<i>p</i>,<i>T</i>-dependence of self-diffusion in liquid hydrogen fluoride

Karger, N.; Vardag, T.; Lüdemann, H.‐D.

doi:10.1063/1.466771

Cited by 28 publications

(11 citation statements)

References 26 publications

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“…Figure 2(b) shows D T as a function of temperature. Our results are compared with those obtained by pulsed-fieldgradient nuclear magnetic resonance (PFG-NMR) [11]. Our QENS data reproduce the PFG-NMR diffusion coefficients at high temperatures.…”

supporting

confidence: 50%

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Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-Bonded Liquid

Fernandez-Alonso

Bermejo²,

McLain

et al. 2007

Phys. Rev. Lett.

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supporting

confidence: 50%

“…We also performed quick runs across the melting point (T 170-205 K). The observation of a sharp and distinct drop in elastic-line intensity at T 190 1K provided an upper limit for the presence of H 2 O of <0:5% mol [11].…”

mentioning

confidence: 99%

Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-Bonded Liquid

Fernandez-Alonso

Bermejo²,

McLain

et al. 2007

Phys. Rev. Lett.

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“…However, we could find data related to the self-diffusion of HF ͑i.e., diffusion of HF in HF͒ from Ref. 21. So for the time being, we will use these data ͑D = 5.51 ϫ 10 −5 cm 2 /s at 283.7 K and E a,d = 0.10 eV͒ as a firstorder approximation to describe the diffusion of HF in a 20% HF solution.…”

Section: Discussionmentioning

confidence: 99%

A Diffusion and Reaction Related Model of the Epitaxial Lift-Off Process

Niftrik

Schermer

Bauhuis

et al. 2007

J. Electrochem. Soc.

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In the present work a so-called diffusion and reaction related model ͑DR model͒ is derived based on the notion that the overall etch rate in the epitaxial lift-off ͑ELO͒ process is determined both by the diffusion rate of hydrofluoric acid to the etch front and its subsequent reaction rate in the process. In contrast to the model that was previously described in the literature, the DR model yields etch rates which are in quantitative agreement with those obtained experimentally. In order to verify the DR model, the ELO etch rate of AlAs 1−y P y release layers is determined as a function of the phosphorus percentage, the release layer thickness and the temperature. In accordance with the DR model, it is shown that the etch rate is reaction rate related by the dependence on the phosphorus percentage in the release layer, and that the etch rate is diffusion rate related by the dependence on the release layer thickness. From the temperature dependence, an activation energy of 0.31 eV could be deduced for the ELO process under the present conditions. © 2007 The Electrochemical Society. ͓DOI: 10.1149/1.2779968͔ All rights reserved. The "epitaxial lift-off" ͑ELO͒ technique ͑see Fig. 1a͒, in which a III/V device structure is separated from its GaAs substrate by using selective wet etching of a thin Al x Ga 1−x As ͑x Ͼ 0.6͒ release layer and transferred to a foreign carrier, allows the production of singlecrystalline thin films of III/V materials.1 Application of this technique is interesting for the optoelectronics industry, because use of thin-film devices potentially results in a more efficient transfer of generated heat from device to carrier or heat sink and significantly reduces the amount of material needed by reuse of the substrates. This is of particular importance for an intrinsically large area, thus expensive devices like high efficiency III/V solar cells, 2,3 and the integration of III/V based components with, e.g., silicon-based devices. 4,5 Recently, at our institute thin-film GaAs solar cells were made based on the ELO technique, which reached record efficiencies of 24.5%.6 This is close to the highest efficiency of 25.1% reported for regular GaAs cells on a GaAs substrate, 7 which indicates that the ELO process is not detrimental to the quality of the thin-film device.In 1978 Konagai et al. 8 described the separation of devices from a GaAs substrate using the extreme selectivity of hydrofluoric acid ͑HF͒ for Al x Ga 1−x As with a high Al fraction. A wax layer was applied to support the 30 µm thick fragile films during the process. Yablonovitch et al. 9 noted that the tension induced by the wax caused the thinner films, of micrometer thickness, to curl up with a radius of curvature r as they became undercut. This was concluded to be beneficial for removal of the etch products, leading to an increased lateral etch rate V e of the AlAs release layer. By assuming that three moles of hydrogen ͑H 2 ͒ gas are produced for each mole of AlAs etched and that the ability of dissolved H 2 , which has a low solubil...

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“…Diffusion coefficients from XPHF and experiments 84 are given in Table VIII The computed diffusion coefficients for the nonsupercritical states A-G and supercritical state K show good agreement with the Arrhenius equations derived from experiments, while that from state H shows a noticeable discrepancy. In the case of state H, the predicted diffusion coefficient is nearly three times that of experiment, indicating that state H is approaching the vapor phase under XPHF.…”

Section: F Diffusionmentioning

confidence: 54%

Quantum mechanical force field for hydrogen fluoride with explicit electronic polarization

Mazack

Gao

2014

The Journal of Chemical Physics

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The explicit polarization (X-Pol) theory is a fragment-based quantum chemical method that explicitly models the internal electronic polarization and intermolecular interactions of a chemical system. X-Pol theory provides a framework to construct a quantum mechanical force field, which we have extended to liquid hydrogen fluoride (HF) in this work. The parameterization, called XPHF, is built upon the same formalism introduced for the XP3P model of liquid water, which is based on the polarized molecular orbital (PMO) semiempirical quantum chemistry method and the dipole-preserving polarization consistent point charge model. We introduce a fluorine parameter set for PMO, and find good agreement for various gas-phase results of small HF clusters compared to experiments and ab initio calculations at the M06-2X/MG3S level of theory. In addition, the XPHF model shows reasonable agreement with experiments for a variety of structural and thermodynamic properties in the liquid state, including radial distribution functions, interaction energies, diffusion coefficients, and densities at various state points.

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p,T-dependence of self-diffusion in liquid hydrogen fluoride

Cited by 28 publications

References 26 publications

Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-Bonded Liquid

Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-Bonded Liquid

A Diffusion and Reaction Related Model of the Epitaxial Lift-Off Process

Quantum mechanical force field for hydrogen fluoride with explicit electronic polarization

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