Atomic structure of metal-free and catalyzed Si nanowires

2011 ◽  
Vol 1305 ◽  
Author(s):  
Giuseppe Nicotra ◽  
Corrado Bongiorno ◽  
Annalisa Convertino ◽  
Massimo Cuscunà ◽  
Faustino Martelli ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanowires ◽  
Wire Diameter ◽  
Si Nanowires ◽  
Metal Free ◽  
Free Process ◽  
Transmission Electron ◽  
Structure Of Metal ◽  
The Wire ◽  
Polytype Structure

ABSTRACTMetal-free and Au-catalyzed silicon nanowires (Si-NWs) grown at low temperatures have been analyzed through transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and their crystalline phase studied. All the observed nanowires are crystalline, grow along two different directions, <110> or <112>, and contain high density of planar defects, such as stacking faults (SFs) and twins. The defect size is comparable to the wire diameter for the metal-free process whilst it is much larger than the wire diameter for the Aucatalyzed Si-NWs. In this latter case parallel SFs may re-arrange and transform in a metastable rhombohedral 9R polytype structure whose formation mechanism is discussed.

The Preparation of Fine Recrystallized Tungsten Wire for Transmission Electron Microscopy

1967 ◽  
Vol 25 ◽  
pp. 362-363
Author(s):  
E. F. Koch ◽  
J. L. Walter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tungsten Wire ◽  
Central Area ◽  
Wire Diameter ◽  
Structure And Properties ◽  
Tungsten Filament ◽  
Transmission Electron ◽  
The Wire ◽  
Coil Winding

In a study of the structure and properties of tungsten wire used for lamp filaments, it became desirable to perform transmission electron microscopy on the wire in the annealed as well as in the drawn condition.Wire used for lamp filaments is generally drawn to diameters less than 0.010" which is too fine for the preparation of transmission samples from single wires. Thus, it is clear that some assembly of wires must be used to form a “wire sheet” similar to that used by Glenn and Duff.Commercially-doped (218) tungsten filament wire in diameters of 0.001", 0.004", and 0.010" was wound on 1" square tungsten plates, 0.060" thick, using standard coil-winding techniques. After winding, the plates were annealed at temperatures of 1800°C to 2200°C, in vacuo. Following the anneal, the samples were treated in one of two ways. The 0.010" and 0.004" diameter wire sheets were encapsulated in epoxy and ground from both faces to a thickness of about 1/2 the wire diameter. The exposed wires were then electropolished with 107. NaOH electrolyte. The epoxy protected the edges of the flat wires so that the central area of the wire could be thinned.

scholarly journals Odd electron diffraction patterns in silicon nanowires and silicon thin films explained by microtwins and nanotwins

2009 ◽  
Vol 42 (2) ◽  
pp. 242-252 ◽  
Author(s):  
Cyril Cayron ◽  
Martien Den Hertog ◽  
Laurence Latu-Romain ◽  
Céline Mouchet ◽  
Christopher Secouard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Silicon Nanowires ◽  
Si Nanowires ◽  
Silicon Thin Films ◽  
Transmission Electron ◽  
Diffraction Patterns

Odd electron diffraction patterns (EDPs) have been obtained by transmission electron microscopy (TEM) on silicon nanowires grownviathe vapour–liquid–solid method and on silicon thin films deposited by electron beam evaporation. Many explanations have been given in the past, without consensus among the scientific community: size artifacts, twinning artifacts or, more widely accepted, the existence of new hexagonal Si phases. In order to resolve this issue, the microstructures of Si nanowires and Si thin films have been characterized by TEM, high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy. Despite the differences in the geometries and elaboration processes, the EDPs of the materials show great similarities. The different hypotheses reported in the literature have been investigated. It was found that the positions of the diffraction spots in the EDPs could be reproduced by simulating a hexagonal structure withc/a= 12(2/3)1/2, but the intensities in many EDPs remained unexplained. Finally, it was established that all the experimental data,i.e.EDPs and HRTEM images, agree with a classical cubic silicon structure containing two microstructural defects: (i) overlapping Σ3 microtwins which induce extra spots by double diffraction, and (ii) nanotwins which induce extra spots as a result of streaking effects. It is concluded that there is no hexagonal phase in the Si nanowires and the Si thin films presented in this work.

Polymorphous silicon nanowires synthesized by plasma-enhanced chemical vapor deposition

2002 ◽  
Vol 737 ◽  
Author(s):  
X.B. Zeng ◽  
X.B. Liao ◽  
H.W. Diao ◽  
Z.H. Hu ◽  
Y.Y. Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Silicon Nanowires ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
The Body ◽  
Si Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ABSTRACTPolymorphous Si nanowires (SiNWS) have been successfully synthesized on Si wafer by plasma enhanced chemical vapor deposition (PECVD) at 440°C, using silane as the Si source and Au as the catalyst. To grow the polymorphous SiNWS preannealing the Si substrate with Au film at 1100 °C is needed. The diameters of Si nanowires range from 15 to 100 nm. The structure, morphology and chemical composition of the SiNWS have been characterized by high resolution x-ray diffraction, scanning electron microscopy, transmission electron microscopy, as well as energy dispersive x-ray spectroscopy. A few interesting nanowires with Au nanoclusters uniformly distributed in the body of the wire were also produced by this technique.

Conversion of Si Nanowires into SiC Nanotubes

2012 ◽  
Vol 717-720 ◽  
pp. 1275-1278
Author(s):  
Maelig Ollivier ◽  
Laurence Latu-Romain ◽  
Edwige Bano ◽  
Arnaud Mantoux ◽  
Thierry Baron
Keyword(s):  
Electron Microscopy ◽  
Silicon Carbide ◽  
Silicon Nanowires ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Si Nanowires ◽  
Silicon Carbide Nanotubes ◽  
Transmission Electron ◽  
Tubular Shape ◽  
Scanning Electron

Carburization of silicon nanowires (NWs), with diameters of about 800 nm and lengths of about 10 µm, under methane at high temperature in order to obtain silicon carbide (SiC) nanostructures is reported here. The produced SiC nanostructures display a tubular shape and are polycrystalline. The as-prepared silicon carbide nanotubes (NTs) were characterized and studied by scanning electron microscopy (SEM), dual focused ion beam – scanning electron microscope (FIB-SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The formation of nanotubes can be explained by the out-diffusion of Si through the SiC during the carburization process.

In Situ Growth of Si Nanowires Using Transmission Electron Microscopy

2013 ◽  
Vol 58 (8) ◽  
pp. 105-111
Author(s):  
Y.-C. Chou ◽  
C.-Y. Wen ◽  
M. C. Reuter ◽  
D. Su ◽  
E. A. Stach ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
In Situ Growth ◽  
Si Nanowires ◽  
Transmission Electron

A systematic study of silicon nanowires array fabricated through metal-assisted chemical etching

2020 ◽  
Vol 92 (3) ◽  
pp. 30402
Author(s):  
Shiying Zhang ◽  
Zhenhua Li ◽  
Qingjun Xu
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanowires ◽  
Chemical Etching ◽  
Optimal Solution ◽  
Solution Concentration ◽  
Etching Time ◽  
Si Nanowires ◽  
Selected Area Electron Diffraction ◽  
Initial Silicon ◽  
Metal Assisted Chemical Etching

Aligned and uniform silicon nanowires (SiNWs) arrays were fabricated with good controllability and reproducibility by metal-assisted chemical etching in aqueous AgNO3/HF etching solutions in atmosphere. The SiNWs formed on silicon were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED). The results show that the as-prepared SiNWs are perfectly single crystals and the axial orientation of the Si nanowires is identified to be parallel to the [111] direction, which is identical to the initial silicon wafer. In addition, a series of experiments were conducted to study the effects of etching conditions such as solution concentration, etching time, and etching temperature on SiNWs. And the optimal solution concentrations for SiNWs have been identified. The formation mechanism of silicon nanowires and silver dendrites were also discussed.

scholarly journals Towards Reconfigurable Electronics: Silicidation of Top-Down Fabricated Silicon Nanowires

2019 ◽  
Vol 9 (17) ◽  
pp. 3462 ◽  
Author(s):  
Muhammad Bilal Khan ◽  
Dipjyoti Deb ◽  
Jochen Kerbusch ◽  
Florian Fuchs ◽  
Markus Löffler ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanowires ◽  
Inductively Coupled Plasma ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Density Functional Theory Calculations ◽  
Silicide Phase ◽  
Top Down ◽  
Inductively Coupled ◽  
Transmission Electron

We present results of our investigations on nickel silicidation of top-down fabricated silicon nanowires (SiNWs). Control over the silicidation process is important for the application of SiNWs in reconfigurable field-effect transistors. Silicidation is performed using a rapid thermal annealing process on the SiNWs fabricated by electron beam lithography and inductively-coupled plasma etching. The effects of variations in crystallographic orientations of SiNWs and different NW designs on the silicidation process are studied. Scanning electron microscopy and transmission electron microscopy are performed to study Ni diffusion, silicide phases, and silicide–silicon interfaces. Control over the silicide phase is achieved together with atomically sharp silicide–silicon interfaces. We find that {111} interfaces are predominantly formed, which are energetically most favorable according to density functional theory calculations. However, control over the silicide length remains a challenge.

Ti-Island-Catalyzed Si Nanowire Growth by Gas-Source MBE: Morphology and Twinning

2002 ◽  
Vol 728 ◽  
Author(s):  
Qiang Tang ◽  
Xian Liu ◽  
Theodore I. Kamins ◽  
Glenn S. Solomon ◽  
James S. Harris
Keyword(s):  
Electron Microscopy ◽  
Silicon Nanowires ◽  
High Energy ◽  
Growth Direction ◽  
Epitaxial Silicon ◽  
First Order ◽  
Gas Source ◽  
Transmission Electron ◽  
Gas Source Mbe

AbstractSilicon nanowires catalyzed by Ti islands have been grown by molecular beam epitaxy (MBE) using Si2H6 as the gas source and characterized by in situ reflection high-energy electron diffraction (RHEED), scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM). Approximately one monolayer of Ti was deposited on Si(001) wafers, which, during annealing, reacted with silicon and formed TiSi2 islands. After annealing, but before Si growth, the stoichiometric TiSi2 (C49) phase was observed with RHEED.The silicon nanowires are typically between 20 and 40 nanometers in diameter and several hundred nanometers long. The nanowires changed their growth direction several times during growth, resulting in complex RHEED patterns, which can be matched very well by simulated RHEED patterns calculated assuming that the nanowires change their direction by twinning along (111) planes. RHEED patterns of epitaxial silicon nanowires, first-order twinned nanowires (twinned relative to the substrate orientation), second-order twinned nanowires (twinned relative to the first-order twin), and TiSi2 were observed.

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