Seebeck coefficient of silicon nanowire forests doped by thermal diffusion

Thermoelectric generators made by large arrays of nanowires perpendicular to a silicon substrate, that is, so-called silicon nanowire forests are fabricated on large areas by an inexpensive metal-assisted etching technique. After fabrication, a thermal diffusion process is used for doping the nanowire forest with phosphorous. A suitable experimental technique has been developed for the measurement of the Seebeck coefficient under static conditions, and results are reported for different doping parameters. These results are in good agreement with numerical simulations of the doping process applied to silicon nanowires. These devices, based on doped nanowire forests, offer a possible route for the exploitation of the high power factor of silicon, which, combined with the very low thermal conductivity of nanostructures, will yield a high efficiency of the conversion of thermal to electrical energy.

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Highly Efficient Silicon Nanowire Surface Passivation by Bismuth Nano-Coating for Multifunctional Bi@SiNWs Heterostructures

Nanomaterials ◽

10.3390/nano10081434 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1434

Author(s):

Mariem Naffeti ◽

Pablo Aitor Postigo ◽

Radhouane Chtourou ◽

Mohamed Ali Zaïbi

Keyword(s):

Silicon Nanowires ◽

Near Infrared ◽

Surface Passivation ◽

Silicon Nanowire ◽

Etching Technique ◽

Highly Efficient ◽

Broadband Emission ◽

New Family ◽

Nano Coating ◽

Nanowire Surface

A key requirement for the development of highly efficient silicon nanowires (SiNWs) for use in various kinds of cutting-edge applications is the outstanding passivation of their surfaces. In this vein, we report on a superior passivation of a SiNWs surface by bismuth nano-coating (BiNC) for the first time. A metal-assisted chemical etching technique was used to produce the SiNW arrays, while the BiNCs were anchored on the NWs through thermal evaporation. The systematic studies by Scanning Electron Microscopy (SEM), energy dispersive X-ray spectra (EDX), and Fourier Transform Infra-Red (FTIR) spectroscopies highlight the successful decoration of SiNWs by BiNC. The photoluminescence (PL) emission properties of the samples were studied in the visible and near-infrared (NIR) spectral range. Interestingly, nine-fold visible PL enhancement and NIR broadband emission were recorded for the Bi-modified SiNWs. To our best knowledge, this is the first observation of NIR luminescence from Bi-coated SiNWs (Bi@SiNWs), and thus sheds light on a new family of Bi-doped materials operating in the NIR and covering the important telecommunication wavelengths. Excellent anti-reflectance abilities of ~10% and 8% are observed for pure SiNWs and Bi@SiNWs, respectively, as compared to the Si wafer (50–90%). A large decrease in the recombination activities is also obtained from Bi@SiNWs heterostructures. The reasons behind the superior improvement of the Bi@SiNWs performance are discussed in detail. The findings demonstrate the effectiveness of Bi as a novel surface passivation coating, where Bi@SiNWs heterostructures are very promising and multifunctional for photovoltaics, optoelectronics, and telecommunications.

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Thermoelectric Properties of Silicon Nanowire Array and Spin-on Glass Composites Fabricated with CMOS-compatible Techniques

MRS Proceedings ◽

10.1557/opl.2012.194 ◽

2012 ◽

Vol 1408 ◽

Cited By ~ 3

Author(s):

Benjamin M. Curtin ◽

John E. Bowers

Keyword(s):

Thermal Conductivity ◽

Seebeck Coefficient ◽

Silicon Nanowires ◽

Silicon Nanowire ◽

Nanowire Array ◽

Square Lattice ◽

Glass Composites ◽

Si Substrates ◽

Silicon Nanowire Array ◽

Work Interference

ABSTRACTSilicon nanowires (NWs) are promising thermoelectric materials as they offer large reductions in thermal conductivity over bulk Si without a significant decrease in the Seebeck coefficient or electrical conductivity. In this work, interference lithography was used to pattern a square lattice photoresist template over 2 cm x 2 cm Si substrates. The resulting vertical Si NW arrays were 1 μm tall with a packing density of ~15%, and the diameter of the Si NWs were 80 - 90 nm. The Si NW arrays were then embedded in spin-on glass (SOG) to form a dense composite material with a measured thermal conductivity of 1.45 W/m-K at 300 K. Devices were fabricated for cross-plane Seebeck coefficient measurements and the Si NW/SOG composite was found to have a Seebeck coefficient of roughly -284 μV/K, which is similar to bulk Si with the same doping. We also report a combined power generation of 29.3 μW from both the Si NW array and Si substrate with a temperature difference of 56 K and 50 μm x 50 μm device area.

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Well incorporation of carbon nanodots with silicon nanowire arrays featuring excellent photocatalytic performances

Physical Chemistry Chemical Physics ◽

10.1039/c7cp01674c ◽

2017 ◽

Vol 19 (19) ◽

pp. 11786-11792 ◽

Cited By ~ 22

Author(s):

Chia-Yun Chen ◽

Po-Hsuan Hsiao ◽

Ta-Cheng Wei ◽

Ting-Chen Chen ◽

Chien-Hsin Tang

Keyword(s):

Silicon Nanowires ◽

High Efficiency ◽

Silicon Nanowire ◽

Broad Band ◽

Nanowire Arrays ◽

Carbon Nanodots ◽

Silicon Nanowire Arrays ◽

Photocatalytic Performances ◽

Fluorescent Carbon Nanodots ◽

Fluorescent Carbon

Broad-band and high efficiency photocatalytic systems were demonstrated through the incorporation of silicon nanowires with highly fluorescent carbon nanodots.

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Silicon Nanowires: A Breakthrough for Thermoelectric Applications

Materials ◽

10.3390/ma14185305 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5305

Author(s):

Giovanni Pennelli ◽

Elisabetta Dimaggio ◽

Antonella Masci

Keyword(s):

Integrated Circuits ◽

Power Factor ◽

Silicon Nanowires ◽

Silicon Nanowire ◽

Large Temperature ◽

Nanowire Diameter ◽

Large Numbers ◽

High Power Factor ◽

Experimental Works ◽

Very High

The potentialities of silicon as a starting material for electronic devices are well known and largely exploited, driving the worldwide spreading of integrated circuits. When nanostructured, silicon is also an excellent material for thermoelectric applications, and hence it could give a significant contribution in the fundamental fields of energy micro-harvesting (scavenging) and macro-harvesting. On the basis of recently published experimental works, we show that the power factor of silicon is very high in a large temperature range (from room temperature up to 900 K). Combining the high power factor with the reduced thermal conductivity of monocrystalline silicon nanowires and nanostructures, we show that the foreseen figure of merit ZT could be very high, reaching values well above 1 at temperatures around 900 K. We report the best parameters to optimize the thermoelectric properties of silicon nanostructures, in terms of doping concentration and nanowire diameter. At the end, we report some technological processes and solutions for the fabrication of macroscopic thermoelectric devices, based on large numbers of silicon nanowire/nanostructures, showing some fabricated demonstrators.

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Review of nanostructured devices for thermoelectric applications

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.5.141 ◽

2014 ◽

Vol 5 ◽

pp. 1268-1284 ◽

Cited By ~ 52

Author(s):

Giovanni Pennelli

Keyword(s):

High Efficiency ◽

Research Effort ◽

Silicon Nanowire ◽

Electrical Energy ◽

Green Energy ◽

Nanowire Arrays ◽

Thermoelectric Devices ◽

Large Area ◽

Thermoelectric Conversion ◽

Silicon Nanowire Arrays

A big research effort is currently dedicated to the development of thermoelectric devices capable of a direct thermal-to-electrical energy conversion, aiming at efficiencies as high as possible. These devices are very attractive for many applications in the fields of energy recovery and green energy harvesting. In this paper, after a quick summary of the fundamental principles of thermoelectricity, the main characteristics of materials needed for high efficiency thermoelectric conversion will be discussed, and a quick review of the most promising materials currently under development will be given. This review paper will put a particular emphasis on nanostructured silicon, which represents a valid compromise between good thermoelectric properties on one side and material availability, sustainability, technological feasibility on the other side. The most important bottom-up and top-down nanofabrication techniques for large area silicon nanowire arrays, to be used for high efficiency thermoelectric devices, will be presented and discussed.

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Optically transparent vertical silicon nanowire arrays for live-cell imaging

Journal of Nanobiotechnology ◽

10.1186/s12951-021-00795-7 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Roey Elnathan ◽

Andrew W. Holle ◽

Jennifer Young ◽

Marina A. George ◽

Omri Heifler ◽

...

Keyword(s):

High Efficiency ◽

Silicon Nanowire ◽

Live Cell ◽

Si Nanowires ◽

Contrast Imaging ◽

Silicon Nanowire Arrays ◽

Transparent Substrate ◽

Optically Transparent ◽

Vertically Aligned

AbstractProgrammable nano-bio interfaces driven by tuneable vertically configured nanostructures have recently emerged as a powerful tool for cellular manipulations and interrogations. Such interfaces have strong potential for ground-breaking advances, particularly in cellular nanobiotechnology and mechanobiology. However, the opaque nature of many nanostructured surfaces makes non-destructive, live-cell characterization of cellular behavior on vertically aligned nanostructures challenging to observe. Here, a new nanofabrication route is proposed that enables harvesting of vertically aligned silicon (Si) nanowires and their subsequent transfer onto an optically transparent substrate, with high efficiency and without artefacts. We demonstrate the potential of this route for efficient live-cell phase contrast imaging and subsequent characterization of cells growing on vertically aligned Si nanowires. This approach provides the first opportunity to understand dynamic cellular responses to a cell-nanowire interface, and thus has the potential to inform the design of future nanoscale cellular manipulation technologies.

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DIELECTRIC CONSTANT AND SEEBECK COEFFICIENT FOR SEMICONDUCTORS: THERMODYNAMIC AND DFT STUDIES

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633613500570 ◽

2013 ◽

Vol 12 (06) ◽

pp. 1350057 ◽

Cited By ~ 2

Author(s):

HSIU-YA TASI ◽

CHAOYUAN ZHU

Keyword(s):

Boundary Condition ◽

Dielectric Constant ◽

Seebeck Coefficient ◽

Gas Phase ◽

Present Method ◽

Dielectric Constants ◽

Semiconductor Materials ◽

Electronic Polarizability ◽

Seebeck Coefficients ◽

Good Agreement

Dielectric constants and Seebeck coefficients for semiconductor materials are studied by thermodynamic method plus ab initio quantum density functional theory (DFT). A single molecule which is formed in semiconductor material is treated in gas phase with molecular boundary condition and then electronic polarizability is directly calculated through Mulliken and atomic polar tensor (APT) density charges in the presence of the external electric field. This electronic polarizability can be converted to dielectric constant for solid material through the Clausius–Mossotti formula. Seebeck coefficient is first simulated in gas phase by thermodynamic method and then its value divided by its dielectric constant is regarded as Seebeck coefficient for solid materials. Furthermore, unit cell of semiconductor material is calculated with periodic boundary condition and its solid structure properties such as lattice constant and band gap are obtained. In this way, proper DFT function and basis set are selected to simulate electronic polarizability directly and Seebeck coefficient through chemical potential. Three semiconductor materials Mg 2 Si , β- FeSi 2 and SiGe are extensively tested by DFT method with B3LYP, BLYP and M05 functionals, and dielectric constants simulated by the present method are in good agreement with experimental values. Seebeck coefficients simulated by the present method are in reasonable good agreement with experiments and temperature dependence of Seebeck coefficients basically follows experimental results as well. The present method works much better than the conventional energy band structure theory for Seebeck coefficients of three semiconductors mentioned above. Simulation with periodic boundary condition can be generalized directly to treat with doped semiconductor in near future.

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Effect of Metal - Silicon Nanowire Contacts on the Performance of Accumulation Metal Oxide Semiconductor Field Effect Transistor

MRS Proceedings ◽

10.1557/proc-1144-ll06-02 ◽

2008 ◽

Vol 1144 ◽

Author(s):

Pranav Garg ◽

Yi Hong ◽

Md. Mash-Hud Iqbal ◽

Stephen J. Fonash

Keyword(s):

Metal Oxide ◽

Silicon Nanowires ◽

Field Effect ◽

Field Effect Transistor ◽

Silicon Nanowire ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Manufacturing Cost ◽

Effect Transistor ◽

The Impact

ABSTRACTRecently, we have experimentally demonstrated a very simply structured unipolar accumulation-type metal oxide semiconductor field effect transistor (AMOSFET) using grow-in-place silicon nanowires. The AMOSFET consists of a single doping type nanowire, metal source and drain contacts which are separated by a partially gated region. Despite its simple configuration, it is capable of high performance thereby offering the potential of a low manufacturing-cost transistor. Since the quality of the metal/semiconductor ohmic source and drain contacts impacts AMOSFET performance, we repot here on initial exploration of contact variations and of the impact of thermal process history. With process optimization, current on/off ratios of 106 and subthreshold swings of 70 mV/dec have been achieved with these simple devices

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MeV Ion-Beam Bombardment Effects on The Thermoelectric Figures of Merit of Zn4Sb3 and ZrNiSn-Based half-heusler compounds

MRS Proceedings ◽

10.1557/proc-1020-gg07-09 ◽

2007 ◽

Vol 1020 ◽

Author(s):

S. Budak ◽

S. Guner ◽

C. Muntele ◽

C. C. Smith ◽

B. Zheng ◽

...

Keyword(s):

Thin Films ◽

Thermal Conductivity ◽

Seebeck Coefficient ◽

Measurement System ◽

Ion Beam ◽

Electrical Energy ◽

Figures Of Merit ◽

Material Systems ◽

The Cross ◽

Conductivity Of Thin Films

AbstractSemiconducting â-Zn4Sb3and ZrNiSn-based half-heusler compound thin films were prepared by co-evaporation for the application of thermoelectric (TE) materials. High-purity solid zinc and antimony were evaporated by electron beam to grow the â-Zn4Sb3thin film while high-purity zirconium powder and nickel tin powders were evaporated by electron beam to grow the ZrNiSn-based half-heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardments for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardments. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam can cause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ù-method measurement system to measure the cross-plane thermal conductivity ,the Van der Pauw measurement system to measure the cross-plane electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.

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Design of a High-Power High-Efficiency Multi-Receiver Wireless Power Transfer System

Electronics ◽

10.3390/electronics10111308 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1308

Author(s):

Yuyu Zhu ◽

Hanyu Zhang ◽

Zuming Wang ◽

Xin Cao ◽

Renyin Zhang

Keyword(s):

Power Distribution ◽

Power Flow ◽

High Efficiency ◽

Control Method ◽

Experimental Models ◽

Wireless Power ◽

Multiple Receivers ◽

Combined Operation ◽

Wireless Power Transfer System ◽

Good Agreement

This paper proposes a new control method to regulate the power flow into multiple receivers. This system consists of one transmitter controller and three receiver controllers. They work independently to decide the power distribution with their combined operation. The simulated and experimental models have been built, and the experimental results are in good agreement with the theoretical analysis results. The proposed method is robust, flexible, and generalizable, and can be employed under various wireless charging conditions.

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