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使用飞秒白光泵浦探测技术研究了GaAs/AlGaAs量子阱材料中超快动力学行为。采用了非共振泵浦,激发了不满足Δn=2p选择定则的光跃迁,观察到差分透射谱中的3个吸收跃迁饱和漂白峰。一方面,E1导带上的电子和HH2上的空穴通过各种散射和复合而快速减少,E1-HH2和E2-HH2峰迅速衰减;另一方面,由于处在带边的复杂性致使E1-HH1峰在25ps内几乎没有衰减。与掺杂多量阱材料的驰豫动力学比较可知,超晶格中由于阱间波函数的耦合使载流子的散射加快;而掺杂多量子阱中由于捕获中心的存在使载流子的复合加快。
The ultrafast kinetic behavior of GaAs / AlGaAs quantum well materials has been investigated using femtosecond white-light pump probing techniques. Non-resonant pumping was used to excite the optical transitions that did not satisfy the selection rule of Δn = 2p, and three saturation peaks of absorption transition in the differential transmission spectrum were observed. On the one hand, the electrons on the conduction band of E1 and the holes on HH2 decrease rapidly through various scattering and recombination, and the peaks of E1-HH2 and E2-HH2 decay rapidly; on the other hand, the E1 The -HH1 peak barely decays within 25 ps. Compared with the relaxation kinetics of the doped quantum well, we can see that the scattering of carriers accelerates in the superlattice due to the coupling between the wells. However, due to the existence of the capture center in the doped multiple quantum wells, Compound faster.