Ⅲ族氮化物量子点中类氢杂质态结合能  

Binding Energy of a Hydrogenic-like Impurity State in Ⅲ-nitrides Quantum Dots

作　　者：郑冬梅[1] 王宗篪[1] 

机构地区：[1]三明学院物理与机电工程系,福建三明365004

出　　处：《淮北煤炭师范学院学报（自然科学版）》2008年第3期8-14,共7页Journal of Huaibei Coal Industry Teachers College(Natural Science edition)

基　　金：三明学院物理学优势学科建设项目(YSXK0602)

摘　　要：在有效质量近似下,运用变分方法,考虑内建电场(BEF)效应和量子点的三维约束效应,研究了纤锌矿结构的GaN/AlxGa1-xN,In xGa1-xN/GaN柱形量子点中类氢杂质态结合能随量子点的结构参数(量子点高度L和量子点半径R)、Al或In含量和类氢杂质位置的变化规律,并计算了考虑量子点内外电子有效质量不同后对杂质态结合能的修正.结果表明:类氢杂质位于量子点中心时,杂质态结合能随量子点高度、半径的增加先增大后减小,存在最大值.对GaN/AlxGa1-xN量子点,随着Al含量的增加,杂质态结合能增大;杂质从量子点下界面沿z轴上移至上界面过程中,结合能存在最大值.对InxGa1-xN/GaN量子点,随着In含量的增加,结合能先缓慢增大后缓慢减小,存在最大值;杂质从量子点下界面沿z轴移至上界面过程中,杂质态结合能增大.量子点内外电子有效质量的失配使杂质态结合能增大.In this paper, we investigate the binding energy of a bydrogenic - like impurity state as function of the different structural parameters of QDs （the height L and the radius R）, Al or In content, and the hydrogeniclike impurity position for the cylindrical wurtzite GaN/AlxGa1-xN and In xGa1-xN/GaN QDs within the framework of effective - mass approximation and a variational approach, including three - dimensional confinement in QDs and a strong built- in electric field effect. Furthermore, the modification of the bingding energy is calculated when the difference in effective electron mass in the barrier and the well are considered. The numerical results show that when the hydrogenic- like impurity in the center of QDs, the binding energy first increases rapidly, reachs a maximum value, then slowly decreases with increasing the height and the radius of QDs. For GaN/AlxGa1-xN QDs, the binding energy increases with the increasing of AI content. And with increasing In content, there is a maximum in the binding energy for InxGa1-xN/GaN QDs. The dependence of the binding energy on the impurity - center position is also considered. For GaN/AlxGa1-xN QDs, the binding energy firstly increases, and then decreases with moving the impurity position from the bottom of QD to the top, there is a maximum. For InxGa1-xN/GaN QDs, the binding energy increases with moving the impurity position from the bottom of QD to the top. The mismatch of the effective electron mass leads to the increasing of impurity binding energy.

关 键 词：类氢杂质 量子点 结合能 

分 类 号：O48[理学—固体物理]