Intraband Transitions in Strongly Confined Quantum Dots: Spectroscopy and Dynamics

9731642 Guyot-Sionnest芝加哥大学詹姆斯·弗兰克研究所的P.Guyot-Sionnest教授的这项研究解决了量子点/量子井行为的关键问题，也称为人造原子或单电子晶体管(SET)。其中之一就是预计会出现的“声子瓶颈”，这将严重限制SET在纳米技术应用中的应用。量子点(QD)的典型尺寸约为自由原子的1000倍，但比传统半导体元素的尺寸小得多。因此，它们的量子力学行为不能通过简单的标度或外推来预测，必须通过实验工作来确定。在这项研究中，PI将使用胶体纳米晶而不是传统的半导体制造技术来制备量子点。红外带内泵浦探测光谱将被用来测定电子激发的量子点的弛豫动力学。这将在赠款期间分阶段完成：通过光激发量子点的单色光谱来研究激发态光谱，以及通过光激发量子点的双色红外泵浦-探测光谱来研究带内跃迁的动力学和精细结构。这些实验将促进我们对量子点电子态的驰豫动力学的了解，这是基于量子点的未来一代光学器件的关键问题。芝加哥大学詹姆斯·弗兰克研究所的P.Guyot-Sionnest教授的这项研究解决了量子点/量子井行为的关键问题，也称为人造原子或单电子晶体管(SET)。其中之一就是预计会出现的“声子瓶颈”，这将严重限制SET在纳米技术应用中的应用。量子点(QD)的典型尺寸约为自由原子的1000倍，但比传统半导体元素的尺寸小得多。因此，它们的量子力学行为不能通过简单的标度或外推来预测，必须通过实验工作来确定。在这项研究中，PI将使用胶体纳米晶而不是传统的半导体制造技术来制备量子点。红外带内泵浦探测光谱将被用来测定电子激发的量子点的弛豫动力学。这将在赠款期间分阶段完成：通过光激发量子点的单色光谱来研究激发态光谱，以及通过光激发量子点的双色红外泵浦-探测光谱来研究带内跃迁的动力学和精细结构。这些实验将促进我们对量子点电子态的驰豫动力学的了解，这是基于量子点的未来一代光学器件的关键问题。*

9731642 Guyot-Sionnest This research by Professor P. Guyot-Sionnest of the James Franck Institute of the University of Chicago addresses crucial questions of the behavior of quantum dots/quantum wells, also known as artificial atoms or single electron transistors (SET). Among these is the predicted "phonon bottle neck" which would severely limit the applicability of SETs in nanotechnological applications. The typical size of a quantum dot (QD) is of the order of 1000 times that of a free atom yet very much smaller than that of conventional semiconductor elements. Their quantum mechanical behavior can thus not be predicted by simple scaling or extrapolation and must be determined by experimental work. In this research the PI will fabricate QDs using colloidal nanocrystals rather than those made by conventional semiconductor fabrication techniques. Infrared intraband pump-probe spectroscopy will be used to determine the relaxation kinetics of electronically excited QDs. This will be done in stages over the duration of the grant: excited state spectroscopy by single color spectroscopy of optically excited QDs, and investigation of the dynamics and fine structure of intraband transitions by dual-color infrared pump-probe spectroscopy of optically excited QDs. These experiments will advance our knowledge of the relaxation dynamics of the electronic states of a QD, which is a basic issue that is key to the future generation of optical devices based on QDs. %%% This research by Professor P. Guyot-Sionnest of the James Franck Institute of the University of Chicago addresses crucial questions of the behavior of quantum dots/quantum wells, also known as artificial atoms or single electron transistors (SET). Among these is the predicted "phonon bottle neck" which would severely limit the applicability of SETs in nanotechnological applications. The typical size of a quantum dot (QD) is of the order of 1000 times that of a free atom yet very much smaller than that of conventional semiconductor elements. Their quantum mechanical behavior can thus not be predicted by simple scaling or extrapolation and must be determined by experimental work. In this research the PI will fabricate QDs using colloidal nanocrystals rather than those made by conventional semiconductor fabrication techniques. Infrared intraband pump-probe spectroscopy will be used to determine the relaxation kinetics of electronically excited QDs. This will be done in stages over the duration of the grant: excited state spectroscopy by single color spectroscopy of optically excited QDs, and investigation of the dynamics and fine structure of intraband transitions by dual-color infrared pump-probe spectroscopy of optically excited QDs. These experiments will advance our knowledge of the relaxation dynamics of the electronic states of a QD, which is a basic issue that is key to the future generation of optical devices based on QDs. *** ***