压力下屏蔽对有限深量子阱中施主结合能的影响

考虑电子有效质量、材料介电常数及禁带宽度随流体静压力的变化,以及准二维电子气对杂质库仑势的屏蔽影响,利用变分法讨论有限深量子阱中的施主杂质态能级.对GaAs/AlxGa1-xAs量子阱系统中的杂质态结合能进行了数值计算,给出结合能随铝组分、阱宽和压力的变化关系,并讨论了有无屏蔽时的区别.结果表明,屏蔽效应随着压力增加而增加且显著降低杂质态的结合能.

Screening Influence on Binding Energies of Donors in Quantum Wells with Finite Barriers Under Hydrostatic Pressure

The energy levels of donors in quantum wells with finite barriers are investigated using a variational method.We consider the variations of the electron effective mass,dielectric constant,and conduction band offset between the well and barriers with hydrostatic pressure,and we take into account the screening effect on the Coulombic potential of an impurity from the 2D electron gas.Numerical calculations are performed for the binding energies of impurity states in GaAs/Al_xGa_1-xAs quantum well systems.The relations between the binding energies of donors and Al concentration,well width,and hydrostatic pressure are given.The difference between the cases with and without screening is discussed.The results indicate that the screening increases with pressure,resulting in a decrease in the binding energies of the impurity states.