Faculté des sciences

Ultrafast carrier dynamics in undoped microcrystalline silicon

Kudrna, J. ; Malý, P. ; Trojánek, F. ; Stepánek, J. ; Lechner, T. ; Pelant, I. ; Meier, Johannes ; Kroll, U.

In: Materials Science and Engineering B, 2000, vol. 69-70, p. 238-242

We have studied ultrafast dynamics of photoexcited carriers in μc-Si:H by pump and probe laser spectroscopy. We have found that the dynamics of photoexcited carriers in μc-Si:H depend on the crystallinity of the material: in the samples with low crystalline fraction, the dynamics have a fast decay and resemble those in a-Si:H, while in the samples with high crystallinity the dynamics are slower... Plus

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    Summary
    We have studied ultrafast dynamics of photoexcited carriers in μc-Si:H by pump and probe laser spectroscopy. We have found that the dynamics of photoexcited carriers in μc-Si:H depend on the crystallinity of the material: in the samples with low crystalline fraction, the dynamics have a fast decay and resemble those in a-Si:H, while in the samples with high crystallinity the dynamics are slower and similar to those in c-Si. We have identified an intensity dependent bimolecular recombination in the samples with lower crystalline fraction (coefficient B=2×10−10 cm3 s−1 for deposition with silane dilution ratio ≈5% at a fixed power of 6 W), and no bimolecular recombination in the samples with high crystallinity.