1. State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China; 2. State Key Laboratory for Mechanics and Control of Mechanical Structures, and MOE Key Laboratory of Intelligent Nano Materials and Devices, Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
We conduct systematical cathodoluminescence study on red-shift of near-band-edge emission energy in elastic bent ZnO nanowires with diameters within the exciton diffusion length (～ 200 nm) in liquid nitrogen temperature (81 K). By charactering the emission spectra of the nanowires with different local curvatures, we find a linear relationship between strain-gradient and the red-shift of near-band-edge emission photon energy, an elastic strain-gradient effect in semiconductor similar to the famous flexoelectric effect in liquid crystals. Our results provide a new route to understand the inhomogeneous strain effect on the energy bands and optical properties of semiconductors and should be useful for designing advanced nano-optoelectronic devices.
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