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Silicon nanowire

Ievgen Kurylo, Abderrahmane Hamdi, Ahmed Addad, Rabah Boukherroub, Yannick Coffinier
We created different TiO₂-based coatings on silicon nanowires (SiNWs) by using either thermal metallization or atomic layer deposition (ALD). The fabricated surfaces were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and reflectivity measurements. Surfaces with different TiO₂ based coating thicknesses were then used for phosphopeptide enrichment and subsequent detection by laser desorption/ionization mass spectrometry (LDI-MS). Results showed that the best enrichment and LDI-MS detection were obtained using the silicon nanowires covered with 10 nm of oxidized Ti deposited by means of thermal evaporation...
September 15, 2017: Nanomaterials
Bo Fu, Guihua Tang, Yifei Li
Nanostructuring technology has been widely employed to reduce the thermal conductivity of thermoelectric materials because of the strong phonon-boundary scattering. Optimizing the carrier concentration can not only improve the electrical properties, but also affect the lattice thermal conductivity significantly due to the electron-phonon scattering. The lattice thermal conductivity of silicon nanostructures considering electron-phonon scattering is investigated for comparing the lattice thermal conductivity reductions resulting from nanostructuring technology and the carrier concentration optimization...
September 13, 2017: Physical Chemistry Chemical Physics: PCCP
Emma E M Cating, Christopher W Pinion, Joseph D Christesen, Caleb A Christie, Erik M Grumstrup, James F Cahoon, John M Papanikolas
Surface trap density in silicon nanowires (NWs) plays a key role in the performance of many semiconductor NW-based devices. We use pump-probe microscopy to characterize the surface recombination dynamics on a point-by-point basis in 301 silicon NWs grown using the vapor-liquid-solid (VLS) method. The surface recombination velocity (S), a metric of the surface quality that is directly proportional to trap density, is determined by the relationship S = d/4τ from measurements of the recombination lifetime (τ) and NW diameter (d) at distinct spatial locations in individual NWs...
September 12, 2017: Nano Letters
Pantea Aurang, Rasit Turan, Husnu Emrah Unalan
Reducing silicon (Si) wafer thickness in the photovoltaic industry has always been demanded for lowering the overall cost. Further benefits such as short collection lengths and improved open circuit voltages can also be achieved by Si thickness reduction. However, the problem with thin films is poor light absorption. One way to decrease optical losses in photovoltaic devices is to minimize the front side reflection. This approach can be applied to front contacted ultra-thin crystalline Si solar cells to increase the light absorption...
October 6, 2017: Nanotechnology
Dong Liu, Leimiao Lin, Qiaofen Chen, Hongzhi Zhou, Jianmin Wu
Silicon nanowires/TiO2 (SiNWs/TiO2) array with core-shell nanostructure was created by sol-gel and drop-casting methods. The hybrid material displayed excellent sensing performance for CH4 detection at room temperature. The chemiresistor sensor has a linear response towards CH4 gas in 30 ~ 120 ppm range with a detection limit of 20 ppm, which is well below most of CH4 sensors reported before. The enhanced gas sensing performance at room temperature was attributed to the creation of heterojunctions that form a depletion layer at the interface of SiNWs and TiO2 layer...
September 11, 2017: ACS Sensors
Xin Min, Minghao Fang, Haitao Liu, Yan'gai Liu, Xiaowen Wu, Zhaohui Huang
Novel silica nanowires and interconnected nanorings were firstly synthesized on a graphite paper by typical thermal catalytic chemical vapor deposition method, using silicon and carbon black powders as raw materials. The field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were used to investigate the composition and structure characterization, which indicates that the silica nanowires and interconnected nanorings were amorphous...
September 5, 2017: Scientific Reports
Yoichi M A Yamada
My mission in catalysis research is to develop highly active and reusable supported catalytic systems in terms of fundamental chemistry and industrial application. For this purpose, I developed three types of highly active and reusable supported catalytic systems. The first type involves polymeric base-supported metal catalysts: Novel polymeric imidazole-Pd and Cu complexes were developed that worked at the mol ppm level for a variety of organic transformations. The second involves catalytic membrane-installed microflow reactors: Membranous polymeric palladium and copper complex/nanoparticle catalysts were installed at the center of a microtube to produce novel catalytic membrane-immobilized flow microreactor devices...
2017: Chemical & Pharmaceutical Bulletin
Xingli Zou, Li Ji, Xionggang Lu, Zhongfu Zhou
Silicon carbide nanowires (SiC NWs) have attracted intensive attention in recent years due to their outstanding performances in many applications. A large-scale and facile production of SiC NWs is critical to its successful application. Here, we report a simple method for the production of SiC NWs from inexpensive and abundantly available silica/carbon (SiO2/C) precursors in molten calcium chloride. The solid-to-solid electroreduction and dissolution-electrodeposition mechanisms can easily lead to the formation of homogenous SiC NWs...
August 30, 2017: Scientific Reports
Hao Zhu, Haitao Li, Joseph Robertson, Arvind Balijepalli, Sergiy Krylyuk, Albert Davydov, John J Kasianowicz, John Suehle, Qiliang Li
Novel nanofluidic chemical cells based on self-assembled solid-state SiO2 nanotubes on silicon-on-insulator (SOI) substrate have been successfully fabricated and characterized. The vertical SiO2 nanotubes with a smooth cavity are built from Si nanowires which were epitaxially grown on the SOI substrate. The nanotubes have rigid, dry-oxidized SiO2 walls with precisely controlled nanotube inner diameter, very attractive for chemical-/bio-sensing applications. No dispersion/aligning procedures were involved in the nanotube fabrication and integration by using this technology, enabling clean and smooth chemical cell...
August 30, 2017: Nanotechnology
Yuxiang Qin, Diao Liu, Tianyi Zhang, Zhen Cui
Surface functionalization is very effective in enhancing sensing properties of a chemiresistive gas sensor. In this work, we develop a novel and cost-effective process to prepare Ag-modified silicon nanowire (SiNW) sensors and further suggest a resistance effect model to clarify the enhanced sensing mechanism of Ag-modified SiNWs. The SiNWs were formed via metal-assisted chemical etching (MACE), and the Ag nanoparticle (NP) modification was achieved in situ based on the MACE-produced Ag dendrites by involving a crucial anisotropic postetching of TMAH...
August 30, 2017: ACS Applied Materials & Interfaces
Zhishan Yuan, Chengyong Wang, Ke Chen, Zhonghua Ni, Yunfei Chen
In this paper, amorphous silicon nanowires (α-SiNWs) were synthesized on (100) Si substrate with silicon oxide film by Cu catalyst-driven solid-liquid-solid mechanism (SLS) during annealing process (1080 °C for 30 min under Ar/H2 atmosphere). Micro size Cu pattern fabrication decided whether α-SiNWs can grow or not. Meanwhile, those micro size Cu patterns also controlled the position and density of wires. During the annealing process, Cu pattern reacted with SiO2 to form Cu silicide. More important, a diffusion channel was opened for Si atoms to synthesis α-SiNWs...
August 10, 2017: Nanoscale Research Letters
Eero S Koivusalo, Teemu V Hakkarainen, Mircea D Guina, Vladimir G Dubrovskii
Herein, we present experimental data on the record length uniformity within the ensembles of semiconductor nanowires. The length distributions of Ga-catalyzed GaAs nanowires obtained by cost-effective lithography-free technique on silicon substrates systematically feature a pronounced sub-Poissonian character. For example, nanowires with the mean length ⟨L⟩ of 2480 nm show a length distribution variance of only 367 nm(2), which is more than twice smaller than the Poisson variance h⟨L⟩ of 808 nm(2) for this mean length (with h = 0...
September 13, 2017: Nano Letters
Matteo Salvato, Reza Baghdadi, Carla Cirillo, Serghej L Prischepa, Alexey Dolgiy, Vitaly Bondarenko, Floriana Lombardi, Carmine Attanasio
Superconducting NbN nanonetworks with a very small number of interconnected nanowires, with diameter of the order of 4 nm, are fabricated combining a bottom-up (use of porous silicon nanotemplates) with a top-down technique (high-resolution electron beam lithography). The method is easy to control and allows to fabricate, on a robust support, devices with electrical properties close to a one-dimensional superconductor that can be fruitfully used for novel applications.
August 7, 2017: Nanotechnology
Brian Ford, Natasha Tabassum, Vasileios Nikas, Spyros Gallis
The following study focuses on the photoluminescence (PL) enhancement of chemically synthesized silicon oxycarbide (SiCxOy) thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD), and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H₂, 95% N₂) ambients, modifying the observed white light emission...
April 23, 2017: Materials
Zhen-Qiang Ye, Bing-Yang Cao
Thermal rectification can help develop modern thermal manipulation devices but has been rarely engineered. Here, we validated the nanoscale bimaterial interface-induced thermal rectification experimentally for the first time and investigated its underlying mechanism via molecular dynamics simulations. The thermal diode consists of polyamide (PA) and silicon (Si) nanowires in contact with each other. The thermal rectification ratio measured by a high-precision nanoscale experiment reached 4% with an uncertainty of <1%...
August 2, 2017: Nanoscale
Hyunseok Kim, Wook-Jae Lee, Alan C Farrell, Akshay Balgarkashi, Diana L Huffaker
Semiconductor nanowire lasers are considered promising ultracompact and energy-efficient light sources in the field of nanophotonics. Although the integration of nanowire lasers onto silicon photonic platforms is an innovative path toward chip-scale optical communications and photonic integrated circuits, operating nanowire lasers at telecom-wavelengths remains challenging. Here, we report on InGaAs nanowire array lasers on a silicon-on-insulator platform operating up to 1440 nm at room temperature. Bottom-up photonic crystal nanobeam cavities are formed by growing nanowires as ordered arrays using selective-area epitaxy, and single-mode lasing by optical pumping is demonstrated...
September 13, 2017: Nano Letters
Liye Zhang, Junshan Yin, Wei Yu, Mingzhu Wang, Huaqing Xie
In this paper, ultra-long copper nanowires (CuNWs) were successfully synthesized at a large scale by hydrothermal reduction of divalent copper ion using oleylamine and oleic acid as dual ligands. The characteristic of CuNWs is hard and linear, which is clearly different from graphene nanoplatelets (GNPs) and multi-wall carbon nanotubes (MWCNTs). The thermal properties and models of silicone composites with three nanomaterials have been mainly researched. The maximum of thermal conductivity enhancement is up to 215% with only 1...
December 2017: Nanoscale Research Letters
Zi Wang, Zhongyu Hou
A room-temperature routine for the fabrication of a three-dimensional silicon porous framework inspired by a polymer foaming process is introduced. The obtained micron-sized pores can be further modified by hydrothermal growth of nanowires to form a hierarchical porous composite framework.
July 24, 2017: Chemical Communications: Chem Comm
Juan Arturo Alanis, Dhruv Saxena, Sudha Mokkapati, Nian Jiang, Kun Peng, Xiaoyan Tang, Lan Fu, Hark Hoe Tan, Chennupati Jagadish, Patrick Parkinson
Single nanowire lasers based on bottom-up III-V materials have been shown to exhibit room-temperature near-infrared lasing, making them highly promising for use as nanoscale, silicon-integrable, and coherent light sources. While lasing behavior is reproducible, small variations in growth conditions across a substrate arising from the use of bottom-up growth techniques can introduce interwire disorder, either through geometric or material inhomogeneity. Nanolasers critically depend on both high material quality and tight dimensional tolerances, and as such, lasing threshold is both sensitive to and a sensitive probe of such inhomogeneity...
July 25, 2017: Nano Letters
Hao Cui, Shuoyu Li, Shaozhi Deng, Huanjun Chen, Chengxin Wang
We demonstrated a flexible transparent and free-standing Si nanowire paper (SiNWP) as a surface enhanced Raman scattering (SERS) platform for in situ chemical sensing on warping surfaces with high sensitivity. The SERS activity has originated from the three-dimension interconnected nanowire network structure and electromagnetic coupling between closely separated nanowires in the SiNWP. In addition, the SERS activity can be highly improved by functionalizing the SiNWP with plasmonic Au nanoparticles. The hybrid substrate not only showed excellent reproducibility and stability of the SERS signal, but also maintained the flexibility and transparency of the pristine SiNWP...
March 24, 2017: ACS Sensors
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