有限宽势垒AlxGa1-xAs/GaAs三角势量子阱中施主结合能及其压力效应

对有限宽势垒Alx Ga1-xAs/GaAs量子阱系统,引入三角势近似势阱能带弯曲,利用变分法讨论施主杂质态结合能.给出结合能随阱宽、杂质位置和铝组分变化关系,并与方阱情形对比.结果显示:三角势近似下结合能明显小于方阱情形,且两者的差别随阱宽和铝组分(势垒高度)而增加,随势垒厚度增加而减少,但阱内杂质位置的变化对其影响不甚敏感.进而,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,所得结果显示,结合能之差在压力作用下明显增大.

Binding Energies of Donors in AlxGa1-xAs/GaAs Triangular Potential Quantum Wells with Finitely Wide Barriers and Their Pressure Effect

A variational method is used to investigate binding energies of donors in AlxGa1-xAs/GaAs quantum wells with finite width of potential barriers by using a triangular potential to approximate the band bending of the well potential.The relations between the binding energies and well width,impurity position,Al concentration are given and compared with the cases of square quantum wells.The results indicate that binding energies with the triangular potential approximation are obviously lower than that of square quantum wells and their difference increases with increasing of well width,Al concentration(barrier height)and decreases with increasing of barrier width.The variation of the impurity position influence on the difference is insensitive.Furthermore,the effects of hydrostatic pressure on the effective band mass of an electron,dielectric constants and band gaps are considered to demonstrate that the difference of binding energies obtained with the above models increases obviously with increasing hydrostatic pressure.