scholarly journals Investigating Processes of Nanocrystal Formation and Transformation via Liquid Cell TEM

2014 ◽  
Vol 20 (2) ◽  
pp. 425-436 ◽  
Author(s):  
Michael H. Nielsen ◽  
Dongsheng Li ◽  
Hengzhong Zhang ◽  
Shaul Aloni ◽  
T. Yong-Jin Han ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Nucleation And Growth ◽  
Ex Situ ◽  
Bulk Solution ◽  
Dynamic Information ◽  
Transmission Electron ◽  
Classical Models ◽  
Liquid Cell ◽  
Temporal And Spatial

AbstractRecent ex situ observations of crystallization in both natural and synthetic systems indicate that the classical models of nucleation and growth are inaccurate. However, in situ observations that can provide direct evidence for alternative models have been lacking due to the limited temporal and spatial resolution of experimental techniques that can observe dynamic processes in a bulk solution. Here we report results from liquid cell transmission electron microscopy studies of nucleation and growth of Au, CaCO3, and iron oxide nanoparticles. We show how these in situ data can be used to obtain direct evidence for the mechanisms underlying nanoparticle crystallization as well as dynamic information that provide constraints on important energetic parameters not available through ex situ methods.

scholarly journals Shape-controlled synthesis and in situ characterisation of anisotropic Au nanomaterials using liquid cell transmission electron microscopy

Nanoscale ◽  
2019 ◽  
Vol 11 (36) ◽  
pp. 16801-16809 ◽  
Author(s):  
Shih-Ting Wang ◽  
Yiyang Lin ◽  
Michael H. Nielsen ◽  
Cheng Yu Song ◽  
Michael R. Thomas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Controlled Synthesis ◽  
Transmission Electron ◽  
Liquid Cell ◽  
Shape Controlled ◽  
Fundamental Requirement

Understanding the mechanisms behind crystal nucleation and growth is a fundamental requirement for the design and production of bespoke nanomaterials with controlled sizes and morphologies.

scholarly journals Application of In Situ Liquid Cell Transmission Electron Microscopy in Corrosion Studies: A Critical Review of Challenges and Achievements

CORROSION ◽  
10.5006/3369 ◽  
2019 ◽  
Vol 76 (1) ◽  
pp. 4-17 ◽  
Author(s):  
Ali Kosari ◽  
Henny Zandbergen ◽  
Frans Tichelaar ◽  
Peter Visser ◽  
Herman Terryn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Real Life ◽  
In Situ Monitoring ◽  
Ex Situ ◽  
Transmission Electron ◽  
Corrosion Studies ◽  
Cell Transmission ◽  
Liquid Cell

Identifying corrosion initiation events in metals and alloys demands techniques that can provide temporal and spatial resolution simultaneously. Transmission electron microscopy (TEM) enables one to obtain microstructural and chemical descriptors of materials at atomic/nanoscopic level and has been used in corrosion studies of many metal-electrolyte combinations. Conventionally, ex situ and quasi in situ TEM studies of pre- and post-corroded samples were performed, but possible experimental artifacts such as dehydrated surfaces might not fully represent the real interfacial conditions as compared to those when actually immersed in the electrolyte. Recent advances in liquid cell transmission electron microscopy (LC-TEM) allows for in situ monitoring morphological and even compositional evolutions in materials resulting from interaction with gas or liquid environments. Corrosion science, as a challenging field of research, can benefit from this unparalleled opportunity to investigate many complicated corroding systems in aqueous environments at high resolution. However, “real life” corrosion with LC-TEM is still not straightforward in implementation and there are limitations and challenging experimental considerations for conducting reliable examinations. Thus, this study has been devoted to discussing the challenges of in situ LC-TEM wherein state-of-the-art achievements in the field of relevance are reviewed.

Evidence for Substitutional C, Ordering Effects and Interdiffusion in Epitaxial GE-C and GE-RICH GE-SI-C Alloys

1998 ◽  
Vol 533 ◽  
Author(s):  
Bi-Ke Yang ◽  
W. H. Weber ◽  
M. Krishnamurthy
Keyword(s):  
Raman Spectroscopy ◽  
Direct Evidence ◽  
Ex Situ ◽  
Local Mode ◽  
Simple Diffusion ◽  
Ordering Effects ◽  
Transmission Electron ◽  
Enhanced Solubility ◽  
Simple Diffusion Model

AbstractWe report on the epitaxial growth of Ge-C and Ge-Si-C alloys (C<10%) grown on Si(100) and Ge(100) substrates using low temperature (∼200°C) molecular beam epitaxy. Thin films (50–70 nm) were characterized in-situ by RHEED and ex-situ by transmission electron microscopy, xray diffraction, and Raman spectroscopy. The films were annealed at 750°C and 850°C in an Ar atmosphere to study interdiffusion effects.Raman spectroscopy of Ge-C on Ge indicates the existence of a Ge-C local mode at 530cm−1 and is direct evidence for the presence of substitutional C in Ge. The GeSiC alloys grown on Ge do not show the Ge-C local mode, consistent with preferential Si-C bonding. There is evidence for strain enhanced solubility of C based on a comparison of the substitutional C content in Ge-C films on Si (∼1 at %) and on Ge substrates (∼0.1 at %). Silicon interdiffusion in annealed Ge-C samples is strongly suppressed by the presence of C. A simple diffusion model is used to illustrate Si indiffusion in Ge.

scholarly journals Atomistic insights into the nucleation and growth of platinum on palladium nanocrystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenpei Gao ◽  
Ahmed O. Elnabawy ◽  
Zachary D. Hood ◽  
Yifeng Shi ◽  
Xue Wang ◽  
...  
Keyword(s):  
Diffusion Path ◽  
Nucleation Site ◽  
Nucleation And Growth ◽  
First Principles Calculations ◽  
High Concentration ◽  
Synthesis Parameters ◽  
Transmission Electron ◽  
Liquid Cell ◽  
Shed Light

AbstractDespite the large number of reports on colloidal nanocrystals, very little is known about the mechanistic details in terms of nucleation and growth at the atomistic level. Taking bimetallic core-shell nanocrystals as an example, here we integrate in situ liquid-cell transmission electron microscopy with first-principles calculations to shed light on the atomistic details involved in the nucleation and growth of Pt on Pd cubic seeds. We elucidate the roles played by key synthesis parameters, including capping agent and precursor concentration, in controlling the nucleation site, diffusion path, and growth pattern of the Pt atoms. When the faces of a cubic seed are capped by Br−, Pt atoms preferentially nucleate from corners and then diffuse to edges and faces for the creation of a uniform shell. The diffusion does not occur until the Pt deposited at the corner has reached a threshold thickness. At a high concentration of the precursor, self-nucleation takes place and the Pt clusters then randomly attach to the surface of a seed for the formation of a non-uniform shell. These atomistic insights offer a general guideline for the rational synthesis of nanocrystals with diverse compositions, structures, shapes, and related properties.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

A New Method of Wafer Level Plan View TEM Sample Preparation by DualBeam

2008 ◽  
Author(s):  
Hyoung H. Kang ◽  
Michael A. Gribelyuk ◽  
Oliver D. Patterson ◽  
Steven B. Herschbein ◽  
Corey Senowitz
Keyword(s):  
Sample Preparation ◽  
Ex Situ ◽  
Wafer Level ◽  
Cross Sectional ◽  
Plan View ◽  
Manufacturing Line ◽  
Transmission Electron ◽  
Thin Lamella ◽  
Preparation Techniques

Abstract Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.

scholarly journals Fabrication of a liquid cell for in situ transmission electron microscopy

Microscopy ◽  
2020 ◽  
Author(s):  
Xiaoguang Li ◽  
Kazutaka Mitsuishi ◽  
Masaki Takeguchi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cost Effective ◽  
Production Method ◽  
Microscopy Imaging ◽  
Transmission Electron ◽  
In Situ Electron Microscopy ◽  
Liquid Cell ◽  
Si Wafer

Abstract Liquid cell transmission electron microscopy (LCTEM) enables imaging of dynamic processes in liquid with high spatial and temporal resolution. The widely used liquid cell (LC) consists of two stacking microchips with a thin wet sample sandwiched between them. The vertically overlapped electron-transparent membrane windows on the microchips provide passage for the electron beam. However, microchips with imprecise dimensions usually cause poor alignment of the windows and difficulty in acquiring high-quality images. In this study, we developed a new and efficient microchip fabrication process for LCTEM with a large viewing area (180 µm × 40 µm) and evaluated the resultant LC. The new positioning reference marks on the surface of the Si wafer dramatically improve the precision of dicing the wafer, making it possible to accurately align the windows on two stacking microchips. The precise alignment led to a liquid thickness of 125.6 nm close to the edge of the viewing area. The performance of our LC was demonstrated by in situ transmission electron microscopy imaging of the dynamic motions of 2-nm Pt particles. This versatile and cost-effective microchip production method can be used to fabricate other types of microchips for in situ electron microscopy.

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