激光与光电子学进展, 2016, 53 (9): 091602, 网络出版: 2016-09-14  

内建电场作用下纤锌矿ZnO/MgxZn1-xO量子阱中束缚极化子结合能和极化子能移随组分x的变化规律

Binding Energy of Bound Polaron and the Polaron Shift as the Functions of Composition x in Wurtzite ZnO/MgxZn1-xO Quantum Well Under the Built-in Electric Field
作者单位
内蒙古师范大学物理与电子信息学院功能材料物理与化学内蒙古自治区重点实验室, 内蒙古 呼和浩特 010022
摘要
用改进的Lee-Low-Pines (LLP) 变分理论讨论了纤锌矿结构的ZnO/MgxZn1-xO量子阱体系中内建电场对束缚极化子结合能和极化子能移的影响,数值研究了基态能量和结合能、不同支光学声子对能量和结合能的贡献随Mg组分x变化的规律。计算中计入了体系的介电常数、电子的带有效质量和不同支光学声子频率等参数的各向异性,并同时考虑了长波光学声子与电子和杂质中心的相互作用。结果显示,该体系中,内建电场对结合能和极化子能移的影响显著,并且不同支光学声子对能量和结合能的贡献受内建电场的影响程度有所不同。内建电场增大了声子对能量的总贡献,而降低了声子对结合能的总贡献。在内建电场作用下,能量和结合能随x增大而急剧减小,而没有内建电场时,变化相对缓慢。计算结果还说明,组分x变大时,无论是否考虑内建电场,界面和定域声子对能量和结合能的贡献变大,半空间声子贡献变小,声子对能量的总贡献变大。而声子对结合能的总贡献则要视是否考虑内建电场而不同:有内建电场时变大,无内建电场时变小。同闪锌矿结构的GaAs/AlxGa1-xAs量子阱相比,纤锌矿ZnO/MgxZn1-xO量子阱体系中光学声子对极化子能量和结合能的影响更大,极化子能移更明显。
Abstract
The influence of the built-in electric field on bound polaron binding energy and the polaron shift in a wurtzite ZnO/MgxZn1-xO quantum well are investigated using the improved Lee-Low-Pines (LLP) variational theory. The ground-state energy and binding energy, the contributions from different branches of optical phonons to the energy and the binding energy are given as the functions of composition x. The anisotropic properties of dielectric constant, electron band mass, different branches of optical phonons frequencies, the optical phonon-electron and the impurity center interaction are considered in the numerical calculations. The results show that the influence of the built-in electric field on the binding energy and polaron shift is obvious, and the degree of the influence of the built-in electric field for the contributions of different phonon modes is different. The built-in electric field increases the total phonon contribution to the energy, but it significantly reduces the total phonon contribution to the binding energy. The binding energy with the built-in electric field rapidly decreases as increasing composition x, but the binding energy without the built-in electric field decreases slightly. The result also show that when increasing the composition x, the contributions of interface and confined phonons to the energy and the binding energy with and without the built-in electric field increase, the contributions of half space phonon reduce, and the total contributions of phonons to the energy increase. But the total contributions of phonons to the binding energy with and without the built-in electric field are different. The total contributions with the built-in electric field increase, while the total contributions without the built-in electric field decrease. In comparison with the zinc blende GaAs/AlxGa1-xAs quantum wells, the influence of optical phonons on the energy and the binding energy of bound polaron in a wurtzite ZnO/MgxZn1-xO quantum well is larger, and polaron shift is more obvious.

赵凤岐, 潘虹宇. 内建电场作用下纤锌矿ZnO/MgxZn1-xO量子阱中束缚极化子结合能和极化子能移随组分x的变化规律[J]. 激光与光电子学进展, 2016, 53(9): 091602. Zhao Fengqi, Pan Hongyu. Binding Energy of Bound Polaron and the Polaron Shift as the Functions of Composition x in Wurtzite ZnO/MgxZn1-xO Quantum Well Under the Built-in Electric Field[J]. Laser & Optoelectronics Progress, 2016, 53(9): 091602.

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