中国物理B ›› 2021, Vol. 30 ›› Issue (5): 53201-053201.doi: 10.1088/1674-1056/abd472

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Anisotropic exciton Stark shift in hemispherical quantum dots

Shu-Dong Wu(吴曙东)   

  1. College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
  • 收稿日期:2020-11-07 修回日期:2020-12-11 接受日期:2020-12-17 出版日期:2021-05-14 发布日期:2021-05-14
  • 通讯作者: Shu-Dong Wu E-mail:sdwu@yzu.edu.cn

Anisotropic exciton Stark shift in hemispherical quantum dots

Shu-Dong Wu(吴曙东)   

  1. College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
  • Received:2020-11-07 Revised:2020-12-11 Accepted:2020-12-17 Online:2021-05-14 Published:2021-05-14
  • Contact: Shu-Dong Wu E-mail:sdwu@yzu.edu.cn

摘要: The exciton Stark shift and polarization in hemispherical quantum dots (HQDs) each as a function of strength and orientation of applied electric field are theoretically investigated by an exact diagonalization method. A highly anisotropic Stark redshift of exciton energy is found. As the electric field is rotated from Voigt to Faraday geometry, the redshift of exciton energy monotonically decreases. This is because the asymmetric geometric shape of the hemispherical quantum dot restrains the displacement of the wave function to the higher orbital state in response to electric field along Faraday geometry. A redshift of hole energy is found all the time while a transition of electron energy from this redshift to a blueshift is found as the field is rotated from Voigt to Faraday geometry. Taking advantage of the diminishing of Stark effect along Faraday geometry, the hemispherical shapes can be used to improve significantly the radiative recombination efficiency of the polar optoelectronic devices if the strong internal polarized electric field is along Faraday geometry.

关键词: anisotropic Stark shift, exciton, hemispherical quantum dots, electric field

Abstract: The exciton Stark shift and polarization in hemispherical quantum dots (HQDs) each as a function of strength and orientation of applied electric field are theoretically investigated by an exact diagonalization method. A highly anisotropic Stark redshift of exciton energy is found. As the electric field is rotated from Voigt to Faraday geometry, the redshift of exciton energy monotonically decreases. This is because the asymmetric geometric shape of the hemispherical quantum dot restrains the displacement of the wave function to the higher orbital state in response to electric field along Faraday geometry. A redshift of hole energy is found all the time while a transition of electron energy from this redshift to a blueshift is found as the field is rotated from Voigt to Faraday geometry. Taking advantage of the diminishing of Stark effect along Faraday geometry, the hemispherical shapes can be used to improve significantly the radiative recombination efficiency of the polar optoelectronic devices if the strong internal polarized electric field is along Faraday geometry.

Key words: anisotropic Stark shift, exciton, hemispherical quantum dots, electric field

中图分类号:  (Zeeman and Stark effects)

  • 32.60.+i
71.35.-y (Excitons and related phenomena) 73.21.La (Quantum dots) 94.20.Ss (Electric fields; current system)