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Hopping Conduction in a-Si:H Studied by Transient Photoconductivity with Optical Bias Illumination

Published online by Cambridge University Press:  21 February 2011

Xing Chen
Affiliation:
Greyhawk Systems, Inc., 1557 Centre Pointe Drive, Milpitas, California 95053
Upali Jayamaha
Affiliation:
The University of Toledo, Toledo, Ohio 43606
Chen-Yu Tai
Affiliation:
The University of Toledo, Toledo, Ohio 43606
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Abstract

Charge transport in a-Si:H films is studied by measuring the intensity and the rate of decay of the transient photocurrent with optical bias illumination. The optical bias enhancement of the transient photocurrent due to the probe beam decreases at first as the temperature is decreased, reaches a minimum at about 21OK, and then increases as the temperature is further decreased. This observation, together with the decay time measurements, indicates a change in the mechanism of charge propagation from conduction band transport at high temperature to hopping conduction in the low temperature. A theory of hopping conduction in tail states is developed to explain the experimental results. A quantitative comparison of the theoretical and experimental results is made to determine the localization length of the tail states.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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References

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