量子链和量子点光学特性的比较研究

COMPARATIVE STUDY OF OPTICAL PROPERTIES BETWEEN QUANTUM DOT CHAINS AND QUANTUM DOTS

比较研究了InGaAs/GaAs量子链和量子点的稳态和瞬态光学特性.实验发现,量子链的荧光寿命有很强的探测能量依赖关系,而量子点的荧光寿命随能量变化较小;量子链的荧光寿命随着激发功率迅速增加,高功率时趋于饱和,而量子点的荧光寿命随激发功率变化缓慢;此外,量子链样品的荧光上升时间也比量子点的小得多.这些结果清楚表明,在量子链结构中,参与发光的载流子之间存在很强的耦合和输运.进一步分析表明,这种耦合作用主要发生在量子链方向.荧光的偏振特性进一步证实了这一点.

A comparative study of the steady-state and transient optical properties was made between InGaAs/GaAs quantum do chains （QDCs） and quantum dots （QDs）. It was found that the photoluminescence （PL） decay time of QDCs exhibited a strong photon energy dependence, while it was less sensitive in QDs. The PL decay time increased much faster with the excitation power in the QDCs than that in QDs. When the excitation power was large enough, the PL decay time tended to be saturated. In addition, it was also found that the PL rise time was much shorter in QDCs than in QDs. All these experimental results show that there is a strong carrier coupling along the chain direction in the QD chain structure. The polarization PL measurements further confirm the carrier transfer process along the chain direction.