Characterization of evaporated erbium films at various stages of growth

Gu, Erdan; Savaloni, Hadi; Player, M.A.; Marr, G. V.

doi:10.1016/0022-3697(92)90020-e

Cited by 19 publications

(15 citation statements)

References 16 publications

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“…This is somewhat inconsistent with the present results, where attribution of the inverse grain size relation to pre-existing hydride would require invocation of more pre-existing hydride at higher-temperature growth. However, very different substrates, preparation methods, and vacuum practices were used between the study of Gu et al and the current study; further, Gu et al noted that at higher temperatures substrate influences become more important [47]. Thus, it not possible to directly compare the previous results to the present results.…”

Section: Erd 2 Filmscontrasting

confidence: 56%

“…This texture selection could imply easier nucleation which could contribute to the smaller grain size of the textured hydrides, in addition to the previously mentioned possibility of faster hydrogen diffusion and growth in the largegrained hydrides. Additionally, Gu et al [47] noted that under certain conditions, the earliest stages of Er-metal growth would proceed as FCC-ErH 2 . Hypothetically, if such a situation obtained in the Metal/High samples but not Metal/Low samples, and this small volume fraction of hydride persisted through metal growth to the beginning of deuterium loading, this pre-existing hydride volume fraction might serve as ready-made nucleation sites for ErD 2 .…”

Section: Erd 2 Filmsmentioning

confidence: 98%

“…The effect of growth parameters on deposited thick-and thinfilm microstructures has been discussed and reviewed by many authors [39][40][41][42][43]; the seminal paper for metal thin-films was that of Grovenor et al [44], and the specific case of Er-thin-films was studied by Savaloni et al [45,46] and Gu et al [47]. These references suggest structure-zone models (SZMs), in which the structure of the polycrystalline thin-film is determined by processing parameters, primarily the homologous substrate temperature during deposition, defined as T S /T M , where T S is the substrate temperature in kelvins and T M the melting point of the film material in kelvins.…”

Section: Expected Behaviormentioning

confidence: 99%

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Processing effects on microstructure in Er and ErD2 thin-films

Parish

Snow

Kammler

et al. 2010

Journal of Nuclear Materials

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a b s t r a c tErbium metal thin-films have been deposited on molybdenum-on-silicon substrates and then converted to erbium dideuteride (ErD 2 ). Here, we study the effects of deposition temperature (%300 or 723 K) and deposition rate (1 or 20 nm/s) upon the initial Er metal microstructure and subsequent ErD 2 microstructure. We find that low deposition temperature and low deposition rate lead to small Er metal grain sizes, and high deposition temperature and deposition rate led to larger Er metal grain sizes, consistent with published models of metal thin-film growth. ErD 2 grain sizes are strongly influenced by the prior-metal grain size, with small metal grains leading to large ErD 2 grains. A novel sample preparation technique for electron backscatter diffraction of air-sensitive ErD 2 was developed, and allowed the quantitative measurement of ErD 2 grain size and crystallographic texture. Finer-grained ErD 2 showed a strong (1 1 1) fiber texture, whereas larger grained ErD 2 had only weak texture. We hypothesize that this inverse correlation may arise from improved hydrogen diffusion kinetics in the more defective fine-grained metal structure or due to improved nucleation in the textured large-grain Er.

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Section: Erd 2 Filmscontrasting

confidence: 56%

Section: Erd 2 Filmsmentioning

confidence: 98%

Section: Expected Behaviormentioning

confidence: 99%

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Processing effects on microstructure in Er and ErD2 thin-films

Parish

Snow

Kammler

et al. 2010

Journal of Nuclear Materials

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“…It is likely that some hydrogen incorporation occurred during film deposition since it is difficult to avoid H 2 even under UHV conditions. 1,8,[55][56][57] There is a large increase in ion yields for H À and OH À in the activated erbium film relative to the as-received film, Fig. 6.…”

Section: H Tof-simsmentioning

confidence: 94%

“…structure. 57 The dihydride is known to be face centered cubic (f.c.c. ), [56][57][58] while Er 2 O 3 is known to have the bixbyite lattice.…”

Section: H Tof-simsmentioning

confidence: 99%

Activation of erbium films for hydrogen storage

Brumbach

Ohlhausen

Zavadil

et al. 2011

Journal of Applied Physics

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Hydriding of metals can be routinely performed at high temperature in a rich hydrogen atmosphere. Prior to the hydrogen loading process, a thermal activation procedure is required to promote facile hydrogen sorption into the metal. Despite the wide spread utilization of this activation procedure, little is known about the chemical and electronic changes that occur during activation and how this thermal pretreatment leads to increased rates of hydrogen uptake. This study utilized variable kinetic energy X-ray photoelectron spectroscopy to interrogate the changes during in situ thermal annealing of erbium films, with results confirmed by time-of-flight secondary ion mass spectrometry and low energy ion scattering. Activation can be identified by a large increase in photoemission between the valence band edge and the Fermi level and appears to occur over a two stage process. The first stage involves desorption of contaminants and recrystallization of the oxide, initially impeding hydrogen loading. Further heating overcomes the first stage and leads to degradation of the passive surface oxide leading to a bulk film more accessible for hydrogen loading.

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