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Femtosecond Far-Infrared Studies of Photoconductivity in a-Si:H and a-SiGe:H

Published online by Cambridge University Press:  21 March 2011

A. V. V. Nampoothiri  and
S. L. Dexheimer
A. V. V. Nampoothiri
Affiliation:
Department of Physics, Washington State University, Pullman, WA 99164-2814
S. L. Dexheimer
Affiliation:
Department of Physics, Washington State University, Pullman, WA 99164-2814
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Abstract

We present femtosecond time-resolved studies of the frequency-dependent photoconductivity in the far-infrared spectral range (∼ 1 – 10 meV) in PECVD a-SiGe:H and a-Si:H thin films. The experiments are carried out using an optical pump / terahertz (THz) probe technique, in which a femtosecond pump pulse excites carriers into the extended states and a time-delayed probe pulse measures the resulting change in the far-infrared optical properties, which are directly related to the ac photoconductivity, as the carrier distribution evolves in time. We find that the frequency-dependent conductivity measured on picosecond time scales shows a strongly non-Drude behavior, with components of the response fitting to a power-law frequency dependence, reflecting processes associated with localized states.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 808: Symposium A – Amorphous and Nanocrystaline Silicon Science and Technology-2004 , 2004 , A5.9
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

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