Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-26T08:16:30.241Z Has data issue: false hasContentIssue false

A Case for Molecular Hydrogen Being the Mobile H Species in a-Si:H

Published online by Cambridge University Press:  17 March 2011

P. A. Fedders*
Affiliation:
Department of Physics, Washington University, St. Louis, Mo 63130
Get access

Abstract

The mechanism (or mechanisms) of hydrogen transport in a-Si:H is of great intrinsic interest but is also important for the understanding of a number of phenomena such as light induced defects. We find that the literature includes many calculations for the activation energy for hydrogen diffusion that are at best misleading and often interpreted incorrectly. In this paper we summarize a number of calculations that apply to particles hopping in complex media and apply the results to a-Si:H. These calculations, coupled with existing estimates of the energy of various H configurations in a-Si:H, show that the standard picture is likely to be incorrect. However, previous work on the mobility of molecular hydrogen in crystalline Si coupled with some molecular dynamics simulations presented in this paper show that the mobile species of hydrogen in a-Si:H may well be molecular.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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. Franz, A. J., Mavrikakis, M., and Gland, J. L., Phys. Rev. B 57, 3927 (1998).Google Scholar
2. Branz, Howard M. and Asher, Sally, Glescova, Helena, and Wagner, Sigurd, Phys. Rev. B 59, 55134 (1999).Google Scholar
3. Walle, Chris G. Van de, Phys. Rev. B 49, 4579 (1994).Google Scholar
4. Street, R. A., Tsai, C. C., Kakakis, J., and Jackson, W. B., Phil. Mag. B56, 305 (1987).Google Scholar
5. Norberg, R. E., Leopold, D. J., and Fedders, P. A., J. Non-Cryst. Solids 227–230, 124 (1998); R. E. Norberg, P. A. Fedders, and D. J. Leopold, Materials Research Society Symposium Proceedings 420, 475 (1996).Google Scholar
6. Fedders, P. A., Physical Review B (submitted).Google Scholar
7. Sánchez-Portal, P., Ordejón, P., Artacho, E., and Soler, J., Int. J. of Quantum Chem. 65, 453 (1997).Google Scholar
8. Buda, F., Chiarotti, Guido L., Car, R., and Parinello, M., Phys. Rev. Lett. 63, 294 (1989).Google Scholar
9. Walle, Chris G. Van de and Tuttle, Blair, in Amorphous and Heterogeneous Silicon Films, MRS Symposia, Vol. 557 (to be published).Google Scholar