Donatini Fabrice, Pernot Julien
Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, F-38000 Grenoble, France.
Nanotechnology. 2018 Mar 9;29(10):105703. doi: 10.1088/1361-6528/aaa638.
In semiconductor nanowires (NWs) the exciton diffusion coefficient can be determined using a scanning electron microscope fitted with a cathodoluminescence system. High spatial and temporal resolution cathodoluminescence experiments are needed to measure independently the exciton diffusion length and lifetime in single NWs. However, both diffusion length and lifetime can be affected by the electron beam bombardment during observation and measurement. Thus, in this work the exciton lifetime in a ZnO NW is measured versus the electron beam dose (EBD) via a time-resolved cathodoluminescence experiment with a temporal resolution of 50 ps. The behavior of the measured exciton lifetime is consistent with our recent work on the EBD dependence of the exciton diffusion length in similar NWs investigated under comparable SEM conditions. Combining the two results, the exciton diffusion coefficient in ZnO is determined at room temperature and is found constant over the full span of EBD.
在半导体纳米线（NWs）中，激子扩散系数可以使用配备有阴极发光系统的扫描电子显微镜来测定。需要高空间和时间分辨率的阴极发光实验来独立测量单个纳米线中的激子扩散长度和寿命。然而，在观察和测量过程中，扩散长度和寿命都会受到电子束轰击的影响。因此，在这项工作中，通过时间分辨阴极发光实验，以50皮秒的时间分辨率测量了ZnO纳米线中的激子寿命与电子束剂量（EBD）的关系。所测量的激子寿命的行为与我们最近在类似的纳米线中研究激子扩散长度对EBD的依赖性的工作一致，该研究是在可比的扫描电子显微镜条件下进行的。结合这两个结果，确定了室温下ZnO中的激子扩散系数，并且发现在整个EBD范围内该系数是恒定的。
