中文摘要：

采用改进的Lee-Low-Pines中间耦合方法研究纤锌矿氮化物抛物量子阱材料中极化子能级，给出极化子基态能量、第一激发态到基态的跃迁能量以及不同支长波光学声子模对极化子能量的影响随阱宽L和外电场F变化的函数关系，在计算中考虑了纤锌矿氮化物GaN和AlxGa1-xN构成的抛物量子阱材料中准LO和准TO声子模的各向异性、电子有效带质量、介电常数、声子频率等随空间坐标：变化（SD）效应以及外电场作用对极化子能量的影响。结果表明，纤锌矿氮化物抛物量子阱材料中电子-声子相互作用、SD效应和外电场对极化子能量有明显影响，它们都使极化子能量降低，sD效应随阱宽L增大而减小，阱宽越大，SD效应越小，最后趋近于零，阱宽较大时，定域准LO声子对极化子能量的影响较大，而半空间准LO声子的影响较小；阱宽较小时，则正好相反，在阱宽三变化的整个范围，氮化物抛物量子阱材料中电子-声子相互作用对极化子基态能量的贡献（约为28-42meV）比GaAs／AlxGa1-xAs抛物量子阱中的相应值（约为0．5-3．2meV）大得多．而准TO声子对极化子基态能量的贡献比较小，要远远小于LO声子对极化子基态能量的总贡献。因此，讨论氮化物抛物量子阱（GaN／AlxGa1-xN）中电子态问题时要考虑电子与准LO声子相互作用，而可以忽略准TO声子的作用。

英文摘要：

The energy levels of a polaron in a wurtzite nitride finite parabolic quantum well （PQW）are studied by a modified Lee-Low- Pines variational method. The ground state of the polaron, the transition energy from first exited state to the ground state and the contribution from different branches of LO（TO）-like phonon modes on energy levels as functions of the well width L and external electric field F in the wurtzite GaN/Alx Ga1-x N PQW are given. The effects of the anisotropy of confined LO （TO）-like phonon modes, the half-space LO （TO）-like phonon modes, the spatial dependence （SD） of effective mass, dielectric constant, phonon frequency, and external electric field on energy levels are considered in the calculation. The results show that the electron- phonon interaction, SD effects and external electric field strongly affect energy levels of a polaron in wurtzite nitride PQW, all of them tend to lower the polaron energy levels. The SD effect decreases with increasing well width L, and finally approaches to zero. The influence of confined LO-like phonon modes on polaron energy levels is greater at large well width, whereas the influence of half-space LO-like phonon modes is smaller, and the situation is reversed at a small well width. The contributions of the electron-phonon interaction to ground state energy of the palaron in wurtzite GaN/AlxGa1-x N PQW （ roughly from 28 to 42 meV） are greater than that in GaAs/AlxGa1-xAs PQW （ roughly from 0.5 to 3.2 meV）. In addition, the contribution of the TO- like phonon modes to polaron energy levels is very small and far smaller than that of the LO-like phonon modes. Therefore, the electron-LO-like phonon interaction should be considered while the electron-TO-like phonon interaction can be neglected in studying the electron states in GaN/Alx Ga1-xN PQW.