The vertical and lateral interactions in a multisheet array of InAs/GaAs quantum dots are analyzed by finite element method （FEM）. It is shown that due to the effects of vertical interaction, nucleation prefers to h...The vertical and lateral interactions in a multisheet array of InAs/GaAs quantum dots are analyzed by finite element method （FEM）. It is shown that due to the effects of vertical interaction, nucleation prefers to happen above buried quantum dots （QDs）. Meanwhile, the effects of lateral interaction adjust the spacing of lateral neighboring QDs. The vertical coupling becomes strong with deceasing GaAs spacer height and increasing number of buried layers, while the lateral coupling becomes strong with increasing InAs wetting layer thickness. The phenomenon that, after successive layers, the spacing and size of QDs islands become progressively more uniform is explained according to the minimum potential energy theory.展开更多
The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energ...The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energies increase for the small base radii and decrease for the larger ones. The energies decrease as the dot height increases. The intersubband and interband transitions of the system are also studied. For both, a spectral peak position shift to lower energies is seen due to the vertical coupling of dots. The interband transition energy decreases as the dot size increases, decreases for the dot shapes with larger heights, and reaches a minimum for coupled semisphere dots.展开更多
基金supported by the National Natural Science Foundation of China(No.10572155 and 10732100)Guangdong Science and Technology Bureau(No.2006A11001002)
文摘The vertical and lateral interactions in a multisheet array of InAs/GaAs quantum dots are analyzed by finite element method （FEM）. It is shown that due to the effects of vertical interaction, nucleation prefers to happen above buried quantum dots （QDs）. Meanwhile, the effects of lateral interaction adjust the spacing of lateral neighboring QDs. The vertical coupling becomes strong with deceasing GaAs spacer height and increasing number of buried layers, while the lateral coupling becomes strong with increasing InAs wetting layer thickness. The phenomenon that, after successive layers, the spacing and size of QDs islands become progressively more uniform is explained according to the minimum potential energy theory.
文摘The electron and heavy hole energy levels of two vertically coupled In As hemispherical quantum dots/wetting layers embedded in a Ga As barrier are calculated numerically. As the radius increases, the electronic energies increase for the small base radii and decrease for the larger ones. The energies decrease as the dot height increases. The intersubband and interband transitions of the system are also studied. For both, a spectral peak position shift to lower energies is seen due to the vertical coupling of dots. The interband transition energy decreases as the dot size increases, decreases for the dot shapes with larger heights, and reaches a minimum for coupled semisphere dots.
