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Possible Origin of Large Response Times and Ambipolar Diffusion Lengths in Hot-Wire-Cvd Silicon Films

Published online by Cambridge University Press:  10 February 2011

R. Schwarz
Affiliation:
Instituto Superior Técnico, Physics Department, P-1096 Lisbon, PORTUGAL
T. Múrias
Affiliation:
Instituto Superior Técnico, Physics Department, P-1096 Lisbon, PORTUGAL
J.P. Conde
Affiliation:
Instituto Superior Técnico, Department of Materials Engineering, P-1096 Lisbon, PORTUGAL
P. Brogueira
Affiliation:
Instituto Superior Técnico, Physics Department, P-1096 Lisbon, PORTUGAL
V. Chu
Affiliation:
Instituto Superior Técnico, Physics Department, P-1096 Lisbon, PORTUGAL Instituto de Engenharia de Sistemase Computadores, P-1000 Lisbon, PORTUGAL
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Abstract

We measured the response time zR and the ambipolar diffusion length Lamb in amorphous (a-Si:H) and microcrystalline silicon films (μ-Si:H) prepared by hot-wire chemical vapor deposition (HW-CVD). The response times in the amorphous and microcrystalline HW films were larger by factors of 100 and 1000, respectively, than in standard PE-CVD a-Si:H films (1-2 μs). The ambipolar diffusion length of the HW-CVD films was about twice as large as in conventional glow-discharge films. Strong doping of microcrystalline HW films with trimethylboron (TMB) led to a reduction of the response time. The results hint to a positive effect of the compact microstructure of HW-CVD films. We suggest the dark conductivity activation energy, Eact, and response time, τR, to be used as suitable parameters to describe optoelectronic film properties.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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