We report the results of the experiments on dynamic nuclear polarization (DNP) of 29Si nuclei under saturation the electron paramagnetic resonance (EPR) transitions of the photoexcited spin S=1 states of the oxygen+vacancy complexes in irradiated 29Si isotopically controlled silicon. The effect of isotope 29Si abundance on the line width and hyperfine structure of the Si-SL1 EPR spectra was observed. It was shown clearly that the decrease of the 29Si abundance leads to the transformation the DNP mechanism from the "differential" to "resolved" solid-effect accompanied with the increase of DNP degree. High steady-state 29Si nuclear polarization of 6% due to "resolved" solid-effect was achieved in silicon crystals with the 29Si isotope abundance below 4.7%. It was found that the DNP induced by saturation the hyperfine structure EPR lines of triplet centers does not follow the symmetric first derivative EPR line shape, showing the additional contribution to the DNP process.
|ジャーナル||Physica B: Condensed Matter|
|出版ステータス||Published - 2009 12月 15|
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