We report on the dephasing dynamics of exciton fine structure (EFS) in a free standing GaN. The EFS was observed and studied by utilizing a four-wave-mixing (FWM) spectroscopy. In the cleavage plane of wurtzite GaN, we can excite the B-exciton fine structure, whose z -polarized state is energetically well separated from the other in-plane polarized exciton states. Due to the large spin exchange interaction in GaN, an energy shift of in-plane polarized fine structure was also observed. Since the each component of EFS is highly polarized, the polarization-dependent FWM successfully resolves their dephasing dynamics. The results show a significant difference in the dephasing time between EFS, suggesting that anisotropic exchange interaction is effective as reported in our previous work using a GaN film on a -plane sapphire.
|ジャーナル||Physica Status Solidi (C) Current Topics in Solid State Physics|
|出版ステータス||Published - 2009 7 1|
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