Document Type

Article

Publication Date

10-1-2003

Abstract

We have studied the effects of remote hydrogen plasma treatment on the defect characteristics in single crystal ZnO. Temperature-dependent (9–300 K) and excitation intensity-dependent photoluminescence spectra reveal that H-plasma exposure of ZnO effectively suppresses the free-exciton transition and redistributes intensities in the bound-exciton line set and two-electron satellites with their phonon replicas. The resultant spectra after hydrogenation exhibit a relative increase in intensity of the I4 (3.363 eV) peak, thought to be related to a neutral donor bound exciton, and a peak feature at 3.366 eV with a distinctly small thermal activation energy. Hydrogenation also produces a violet 100 meV wide peak centered at ∼3.15 eV. Remote plasma hydrogenation yields similar changes in room-temperature depth-dependent cathodoluminescence spectra: the emission intensity increases with hydrogenation mostly in the violet and near-ultraviolet range. Subsequent annealing at 450 °C within the same plasma environment completely restores both the photoluminescence and cathodoluminescence spectra in the subband gap range. The appearance of another bound-exciton feature at 3.366 eV and a relative intensity increase of the donor-bound exciton at line I4 with H-plasma exposure, and the reversibility with annealing of the spectral changes, indicate a direct link between hydrogen indiffusion and appearance of a shallow donor.

Comments

Copyright © 2003, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in the Journal of Applied Physics 94.7, and may be found at http://jap.aip.org/resource/1/japiau/v94/i7/p4256_s1

DOI

10.1063/1.1606859

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