Research Article

Nano Research

, Volume 4, Issue 3, pp 308-314

Linear strain-gradient effect on the energy bandgap in bent CdS nanowires

  • Qiang FuAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Zi Yue ZhangAffiliated withInstitute of Nanoscience, Nanjing University of Aeronautics and Astronautics
  • , Liangzhi KouAffiliated withInstitute of Nanoscience, Nanjing University of Aeronautics and Astronautics
  • , Peicai WuAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Xiaobing HanAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Xinli ZhuAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Jingyun GaoAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Jun XuAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
  • , Qing ZhaoAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University
    • , Wanlin GuoAffiliated withInstitute of Nanoscience, Nanjing University of Aeronautics and Astronautics Email author 
    • , Dapeng YuAffiliated withState Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University Email author 

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Abstract

Although possible non-homogeneous strain effects in semiconductors have been investigated for over a half century and the strain-gradient can be over 1% per micrometer in flexible nanostructures, we still lack an understanding of their influence on energy bands. Here we conduct a systematic cathodoluminescence spectroscopy study of the strain-gradient induced exciton energy shift in elastically curved CdS nanowires at low temperature, and find that the red-shift of the exciton energy in the curved nanowires is proportional to the strain-gradient, an index of lattice distortion. Density functional calculations show the same trend of band gap reduction in curved nanostructures and reveal the underlying mechanism. The significant linear strain-gradient effect on the band gap of semiconductors should shed new light on ways to tune optical-electronic properties in nanoelectronics.
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Keywords

Strain-gradient effect CdS nanowire bending deformation cathodoluminescence