Surface energy driven miscibility gap suppression during nucleation of III-V ternary alloys

Recent electron diffraction studies have found ordered phases in AlxGa1-xAs, GaAsxSb1-x, and InxGa1-xAs alloy systems, and these ordered phases are likely to be found in many other III-V ternary alloys as well. The presence of ordered phases in these alloys was detected in the diffraction patterns through the appearance of superstructure reflections between the Bragg peaks (Fig. 1). The ordered phase observed in the AlxGa1-xAs and InxGa1-xAs systems is of the CuAu-I type, whereas in GaAsxSb1-x this phase and a chalcopyrite type ordered phase can be present simultaneously. The degree of order in these alloys is strongly dependent on the growth conditions, and during the growth of these alloys, high surface mobility of the depositing species is essential for the onset of ordering. Thus, the growth on atomically flat (110) surfaces usually produces much stronger ordering than the growth on (100) surfaces. The degree of order is also affected by the presence of antiphase boundaries (APBs) in the ordered phase. As shown in Fig. 2(a), a perfectly ordered In0.5Ga0.5As structure grown along the <110> direction consists of alternating InAs and GaAs monolayers, but due to local growth fluctuations, two types of APBs can occur: one involves two consecutive InAs monolayers and the other involves two consecutive GaAs monolayers.

Polycrystalline GeC Thin Films Deposited Using a Unique Hollow Cathode Sputtering Technique

MRS Proceedings ◽

10.1557/proc-862-a20.2 ◽

2005 ◽

Vol 862 ◽

Cited By ~ 5

Author(s):

R. J. Soukup ◽

N. J. Ianno ◽

J. S. Schrader ◽

V. L. Dalal

Keyword(s):

Thin Films ◽

Raman Spectroscopy ◽

Hollow Cathode ◽

Growth Conditions ◽

Group Iv ◽

Native Oxide ◽

Cathode Sputtering ◽

Si Substrates ◽

New Material ◽

Equilibrium Growth

AbstractExperimental results on thin films of the new material GexC1-x, deposited by a unique dual plasma hollow cathode sputtering technique are presented. The mostimportant contribution of this work is that it shows that by using non-equilibrium growth conditions resulting from the hollow cathode technique, one can grow Group IV materials which cannot otherwise be grown using normal CVD or MBE processes. The sputtering is accomplished by igniting a dc plasma in the Ar and H2 gases which are fed through Ge and C nozzles.The GeC films are grown on etched Si (100), on Si with the native oxide and on glass. The films grown on glass were quite disordered, but the films grown on both types of Si substrates were very ordered in nature. This order has been characterized using Xray diffraction (XRD) and Raman spectroscopy.Films with as much as 8% C have been deposited. In order to produce useful GexC1-x films, the C must bond to the Ge at lattice sites. Evidence of this desired GeC bond has been seen using Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and XRD.

Equilibrium Phase Diagrams for Analysis of the Oxidation of III-V Compound Semiconductors

MRS Proceedings ◽

10.1557/proc-148-177 ◽

1989 ◽

Vol 148 ◽

Cited By ~ 1

Author(s):

G. P. Schwartz

Keyword(s):

High Pressure ◽

Phase Diagrams ◽

Equilibrium Phase ◽

Compound Semiconductors ◽

Growth Conditions ◽

Pressure Oxidation ◽

Recent Interest ◽

Equilibrium Growth ◽

Thermodynamic Factors

ABSTRACTThe phases which result from the oxidation of III-V compound semiconductors can be predicted from a knowledge of the condensed phase portion of their equilibrium phase diagrams. Examples will be shown for arsenides, antimonides, and phosphides. Use of these diagrams explicitly presumes equilibrium growth conditions, and that assumption often fails. In such cases kinetic rather than thermodynamic factors dominate the determination of the observed phases. Examples of this phenomenon for anodic oxidation will be presented. Recent interest in high pressure oxidation conditions as a means of alleviating kinetic limitations will be discussed for InP. The phase diagrams can also be used to predict interfacial reactions under certain conditions and data for GaAs will serve to illustrate this point.

Quaternary Hydrides Pd1-y-zAgyCuzHx Embedded Atom Method Potentials for Hydrogen Energy Applications

10.21926/jept.2101006 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Chaonan Zhang ◽

Robert Fuller ◽

Iyad Hijazi ◽

Keyword(s):

Mechanical Properties ◽

Carbon Monoxide Poisoning ◽

Hydrogen Permeability ◽

Sulfur Poisoning ◽

Ternary Alloys ◽

Miscibility Gap ◽

Embedded Atom Method ◽

Hydrogen Energy ◽

Energy Applications ◽

Embedded Atom

The Pd-H system has attracted extensive attention. Pd can absorb considerable amount of H at room temperature, this ability is reversible, so it is suitable for multiple energy applications. Pd-Ag alloys possess higher H permeability, solubility and narrower miscibility gap with better mechanical properties than pure Pd, but sulfur poisoning remains an issue. Pd-Cu alloys have excellent resistance to sulfur and carbon monoxide poisoning and hydrogen embrittlement, good mechanical properties, and broader temperature working environments over pure Pd, but relatively lower hydrogen permeability and solubility than pure Pd and Pd-Ag alloys. This suggests that alloying Pd with Ag and Cu to create Pd-Ag-Cu ternary alloys can optimize the overall performance and substantially lowers the cost. Thus, in this paper, we provide the first embedded atom method potentials for the quaternary hydrides Pd1-y-zAgyCuzHx. The fully analytical potentials are fitted utilizing the central atom method without performing time-consuming molecular dynamics simulations.

Chemical ordering in AlGaN layers grown by MOCVD

MRS Proceedings ◽

10.1557/proc-639-g3.10 ◽

2000 ◽

Vol 639 ◽

Author(s):

P. Ruterana ◽

F. Omnes

Keyword(s):

Composition Range ◽

Optoelectronic Devices ◽

Superlattice Reflection ◽

Growth Conditions ◽

Ternary Alloys ◽

Adequate Model ◽

Chemical Ordering ◽

New Type ◽

Stable Growth ◽

First Time

ABSTRACTOne of the applications of wurtzite gallium based nitride compounds will be to provide optoelectronic devices from 6.2eV (AlN) to 1.89eV (InN). This will depend on the possibility to grow wurtzite AlGaN and InGaN ternary alloys. As expected, the most difficult region is InGaN due to the large misfit between GaN and InN (= 10%), in this case, ordering, phase separation and growth instabilities have been reported. In the case of AlN and GaN, the misfit is smaller (∼ 2.5%) and one would expect more stable growth. However, it was in this system that ordering along the c axis between AlN and GaN was reported for the first time.In this work, we have found that the growth of AlGaN may be more complicated. Not only the wurtzite lattice can be decreased to simple hexagonal by AlN/GaN ordering along the c axis, but the growth can lead to other types of stackings. Even in the low Al composition range, 10 - 15%, we have found that three processes can operate:1. Ordering into AlN/GaN as two simple hexagonal sublattices.2. The 3:1 ordering which has been recently reported to occur in InGaN.3. A new type of ordering where diffraction experiments (XR and electron diffraction) detect superlattice reflection with a period close to 3 nm. The most adequate model which was found to take this into account shows that, in these growth conditions, the system has preferred to form one AlN cell in between 5 GaN cells, leading to a 5:1 ordering.

Surface Energy Constraints for Heteroepitaxial Growth on Compliant Substrates: Morphology of GaN Grown on Sc Layers

MRS Proceedings ◽

10.1557/proc-449-347 ◽

1996 ◽

Vol 449 ◽

Cited By ~ 2

Author(s):

D. D. Koleske ◽

A. E. Wickenden ◽

J. A. Freitas ◽

R. Kaplan ◽

S. M. Prokes

Keyword(s):

Low Temperature ◽

Surface Energy ◽

Empirical Relationship ◽

Growth Conditions ◽

Heteroepitaxial Growth ◽

Nucleation Layer ◽

Lattice Matching ◽

Surface And Interface ◽

Compliant Substrates ◽

Gan Film

ABSTRACTAn empirical relationship linking surface energy to bulk modulus is presented which suggests that the thermodynamic growth mode for heteroepitaxy on compliant substrates should be 3-D. As an example of this behavior, GaN growth on Sc is shown for various growth conditions. 2-D growth is obtained when the GaN is grown on top of a low temperature GaN nucleation layer. Our results indicate that surface and interface energies, in addition to, lattice matching and thermal matching play an important role in determining the heteroexpitaxial growth morphology of GaN. There appears to be no net reduction in the dislocation density for GaN films grown on the Sc layers, because the GaN film has to be grown on a low temperature nucleation layer.

Estimation of Interfacial Energies Based on the Shapes of Coherent Intragranular Precipitates

Microscopy and Microanalysis ◽

10.1017/s1431927600017645 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 864-865

Author(s):

Xiao Chen ◽

L. Rabenberg

Keyword(s):

Solid Solution ◽

Surface Energy ◽

Interfacial Energy ◽

Elastic Anisotropy ◽

Ternary Alloys ◽

Interfacial Energies ◽

Simultaneous Measurements ◽

Precise Shape ◽

Invar Composition ◽

Favorable Conditions

In a study of the precipitation and aging of Invar particles in Cu, we observed that the particles evolved from spherical to cuboidal as they grew in size. This behavior has been observed in other systems, and predicted by Voorhees et al. ; they showed that the precise shape of the particle is a balance between elastic anisotropy and surface energy. The correlation between our results and their predictions are very good. It is the purpose of this note to point out that simultaneous measurements of size, shape, and mismatch of a coherent particle can be used to estimate the interfacial energy under favorable conditions.Ternary alloys consisting of Cu - 12.8 wt% Ni -7.2 wt% Fe were arc-melted, held at 1030°C to develop extended regions of the Cu-rich solid solution, quenched, then aged at various times and temperatures to develop FCC precipitates near the Invar composition in the FCC Cu matrix.

Ab-initio study of structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys

Materials Science-Poland ◽

10.1515/msp-2015-0108 ◽

2015 ◽

Vol 33 (4) ◽

pp. 879-886 ◽

Cited By ~ 1

Author(s):

S. Chelli ◽

S. Touam ◽

L. Hamioud ◽

H. Meradji ◽

S. Ghemid ◽

...

Keyword(s):

Thermodynamic Properties ◽

Bulk Modulus ◽

Lattice Constant ◽

Theoretical Data ◽

Calculated Phase Diagram ◽

Enthalpy Of Mixing ◽

Ternary Alloys ◽

Miscibility Gap ◽

Full Potential ◽

Vegard’S Law

AbstractThe structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys have been investigated using the full-potential (linearized) augmented plane wave method. The ground state properties, such as lattice constant, bulk modulus and elastic constants, are in good agreement with numerous experimental and theoretical data. The dependence of the lattice parameters, bulk modulus and band gap on the composition x was analyzed. Deviation of the lattice constant from Vegard’s law and the bulk modulus from linear concentration dependence (LCD) was observed. The microscopic origins of the gap bowing were explained by using the approach of Zunger et al. The thermodynamic stability of BaxSr1−xS alloy was investigated by calculating the excess enthalpy of mixing, ΔHm and the calculated phase diagram showed a broad miscibility gap with a critical temperature.

Initial stages of Ge epitaxy on Si(111) under quasi-equilibrium growth conditions

JETP Letters ◽

10.1134/s0021364010180062 ◽

2010 ◽

Vol 92 (6) ◽

pp. 388-395 ◽

Cited By ~ 11

Author(s):

S. A. Teys ◽

E. M. Trukhanov ◽

A. S. Ilin ◽

A. K. Gutakovskii ◽

A. V. Kolesnikov

Keyword(s):

Growth Conditions ◽

Quasi Equilibrium ◽

Equilibrium Growth

The miscibility gap region in liquid ternary alloys

Journal of Non-Crystalline Solids ◽

10.1016/s0022-3093(99)00257-4 ◽

1999 ◽

Vol 250-252 ◽

pp. 325-328 ◽

Cited By ~ 5

Author(s):

Yu. Plevachuk ◽

V. Didoukh ◽

B. Sokolovskii

Keyword(s):

Ternary Alloys ◽

Miscibility Gap