scholarly journals Fabrication of Needle-Like Silicon Nanowires by Using a Nanoparticles-Assisted Bosch Process for Both High Hydrophobicity and Anti-Reflection

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1009
Author(s):  
Zengxing Zhang ◽  
Guohua Liu ◽  
Kaiying Wang
Keyword(s):  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Film Deposition ◽  
Au Nps ◽  
Aspect Ratios ◽  
Hydrophobic Behavior ◽  
Hydrophobic Chemical ◽  
Wave Range ◽  
Reflection Characteristics

In this work, a modified Bosch etching process is developed to create silicon nanowires. Au nanoparticles (NPs) formed by magnetron sputtering film deposition and thermal annealing were employed as the hard mask to achieve controllable density and high aspect ratios. Such silicon nanowire exhibits the excellent anti-reflection ability of a reflectance value of below 2% within a broad light wave range between 220 and 1100 nm. In addition, Au NPs-induced surface plasmons significantly enhance the near-unity anti-reflection characteristics, achieving a reflectance below 3% within the wavelength range of 220 to 2600 nm. Furthermore, the nanowire array exhibits super-hydrophobic behavior with a contact angle over ~165.6° without enforcing any hydrophobic chemical treatment. Such behavior yields in water droplets bouncing off the surface many times. These properties render this silicon nanowire attractive for applications such as photothermal, photocatalysis, supercapacitor, and microfluidics.

A review and analysis on growth and optical absorption properties of silicon nanowire array for photovoltaic applications

2015 ◽  
Vol 29 (30) ◽  
pp. 1530007 ◽  
Author(s):  
Ritu Sharma ◽  
Lalit Kumar Dusad
Keyword(s):  
Solar Cells ◽  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Major Research ◽  
Absorption Properties ◽  
Silicon Nanowire Array ◽  
Photovoltaic Applications ◽  
Research Findings ◽  
Experimental Approaches

In this paper, optical absorptions in silicon nanowires (SiNWs) arrays obtained from theoretical studies and experimental approaches have been reviewed. A brief description on the different growth techniques for SiNW arrays reported so far is presented. Comparative analysis based on major research findings has been done and the advantages of SiNW-based solar cells over thin film solar cells are presented. Furthermore, future aspects of the use of SiNWs for photovoltaic applications are discussed.

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

2012 ◽  
Vol 1408 ◽  
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.

scholarly journals A Novel Top-Down Fabrication Process for Vertically-Stacked Silicon-Nanowire Array

2020 ◽  
Vol 10 (3) ◽  
pp. 1146 ◽  
Author(s):  
Kangil Kim ◽  
Jae Keun Lee ◽  
Seung Ju Han ◽  
Sangmin Lee
Keyword(s):  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Nanowire Arrays ◽  
Fabrication Method ◽  
Top Down ◽  
Silicon Nanowire Arrays ◽  
Sensing Applications ◽  
Silicon Nanowire Array ◽  
Cross Sectional Dimension

Silicon nanowires are widely used for sensing applications due to their outstanding mechanical, electrical, and optical properties. However, one of the major challenges involves introducing silicon-nanowire arrays to a specific layout location with reproducible and controllable dimensions. Indeed, for integration with microscale structures and circuits, a monolithic wafer-level process based on a top-down silicon-nanowire array fabrication method is essential. For sensors in various electromechanical and photoelectric applications, the need for silicon nanowires (as a functional building block) is increasing, and thus monolithic integration is highly required. In this paper, a novel top-down method for fabricating vertically-stacked silicon-nanowire arrays is presented. This method enables the fabrication of lateral silicon-nanowire arrays in a vertical direction, as well as the fabrication of an increased number of silicon nanowires on a finite dimension. The proposed fabrication method uses a number of processes: photolithography, deep reactive-ion etching, and wet oxidation. In applying the proposed method, a vertically-aligned silicon-nanowire array, in which a single layer consists of three vertical layers with 20 silicon nanowires, is fabricated and analyzed. The diamond-shaped cross-sectional dimension of a single silicon nanowire is approximately 300 nm in width and 20 μm in length. The developed method is expected to result in highly-sensitive, reproducible, and low-cost silicon-nanowire sensors for various biomedical applications.

scholarly journals Characterization of Si nanowires synthesized using metal-assisted wet-chemical etching

2014 ◽  
Vol 8 (3) ◽  
Author(s):  
Eman S. M. Ashour ◽  
M.Y. Sulaiman ◽  
N. Amin ◽  
Z. Ibrahim
Keyword(s):  
Silicon Nanowires ◽  
Chemical Etching ◽  
Growth Parameters ◽  
Silicon Nanowire ◽  
Incident Light ◽  
Nanowire Array ◽  
Solution Concentration ◽  
Etching Time ◽  
Si Nanowires ◽  
Potential Applications

A synthesis of vertical silicon nanowire array through metal-assisted chemical etching of highly doped p-type silicon wafers (100) in a solution of hydrofluoric acid and silver nitrate has been proposed. . The influences of the growth parameters such as solution concentration, etching time have been investigated. In addition, we consider other common parameters like wafer resistivity and temperature, which rely on the silicon nanowires formation. The results indicate that the silicon nanowires retain the single crystalline structure and crystallographic orientation of the starting silicon wafer. Furthermore, They provide excellent antireflection property with a low reflection loss of 3% for incident light within the wavelength range of 200–900 nm. Such nanowire arrays may have potential applications as antireflection surface for silicon solar cells

A Systematic Study of Metal-assisted Chemical Etching Parameters for Well-Ordered Silicon Nanowire Array Fabrication

2012 ◽  
Vol 1408 ◽  
Author(s):  
Arif S. Alagoz ◽  
Tansel Karabacak
Keyword(s):  
Silicon Nanowires ◽  
Chemical Etching ◽  
Crystalline Silicon ◽  
Silicon Nanowire ◽  
Etching Rate ◽  
Nanowire Array ◽  
Lithium Ion ◽  
Nanowire Diameter ◽  
Silicon Nanowire Array ◽  
Metal Assisted Chemical Etching

ABSTRACTMetal-assisted chemical etching is a simple and low-cost silicon nanowire fabrication method which allows control of nanowire diameter, length, shape and orientation. In this work, we fabricated well-ordered silicon nanowire array by patterning gold thin film by nanosphere lithography and etching single crystalline silicon wafer by metal-assisted chemical etching technique. We investigated relation between etched solution concentration and nanowire morphology, wafer crystal orientation, etching rate. This well-ordered silicon nanowires arrays have the potential applications in many fields but especially next generation energy related applications from solar cells to lithium-ion batteries.

Chemical synthesis and structural studies of thiol-capped gold nanoparticles

2009 ◽  
Vol 87 (1) ◽  
pp. 335-340 ◽  
Author(s):  
Peng Zhang ◽  
Andy Yuan-Chi Chu ◽  
Tsun-Kong Sham ◽  
Yun Yao ◽  
Shuit-Tong Lee
Keyword(s):  
Chemical Synthesis ◽  
Chain Length ◽  
Silicon Nanowires ◽  
Au Nanoparticles ◽  
Silicon Nanowire ◽  
Spherical Particles ◽  
Phase System ◽  
Structural Studies ◽  
Two Phase ◽  
Au Nps

We report the chemical synthesis and structural studies of thiol-capped Au nanoparticles (NPs) using extended X-ray absorption fine structures (EXAFS) and high-resolution transmission electron microscopy (HRTEM). Synthesis of Au NPs was conducted in one case in a toluene/water two-phase system using alkanethiols with varied hydrocarbon chain length (C6, C12, and C18), resulting in NPs of sizes ranging from 1.6 nm to 5.4 nm. Au L3-edge EXAFS reveals a systematical trend of the local structure of Au in the NPs when the Au/S ratio and chain-length of thiols are varied. In another synthesis, thiol-capped Au NPs were prepared on the surface of silicon nanowires, which act as both substrates and reducing agents. HRTEM reveals that not only spherical particles but also very small quasi-1D nanostructures of Au were formed. The formation and structure of these Au NPs was discussed in terms of ligand and template effect associated with the silicon nanowire substrates.Key words: thiol-capped Au nanoparticles, EXAFS, silicon nanowires, electroless deposition, quasi-1D Au nanostructures.

Wideband Tunable Omnidirectional Infrared Absorbers Based on Doped-Silicon Nanowire Arrays

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
X. L. Liu ◽  
L. P. Wang ◽  
Z. M. Zhang
Keyword(s):  
Silicon Nanowires ◽  
Doping Concentration ◽  
Effective Medium Theory ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Wavelength Region ◽  
Nanowire Arrays ◽  
Radiative Properties ◽  
Silicon Nanowire Arrays ◽  
Doped Silicon

The present study considers the directional and spectral radiative properties of vertically aligned, heavily doped silicon nanowires for applications as broadband infrared diffuse absorbers. The nanowire array is modeled as a uniaxial medium whose anisotropic dielectric function is based on an effective medium theory. The approximation model is verified by the finite-difference time-domain method. It is found that the radiative properties of this type of nanostructured material could be tailored by controlling the doping concentration, volume filling ratio, and length of the nanowires. Increasing the wire length yields a broadening of the absorption plateau, while increasing the doping concentration results in a shift of the plateau to shorter wavelengths. Moreover, two kinds of omnidirectional absorbers/emitters could be realized based on the doped-silicon nanowire arrays. The first one is a wavelength-tunable wideband absorber, which may be important for applications in thermal imaging and thermophotovoltaic devices. The second acts as a quasi-blackbody in the wavelength region from 3 to 17 μm and, therefore, is promising for use as an absorber in bolometers that measure infrared radiation and as an emitter in space cooling devices that dissipate heat into free space via thermal radiation.

Large-Area Synthesis and Microstructural Investigations of Silicon Nanowires and Te/Bi2Te3-Si Core-Shell Structures

2011 ◽  
Vol 364 ◽  
pp. 243-247
Author(s):  
Inn Khuan Ng ◽  
Kuan Ying Kok ◽  
Siti Salwa Zainal Abidin ◽  
Nur Ubaidah Saidin ◽  
Thye Foo Choo
Keyword(s):  
Silicon Nanowires ◽  
Silicon Nanowire ◽  
Growth Conditions ◽  
Shell Structures ◽  
Core Shell ◽  
Redox Potentials ◽  
Large Area ◽  
Aspect Ratios ◽  
P Type ◽  
Microstructural Studies

Large-area randomly-oriented silicon nanowires (SiNWs) were synthesized using Au-coated p-type Si (100) substrates via the solid-liquid-solid (SLS) process under different growth conditions. Microstructural studies on the NWs produced showed that straight crystalline nanowires of large aspect ratios were generally obtained at a growth temperature of 1000°C along with some worm-like amorphous structures. Large-area vertically aligned silicon nanowire (SiNW) arrays on p-type (001) Si substrates were also synthesized in an aqueous solution containing AgNO3 and HF by self-selective electroless etching. Diameters of the SiNWs produced from both methods varied from 50 nm to 350 nm and their lengths generally extended from several to approximately a few tens of µm depending on the growth conditions used. Te-Si and Bi2Te3-Si core-shell structures were subsequently obtained via galvanic displacement of SiNWs in acidic HF electrolytes containing HTeO2+ and Bi3+/HTeO2+ ions. The reactions were basically a nanoelectrochemical process due to the difference in redox potentials between the materials. The modified SiNWs of core-shell structures had roughened surface morphologies and, therefore, higher surface-to-bulk ratios compared to unmodified SiNWs. They should have potential applications in sensors, photovoltaic and thermoelectric nanodevices. Microstructural studies on the SiNWs and core-shell structures produced are presented using various microscopy, diffraction and probe-based techniques for characterization.

scholarly journals Reusable Surface-Enhanced Raman Spectroscopy Substrates Made of Silicon Nanowire Array Coated with Silver Nanoparticles Fabricated by Metal-Assisted Chemical Etching and Photonic Reduction

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1531 ◽  
Author(s):  
Shi Bai ◽  
Yongjun Du ◽  
Chunyan Wang ◽  
Jian Wu ◽  
Koji Sugioka
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Etching ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate ◽  
Silicon Nanowire Array ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Metal Assisted Chemical Etching

Surface-enhanced Raman spectroscopy (SERS) has advanced over the last four decades and has become an attractive tool for highly sensitive analysis in fields such as medicine and environmental monitoring. Recently, there has been an urgent demand for reusable and long-lived SERS substrates as a means of reducing the costs associated with this technique To this end, we fabricated a SERS substrate comprising a silicon nanowire array coated with silver nanoparticles, using metal-assisted chemical etching followed by photonic reduction. The morphology and growth mechanism of the SERS substrate were carefully examined and the performance of the fabricated SERS substrate was tested using rhodamine 6G and dopamine hydrochloride. The data show that this new substrate provides an enhancement factor of nearly 1 × 108. This work demonstrates that a silicon nanowire array coated with silver nanoparticles is sensitive and sufficiently robust to allow repeated reuse. These results suggest that this newly developed technique could allow SERS to be used in many commercial applications.

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

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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