Acquisition of an Ultrafast Laser System and Near-Field Spectrometer for Investigating II-VI Quantum Dots and for Education

9975655 Jackson该奖项将提供部分支持收购的国家的最先进的系统的时间和空间分辨光谱。 该系统将包括两个主要部件：（1）飞秒光参量放大器（OPA）系统，可从240 nm到2.7微米广泛调谐，以及（2）带有驱动电子器件的低温扫描探针（CryoSXM）显微镜。 该系统将实现超快（200 fs）的时间分辨率和亚微米（100至500 nm）的空间分辨率。 该仪器将用于直接研究自组装CdSe量子点（SAQD）中激子的电子态性质。 我们的团队和其他人最近在德国和日本的实验强烈表明，CdSe量子点的结构和它们的电子激发与在原型InAs/GaAs量子点中观察到的显著不同。 这些差异并不出乎意料，因为II-VI族材料作为一个组更具有极性，具有更大的激子效应，更突出的电子-声子相互作用，并且价带偏移比III-V族材料小得多。时间分辨的迁移测量;及（v）单量子点的激子自旋弛豫。使用这套先进的设备，将为参与这些领域的本科生提供重要的新培训机会。这套设备将大大提高研究人员研究自组装量子点性质的能力，并在材料研究和技术的一个非常重要的领域培养学生。

9975655JacksonThis award will provide partial support for the acquisition of a state-of-the-art system for temporally- and spatially-resolved optical spectroscopy. This system will involve two main components: (1) A Femtosecond Optical Parametric Amplifier (OPA) systems which is broadly tunable from 240 nm to 2.7 microns, and (2) a low-temperature scanned probe (CryoSXM) microscope with drive electronics. This system will achieve both ultrafast (200 fs) time-resolution and sub-micron (100 to 500 nm) spatial resolution. This instrument will be used to study directly the nature of the electronic states of excitons confined to self-assembled CdSe quantum dots (SAQDs). Recent experiment by our groups and others in Germany and Japan have suggested strongly that the structure of the CdSe dots and their electronic excitations are significantly different than observed in the prototypical InAs/GaAs quantum dots. Such differences are not unexpected as II-VI materials as a group are more polar, with larger excitonic effects, more prominent electron-phonon interactions, and the valence band offsets are significantly smaller than for the III-V materials.Research to be undertaken includes:(i) Nano-scale mapping of the CdSe dots;(ii) Time-resolved Photoluminescence Excitation (PLE); (iii) Magneto-Photoluminescence of Single Quantum Dots; (iv) Time-resolved Transport Measurements; and (v) Exciton Spin-Relaxation of Single Quantum Dots.Acess to this state-of-the-art equipment will also provide significant new training opportunities for undergraduate students participating in these areas.This equipment will provide the investigators with significantly increased capabilities to investigate the properties of self assembled quantum dots, and train students in a very important area of materials research and technology.