Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
Nano Lett. 2011 Jul 13;11(7):2672-7. doi: 10.1021/nl200770h. Epub 2011 Jun 1.
A combination of electrostatic force microscopy and optical microscopy was used to investigate the charge state of individual CdSe nanowires upon local illumination with a focused laser beam. The nanowires were found to be positively charged at the excitation spot and negatively charged at the distant end(s). For high laser powers, the amount of accumulated charges increases logarithmically with the laser power. These effects are described by a diffusion-based model where the results are in good agreement with the experimentally observed effects. On the basis of this model the charge imbalance along the nanowire should establish in the course of nanoseconds. The net charge separation within homogeneous nanowires upon local illumination is of importance for several electronic devices.
采用静电力显微镜和光学显微镜相结合的方法，研究了在聚焦激光束局部照射下单个 CdSe 纳米线的荷电状态。结果发现，纳米线在激发点带正电，在远端带负电。对于高激光功率，积累的电荷量随激光功率呈对数增加。这些效应可以用基于扩散的模型来描述，结果与实验观察到的效应非常吻合。基于该模型，在纳秒级的时间内，纳米线内的电荷不平衡应该建立起来。在局部光照下，均匀纳米线内的净电荷分离对于几种电子器件非常重要。
