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N. Y. Arutyunov, V. V. Emtsev, R. Krause-Rehberg, C. Kessler, M. Elsayed, G. A. Oganesyan, V. V. Kozlovski
Cascade phonon-assisted trapping of positrons by divacancies in n-FZ-Si (P) single crystals irradiated with 15 MeV protons.
AIP Conf. Proc. 1583, 41 (2014), 41-45

The trapping of positrons by the radiation defects in moderately doped oxygen-lean n-FZ-Si(P) single crystal irradiated with 15 MeV protons has been investigated in a comparative way using the positron lifetime spectroscopy and Hall effect measurements. The experiments were carried out within a wide temperature interval ranging from 25 K - 29 K to 300 K. The positron trapping rate for divacancies was reconstructed in the course of many-stage isochronal annealing. The concentration and the charged states of divacancies (V - 2 and V -- 2) were estimated. The temperature dependency of the trapping cross section of positrons by the negatively charged divacancies is in a good agreement with the data of calculations based on the assumptions of the cascade phonon-assisted mechanism of exchange of the energy between the positron and acoustic long-wave phonons. Obeying T -3 law, the cross-section of the trapping of positrons by divacancies changes considerably ranging from ca. 1.7×10 -12 cm2 (66 - 100 K) to ca. 2×10-14 cm2 (ca. 250 K). The characteristic length of trapping of the positron by V -- 2 divacancy was estimated to be i0(V -- 2) ca. (3.4±0.2)×10 -8 cm.

Keywords: positron annihilation; vacancies; silicon; irradiation; lifetime; Hall; temperature dependence; charge

DOI 10.1063/1.4865601
© AIP 2014

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