Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-02T22:48:34.213Z Has data issue: false hasContentIssue false

The manifestation of oxygen contamination in ErD2 thin films

Published online by Cambridge University Press:  31 January 2011

Chad M. Parish*
Affiliation:
Sandia National Laboratories, Albuquerque, New Mexico 87185
Luke N. Brewer
Affiliation:
Sandia National Laboratories, Albuquerque, New Mexico 87185
*
a) Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Erbium dihydride Er(H,D,T)2 is a fluorite structure rare-earth dihydride useful for the storage of hydrogen isotopes in the solid state. However, thermodynamic predictions indicate that erbium oxide formation will proceed readily during processing, which may detrimentally contaminate Er(H,D,T)2 films. In this work, transmission electron microscopy (TEM) techniques including energy-dispersive x-ray spectroscopy, energy-filtered TEM, selected area electron diffraction, and high-resolution TEM are used to examine the manifestation of oxygen contamination in ErD2 thin films. An oxide layer ∼30–130 nm thick was found on top of the underlying ErD2 film, and showed a cube-on-cube epitaxial orientation to the underlying ErD2. Electron diffraction confirmed the oxide layer to be Er2O3. While the majority of the film was observed to have the expected fluorite structure for ErD2, secondary diffraction spots suggested the possibility of either nanoscale oxide inclusions or hydrogen ordering. In situ heating experiments combined with electron diffraction ruled out the possibility of hydrogen ordering, so epitaxial oxide nanoinclusions within the ErD2 matrix are hypothesized. TEM techniques were applied to examine this oxide nanoinclusion hypothesis.

Type
Articles
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Sakintuna, B., Lamari-Darkrim, F., and Hirscher, M.: Metal hydride materials for solid hydrogen storage: A review. Int. J. Hydro-gen Enerev 32, 1121 (2007).CrossRefGoogle Scholar
2.Lynch, F.E.: Metal hydride practical applications. J. Less-Common Met. 172–174, 943 (1991).CrossRefGoogle Scholar
3.Crabtree, G.W. and Dresselhaus, M.S.: The hydrogen fuel alternative. MRS Bull. 33, 421 (2008).CrossRefGoogle Scholar
4.Grochala, W. and Edwards, P.P.: Thermal decomposition of the non-interstitial hydrides for the storage and production of hydrogen. Chem. Rev. 104, 1283 (2004).CrossRefGoogle ScholarPubMed
5.Chen, P. and Zhu, M.: Recent progress in hydrogen storage. Mater. Today 11, 36 (2008).CrossRefGoogle Scholar
6.Provo, J.L.: Effects of vacuum processing erbium dideuteride-ditritide films deposited on chromium underlays on copper substrates. J. Vac. Sci. Technol. 16, 230 (1979).CrossRefGoogle Scholar
7.Dow, P.A., Briers, G.W., Dewey, M.A.P., and Stark, D.S.: Structure of erbium deuteride targets for neutron generators. Nucl. Instrum. Methods 60, 293 (1968).CrossRefGoogle Scholar
8.Bach, H.T., Steinkruger, F.J., Chamberlin, W.S., and Walthers, C.R.: Quantitative analysis of deuterium and tritium in erbium hydride films of neutron tube targets. J. Vac. Sci. Technol., B 22. 1738 (2004).CrossRefGoogle Scholar
9.Chichester, D.L. and Simpson, J.D.: Compact accelerator neutron generators. Industr. Physicist 9, 22 (20032004).Google Scholar
10.Gabis, I., Evard, E., Voyt, A., Chernov, I., and Zaika, Y.: Kinetics of decomposition of erbium hydride. J. Alloys Compd. 356, 353 (2003).CrossRefGoogle Scholar
11.Fernandez, E.J. and Holloway, D.M.: Oxidation studies of erbium hydride system. J. Vac. Sci. Technol. 11, 612 (1974).CrossRefGoogle Scholar
12.Mitchell, D.J. and Patrick, R.C.: Temperature dependence of helium release from erbium tritide films. J. Vac. Sci. Technol. 19, 236 (1981).CrossRefGoogle Scholar
13.Tewell, C.R. and King, S.H.: Observation of metastable erbium trihydride. Appl. Surf. Sci. 253, 2597 (2006).CrossRefGoogle Scholar
14.Curzon, A.E. and Chlebek, H.G.: Observation of face centered cubic erbium in thin-films and its oxidation. J. Less-Common Met. 27, 411 (1972).CrossRefGoogle Scholar
15.Rahman Khan, M.S.: Epitaxial growth of erbium dihydride films. Thin Solid Films 113, 207 (1984).CrossRefGoogle Scholar
16.Rahman Khan, M.S. and Miller, R.F.: The growth and structure of epitaxial films of the rare-earth dihydrides. J. Phys. D: Appl. Phys. 12, 271 (1979).CrossRefGoogle Scholar
17.Blewer, R.S. and Maurin, J.K.: Dimensional expansion and surface microstructure in helium-implanted erbium and erbium-hydride films. J. Nucl. Mater. 44, 260 (1972).CrossRefGoogle Scholar
18.Guthrie, J.W., Beavis, L.C., Begeal, D.R., and Perkins, W.G.: Properties of hydride-forming metals and of multilayer hydrogen permeation barriers. J. Nucl. Mater. 53, 313 (1974).CrossRefGoogle Scholar
19.Gu, E.D., Savaloni, H., Player, M.A., and Marr, G.V.: Characterization of evaporated erbium films at various stages of growth. J. Phys. Chem. Solids 53, 127 (1992).CrossRefGoogle Scholar
20.Rahman Khan, M.S.: Changes produced in the electrical resistivity of ErH2 thin films when converted to ErH3 due to hydrogen treatment. Appl. Phys. A 35, 263 (1984).CrossRefGoogle Scholar
21.Knapp, J.A. and Browning, J.F.: Nanoindentation characterization of ErT2 thin films. J. Nucl. Mater. 350, 147 (2006).CrossRefGoogle Scholar
22.Snow, C.S., Brewer, L.N., Gelles, D.S., Rodriguez, M.A., Kotula, P.G., Mangan, M.A., and Browning, J.F.: Helium release and microstructural changes in Er(D,T)2−x3Hex films. J. Nucl. Mater. 374, 147 (2007).CrossRefGoogle Scholar
23.Vajda, P.: Hydrogen ordering and metal-semiconductor transitions in superstoichiometric rare earth dihydrides. J. Alloys Compd. 231, 170 (1995).CrossRefGoogle Scholar
24.DeHoff, R.T.: Thermodynamics in Materials Science (McGraw-Hill, New York, 1993).Google Scholar
25.Holloway, D.M.: The quantitative determination of surface oxide thickness on deposited metal films by combination auger spectroscopy and inert gas ion bombardment. Appl. Spectrosc. 27, 95 (1973).CrossRefGoogle Scholar
26.Cowgill, D.F.: Helium nano-bubble evolution in aging metal tritides. Fus. Sci. Technol. 48, 539 (2005).CrossRefGoogle Scholar
27.Fromm, E. and Uchida, H.: Effect of oxygen sorption layers on the kinetics of hydrogen absorption by tantalum at 77–700 K. J. Less-Common Met. 66, 77 (1979).CrossRefGoogle Scholar
28.Wenzl, H., Klatt, K-H., Meuffels, P., and Papathanassopoulos, K.: Hydrogen storage in thin film metal hydrides. J. Less-Common Met. 89, 489 (1983).CrossRefGoogle Scholar
29.Jain, I.P., Devi, B., and Williamson, A.: Hydrogen in UHV deposited FeTi thin films. Int. J. Hydrogen Energy 26, 1183 (2001).CrossRefGoogle Scholar
30.Venhaus, T. and Poths, J.: Observations on He-3 release from ErT2 films. Fus. Sci. Technol. 48, 601 (2005).CrossRefGoogle Scholar
31.Brydson, R.: Electron Energy Loss Spectroscopy (Royal Microscopical Society Handbook #48) (BIOS Scientific Publishers, Oxford, 2001).Google Scholar
32.Kothleitner, G. and Hofer, F.: Optimization of the signal to noise ratio in EFTEM elemental maps with regard to different ioniza-tion edge types. Micron 29, 349 (1998).CrossRefGoogle Scholar
33.Mayer, J.: Nanoscale analysis by energy-filtering TEM, in Advances in Imaging and Electron Physics, Vol. 123, edited by Hawkes, P.W. (Academic Press, Amsterdam, 2002), p. 399.Google Scholar
34.Thomas, P.J. and Midgley, P.A.: An introduction to energy-filtered transmission electron microscopy. Top. Catal. 21, 109 (2002).CrossRefGoogle Scholar
35.Williams, D.B. and Carter, C.B.: Transmission Electron Microscopy (Plenum, New York, 1996).CrossRefGoogle Scholar
36.Jain, I.P., Vijay, Y.K., Malhotra, L.K., and Uppadhyay, K.S.: Hydrogen storage in thin-film metal hydride-A review. Int. J. Hydrogen Energy 13, 15 (1988).CrossRefGoogle Scholar
37.Grier, E.J., Petford-Long, A.K., and Ward, R.C.C.: Determination of hydrogen ordering within the ss-RH2 + x phase (R = Ho, Y) using electron diffraction techniques. J. Appl. Crystallogr. 33, 1246 (2000).CrossRefGoogle Scholar
38.Goldstone, J.A., Eckert, J., Richards, P.M., and Venturini, E.L.: Temperature and concentration-dependence of hydrogen site occupancy in several rare-earth dihydrides. Phys. B + C (Amsterdam) 136, 183 (1986).Google Scholar
39.Vajda, P., Daou, J.N., and Burger, J.P.: Observations of magnetic and structural ordering in TbH2+x compounds through electrical-resistivity measurements. Phys. Rev. B 36, 8669 (1987).CrossRefGoogle ScholarPubMed
40.Sun, S.N., Wang, Y., and Chou, M.Y.: First principles study of hydrogen ordering in b-YH2+x. Phys. Rev. B 49, 6481 (1994).CrossRefGoogle Scholar
41.Udovic, T.J., Rush, J.J., and Anderson, I.S.: Neutron spectroscopic evidence of concentration-dependent hydrogen ordering in the octahedral sublattice of b-TbH2+x. Phys. Rev. B 50, 7144 (1994).CrossRefGoogle Scholar
42.Vajda, P. and Daou, J.N.: Magnetic and metal-semiconductor transitions in ordered and disordered ErH(D)(2+x). Phys. Rev. B 49, 3275 (1994).CrossRefGoogle ScholarPubMed
43.Udovic, T.J., Rush, J.J., and Anderson, I.S.: Neutron spectroscopic comparison of b-phase rare-earth hydrides. J. Alloys Compd. 231, 138 (1995).CrossRefGoogle Scholar
44.Ratishvili, I.G. and Vajda, P.: Hydrogen ordering in superstoichiometric rare-earth hydrides for a system with an energy-constants ratio p = V2/V1 < 1: LaH2+x. Phys. Rev. B 53, 581 (1996).CrossRefGoogle Scholar
45.Udovic, T.J., Huang, Q., and Rush, J.J.: Hydrogen and deuterium site separation in fcc-based mixed-isotope rare-earth hydrides. Phys. Rev. B 61, 6611 (2000).CrossRefGoogle Scholar
46.De Graef, M.: Introduction to Conventional Transmission Electron Microscopy (Cambridge University Press, Cambridge, 2003).CrossRefGoogle Scholar