scholarly journals Post-nucleation evolution of the liquid-solid interface in nanowire growth

2021 ◽  
Author(s):  
Carina B Maliakkal ◽  
Daniel Jacobsson ◽  
Marcus Ulf Tornberg ◽  
Kimberly Dick
Keyword(s):  
Interface Energy ◽  
Growth Direction ◽  
Direction Selectivity ◽  
Nanowire Growth ◽  
Catalyst Droplet ◽  
Transmission Electron ◽  
Gaas Nanowires ◽  
Amorphous Substrates ◽  
First Time

Abstract We study using in situ transmission electron microscopy the birth of GaAs nanowires from liquid Au-Ga catalysts on amorphous substrates. Lattice-resolved observations of the starting stages of growth are reported here for the first time. It reveals how the initial nanostructure evolves into a nanowire growing in a zincblende <111> or the equivalent wurtzite <0001> direction. This growth direction(s) is what is typically observed in most III-V and II-VI nanowires. However, the reason for this preferential nanowire growth along this direction is still a dilemma. Based on the videos recorded shortly after the nucleation of nanowires, we argue that the lower catalyst droplet-nanowire interface energy of the {111} facet when zincblende (or the equivalent {0001} facet in wurtzite) is the reason for this direction selectivity in nanowires.

scholarly journals In situ analysis of catalyst composition during gold catalyzed GaAs nanowire growth

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Carina B. Maliakkal ◽  
Daniel Jacobsson ◽  
Marcus Tornberg ◽  
Axel R. Persson ◽  
Jonas Johansson ◽  
...  
Keyword(s):  
Catalyst Particle ◽  
Nanowire Growth ◽  
Clear Understanding ◽  
X Ray ◽  
Catalyst Composition ◽  
Gaas Nanowires ◽  
Gaas Nanowire ◽  
First Time ◽  
Novel Structures

Abstract Semiconductor nanowires offer the opportunity to incorporate novel structures and functionality into electronic and optoelectronic devices. A clear understanding of the nanowire growth mechanism is essential for well-controlled growth of structures with desired properties, but the understanding is currently limited by a lack of empirical measurements of important parameters during growth, such as catalyst particle composition. However, this is difficult to accurately determine by investigating post-growth. We report direct in situ measurement of the catalyst composition during nanowire growth for the first time. We study Au-seeded GaAs nanowires inside an electron microscope as they grow and measure the catalyst composition using X-ray energy dispersive spectroscopy. The Ga content in the catalyst during growth increases with both temperature and Ga precursor flux.

scholarly journals Влияние температуры на морфологию планарных нанопроволок GaAs (моделирование)

2020 ◽  
Vol 54 (2) ◽  
pp. 160
Author(s):  
А.А. Спирина ◽  
Н.Л. Шварц
Keyword(s):  
Monte Carlo Model ◽  
Growth Direction ◽  
Effect Of Temperature ◽  
Nanowire Growth ◽  
Catalyst Droplet ◽  
Lattice Monte Carlo ◽  
Gaas Nanowires ◽  
Kinetic Lattice Monte Carlo ◽  
Stable Growth ◽  
The One

Using a kinetic lattice Monte Carlo model, the self-catalyzed growth of planar GaAs nanowires was analyzed. The nanowire growth via the vapor-liquid-crystal mechanism was considered. The effect of temperature and the catalyst droplet location on the morphology and growth direction of planar GaAs nanowires was studied. For GaAs(111)A and GaAs(111)B substrates, a temperature range corresponding to stable growth of planar GaAs nanowires was revealed. The special asymmetric arrangement of droplets allows the one-directional nanowire growth.

A Novel TEM Technique for Characterizing As-Grown CVD Diamond Films

1991 ◽  
Vol 49 ◽  
pp. 956-957 ◽  
Author(s):  
Z.L. Wang ◽  
J. Bentley ◽  
R.E. Clausing ◽  
L. Heatherly ◽  
L.L. Horton
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Dark Field ◽  
Growth Surface ◽  
Specimen Preparation ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
First Time ◽  
Microstructural Studies

Microstructural studies by transmission electron microscopy (TEM) of diamond films grown by chemical vapor deposition (CVD) usually involve tedious specimen preparation. This process has been avoided with a technique that is described in this paper. For the first time, thick as-grown diamond films have been examined directly in a conventional TEM without thinning. With this technique, the important microstructures near the growth surface have been characterized. An as-grown diamond film was fractured on a plane containing the growth direction. It took about 5 min to prepare a sample. For TEM examination, the film was tilted about 30-45° (see Fig. 1). Microstructures of the diamond grains on the top edge of the growth face can be characterized directly by transmitted electron bright-field (BF) and dark-field (DF) images and diffraction patterns.

scholarly journals Direct TEM observation of the “acanthite α-Ag2S–argentite β-Ag2S” phase transition in a silver sulfide nanoparticle

2019 ◽  
Vol 1 (4) ◽  
pp. 1581-1588 ◽  
Author(s):  
S. I. Sadovnikov ◽  
E. Yu. Gerasimov
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Silver Sulfide ◽  
Transmission Electron ◽  
Silver Sulfide Nanoparticles ◽  
Microscopy Method ◽  
Electron Microscopy Method ◽  
First Time

For the first time, the α-Ag2S (acanthite)–β-Ag2S (argentite) phase transition in a single silver sulfide nanoparticles has been observed in situ using a high-resolution transmission electron microscopy method in real time.

Metastable Phase Formation in the Y-TI System by Ion Mixing

1991 ◽  
Vol 235 ◽  
Author(s):  
S. L. Lai ◽  
Z. J. Zhang ◽  
J. R. Ding ◽  
B. X. Liu
Keyword(s):  
Metastable Phase ◽  
Heat Of Formation ◽  
Crystalline Lattice ◽  
Vacuum Furnace ◽  
Multilayered Films ◽  
Glass Forming ◽  
Transmission Electron ◽  
Metastable Phase Formation ◽  
First Time

ABSTRACTAmorphization behavior was studied for the Y-Ti system, which has rather positive heat of formation being around + 22 kJ/mol, by room temperature 360 keV xenon ion mixing of YxTi100−xmultilayered films to various doses, ranging from 7×1014 to 1×1016 xe/cm2 Single and uniform amorphous phase was obtained in a narrow composition region, i.e. x=65 to 75, after ion mixing to the relevant doses. Moreover, a metastable fee crystalline Y-Ti phase was observed, for the first time, in this system. The crystalline lattice constant of the metastable phase was determined to be 4.012 Å. The re-crystallization temperature of the formed amorphous alloy was found out to be 600°C by in situ transmission electron microscope annealing as well as by vacuum furnace experiments. Possible interpretation is also discussed by comparing the experimental results with those proposed models for predicting glass forming ability.

Direct Synthesis of Silicon Nanowires using Silane and Molten Gallium

2002 ◽  
Vol 737 ◽  
Author(s):  
Shashank Sharma ◽  
Mahendra K. Sunkara ◽  
Elizabeth C. Dickey
Keyword(s):  
Silicon Nanowires ◽  
Crystalline Silicon ◽  
Direct Synthesis ◽  
Growth Direction ◽  
Single Crystalline ◽  
Gas Phase Chemistry ◽  
Transmission Electron ◽  
Phase Chemistry ◽  
First Time ◽  
Low Solubility

ABSTRACTWe report for the first time, bulk synthesis of single crystalline silicon nanowires using molten gallium pools and an activated vapor phase containing silane. The resulting silicon nanowires were single crystalline with <100> growth direction. Nanowires contained an unexpectedly thin, non-uniform oxide sheath determined using high-resolution Transmission Electron Microscopy (TEM). Nanowires were tens of nanometers in diameter and tens to hundreds of microns long. The use of activated gas phase chemistry containing solute of interest over molten metal pools of low-solubility eutectics such as gallium offer a viable route to generate nanowire systems containing abrupt compositional hetero-interfaces.

Formation of Sub-100 NM GE Wires on Si by E-Beam Evaporation/Lithography

1995 ◽  
Vol 380 ◽  
Author(s):  
C. Deng ◽  
J. C. Wu ◽  
C. J. Barbero ◽  
T. W. Sigmon ◽  
M. N. Wybourne
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Si Substrates ◽  
Novel Technique ◽  
Atomic Force ◽  
Transmission Electron ◽  
First Time ◽  
Scanning Electron

ABSTRACTA fabrication process for sub-100 nm Ge wires on Si substrates is reported for the first time. Wires with a cross section of 6 × 57 nm2 are demonstrated. The wire structures are analyzed by atomic force (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Sample preparation for TEM is performed using a novel technique using both pre and in situ deposition of multiple protection layers using a Focused Ion Beam (FIB) micromachining system.

Electron Beam Enhanced Precipitation in Highly Carbon Doped GaAs Layers

1996 ◽  
Vol 439 ◽  
Author(s):  
P. Werner ◽  
U. Gösele ◽  
H. Kohda
Keyword(s):  
Point Defects ◽  
Growth Direction ◽  
Precipitation Mechanism ◽  
Native Defects ◽  
Carbon Doped ◽  
Organic Vapor ◽  
Transmission Electron ◽  
Metal Organic ◽  
O 10

AbstractHighly carbon doped GaAs layers grown by metal organic vapor phase epitaxy (MOVPE) Has been investigated by transmission electron microscopy (TEM). Electron irradiation has been applied to generate point defects interacting with native defects, e.g., substitutional carbon. This irradiation induces periodically arranged striations perpendicular to the growth direction, which were observed in situ by TEM. Furthermore, precipitates (Ø= 10–15nm) were formed containing non-crystalline material, which most likely is gallium. To explain these phenomena a precipitation mechanism is proposed. It involvs small fluctuations of the incorporated C as well as the interaction of irradiation induced point defects, mainly As and C interstitials and As vacancies.

scholarly journals Characterization of individual stacking faults in a wurtzite GaAs nanowire by nanobeam X-ray diffraction

2017 ◽  
Vol 24 (5) ◽  
pp. 981-990 ◽  
Author(s):  
Arman Davtyan ◽  
Sebastian Lehmann ◽  
Dominik Kriegner ◽  
Reza R. Zamani ◽  
Kimberly A. Dick ◽  
...  
Keyword(s):  
Bragg Peak ◽  
Stacking Faults ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Patterson Function ◽  
Transmission Electron ◽  
Gaas Nanowires ◽  
Gaas Nanowire

Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the [000\bar{1}] direction in the vicinity of the wurtzite 00\bar{1}\bar{5} Bragg peak. The maxima of the Patterson function encode both the distances between the fault planes and the type of the fault planes with the sensitivity of a single atomic bilayer. The positions of the fault planes are deduced from the positions and shapes of the maxima of the Patterson function and they are in excellent agreement with the positions found with transmission electron microscopy of the same nanowire.

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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