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Journal Articles Journal of Physics: Condensed Matter Year : 2021

Time resolved study of carrier relaxation dynamics in α-Al 2 O 3

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Abstract

The relaxation of excited carriers in α-Al 2 O 3 is complex, depending for instance on the type of ionizing radiation. Using femtosecond time-resolved absorption spectroscopy, we can induce a controllable excitation density on a wide range, and follow the relaxation dynamics from 30 fs to 7 ns. We show that the excited carrier decay is non-exponential: it is dependent on the pump intensity, i.e. on the initial carrier concentration. We describe the relaxation as a two-steps process, involving the trapping of initially free electron-hole pairs, followed by recombination. A numerical model taking into account the initial electronic excitation by multiphoton absorption and the subsequent relaxation allows to quantitatively reproduce the amplitude of the measured absorption and its temporal evolution.
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Dates and versions

cea-03293120 , version 1 (11-07-2022)

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A Bildé, K Redeckas, A. Melninkaitis, M Vengris, S Guizard. Time resolved study of carrier relaxation dynamics in α-Al 2 O 3. Journal of Physics: Condensed Matter, 2021, 33 (31), pp.315402. ⟨10.1088/1361-648X/ac0475⟩. ⟨cea-03293120⟩
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