Identification of hydrogen molecules in ZnO.
Hydrogen molecules in ZnO are identified by their local vibrational modes. In a Raman study, interstitial H2, HD, and D2 species were found to exhibit local vibrational modes at frequencies 4145, 3628, and 2985 cm-1, respectively. After thermal treatment of vapor phase grown ZnO samples in hydrogen atmosphere, most hydrogen forms shallow donors at the bond-centered site (HBC). Subsequently, HBC migrates through the crystal and forms electrically inactive H2. These results imply that the "hidden" hydrogen in ZnO [G. A. Shi et al., Appl. Phys. Lett. 85, 5601 (2004)10.1063/1.1832736] occurs in the form of interstitial H2.
Lavrov
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Technische Universität Dresden, 01062 Dresden, Germany. edward.lavrov@physik.tu-dresden.de
Herklotz
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Weber
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