In-Situ UHV Tem Investigations of the Initial Oxidation Stage of Copper Thin Films

1997 ◽  
Vol 481 ◽  
Author(s):  
J. C. Yang ◽  
M. Yeadon ◽  
B. Kolasa ◽  
J. M. Gibson
Keyword(s):  
Oxygen Diffusion ◽  
Copper Film ◽  
Nucleation And Growth ◽  
Rate Theory ◽  
Initial Oxidation ◽  
Nucleation Sites ◽  
Partial Pressures ◽  
Oxidation Stage ◽  
Preferential Nucleation

ABSTRACTThe nucleation and growth of Cu2O due to oxidation of Cu(001) films were monitored at various temperatures and oxygen partial pressures. For all examined temperatures and pressures, Cu2O islands were observed to form epitaxially with respect to the copper film. The nucleation of these oxide islands was homogeneous –no clear evidence was observed for either steps or dislocations being preferential nucleation sites. Based on this data, we have developed a semiquantitative model of the initial oxidation stage where the dominant mechanism for transport, nucleation and growth of oxide islands is oxygen diffusion on the Cu surface. We are presently comparing our experimental data with nucleation rate theory, where the predictions qualitatively describe our observations, but not quantitatively.

Kinetic Investigations of the Initial Oxidation Stage of Copper by In-Situ UHV-TEM

1996 ◽  
Vol 466 ◽  
Author(s):  
J. C. Yang ◽  
M. Yeadon ◽  
B. Kolasa ◽  
D. Olynick ◽  
J. M. Gibson
Keyword(s):  
Copper Film ◽  
Quantitative Model ◽  
Nucleation And Growth ◽  
Initial Oxidation ◽  
Methanol Vapor ◽  
In Situ Oxidation ◽  
Transmission Electron ◽  
Oxidation Stage ◽  
Kinetic Investigations

ABSTRACTWe have examined the nucleation and growth of copper oxides formed by in-situ oxidation of copper thin films inside a modified transmission electron microscope (TEM). Based on this data, we have developed a semi-quantitative model of the initial oxidation stage where the dominant mechanism for transport, nucleation and growth of oxide islands is oxygen diffusion on the surface. The copper oxide can be desorbed by annealing and introducing methanol vapor into the chamber. The clean copper film can be oxidized by introducing oxygen gas. Both the desorption and oxidation processes were observed by planar TEM techniques. The copper film was oxidized in-situ at a partial pressure of 5×104 torr. Cu2O islands, which formed epitaxially to the copper film, nucleated and grew into the copper film.

Initial Oxidation Kinetics of Cu(100), (110), and (111) Thin Films Investigated by in Situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1684-1694 ◽  
Author(s):  
Guangwen Zhou ◽  
Judith C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Oxygen Surface

The initial oxidation stages of Cu(100), (110), and (111) surfaces have been investigated by using in situ ultra-high-vacuum transmission electron microscopy (TEM) techniques to visualize the nucleation and growth of oxide islands. The kinetic data on the nucleation and growth of oxide islands shows a highly enhanced initial oxidation rate on the Cu(110) surface as compared with Cu(100), and it is found that the dominant mechanism for the nucleation and growth is oxygen surface diffusion in the oxidation of Cu(100) and (110). The oxidation of Cu(111) shows a dramatically different behavior from that of the other two orientations, and the in situ TEM observation reveals that the initial stages of Cu(111) oxidation are dominated by the nucleation of oxide islands at temperatures lower than 550 °C, and are dominated by two-dimensional oxide growth at temperatures higher than 550 °C. This dependence of the oxidation behavior on the crystal orientation and temperature is attributed to the structures of the oxygen-chemisorbed layer, oxygen surface diffusion, surface energy, and the interfacial strain energy.

Nucleation Dynamics of Water Nanodroplets

2014 ◽  
Vol 20 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Dipanjan Bhattacharya ◽  
Michel Bosman ◽  
Venkata R.S.S. Mokkapati ◽  
Fong Yew Leong ◽  
Utkur Mirsaidov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Heterogeneous Nucleation ◽  
Flat Surface ◽  
Nucleation And Growth ◽  
Length Scale ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractThe origin of the condensation of water begins at the nanoscale, a length-scale that is challenging to probe for liquids. In this work we directly image heterogeneous nucleation of water nanodroplets by in situ transmission electron microscopy. Using gold nanoparticles bound to a flat surface as heterogeneous nucleation sites, we observe nucleation and growth of water nanodroplets. The growth of nanodroplet radii follows the power law: R(t)~(t−t0)β, where β~0.2−0.3.

The Low-temperature Initial Oxidation Stages of Cu(100) Investigated by in situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1910-1917 ◽  
Author(s):  
L. Sun ◽  
J.C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Vacuum ◽  
Three Dimensional ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Triangular Shape ◽  
Transmission Electron

The nucleation and growth of Cu2O islands due to Cu(100) oxidation at temperatures from 200 to 350 °C have been observed by in situ ultra-high-vacuum transmission electron microscopy. For this temperature range, epitaxial Cu2O islands form a triangular shape with rounded edges when Cu(100) is exposed to dry oxygen at 5 × 10−4 Torr in situ. Our initial analysis on the nucleation and growth of these three-dimensional Cu2O islands agrees well with the heteroepitaxial model of surface diffusion of oxygen.

Airspace structure and mathematical modelling of oxygen diffusion, aeration and anoxia in Eleocharis sphacelata R. Br. Roots

1994 ◽  
Vol 45 (8) ◽  
pp. 1529 ◽  
Author(s):  
BK Sorrell
Keyword(s):  
Root Length ◽  
Oxygen Diffusion ◽  
Apical Meristem ◽  
Respiratory Activity ◽  
Quantitative Description ◽  
Main Axis ◽  
Fine Scale ◽  
Oxygen Release ◽  
Partial Pressures

A quantitative description of the structure of the roots of Eleocharis sphacelata is presented, forming the basis of a mathematical analysis of their aeration via the intercellular airspace system. The mature aerenchymatous roots have cortical porosites as high as 70% and resistances to axial diffusion of 0.015-0.04 Ms mm-3 per mm root length. The corresponding resistance in the younger, non-aerenchymatous tissue just behind the apex is 0.08-0.14 Ms mm-3 per mm, root length. The observed maximum length of the roots (about 0.3 m) is not caused by the oxygen limitations at the apical meristem of the main axis because axial fluxes could theoretically support the meristem in much longer roots. However, the phloem and pericycle of the stele become hypoxic at 0.25 to 0.3 m, suggesting that length could be limited by the need to prevent excessive hypoxia in these tissues. Rates of root oxygen release into the sediment are predicted to be as high as 2.5 �mol h-1 per 0.3-m-long root and higher still for shorter roots. The prevention of anoxia depends greatly on the basal oxygen concentration at the root base: oxygen partial pressures below 8 kPa in the rhizome would cause meristematic anoxia in 0.3 m-long roots. A better resolution of fine-scale variations in respiratory activity in the roots and in the sediment rhizosphere could improve the accuracy of the model, but it does nevertheless indicate that roots of E. sphacelata would normally remain aerobic and significantly oxidize anaerobic sediments in situ.

scholarly journals In Situ Atomic Scale ETEM Observation of Oxide Nucleation and Growth During Initial Oxidation of Cu and Cu-Ni Alloy

2020 ◽  
Vol 26 (S2) ◽  
pp. 1672-1673
Author(s):  
Meng Li ◽  
Matthew Curnan ◽  
Richard Garza ◽  
Michael Gresh-Sill ◽  
Stephen House ◽  
...  
Keyword(s):  
Nucleation And Growth ◽  
Atomic Scale ◽  
Initial Oxidation ◽  
Ni Alloy

In Situ EBSD Observation of Pearlite-Austenite Reverse Transformation in Eutectoid Steel

2020 ◽  
Vol 985 ◽  
pp. 42-47
Author(s):  
Anh Hoang Pham ◽  
Shigekazu Morito ◽  
Takuya Ohba ◽  
Taisuke Hayashi
Keyword(s):  
Quantitative Information ◽  
Nucleation And Growth ◽  
Reverse Transformation ◽  
High Angle ◽  
Eutectoid Steel ◽  
Orientation Selection ◽  
Nucleation Sites ◽  
Coarse Grains ◽  
Selection Of

The reverse transformation of austenite from pearlite was observed in-situ by using a sophisticated EBSD system. Quantitative information on the nucleation sites and orientation selection of the austenite was obtained. Initially, the nucleation sites were restricted to high-angle grain boundary (HAB) and all the austenite orientations were selected by Kurdjumov-Sachs (K-S) orientation relationship. Latterly, the constraints were relaxed as new nucleation sites were involved. The γ growth was preferentially into the pearlite grains without K-S relation. Nucleation and growth at HAB edge may contribute to γ coarse grains, whereas nucleation at pre-existing γ boundary is important to grain refinement of γ structure.

Nucleation and Growth of Triangular Prismatic Iron Carbides in Amorphous Films by In Situ Transmission Electron Microscopy

2011 ◽  
Vol 172-174 ◽  
pp. 959-964 ◽  
Author(s):  
Elizabeth Bauer-Grosse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Content ◽  
Carbon Film ◽  
Nucleation And Growth ◽  
Orientation Relationships ◽  
Iron Carbides ◽  
Transmission Electron ◽  
Nucleation Sites

The crystallization mechanisms of sputtered Fe1-xCx amorphous thin films for three values of atomic carbon content x = 0.28, 0.30 and 0.32 are directly observed using hot stage transmission electron microscopy. Images recorded sequentially are used to track the change caused by heating. Observations concern the nucleation and the growth of iron carbides and their structural identification. Information is also given about their crystallochemistry. They belong to the family of interstitial carbides with carbon atoms located inside iron Triangular Prisms (TP). They are built either from TP Sheets (TPS) stacks deriving from the cementite θ-Fe3C or from TP Chains (TPC) arrangements deriving from the Eckström-Adcock Fe7C3 carbide. The sharp transition between dominant TPS and dominant TPC carbides formations is illustrated. Nucleation and growth processes of both types of carbides are discussed and focus is put on the TPC crystals. They are the first to be formed whatever carbon content of the specimen and really correspond to the dominant phase for the richest-carbon film. When they are less numerous, they can act as nucleation sites for TPS carbides and it is in situ illustrated during the crystallization of the poorest-carbon film where orientation relationships can be found between the TPC-Fe7C3 carbideand a TPS carbide close to the Hägg carbide χ-Fe5C2 The crystallization ofFe0.70C0.30 film corresponds to a particular case where TPC carbides and TPS carbides can coexist with the same composition.

Model Calculation of SiC Oxidation Rates in the Thin Oxide Regime

2008 ◽  
Vol 600-603 ◽  
pp. 663-666 ◽  
Author(s):  
Yasuto Hijikata ◽  
Takeshi Yamamoto ◽  
Hiroyuki Yaguchi ◽  
Sadafumi Yoshida
Keyword(s):  
Growth Rate ◽  
Model Calculation ◽  
Oxidation Mechanism ◽  
Oxide Thickness ◽  
Emission Model ◽  
Initial Oxidation ◽  
Oxidation Rates ◽  
Oxidation Stage ◽  
Thin Oxide

To explain the growth rate enhancement of SiC oxidation in the thin oxide regime, which was recently found from the real time monitoring experiments of the initial oxidation stage of SiC (000–1) C-face using an in-situ spectroscopic ellipsometer, we tried to apply the interfacial Si emission model, which has been originally proposed for Si oxidation, and found that the Si emission model successfully reproduced the SiC oxidation rates at the whole range of oxide thickness and at oxidation temperatures measured. By comparing with the simulations for Si oxidation, we have discussed the oxidation mechanism of SiC.

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