The transport properties of excitons are important in semiconductor research as they can affect such applications as the efficiency of excitonic solar cells and stimulated emission in nano-crystalline thin films. Until now, the observation of exciton diffusion in semiconductors has proved very difficult as a result of the excitons' limited lifetime. Exciton transport is also sensitive to disorder scattering and localization at low temperature. Now, in a new work published this month in Small, Gyu-Chul Yi and Le Si Dang havernfound a way to study exciton transport, by measuring the cathodolumi-nescence (CL) of single nanorods embedding a single quantum well on their tips. Excitons from injected carriers are diffused into the quantum well along the nanorod axis, inducing light emission from the quantum well. The exciton diffusion is examined by monitoring CL at various electron-beam spots. The researchers now plan to investigate the effects of surface recombination, which has so far been found to limit diffusion.
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机译：激子的传输特性在半导体研究中很重要，因为它们会影响激子太阳能电池的效率和纳米晶体薄膜中受激发射等应用。迄今为止，由于激子的寿命有限，事实证明，观察激子在半导体中的扩散非常困难。激子运输对低温下的无序散射和局部化也很敏感。现在，在本月发表于Small的新著作中，Gyu-Chul Yi和Le Si Dang找到了一种研究激子输运的方法，方法是测量在尖端上嵌入单个量子阱的单个纳米棒的阴极发光（CL）。来自注入的载流子的激子沿着纳米棒轴扩散到量子阱中，从而诱导来自量子阱的光发射。激子的扩散通过监测电子束在各个电子束点的位置来检查。研究人员现在计划研究表面重组的作用，到目前为止，发现这种复合限制了扩散。
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