外加电场对GaN/Al_xGa_(1-x)N双量子阱中性施主束缚能的影响

Influence of electric field on binding energy of neutral donor in symmetrical GaN/Al_xGa_(1-x)N double quantum wells

在有效质量包络函数理论下,利用变分法计算了未加电场以及加入电场后GaN/Al_xGa_(1-x)双量子阱中施主杂质各种情况下的束缚能,讨论了双量子阱中间势垒高度、施主杂质位置对杂质束缚能的影响。给出了加入电场后施主位置不同时的束缚能和波函数,以及量子阱宽度不同时的束缚能,并且计算了未加电场和加入电场后中间势垒高度变化以及宽度不同时的束缚能。当双量子阱中间垒宽一定时,束缚能随着阱宽的变化会出现一个峰值。在阱宽一定时,随着中间垒宽度的增加,束缚能逐渐减小,并在垒宽增加到一定宽度时双量子阱情况与单量子阱情况相似,束缚能不再明显变化。计算结果对设计和研究GaN/Al_xGa_(1-x)N量子阱发光和探测器件有一定的参考价值。

Under the effectives-mass envelope-function theory, the binding energy of the system in GaN/AlxGal-xN symmetric double quantum wells were theoretically calculated using the variational method. The influence of applied external electric fields, barrier height, quantum well width and the position of donors on the binding energies of donor impurities were investigated. The potential quantum well energy changes significantly with applied external electric field. The binding energy and wave functions with the donor in different positions were presented with and without external electric field. Variations of donor binding energy with the centre barrier width were also calculated. With the fixed middle barrier of double quantum wells, the binding energy increases until it reaches a maximum value, and then decreases as the well width increases. The results are meaningful in the design of optoelectronic devices based on GaN/AlxGa1-xN quantum well structures.