Magnetic polaron formation of localized excitons in semimagnetic semiconductor alloys of Cd0.8Mn0.2Te
Magnetic polaron formation of localized excitons in semimagnetic semiconductor alloys of Cd0.8Mn0.2Te
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Cd0.8Mn0.2Te半磁性半导体合金中局域激子的磁极化子形成
DOI：
10.1016/0022-2313(87)90124-4
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发表时间：
1987
影响因子：
3.6
通讯作者：
E. Komatsu
中科院分区：
文献类型：
--
作者：
T. Itoh;E. Komatsu
本文研究了Cd_（0.8）Mn_（0.2）Te在激子共振以下的选择性激发下的激子动力学。在稳态光谱中，激子发光带在4.2K处相对于激发能有16.5meV的Stokes位移。斯托克斯位移随晶格温度或磁场的增加而显著减小。在100 ps内，时间分辨光谱显示出发光峰的快速红移，这是斯托克斯位移的主要原因。斯托克斯位移的结论是与激子磁极化子形成的直接产生的激子是本地化的合金势威尔斯。极化子形成时间在2K时约为40 ps，并随温度的升高而增加。在带-带激发下，局域态之间的激子扩散在激子动力学中起着竞争作用，极化子的形成也是如此。
Exciton dynamics has been studied in Cd0.8Mn0.2Te under selective excitation just below the exciton resonance. In stationary spectra, the exciton luminescence band is found to show a constant Stokes shift of 16.5 meV from the excitation energy at 4.2 K. The Stokes shift decreases considerably with increasing lattice temperature or magnetic field. Within a hundred ps the time- resolved spectra show a rapid red shift of the luminescence peak, which is the main cause of the Stokes shift. The Stokes shift is concluded to be associated with exciton magnetic polaron formation from the directly generated excitons which are localized in alloy potential wells. The polaron formation time is found to be about 40 ps at 2 K and to increase with rising temperature. Under band-to-band excitation the exciton diffusion among the localized states is found to play a competitive role in the exciton dynamics, together with the polaron formation.