External Electric Field Effect on Shallow Donor Impurity States in Zinc-Blende InxGa1−xN/GaN Symmetric Coupled Quantum Dots

Autor: Guang-Xin Wang, Li-Li Zhang, Huan Wei
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Advances in Condensed Matter Physics, Vol 2017 (2017)
Druh dokumentu: article
ISSN: 1687-8108
1687-8124
DOI: 10.1155/2017/5652763
Popis: Based on the effective-mass approximation and variational procedure, the ground-state donor binding energy in a cylindrical zinc-blende InxGa1-xN/GaN symmetric coupled quantum dots (SCQDs) is investigated in the presence of the external electric field. Numerical results show that the donor binding energy increases firstly until a maximum value, and then it begins to drop quickly in all the cases with decreasing the dot radius. As the thickness of left dot and right dot decreases, the donor binding energy increases monotonically at first, reaches a maximum value, and then drops rapidly for an impurity ion located at the right dot center and the middle barrier center. Moreover, the donor binding energy for an impurity ion located at the center of the left dot is insensitive to the variation of dot thickness for large dot thickness due to the Stark effect. Meanwhile, the impurity position plays an important role on the change of the donor binding energy under the external electric field. In particular, the impurity position corresponding to the peak value of the donor binding energy is shifted toward the left QD with increasing the external electric field strength.
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