有限元法计算GaN/AlN量子点结构中的电子结构

The calculation of electronic structure in GaN/AlN quantum dots with finite element method

根据有效质量理论单带模型,采用有限元方法(FEM)计算了GaN/AlN量子点结构中的电子结构,分析了应变和极化对电子结构的影响,计算了不同尺寸的量子点的能级,分析了量子点的大小对电子能级的影响.结果表明,形变势和压电势提升了电子能级,而且使简并能级分裂.随着量子点尺寸的增大,量子限制能减小,而压电势能起到更显著的作用,使电子的能级降低,吸收峰发生红移.

We investigate electronic structure theoretically in strained GaN/AlN quantum dots （QDs） with wurtzite （WZ） crystal structure. The QD electron energy levels are calculated using the finite element method （FEM） in the framework of effective mass approximation （EMA）. We analyze the influence of strain and polarization to the electron energy levels and calculate electron energy levels with different dot sizes. It is shown that the strain dependent deformation potential and piezoelectric potential increase the electron energy levels and split the degenerate states. The electron energy levels decreases rapidly with increasing QD height, which is partly due to the confinement energy reduction. However, the piezoelectric field makes a more significant contribution.