Abstract
In this work we investigated the stability of a-Si:H films under illumination and following recovery in darkness at different temperatures. The a-Si:H films were fabricated with 55 kHz PECVD and with conventional rf 13.56 MHz PECVD. We measured the steady-state photocurrent and the dark-current after switching off the light source as a function of time. We observed photocurrent degradation and the following recovery of the dark current. The kinetics of the photocurrent degradation as well as the dark-current recovery demonstrated stretched-exponential behavior. The results of these straightforward measurements in combination with computer simulation were used to determine the effect of light-induced degradation and thermal recovery on the density of states distribution in the band gap of a-Si:H. We have found that the photocurrent degradation and the corresponding increase in the total defect concentration have different kinetics. The different kinetics were also determined for the dark-current recovery and the corresponding decrease in the total defect concentration. The results point out that slow and fast types of defects in a-Si:H films control the kinetics of light-induced changes of the defect distribution in the band gap. A model is proposed that relates the origin of the fast and slow metastable defects with the distribution of Si-Si bond lengths.
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From Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 6, 2000, pp. 742–747.
Original English Text Copyright © 2000 by Meytin, Zeman, Budaguan, Metselaar.
This article was submitted by the authors in English.
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Meytin, M.N., Zeman, M., Budaguan, B.G. et al. Kinetics of light-induced degradation in a-Si:H films investigated by computer simulation. Semiconductors 34, 717–722 (2000). https://doi.org/10.1134/1.1188060
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DOI: https://doi.org/10.1134/1.1188060