Meiling Jiang, Liheng Zheng, Yu Li, Hangyong Shan, Cheng Chi, Zhixin Liu, Yijing Huang, Zhibo Dang, Feng Lin and Zheyu Fang*
Abstract: Cathodoluminescence can probe photonic responses of nanostructures at high spatial and energy resolution, providing a powerful tool to investigate radiative properties under electron excitations in nanophotonics. The radiative properties of semiconductors can be effectively modulated by the surrounding electromagnetic environment that directly determines the efficiency of emitters. As emitter devices develop into nano-region, the nanoscale control of their spontaneous emission is essential for the deeper comprehension of intrinsic physics. Plasmonic nanostructures have been employed to enhance the emitter spontaneous emission due to their remarkable capability in confining light beyond the diffraction limit. In this paper, we realize efficiently selective modulation of ZnO emission at nanoscale by using cathodoluminescence microscopy and spectroscopy. By controlling the excitation position of the electron beam, different plasmon resonant modes of Al nonamer structure can be selectively stimulated. With the plasmon resonance tuned from ultraviolet to visible region, the spontaneous emission rate of ZnO corresponding to bandgap transition and defect transition can be selectively enhanced with increased plasmonic radiative local density of states. The experimental method gives fundamental insights of plasmon-enhanced luminescence of semiconductors at nanoscale, which facilitates ZnO-based applications in future opto-electronic devices and promotes the development of nanophotonics.
The Journal of Physical Chemistry C, 2020. 124(25) 
acs.jpcc.0c02825.pdf
