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Light-Induced Metastable Defects or Light-Induced Metastable H Atoms in a-Si:H Films?

Published online by Cambridge University Press:  15 February 2011

C. Godet
C. Godet*
Affiliation:
Laboratoire de Physique des Interfaces et des Couches Minces (UPR 0258 CNRS) Ecole Polytechnique, 91128 Palaiseau-Cedex (France), [email protected]
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Abstract

In hydrogenated amorphous silicon (a-Si:H) films, the increase of the metastable defect density under high-intensity illumination is usually described by an empirical two-parameter stretched-exponential time dependence (characteristic time τSE and dispersion parameter β). In this study, a clearly different (one-parameter) analytic function is obtained from a microscopic model based on the formation of metastable H (MSH) atoms in a-Si:H films. Assuming that MSH atoms are the only mobile species, only three chemical reactions are significant : MSH are produced from doubly hydrogenated (SiH HSi) configurations and trapped either at broken bonds or Si-H bonds, corresponding respectively to light-induced annealing (LIA) and light-induced creation (LIC) of defects. Competition between trapping sites results in a saturation of N(t) at a steady-state value Nss. A one-parameter fit of this analytical function to experimental data is generally good, indicating that the use of a statistical distribution of trap energies is not necessary.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 467: Symposium A – Amorphous and Microcrystalline Silicon Technology - 1997 , 1997 , 79
Copyright
Copyright © Materials Research Society 1997

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References

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