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Effect of C Impurities in a-Si:H as Measured by Drive-Level Capacitance, Photo Current, and Electron Spin Resonance

Published online by Cambridge University Press:  01 January 1993

J. Hautala ,
T. Unold  and
J.D. Cohen
J. Hautala
Affiliation:
University of Oregon, Department of Physics, Eugene OR 97403
T. Unold
Affiliation:
University of Oregon, Department of Physics, Eugene OR 97403
J.D. Cohen
Affiliation:
University of Oregon, Department of Physics, Eugene OR 97403
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Abstract

The effect of C impurities in a-Si:H in levels of 0.4 to 2.6 at. % were studied over a wide range of metastable defect densities. Three complimentary experimental techniques [electron spin resonance (ESR), drive-level capacitance (DLC) and photo-current] were employed to track the material's defect density with light soaking and annealing, as well as Urbach energies, midgap absorption and mobility gaps energies as a function of the C content. Our results show C impurities have a definite effect on the initial and saturated defect densities, as well as the midgap absorption and Urbach energies at levels 1 at. % and above. The results indicate that C acts mainly as a center for increased disorder in the material which results in an increase in the bandtail widths, and consequently an increase in intrinsic defects. Comparison to the ESR and drive-level data show an excellent agreement between these two techniques in determining the bulk defect densities in a-Si:H.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 297: Symposium A – Amorphous Silicon Technology - 1993 , 1993 , 375
Copyright
Copyright © Materials Research Society 1993

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References

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