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在连续介电模型和有效质量近似下,考虑电子有效质量随位置的变化,利用变分法从理论上研究了半导体有限高势垒球形量子点中杂质态的结合能.数值计算了AlxGa1-xAs/GaAs球形量子点杂质态基态结合能随量子点尺寸和垒材料Al组分的变化关系,讨论了有效质量随位置变化对基态结合能的影响,并与不考虑有效质量随位置变化做了比较.结果表明:当量子点半径较小时,电子有效质量随位置的变化增加了杂质态基态结合能,随量子点半径增大,杂质态基态结合能的增加幅度变小;量子点半径较大时,电子有效质量随位置变化降低了杂质态基态结合能.随着Al组分增大,杂质态基态结合能单调递增.
In the continuous dielectric model and effective mass approximation, considering the change of electron effective mass with position, the binding energies of impurity states in the spherical quantum dots of a finite-height-barrier semiconductor are studied theoretically by using the variational method. The numerical calculations for the AlxGa1-xAs / GaAs Spherical Quantum Dots The binding energies of the ground states vary with the size of the quantum dots and the Al composition of the barrier material. The effect of effective mass with position on the ground state binding energy is discussed. The results show that when the radius of quantum dots is small, the effective mass of electrons increases with the change of position, which increases the ground state binding energy of impurity states. As the radius of quantum dots increases, the increase of ground state binding energy of impurity states becomes smaller. , The effective mass of electrons decreases with the change of position, and the ground state binding energy of impurity states decreases with the increase of Al composition.