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Silicon nanowire

Stepan Nichkalo, Anatoly Druzhinin, Anatoliy Evtukh, Oleg Bratus', Olga Steblova
This work pertains to the method for modification of silicon (Si) wafer morphology by metal-assisted chemical etching (MacEtch) technique suitable for fabrication of antireflective Si surfaces. For this purpose, we made different Au catalyst patterns on the surface of Si substrate. This modification allowed to obtain the close-packed Au nanodrop (ND) pattern that generates the nanowires (NWs) and the well-separated Au NDs, which induce the nanopore (NP) formation. The antireflective properties of these structures in comparison with NWs produced by the conventional Ag-MacEtch method were analysed...
December 2017: Nanoscale Research Letters
Mustafa Yılmaz, Nicole Wollschläger, Mohammad Nasr Esfahani, Werner Österle, Yusuf Leblebici, B Erdem Alaca
Silica nanowires spanning 10 μm-deep trenches are fabricated from different types of silsesquioxane-based precursors by direct e-beam patterning on silicon followed by release through deep reactive ion etching. Nanowire aspect ratios as large as 150 are achieved with a critical dimension of about 50 nm and nearly rectangular cross-sections. In situ bending tests are carried out inside a scanning electron microscope, where the etch depth of 10 [Formula: see text] provides sufficient space for deformation. Silica NWs are indeed observed to exhibit superplastic behavior without fracture with deflections reaching the full etch depth, about two orders of magnitude larger than the nanowire thickness...
February 16, 2017: Nanotechnology
P Lagonegro, F Rossi, C Galli, A Smerieri, R Alinovi, S Pinelli, T Rimoldi, G Attolini, G Macaluso, C Macaluso, S E Saddow, G Salviati
GOAL: Nanowires are promising biomaterials in multiple clinical applications. The goal of this study was to investigate the cytotoxicity of carbon-doped silica nanowires (SiOxCy NWs) on a fibroblastic cell line in vitro. MATERIALS AND METHODS: SiOxCy NWs were grown on Si substrates by CVD process. Murine L929 fibroblasts were cultured in complete DMEM and indirect and direct cytotoxicity tests were performed in agreement with ISO 19003-5, by quantitating cell viability at MTT and chemiluminescent assay...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Cheol-Min Lim, In-Kyu Lee, Ki Joong Lee, Young Kyoung Oh, Yong-Beom Shin, Won-Ju Cho
This work describes the construction of a sensitive, stable, and label-free sensor based on a dual-gate field-effect transistor (DG FET), in which uniformly distributed and size-controlled silicon nanowire (SiNW) arrays by nanoimprint lithography act as conductor channels. Compared to previous DG FETs with a planar-type silicon channel layer, the constructed SiNW DG FETs exhibited superior electrical properties including a higher capacitive-coupling ratio of 18.0 and a lower off-state leakage current under high-temperature stress...
2017: Science and Technology of Advanced Materials
Q D Zhuang, H Alradhi, Z M Jin, X R Chen, J Shao, X Chen, Ana M Sanchez, Y C Cao, J Y Liu, P Yates, K Durose, C J Jin
InAsSb nanowires (NWs) with a high Sb content have potential in the fabrication of advanced silicon-based optoelectronics such as infrared photondetectors/emitters and highly sensitive phototransistors, as well as in the generation of renewable electricity. However, producing optically efficient InAsSb NWs with a high Sb content remains a challenge, and optical emission is limited to 4.0 μm due to the quality of the nanowires. Here, we report, for the first time, the success of high-quality and optically efficient InAsSb NWs enabling silicon-based optoelectronics operating in entirely mid-wavelength infrared...
March 10, 2017: Nanotechnology
Laura Andolfi, Anna Murello, Damiano Cassese, Jelena Ban, Simone Dal Zilio, Marco Lazzarino
The cell-cell and cell-matrix interactions are essential to the survival and proliferation of most cells, and are responsible of triggering a wide range of biochemical pathways. More recently, also the biomechanical role of those interactions was highlighted, showing, for instance that adhesion forces are essential for the cytoskeleton organization. Silicon-nanowires (Si-NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in the cellular development...
February 8, 2017: Nanotechnology
Janneke Veerbeek, Liang Ye, Wouter Vijselaar, Tibor Kudernac, Wilfred G van der Wiel, Jurriaan Huskens
Controlling the doping concentration of silicon nanostructures is challenging. Here, we investigated three different monolayer doping techniques to obtain silicon nanowires with a high doping dose. These routes were based on conventional monolayer doping, starting from covalently bound dopant-containing molecules, or on monolayer contact doping, in which a source substrate coated with a monolayer of a carborane silane was the dopant source. As a third route, both techniques were combined to retain the benefits of conformal monolayer formation and the use of an external capping layer...
February 7, 2017: Nanoscale
Daksh Agarwal, Carlos Aspetti, Matteo Cargnello, Mingliang Ren, Jinkyoung Yoo, Christopher B Murray, Ritesh Agarwal
The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat. We report a highly engineered nanowire cavity, which utilizes a high dielectric silicon core with a thin plasmonic film (Au) to create an effective metallic cavity to strongly confine light, which when coupled with localized surface plasmons in the nanoparticles of the thin metal film produces exceptionally high temperatures upon laser irradiation...
February 6, 2017: Nano Letters
Yi Hou, Laifei Cheng, Yani Zhang, Yong Yang, Chaoran Deng, Zhihong Yang, Qi Chen, Peng Wang, Lianxi Zheng
Fe/SiC hybrid fibers have been fabricated by electrospinning and subsequent high-temperature (1300 °C) pyrolysis in Ar atmosphere using polycarbosilane (PCS) and Fe3O4 precursors. It is found that the introduction of Fe has had a dramatic impact on the morphology, crystallization temperature, and microwave electromagnetic properties of the hybrid fibers. In addition, the Fe particles have acted as catalyst sites to facilitate the growth of SiCO nanowires on the surface of the hybrid fibers. As a result, the permittivity and permeability have been enhanced effectively, and the high reflection loss (RL) has been achieved at a low frequency band with a thin absorber thickness...
February 16, 2017: ACS Applied Materials & Interfaces
Houyu Wang, Yao He
During the past decades, owing to silicon nanomaterials' unique optical properties, benign biocompatibility, and abundant surface chemistry, different dimensional silicon nanostructures have been widely employed for rationally designing and fabricating high-performance fluorescent sensors for the detection of various chemical and biological species. Among of these, zero-dimensional silicon nanoparticles (SiNPs) and one-dimensional silicon nanowires (SiNWs) are of particular interest. Herein, we focus on reviewing recent advances in silicon nanomaterials-based fluorescent sensors from a broad perspective and discuss possible future directions...
February 3, 2017: Sensors
Bilal Janjua, Haiding Sun, Chao Zhao, Dalaver H Anjum, Davide Priante, Abdullah A Alhamoud, Feng Wu, Xiaohang Li, Abdulrahman M Albadri, Ahmed Y Alyamani, Munir M El-Desouki, Tien Khee Ng, Boon S Ooi
Currently the AlGaN-based ultraviolet (UV) solid-state lighting research suffers from numerous challenges. In particular, low internal quantum efficiency, low extraction efficiency, inefficient doping, large polarization fields, and high dislocation density epitaxy constitute bottlenecks in realizing high power devices. Despite the clear advantage of quantum-confinement nanostructure, it has not been widely utilized in AlGaN-based nanowires. Here we utilize the self-assembled nanowires (NWs) with embedding quantum-disks (Qdisks) to mitigate these issues, and achieve UV emission of 337 nm at 32 A/cm<sup>2</sup> (80 mA in 0...
January 23, 2017: Optics Express
Jeremie Maire, Roman Anufriev, Masahiro Nomura
We have experimentally investigated the impact of dimensions and temperature on the thermal conductivity of silicon nanowires fabricated using a top-down approach. Both the width and temperature dependences of thermal conductivity agree with those in the existing literature. The length dependence of thermal conductivity exhibits a transition from semi-ballistic thermal phonon transport at 4 K to fully diffusive transport at room temperature. We additionally calculated the phonon dispersion in these structures in the framework of the theory of elasticity and showed that the thermal conductance increases with width...
February 2, 2017: Scientific Reports
Zhenning Dong, Yamina André, Vladimir G Dubrovskii, Catherine Bougerol, Christine Leroux, Mohammed R Ramdani, Guillaume Monier, Agnès Trassoudaine, Dominique Castelluci, Evelyne Gil
Gold-free GaAs nanowires on silicon substrates can pave the way for monolithic integration of photonic nanodevices with silicon electronic platforms. It is extensively documented that the self-catalyzed approach works well in molecular beam epitaxy but is much more difficult to implement in vapor phase epitaxies. Here, we report the first gallium-catalyzed hydride vapor phase epitaxy growth of long (more than 10 μm) GaAs nanowires on Si(111) substrates with a high integrated growth rate up to 60 μm h(-1) and pure zincblende crystal structure...
January 31, 2017: Nanotechnology
Stefano Stassi, Alessandro Chiadò, Valentina Cauda, Gianluca Palmara, Giancarlo Canavese, Marco Laurenti, Carlo Ricciardi
An efficient way to increase the binding capability of microcantilever biosensors is here demonstrated by growing zinc oxide nanowires (ZnO NWs) on their active surface. A comprehensive evaluation of the chemical compatibility of ZnO NWs brought to the definition of an innovative functionalization method able to guarantee the proper immobilization of biomolecules on the nanostructured surface. A noteworthy higher amount of grafted molecules was evidenced with colorimetric assays on ZnO NWs-coated devices, in comparison with functionalized and activated silicon flat samples...
January 30, 2017: Analytical and Bioanalytical Chemistry
Minjae Gang, Joo-Hyoung Lee
We propose a novel hybrid structure for improving the efficiency of crystalline silicon solar cells. By employing first-principles calculations, we demonstrate that ordered, nanoporous silicon (np-Si), when filled with polythiophene (PT) inside the pores, exhibits a substantially enhanced absorption coefficient compared to both np-Si and the bulk, which makes the np-Si/PT heterojunction a superior light absorbing material. In addition, the PT-filled porous structure forms a staggered gap, or type II, heterojunction at the interfaces, where the valence band maximum and conduction band minimum of the composite reside on PT and np-Si, respectively...
January 31, 2017: Physical Chemistry Chemical Physics: PCCP
Zhiqiang Mu, Haochi Yu, Miao Zhang, Aimin Wu, Gongmin Qi, Paul K Chu, Zhenghua An, Zengfeng Di, Xi Wang
Besides the well-known quantum confinement effect, hot luminescence from indirect bandgap Si provides a new and promising approach to realize monolithically integrated silicon optoelectronics due to phonon-assisted light emission. In this work, multiband hot photoluminescence is generated from Si nanowire arrays by introducing trapezoid-shaped nanocavities that support hybrid photonic-plasmonic modes. By continuously adjusting the geometric parameters of the Si nanowires with trapezoidal nanocavities, the multiband hot photoluminescence can be tuned in the range from visible to near infrared independent of the excitation laser wavelength...
January 30, 2017: Nano Letters
Laura Scheidegger, Miguel Ángel Fernández-Rodríguez, Karen Geisel, Michele Zanini, Roey Elnathan, Walter Richtering, Lucio Isa
Controlling the microstructure of monolayers of microgels confined at a water/oil interface is the key to their successful application as nanolithography masks after deposition on a solid substrate. Previous work demonstrated that compression of the monolayer can be used to tune the microgel arrangement and to explore the full two-dimensional area-pressure phase diagram of the particles trapped at the interface. Here, we explore a new size range, using microgels with 210 nm and 1.45 μm bulk diameters, respectively...
January 27, 2017: Physical Chemistry Chemical Physics: PCCP
Qian Liu, Zhe Cui, Rujia Zou, Jianhua Zhang, Kaibing Xu, Junqing Hu
Here a simple and an environmentally friendly approach is developed for the fabrication of Si-void@SiOx nanowires of a high-capacity Li-ion anode material. The outer surface of the robust SiOx backbone and the inside void structure in Si-void@SiOx nanowires appropriately suppress the volume expansion and lead to anisotropic swelling morphologies of Si nanowires during lithiation/delithiation, which is first demonstrated by the in situ lithiation process. Remarkably, the Si-void@SiOx nanowire electrode exhibits excellent overall lithium-storage performance, including high specific capacity, high rate property, and excellent cycling stability...
January 25, 2017: Small
Samit K Ray, Ajit K Katiyar, Arup K Raychaudhuri
Remarkable progress has been made in the field of one-dimensional semiconductor nanostructures for electronic and photonic devices. Group-IV semiconductors and their heterostructures have dominated the years of success in microelectronic industry. However their use in photonic devices is limited since they exhibit poor optical activity due to indirect band gap nature of Si and Ge. Reducing their dimensions below a characteristic length scale of various fundamental parameters like exciton Bohr radius, phonon mean free path, critical size of magnetic domains, exciton diffusion length etc result in the significant modification of bulk properties...
January 25, 2017: Nanotechnology
Jun-Sik Yoon, Kihyun Kim, Chang-Ki Baek
We propose three-terminal core-shell (CS) silicon vertical nanowire tunneling field-effect transistors (TFETs), which can be fabricated by conventional CMOS technology. CS TFETs show lower subthreshold swing (SS) and higher on-state current than conventional TFETs through their high surface-to-volume ratio, which increases carrier-tunneling region with no additional device area. The on-state current can be enhanced by increasing the nanowire height, decreasing equivalent oxide thickness (EOT) or creating a nanowire array...
January 23, 2017: Scientific Reports
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