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Electronic Properties of Improved Amorphous Silicon-Germanium Alloys Deposited by a Low Temperature Hot Wire Chemical Vapor Deposition Process

Published online by Cambridge University Press:  01 February 2011

Shouvik Datta
Affiliation:
Department of Physics, University of Oregon, Eugene, OR 97403, USA.
J. David Cohen
Affiliation:
Department of Physics, University of Oregon, Eugene, OR 97403, USA.
Yueqin Xu
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401,USA.
A. H. Mahan
Affiliation:
National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401,USA.
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Abstract

We report novel material properties of a series of a-Si,Ge:H alloys grown by hot-wire chemical vapor deposition under low filament temperature (˜1800°C) and low substrate temperature (˜200-300°C). These alloys exhibit significantly improved electronic properties including low defect densities and sharp band tails (Urbach energies ≤ 45meV even for Ge fractions as high as 47at.%). On the other hand, comparisons of the transient photocapacitance and transient photocurrent spectra do not indicate very efficient hole collection in these materials. We found two distinct regimes of light-induced degradation in the alloy sample with 29at.% Ge fraction, possibly corresponding to the light induced increase of Ge and Si dangling bonds, respectively.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

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