been neglected, as has the Peltier effect in general due to the complexity of measuring small temperature gradients locally. Here we report that reducing the width of a graphene channel to 100 nm changes the Seebeck coefficient by orders of magnitude. Using a scanning thermal microscope allows us to probe the local temperature of electrically contacted graphene two-terminal devices or to locally heat the sample. We show that constrictions in mono- and bilayer graphene facilitate a spatially correlated gradient in the Seebeck and Peltier coefficient, as evidenced by the pronounced thermovoltage Vth and heating/cooling response ΔTPeltier, respectively. This geometry dependent effect, which has not been reported previously in 2D materials, has important implications for measurements of patterned nanostructures in graphene and points to novel solutions for effective thermal management in electronic graphene devices or concepts for single material thermocouples.

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confidence: 62%

“…13,14 Moreover, classical rather than quantum confinement has been reported to cause an increase in the Seebeck coefficient in gold and antimony telluride nanowires. 15,16…”

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confidence: 99%

Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions

et al. 2018

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“…In addition, since the measurement was done in zero magnetic field, the magnetic secondary phase does not exhibit anomalous Nernst or spin Seebeck effect. We also note that the sign changes of thermopowers in Pt may occur owing to local variations in Seebeck coefficients due to grain boundaries and other structural features, as discussed in metal nanowires [23,24]. However, such grains and structural defects in Pt|MnPS 3 are insensitive to T , and thus difficult to explain the unconventional T dependence of S pt2 observed only in the limited T -range below T N [ Fig.…”

Section: Resultsmentioning

confidence: 92%

Experimental evidence consistent with a magnon Nernst effect in the antiferromagnetic insulator MnPS3

2017

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A magnon Nernst effect, an antiferromagnetic analogue of the magnon Hall effect in ferromagnetic insulators, has been studied experimentally for a layered antiferromagnetic insulator MnPS 3 in contact with two Pt strips. Thermoelectric voltage in the Pt strips grown on MnPS 3 single crystals exhibits non-monotonic temperature dependence at low temperatures, which is unlikely to be explained by electronic origins in Pt but can be ascribed to the inverse spin Hall voltage induced by a magnon Nernst effect. Control of antiferromagnetic domains in the MnPS 3 crystal by magnetoelectric cooling is found to modulate the low-temperature thermoelectric voltage in Pt, which is evidence consistent with the emergence of the magnon Nernst effect in Pt|MnPS 3 hybrid structures.

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“…For the Au nanowire longer than the laser spot size, multiple PTE voltage sign reversal was observed in the spatial mapping of photovoltage . Under the illumination by 785 nm laser, surface plasmon resonance of Au nanowire can be excited, which can be further used to locally heat the nanowire.…”

Section: D Material–based Photothermoelectric Detectorsmentioning

confidence: 99%

“…Natelson and co‐workers have performed systematic investigations on the PTE response of single‐metal thermocouples, which are composed of a gold nanowire and a wide fan‐out gold electrode . When the nanowire length is less than the laser spot size, the antisymmetric photovoltage pattern with respect to the center of the device can be observed ( Figure a,b) .…”

Section: D Material–based Photothermoelectric Detectorsmentioning

confidence: 99%

Progress of Photodetectors Based on the Photothermoelectric Effect

et al. 2019

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the radiation emitted by the room-temperature object is mainly in the LWIR region, with the peak wavelength of about 10 µm. [1] Because of these two properties, photodetectors operating in the LWIR range are of significant importance for the heat-seeking technologies, such as all-weather surveillance, night vision, and missile guidance. To detect such lowenergy radiation by photon detectors, commonly used photosensitive materials are narrow-bandgap semiconductors (e.g., HgCdTe) and quantum wells (e.g., GaAs/ InGaAs). [2,3] For these photodetectors, the dark current at room temperature usually is large, and thus a cryogenic cooling unit is indispensable, which certainly increases the size and weight of photon detectors. Therefore, to miniaturize the volume and weight of LWIR detectors, the development of high-performance uncooled photodetectors is vital. Thermal detectors are well known for their ultra-broadband spectral response from UV to far-infrared and even to terahertz at room temperature. The excellent ability of terahertz radiation (0.1-1 mm) to penetrate through nonconducting materials renders it particularly attractive for applications in tomographic inspection. [4,5] Thermal detectors are based on the measurement of temperature-dependent properties, such as the resistance for bolometers, the temperature-difference-driven voltage for photothermoelectric (PTE) detectors, and the spontaneous polarization for pyroelectric (PE) detectors. The photoresponse in PE detectors depends on the variation of the spontaneous polarization vector with temperature; therefore, an external chopper is needed when measuring the power of continuous-wave (CW) radiation. For bolometers, an external bias is required, which introduces the extra 1/f noise. The typical temperature-sensitive materials in commercial bolometers are vanadium oxide (VO x ) or amorphous silicon. The main advantage of VO x lies in that its temperature coefficient of resistance is high (≈4% K −1 ) while the resistivity remains low, which is beneficial to reduce the noise level. [6] Detailed comparisons among different kinds of photodetectors are listed in Table 1.PTE detectors are based on the photothermal conversion and thermoelectric effect. As schematically shown in Figure 1, after absorbing the photons on one side of PTE detector, a temperature difference (ΔT) is built up, which drives the directed diffusion of charge carriers from the hot end to the cold end, establishing an electric potential difference (ΔU). This process High-performance uncooled photodetectors operating in the long-wavelength infrared and terahertz regimes are highly demanded in the military and civilian fields. Photothermoelectric (PTE) detectors, which combine photothermal and thermoelectric conversion processes, can realize ultra-broadband photodetection without the requirement of a cooling unit and external bias. In the last few decades, the responsivity and speed of PTE-based photodetectors have made impressive progress with the discovery of novel thermoelectric materials and ...

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Substantial local variation of the Seebeck coefficient in gold nanowires

Cited by 27 publications

References 56 publications

Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions

Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions

Experimental evidence consistent with a magnon Nernst effect in the antiferromagnetic insulator MnPS3

Progress of Photodetectors Based on the Photothermoelectric Effect

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