Thermodynamics of (gallium + chlorine)(g) I. Vapour-pressure measurements and thermodynamic stability of GaCl(g), GaCl2(g), GaCl3(g), Ga2Cl2(g), Ga2Cl4(g), and Ga2Cl6(g)

Bérnard, C.; Chatillon, C.; Aǐt-Hou, A.; Hillel, R.; Monteil, Y.; Bouix, J.

doi:10.1016/0021-9614(88)90148-6

Cited by 18 publications

(5 citation statements)

References 21 publications

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“…In addition, no clear temperature dependency was observed in the temperature range (550 C-650 C) investigated, and no activation energy for the etching could be deduced. However, comparing the formation enthalpies of GaCl, GaCl 3 , 30 and GaAs, 31 one nds that GaCl 3 is the energetically most favorable product, assuming the same initial conditions for the reactants (liquid Ga, gaseous Cl and As). Detailed thermodynamic calculations on the suggested reactions are beyond the scope of this study, and are therefore only discussed qualitatively.…”

Section: Post-growth Etchingmentioning

confidence: 99%

Crystal structure tuning in GaAs nanowires using HCl

2014

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The use of HCl during growth of nanowires presents new possibilities for controlling the growth dynamics and resulting nanowire properties. In this paper, we investigate the effects of in situ HCl on the growth of Au-seeded GaAs nanowires in a growth regime where both wurtzite and zinc blende crystal structures are possible to achieve. We find that HCl changes the crystal structure of the nanowires from pure wurtzite to defect-free zinc blende. By comparing the growth of wurtzite-zinc blende heterostructures with and without the addition of HCl, it is deduced that HCl mainly interacts with Ga species prior incorporation, reducing the amount of Ga available to contribute to the growth. We conclude that the change in crystal structure is related to the reduction of Ga adatoms, and demonstrate the realization of wurtzite-zinc blende heterostructures with atomically sharp interfaces achieved only by adding HCl.

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Section: Post-growth Etchingmentioning

confidence: 99%

Crystal structure tuning in GaAs nanowires using HCl

2014

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“…This value is higher than those found in literature obtained by second-law treatment of the vapor pressures: Komshilova et al, (72.8 ± 2.1) kJ·mol −1 , Dumas and Potier and Laubengayer and Schirmer, both equal to 73.5 kJ·mol −1 (as recalculated by us using the heat content functions in ref ), Opperman et al, (68.5 ± 3.0) kJ·mol −1 , and Chusova et al (80.3 and 67.2) kJ·mol −1 from second- and third-law treatments of their vapor pressures, respectively. In particular it is interesting to note that the third-law sublimation enthalpy value calculated by Chusova et al (67.2 kJ·mol −1 ) using heat capacities and entropies of Ga 2 Cl 6 (g) and of GaCl 3 (s) found in literature is different than those recalculated by us using the IVTANTHERMO’s fef, (101.0 and 89.6) kJ·mol −1 at the extreme experimental temperatures of the work and (310 and 350) K, respectively. Besides, these values show a decidedly evident temperature trend considering the small range.…”

Section: Experimental and Results Sectionmentioning

confidence: 57%

Vapor Pressures of Gallium Trifluoride, Trichloride, and Triiodide and Their Standard Sublimation Enthalpies

2009

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The vapor pressures of gallium trihalides GaF(3), GaCl(3), and Gal(3) were measured by a torsion effusion apparatus, and their temperature dependences fit the following equation: log(p/Pa) = (14.30 +/- 0.30) - (12600 +/- 200)/(T/K) (from 808 to 958 K), log(p/Pa) = 13.80 - 3800/(T/K) (from 289 to 308 K), and log(p/Pa) = (14.00 +/- 0.50) - (5130 +/- 150)/(T/K) (from 345 to 401 K) for GaF(3), GaCl(3), and Gal(3), respectively. Both GaF(3) and Gal(3) vaporize practically congruently in monomeric Form while GaCl(3) is in dimer form. Treating the vapor pressures by second- and third-law methods, the selected standard enthalpies Delta H degrees(298 K) = (252 +/- 4) kJ.mol(-1), (89 +/- 2) kJ.mol(-1), and (100.5 +/- 2.0) kJ.mol(-1) associated with the Sublimation of GaF(3), GaCl(3), and Gal(3), respectively, were obtained

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“…The Cl-Cl bonds are associated with molecular chlorine formed in the supercritical fluid resulting from the monomer disproportionation: GaCl 3 ⇌ GaCl + Cl 2 . Gallium monochloride is typically observed at high temperatures, becoming predominant above 1100 K [ 17 , 18 ]. In our case, GaCl remains elusive, either forming intermediate species via homopolar Ga-Ga and heteropolar Ga-Cl bonding or persisting as diatomic molecules (with a residual 50% occurrence in the latter two cases).…”

Section: Resultsmentioning

confidence: 99%

Gallium Trichloride Fluid: Dimer Dissociation Mechanism, Local Structure, and Atomic Dynamics

Khomenko,

Sokolov,

Tverjanovich

et al. 2024

Molecules

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Molten gallium trichloride emerges as a promising solvent for oxidative metal recycling. The use of supercritical fluid enhances the performance and kinetics of metal dissolution due to significantly lower viscosity in the reaction media. Additionally, the dual molecular nature of gallium trichloride, existing as edge-sharing ES-Ga2Cl6 dimers at low temperatures and high pressure, or flat trigonal GaCl3 monomers in the vicinity of the critical point and low pressures, creates the possibility to tailor the chemical geometry to a particular metallic species. Nevertheless, the mechanism of dimer dissociation, local structure, and atomic dynamics in supercritical gallium trichloride fluids are not known. Using first-principles molecular dynamics, validated by comparison with our high-energy X-ray diffraction results, we illustrate the elementary steps in dimer dissociation. These include the formation of intermediate corner-sharing CS-Ga2Cl6 dimers, the partial disproportionation of GaCl3 monomers at high temperatures and low pressures, changes in the local environment of molecular entities, and unusual atomic dynamics in supercritical fluids.

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Thermodynamics of (gallium + chlorine)(g) I. Vapour-pressure measurements and thermodynamic stability of GaCl(g), GaCl2(g), GaCl3(g), Ga2Cl2(g), Ga2Cl4(g), and Ga2Cl6(g)

Cited by 18 publications

References 21 publications

Crystal structure tuning in GaAs nanowires using HCl

Crystal structure tuning in GaAs nanowires using HCl

Vapor Pressures of Gallium Trifluoride, Trichloride, and Triiodide and Their Standard Sublimation Enthalpies

Gallium Trichloride Fluid: Dimer Dissociation Mechanism, Local Structure, and Atomic Dynamics

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