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Picosecond Photocarrier Lifetimes in Ion-Irradiated Amorphous and Crystalline Silicon

  • P. A. Stolk (a1), L. Calcagnile (a1), S. Roorda (a1), H. B. van Linden (a1), Van den Heuvell (a1) and F. W. Saris (a1)...

Abstract

Crystalline silicon (c-Si) and structurally relaxed amorphous silicon (a-Si) were implanted with 1 MeV Si+ at liquid nitrogen temperature. The photocarrier lifetime τ in the implanted samples was determined with sub-picosecond resolution through pump-probe reflectivity measurements. At low damage levels (i.e. <1014 ions/cm2), τ decreases with increasing ion dose in both materials, indicating a build up of trapping and recombination centers. The dominant centers in c-Si appear to be related to simple defects. The generation rate of electrically active defects is found to be the same in relaxed a-Si and c-Si, which suggests that the structural defects formed in a-Si strongly resemble the simple defects in c-Si. For ion doses > 1014 /cm2, τ saturates at a level of 0.8 ps for both materials. Strikingly, the saturation sets in far below the dose needed to amorphize (>1015 /cm2). The defect density in a-Si at saturation is estimated to be ≈1.6 at.%.

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Picosecond Photocarrier Lifetimes in Ion-Irradiated Amorphous and Crystalline Silicon

  • P. A. Stolk (a1), L. Calcagnile (a1), S. Roorda (a1), H. B. van Linden (a1), Van den Heuvell (a1) and F. W. Saris (a1)...

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