Ultrafast carrier dynamics in undoped microcrystalline silicon
نویسندگان
چکیده
We have studied ultrafast dynamics of photoexcited carriers in mc-Si:H by pump and probe laser spectroscopy. We have found that the dynamics of photoexcited carriers in mc-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 cm s for deposition with silane dilution ratio :5% at a fixed power of 6 W), and no bimolecular recombination in the samples with high crystallinity.
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