无限深势阱下杂质量子点的能级计算

在有效质量近似下,垂直方向采用无限深势阱限制势,在x-y平面上,量子点内采用抛物势近似,在量子点边界处采用与实际情况更接近的无限深势阱.在中心杂质电荷为ηe时,利用波函数近似,得到基态和低激发态的能级,与x-y平面均采用抛物势时得到的能级进行了比较.计算发现在量子点真实半径比较小时,电子的基态和低激发态受其影响很大,而相应的能级随量子点的半径逐步增大.在量子点半径大于5倍有效玻尔半径时,能级受其影响已经变得很弱.并且,随着磁场的变化,量子点半径对基态和第一激发态的能级差的影响也很大.最后我们计算了杂质电子的基态束缚能并讨论了声子对其影响.

Computation of Electron Energy Levels of a Quantum Dot with an Impurity in the Dot Center

We chlculate the ground state energy and low-lying energies of electron in a dot with an impurity in the dot center by using effective mass approximation.We find that when the radius of the dot is smaller,the ground energy and low-lying energies are affected very strongly by the radius of the dot,and the energies are becoming stronger with increasing of the radius.When the radius becomes five times of the effective Bohr radius,the influence of radius to the energies of the electron becomes very weak.In addition,the difference between ground energy and first excited energy is affected very strongly by the change of the magnetic field.Finally we compute the binding energy of the impurity and discuss the influence of the phonon on the binding energy.