Electric-Field Effects on Reactions Between Oxides

1997 ◽  
Vol 481 ◽  
Author(s):  
Matthew T. Johnson ◽  
Shelley R. Gilliss ◽  
C. Barry Carter
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Elevated Temperatures ◽  
Ionic Current ◽  
Reaction Rates ◽  
Solid State Reactions ◽  
Interfacial Stability ◽  
Electric Field Effects ◽  
Thin Film Diffusion ◽  
Microscopy Techniques

ABSTRACTThin films of In2O3 and Fe2O3 have been deposited on (001) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples were then reacted in an applied electric field at elevated temperatures. In this type of solid-state reaction, both the reaction rate and the interfacial stability are affected by the transport properties of the reacting ions. The electric field provides a very large external driving force that influences the diffusion of the cations in the constitutive layers. This induced ionic current causes changes in the reaction rates, interfacial stability and distribution of the phases. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated in these spinel-forming systems, to gain a better understanding of the influence of an electric field on solid-state reactions.

solid-state reactions in the presence of an electric field

1997 ◽  
Vol 3 (S2) ◽  
pp. 623-624
Author(s):  
Matthew T. Johnson ◽  
C.Barry Carter
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Elevated Temperatures ◽  
Reaction Rates ◽  
Laser Deposition ◽  
Solid State Reactions ◽  
Interfacial Stability ◽  
Interface Morphology ◽  
Charged Species ◽  
Microscopy Techniques

It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an electric field should provide a very powerful driving force for mass transport. In the present study, solid-state reactions, in the presence of an electric field, have been carried out between thin films of In2O3 and bulk monocrystalline MgO ﹛001﹜. In solid-state reactions of this type, reaction rates and interfacial stability are affected by the transport properties of the reacting ions. by applying an electric field across the sample, at elevated temperatures, the reaction rates and interfaces are affected as a result of ionic conductivity. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated, in this spinel forming system, to gain a better understanding of the influence of an electric field on interface morphology and solid-state reactions.The reaction couples used in this study were produced by means of pulsed-laser deposition (PLD).

The Effect of an Electric Field on the Reaction Between Oxides

1998 ◽  
Vol 4 (S2) ◽  
pp. 594-595
Author(s):  
Matthew T. Johnson ◽  
C. Barry Carter
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Elevated Temperatures ◽  
Ionic Current ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Diffusion Couples ◽  
Charged Species ◽  
Thin Film Diffusion ◽  
Reaction Processes

It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an applied electric field can provide a very large driving force for mass transport. In the present study, thin films of In2O3 and Fe2O3 have been deposited on (001) and (111) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples have then been reacted in an applied electric field at elevated temperatures. The electric field directly influences the diffusion of the cations in the constitutive layers. Through the use of both transmission (TEM) and scanning (SEM) electron microscopy, diffusion couples reacted either with and without an electric field have been analyzed to examine the effect that an induced ionic current can have on solid-state reaction processes.The apparatus for reacting the diffusion couples in a field has been described elsewhere. The diffusion couples were characterized in cross-section by SEM and TEM techniques.

Electric-Field Effects in Solid-State Ionic Devices

2019 ◽  
Vol 16 (51) ◽  
pp. 355-366
Author(s):  
Bryan M. Blackburn ◽  
F. Martin Van Assche ◽  
E. D. Wachsman
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Solid State Ionic ◽  
Electric Field Effects ◽  
Field Effects ◽  
Ionic Devices ◽  
State Ionic

Use of Pt Markers in the Study of Solid-State Reactions in the Presence of an Electric Field

1998 ◽  
Vol 4 (2) ◽  
pp. 158-163 ◽  
Author(s):  
Matthew T. Johnson ◽  
Shelley R. Gilliss ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Electric Field ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Solid State Reactions ◽  
Single Crystal Substrate ◽  
Fine Scale ◽  
Initial Location ◽  
Crystal Substrate

The use of Pt to mark the initial location of heterophase boundaries in solid-state reactions was extended to investigate the motion of interfaces during a thin-film solid-state reaction between In2O3 and MgO in the presence of an electric field. The Pt markers were prepared by sputtering a thin Pt film onto a single-crystal substrate. The resulting multilayer was then heated prior to thin-film deposition to de-wet the Pt film and thus form an array of small, isolated particles. These particles serve as fine-scale markers for tracking the motion of interfaces. However, there are certain situations in which the markers can move with the interface.

Kinetics of Triplet Sublevel Selective Photochemical Reactions in the Solid State

1981 ◽  
Vol 36 (7) ◽  
pp. 743-750
Author(s):  
Manfred Gehrtz ◽  
Christoph Bräuchle ◽  
Jürgen Voitländer
Keyword(s):  
Solid State ◽  
Reaction Rates ◽  
Photochemical Reactions ◽  
Solid State Reactions ◽  
Physical Activation ◽  
Zero Field ◽  
Excited Triplet ◽  
The Individual ◽  
Activation Rates ◽  
Kinetics Of

Abstract A detailed description of the overall kinetics of photochemical reactions has to deal with photo-physical activation and de-activation rates as well as with true photochemical rates. Based on the hypothesis that for photoreactions involving the lowest excited triplet state the chemical reaction rates of the individual triplet zero-field levels have different values, a method is presented for the evaluation of these rates from bulk measurements under steady state illumination conditions. The complications arising from the detection of solid state reactions are discussed, and a simple solution is given, illustrated by a numerical example.

Heterogeneous solid-state reactions between MgO(00l) and iron oxide

1996 ◽  
Vol 54 ◽  
pp. 642-643
Author(s):  
Matthew T. Johnson ◽  
Hermann B. Schmalzried ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Iron Oxide ◽  
Solid State ◽  
Electric Fields ◽  
Stress Fields ◽  
Solid State Reactions ◽  
Concentration Gradients ◽  
Transmission Electron ◽  
Microscopy Techniques ◽  
Heterogeneous Solid

The transport properties of the diffusing species in heterogeneous solid-state reactions are affected by concentration gradients, temperature gradients, stress fields and electric fields. In the present study, interfacial reactions between thin films of iron oxide and bulk monocrystalline MgO{001}, resulting in the formation of the spinel product MgFe2O4, were carried out separately as a function of time and temperature, applied external electric field and partial pressure of oxygen. Electron microscopy techniques have been utilized to investigate the reaction kinetics and interface morphology.The reaction couples were produced by means of pulsed-laser deposition (PLD). The setup for PLD has been described elsewhere. By depositing high-quality oxide films on bulk substrates, a well controlled geometry can be fabricated which is conducive to the study of fundamental processes in solid-state reactions. In producing the reaction couples, 600nm of iron oxide was deposited on monocrystalline MgO{001}. The reaction couples were then reacted under varying conditions and analyzed, using both scanning (SEM) and transmission electron microscopy (TEM).

Correlations Between Electrical Properties and Solid-State Reactions in Co/N-GaAs Contacts: A Bulk and Thin-Film Study

1989 ◽  
Vol 148 ◽  
Author(s):  
F.-Y. Shiau ◽  
Y. A. Chang
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Solid State ◽  
Electrical Properties ◽  
Phase Formation ◽  
Electrical Characterization ◽  
Solid State Reactions ◽  
Film Diffusion ◽  
Film Study ◽  
Thin Film Diffusion

ABSTRACTA fundamental and comprehensive approach has been taken to study Co//GaAs interfacial reactions, using phase diagram determination, bulk and thin-film diffusion couple studies, and electrical characterization. Phase formation sequences and interfacial morphologies are found to be similar in bulk and thin-film couples. Thermodynamic and kinetic analyses are used to rationalize the contact formations. The electrical properties of the contacts are correlated to the phase formation sequences and phase diagram information.

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