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Laplace-transform Transient Photocurrent Spectroscopy as a Probe of Metastable Defect Distributions in Hydrogenated Amorphous Silicon

Published online by Cambridge University Press:  17 March 2011

Mariana J. Gueorguieva
Affiliation:
School of Science and Engineering, University of Abertay Dundee, Bell Street, Dundee, DD1 1HG, U.K
Charlie Main
Affiliation:
School of Science and Engineering, University of Abertay Dundee, Bell Street, Dundee, DD1 1HG, U.K
Steve Reynolds
Affiliation:
School of Science and Engineering, University of Abertay Dundee, Bell Street, Dundee, DD1 1HG, U.K
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Abstract

Three Laplace transform methods for recovering the density of electronic states from transient photocurrent data are evaluated through a study of light-induced defect creation in PECVD a-Si:H films. A mathematically approximate method is shown to be sufficient to resolve the deep defects, whose density is estimated to increase by a factor of five from the annealed state after 3 hours' exposure to simulated AM1 illumination. An exact method, and a method employing Tikhonov regularisation, are found to give very similar results, provided the current-time data are smoothed beforehand in the former case. The increased resolution available is, however, unnecessary here, and these methods are shown to be more suited to the study of discrete levels or narrow distributions.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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