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Nano Research

Article Title

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

Authors

Qiang Fu, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Zi Yue Zhang, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Liangzhi Kou, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Peicai Wu, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Xiaobing Han, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Xinli Zhu, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Jingyun Gao, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Jun Xu, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Qing Zhao, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China
Wanlin Guo, Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Dapeng Yu, State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University, Beijing 100871, China

Keywords

Strain-gradient effect, CdS nanowire, bending deformation, cathodoluminescence

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.

Graphical Abstract

Publisher

Tsinghua University Press

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