Electrothermally driven current vortices in inhomogeneous bipolar semiconductors

Fu, Deyi; Levander, A. X.; Zhang, R.; Ager, Joel W.; Wu, Junqiao

doi:10.1103/physrevb.84.045205

Cited by 20 publications

(21 citation statements)

References 26 publications

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“…Besides, these current vortices can be connected to internal losses due to Joule heating. A similar effect has been independently observed by others .…”

Section: Devicessupporting

confidence: 90%

Silicon‐based nanocomposites for thermoelectric application

Schierning

Stoetzel

Chavez

et al. 2016

Physica Status Solidi (a)

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Here we present the realization of efficient and sustainable silicon‐based thermoelectric materials from nanoparticles. We employ a gas phase synthesis for the nanoparticles which is capable of producing doped silicon (Si) nanoparticles, doped alloy nanoparticles of silicon and germanium (Ge), SixGe1–x, and doped composites of Si nanoparticles with embedded metal silicide precipitation phases. Hence, the so‐called “nanoparticle in alloy” approach, theoretically proposed in the literature, forms a guideline for the material development. For bulk samples, a current‐activated pressure‐assisted densification process of the nanoparticles was optimized in order to obtain the desired microstructure. For thin films, a laser annealing process was developed. Thermoelectric transport properties were characterized on nanocrystalline bulk samples and laser‐sintered‐thin films. Devices were produced from nanocrystalline bulk silicon in the form of p–n junction thermoelectric generators, and their electrical output data were measured up to hot side temperatures of 750 °C. In order to get a deeper insight into thermoelectric properties and structure forming processes, a 3D‐Onsager network model was developed. This model was extended further to study the p–n junction thermoelectric generator and understand the fundamental working principle of this novel device architecture. Gas phase synthesis of composite nanoparticles; nanocrystalline bulk with optimized composite microstructure; laser‐annealed thin film.

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“…Besides, these current vortices can be connected to internal losses due to Joule heating. A similar effect has been independently observed by others .…”

Section: Devicessupporting

confidence: 90%

Silicon‐based nanocomposites for thermoelectric application

Schierning

Stoetzel

Chavez

et al. 2016

Physica Status Solidi (a)

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“…by relaxation of the photogenerated charge carriers via electron‐electron scattering and phonon generation . On the other hand, a temperature difference ∆T at the interface of two materials with different Seebeck coefficients S can result in a thermoelectric current :

I_{Thermo} = (S_{Nanowire} - S_{Stripline}) Δ T / R

with R the total resistance of the electrical circuit. The direction of I Thermo in (3) depends only on the sign of Δ T , since in first approximation, S Nanowire and S Stripline are independent of the bias voltage.…”

Section: Resultsmentioning

confidence: 99%

“…Scanning photocurrent microscopy is a widely used method to investigate diffusive and ballistic carrier transport, and to map the electronic band bending in contacted nanostructures, such as semiconducting nanowires . The photocurrent generation in single semiconducting nanowires has been explained either by carrier drift due to internal and external electric potentials , by a photo‐thermoelectric effect , or by carrier diffusion processes . We recently presented an on‐chip pump‐probe photocurrent spectroscopy based on coplanar stripline circuits to investigate such photocurrent dynamics in single p‐doped GaAs‐nanowires with a picosecond time‐resolution .…”

Section: Introductionmentioning

confidence: 99%

Ultrafast photocurrents and THz generation in single InAs‐nanowires

et al. 2012

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To clarify the ultrafast temporal interplay of the different photocurrent mechanisms occurring in single InAs-nanowire-based circuits, an on-chip photocurrent pumpprobe spectroscopy based on coplanar striplines was utilized. The data are interpreted in terms of a photo-thermoelectric current and the transport of photogenerated holes to the electrodes as the dominating ultrafast photocurrent contributions. Moreover, it is shown that THz radiation is generated in the optically excited InAs-nanowires, which is interpreted in terms of a dominating photo-Dember effect. The results are relevant for nanowire-based optoelectronic and photovoltaic applications as well as for the design of nanowire-based THz sources.

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“…If the hot end of the pn junction TEG would be hot enough to bring the pn junction close to its intrinsic regime, there is no interface anymore and consequently no Peltier cooling at the hot side. The Peltier contribution is then shifted into the inner parts of the device and may not necessarily contribute the heat flux balance as a loss mechanism. Fu et al showed by numerical simulations that internal current vortices build up within such a pn device under open voltage conditions. Hence, tailoring the current paths with respect to such current vortices is necessary within a pn junction TEG. The device concept combines elements from photovoltaic cells with elements from thermoelectric devices.…”

Section: Device Concepts For Thermoelectric Heat‐to‐electricity Convementioning

confidence: 99%

Silicon nanostructures for thermoelectric devices: A review of the current state of the art

Schierning

2014

Physica Status Solidi (a)

102

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Silicon is the most important element of modern semiconductor industry. As a thermoelectric converter material, it would be able to promote applications dramatically since device integration and scaling of the fabrication processes could be borrowed from existing technology. Though the thermoelectric performance of single crystalline silicon is only poor, silicon nanostructures have demonstrated a competitive figure of merit. To make use of these nanostructures, novel device architectures are necessary. This review provides an overview over the physical background of silicon as thermoelectric converter material as well as different nanostructures like nanowires, porous nanomeshes, and nanocrystalline bulk and their thermoelectric properties, focusing mostly on experimental data. Further, different thermoelectric converter device concepts including nanowire device concepts, pn junction thermoelectric generators and integrated spot coolers are discussed and their realization with silicon nanostructures briefly sketched. (a) Nanowires, porous nanomeshes and nanocrystalline bulk with promising thermoelectric material's figure of merit. (b) Innovative device concepts using nanowires or large area pn junctions for thermoelectric heat‐to‐electricity conversion.

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Electrothermally driven current vortices in inhomogeneous bipolar semiconductors

Cited by 20 publications

References 26 publications

Silicon‐based nanocomposites for thermoelectric application

Silicon‐based nanocomposites for thermoelectric application

Ultrafast photocurrents and THz generation in single InAs‐nanowires

Silicon nanostructures for thermoelectric devices: A review of the current state of the art

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