SYNTHETIC INORGANIC AND MATERIALS CHEMISTRY

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 半导体量子线和几何约束性对量子限制的影响：量子限制效应是由于电子和空穴的几何约束而在小的半导体微晶中发生的电子和光学性质的急剧变化。当电子-空穴对被压缩到接近体激子玻尔半径（~2-60 nm）时，半导体的有效带隙随激子尺寸的减小而增大。因此，量子限制的大小取决于晶体的尺寸和组成。但是，如果是圆形的呢？人们可能会好奇，究竟是量子阱（层）、量子线、量子棒（短线）还是量子点，哪一种形状的量子限制效应更强。理论上已经知道答案：3D限制比2D限制更强，而2D限制又比1D限制更强。因此，量子限制的大小应该按照威尔斯<线<棒<点的顺序增加。我的小组正在对这些预测进行定量的实验验证。我们使用单分散金属纳米颗粒催化剂通过溶液化学生长可溶的、直径可控的量子线。与卢米斯教授合作，对这些金属丝进行光谱表征，从中确定它们的带隙和其他光学特性。量子线带隙和其他性质的尺寸依赖性与相应的点、棒和威尔斯的尺寸依赖性进行了比较，并与Lin-Wang Wang博士（劳伦斯伯克利国家实验室）小组提供的高级理论计算结果进行了比较。我们的工作证实了健美运动员、长跑运动员、建筑师和量子力学都同意：在功能、性能和行为方面，形状很重要。 H. Yu，J. Li，R.A.卢米斯湖W. Wang和W. E. Buhro，*“磷化铟线和点中的二维与三维量子限制”，《自然材料》，2，517（2003）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Semiconductor Quantum Wires and the Influence of Geometric Dimensionality on Quantum Confinement: Quantum-confinement effects are the dramatic changes in electronic and optical properties occurring in small semiconductor crystallites as a result of the geometric confinement of electrons and holes. When an electron-hole pair in an excited nanocrystal is squeezed into a dimension approaching the bulk exciton Bohr radius (~2-60 nm), the effective band gap of the semiconductor increases with decreas innanocrystal size. Thus, the magnitude of quantum confinement depends upon nanocrystal size and composition. But how about the nanocrystal shape? One may reasonably wonder which nanocrystal shape- the quantum well (layer), quantum wire, quantum rod (short wire), orquantum dot - should exhibit the inherently stronger quantum-confinement effects.The answer is known theoretically: 3D confinement is stronger than 2D confinement, which in turn is stronger than 1D confinement. Thus, the magnitude of quantum confinement should increase in the order wells < wires < rods < dots. My group is now providing quantitative experimental ver-ification of these predictions. We grow soluble, diameter-controlled quantum wires by solution chemistry using monodisperse metallic-nanoparticle catalysts. Spectroscopic characterization of the wires, from which their band gaps and other optical properties are determined, is conducted in collaboration with Prof. Loomis. The size dependences of the quantum-wire band gaps and other properties are compared to those of the corresponding dots, rods, and wells, and to the results of high-level theoretical calculations provided by the group of Dr. Lin-Wang Wang (Lawrence Berkeley National Lab.). Our work affirms that bodybuilders, distance runners, architects, and quantum mechanics all agree: in function, performance, and behavior - shape matters. H. Yu, J. Li, R.A. Loomis, L.-W. Wang, and W.E. Buhro,* "Two- versus three-dimensional quantum confinement in indium phosphide wires and dots," Nature Mater., 2, 517 (2003).