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HL: Halbleiterphysik

HL 26: II-VI semiconductors II

HL 26.8: Talk

Tuesday, March 28, 2006, 17:00–17:15, POT 51

Hyperfine splitting in hydrogenated ZnO measured by electron spin resonance — •Marc A. Gluba, Felice Friedrich, and Norbert H. Nickel — Hahn-Meitner-Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstraße 5, D-12489 Berlin

The source of the natural n-type doping of zinc oxide single crystals is still not completely clarified. However, hydrogen as an indispensable permanent impurity plays a crucial role. To elucidate the importance of hydrogen X-band electron spin resonance (ESR) measurements were performed on zinc oxide single crystals before and after hydrogenation. Hydrogen was introduced by annealing the samples for two hours at 830^∘C in sealed ampoules under hydrogen atmosphere. The ESR-measurements were performed at 5K.

As-grown zinc oxide exhibits a single ESR line arising from two shallow donors with similar g-values (g_||=1,957, g_⊥=1,956). One of which was identified as hydrogen [1]. On the other hand, hydrogenated zinc oxide shows distinctly different ESR spectra. Besides the intensification of the donor related line a variety of new features in a broad range of about 1000G around the center line is observed. These are likely to arise from hyperfine interaction between electrons of neutralized hydrogen donors and adjacent ⁶⁷Zn nuclei of spin 5/2. Based on the performed experiments conclusions on the position of the hydrogen centers in the ZnO lattice can be drawn.

[1] Detlev M. Hofmann et al., Phys. Rev. Lett., 88 no. 4, 045504 (2002)