Mechanisms of void shrinkage in aluminium

2016 ◽  
Vol 49 (5) ◽  
pp. 1459-1470 ◽  
Author(s):  
Zezhong Zhang ◽  
Tianyu Liu ◽  
Andrew E. Smith ◽  
Nikhil V. Medhekar ◽  
Philip N. H. Nakashima ◽  
...  
Keyword(s):  
Electron Irradiation ◽  
Equilibrium Shape ◽  
Bulk Diffusion ◽  
Atomic Layer ◽  
Atomic Diffusion ◽  
Total Surface Energy ◽  
Transmission Electron ◽  
Void Shape ◽  
Rare Opportunity

Voids can significantly affect the performance of materials and a key question is how voids form and evolve. Voids also provide a rare opportunity to study the fundamental interplay between surface crystallography and atomic diffusion at the nanoscale. In the present work, the shrinkage of voids in aluminium from 20 to 1 nm in diameter throughin situannealing is imaged in a transmission electron microscope. It is found that voids first shrink anisotropically from a non-equilibrium to an equilibrium shape and then shrink while maintaining their equilibrium shape until they collapse. It is revealed that this process maximizes the reduction in total surface energy per vacancy emitted. It is also observed that shrinkage is quantized, taking place one atomic layer and one void facet at a time. By taking the quantization and electron irradiation into account, the measured void shrinkage rates can be modelled satisfactorily for voids down to 5 nm using bulk diffusion kinetics. Continuous electron irradiation accelerates the shrinkage kinetics significantly; however, it does not affect the energetics, which control void shape.

In Situ Observation of Nucleation and Growth of Carbon Nanotubes from Iron Carbide Nanoparticles

2008 ◽  
Vol 1142 ◽  
Author(s):  
Hideto Yoshida ◽  
Seiji Takeda ◽  
Tetsuya Uchiyama ◽  
Hideo Kohno ◽  
Yoshikazu Homma
Keyword(s):  
Carbon Nanotubes ◽  
Iron Carbide ◽  
Bulk Diffusion ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Atomic Scale ◽  
In Situ Observation ◽  
Transmission Electron ◽  
Cvd Growth

ABSTRACTNucleation and growth processes of carbon nanotubes (CNTs) in iron catalyzed chemical vapor deposition (CVD) have been observed by means of in-situ environmental transmission electron microscopy. Our atomic scale observations demonstrate that solid state iron carbide (Fe3C) nanoparticles act as catalyst for the CVD growth of CNTs. Iron carbide nanoparticles are structurally fluctuated in CVD condition. Growth of CNTs can be simply explained by bulk diffusion of carbon atoms since nanoparticles are carbide.

scholarly journals Tailoring atomic diffusion for in situ fabrication of different heterostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hui Zhang ◽  
Tao Xu ◽  
Kaihao Yu ◽  
Wen Wang ◽  
Longbing He ◽  
...  
Keyword(s):  
Surface Diffusion ◽  
Bulk Diffusion ◽  
Diffusion Reaction ◽  
Atomic Diffusion ◽  
Solid Diffusion ◽  
In Situ Fabrication ◽  
State Diffusion ◽  
New Process ◽  
Insight Into

AbstractAtomic diffusion has been recognized as a particularly powerful tool in the synthesis of heterostructures. However, controlled atomic diffusion is very difficult to achieve in the fabrication of individual nanostructures. Here, an electrically driven in situ solid-solid diffusion reaction inside a TEM is reported for the controlled fabrication of two different hetero-nanostructures in the Ag-Te system. Remarkably, the morphology and structure of the as-formed heterostructures are strongly dependent on the path of atomic diffusion. Our experiments revealed that the surface diffusion of Te atoms to Ag nanowires leads to a core-shell structure, while the bulk diffusion of Ag atoms give rise to a Ag2Te-Te segmented heterostructure. Heat released by Joule heating caused the surface diffusion process to be replaced by bulk diffusion and thereby determined the structure of the final product. Our experimental results provide an insight into solid-state diffusion reactions under an electric field and also propose a new process for the fabrication of complex nanostructures.

The Interface Properties of La2O3/GaAs System by Surface Passivation

2012 ◽  
Vol 557-559 ◽  
pp. 1815-1818 ◽  
Author(s):  
Ting Ting Jia ◽  
Xing Hong Cheng ◽  
Duo Cao ◽  
Da Wei Xu ◽  
You Wei Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Gate Dielectric ◽  
Surface Preparation ◽  
Atomic Layer ◽  
Native Oxide ◽  
Atomic Force ◽  
Transmission Electron ◽  
Layer Deposition

In this work, La2O3 gate dielectric film was deposited by plasma enhanced atomic layer deposition. we investigate the effect of surface preparation of GaAs substrate, for example, native oxide, S-passivation, and NH3 plasma in situ treatment. The interfacial reaction mechanisms of La2O3 on GaAs is studied by means of X-ray photoelectron spectroscopy(XPS), high-resolution transmission electron microscopy(HRTEM) and atomic force microscope (AFM). As-O bonding is found to get effectively suppressed in the sample GaAs structures with both S-passivation and NH3 plasma surface treatments.

In situ growth of In2O3 nanocrystals by electron irradiation in transmission electron microscope

2014 ◽  
Vol 120 ◽  
pp. 208-211 ◽  
Author(s):  
Qingmei Su ◽  
Gaohui Du ◽  
Bingshe Xu
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Electron Irradiation ◽  
In Situ Growth ◽  
Transmission Electron

Surface study by UHV electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 458-459
Author(s):  
K. Yagi ◽  
K. Takayanagi ◽  
K. Kobayashi ◽  
N. Osakabe ◽  
Y. Tanishiro ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Film Growth ◽  
Atomic Layer ◽  
Chemical Compositions ◽  
Surface Phenomena ◽  
Transmission Electron ◽  
In Situ Deposition ◽  
Complementary Role ◽  
Atomically Flat

Recent advances of UHV techniques, LEED, RHEED and AES, arose a surge of interest on the surface of solids. These techniques reveal structures and chemical compositions at the mono-atomic or mono-molecular level. All of them, however, are devoid of detailed topographic informations, although some efforts to introduce the scanning techniques have been done[l]. Transmission electron microscopy of high resolution should play a complementary role to these techniques. No attempt, however, has been done previously to use it to such a purpose. This was because it was difficult to get and keep clean surfaces in the poor vacuum at 1x10-5 Torr level of the conventional electron microscope.The present paper reports observations of surface phenomena of one or two atomic layer level using a UHV JEM 100B electron microscope (10-8 -10-10Torr), recently developed for insitu thin film growth studies[2]. Atomically flat (111) surfaces of Ag, Pd, Au and Cu were prepared by in- situ deposition at 150-350°C on M0S2, graphite and MgO. Air Cleaved thin films of MoS2 and graphite were preheated to 800°C to get clean surfaces[3].

Dopant Dependent Extended Defect Nucleation and Growth Kinetics in Silicon During 1 Mev Electron Irradiation

1992 ◽  
Vol 262 ◽  
Author(s):  
Albert Romano-Rodriguez ◽  
Jan Vanhellemont
Keyword(s):  
Electron Irradiation ◽  
Growth Kinetics ◽  
Dopant Concentration ◽  
Extended Defects ◽  
Extended Defect ◽  
Transmission Electron ◽  
Defect Growth ◽  
Defect Reactions ◽  
Defect Nucleation

ABSTRACTIn this paper results of a study of electron irradiation induced extended defect generation in doped silicon is presented. The irradiations are performed in-situ with 1 MeV electrons in a high voltage transmission electron microscope. Preferential generation of extended defects is observed in certain areas of the sample which can be correlated with well defined dopant concentration levels. The defect growth kinetics is studied as a function of the irradiation temperature and dose and the type and concentration of dopant.After the first irradiation experiment some of the samples received a second electron irradiation, during which shrinkage and even complete annihilation of the previously generated defects can be observed. The observed results are interpreted on the base of point defect reactions.

Properties of High-Quality LaAlO3 Film Deposited by In Situ Plasma-Enhanced-Atomic-Layer-Deposition

2013 ◽  
Vol 721 ◽  
pp. 24-28 ◽  
Author(s):  
Duo Cao ◽  
Xin Hong Cheng ◽  
Ting Ting Jia ◽  
Da Wei Xu ◽  
Li Zheng ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Atomic Layer ◽  
Valence Band Offset ◽  
Xps Spectra ◽  
Transmission Electron ◽  
Layer Deposition ◽  
Interfacial States ◽  
Current Densities

Plasma enhanced atomic layer deposition (PEALD) method can decrease film growing temperature, and allow in-situ plasma treatment. LaAlO3 films were deposited with PEALD at 180°C. High resolution transmission electron microscopy (HRTEM) results exhibited amorphous microstructure of both films even after rapid thermal annealing (RTA) at 800°C. X-ray photoelectron spectroscopy (XPS) spectra suggested that the valence-band offset between the LaAlO3 film and the substrate was 3.3 eV. The electrical experimental results indicated that the leakage current densities were 0.10mA/cm2 and 0.03mA/cm2 respectively at a gate bias of |Vg-Vfb|=1V and the equivalent oxide thicknesses (EOT) of them were 1.2 nm and 1.4 nm, respectively. The densities of interfacial states were calculated to be 1.70×1012eV-1cm-2 and 1.09×1012eV-1cm-2, respectively.

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