Reduction in built-in polarization potentials in three vertically arranged InGaN/GaN quantum dots

Abstract

The barrier thickness dependence of built-in polarization potentials is investigated using a finite-element method (FEM) based on the theory of continuum elasticity for three vertically arranged InGaN/GaN quantum-dot (QD) structures. In the case of a relatively thick barrier thickness dDD between QDs, the potential drop in a lower or centered QD is similar to that of the QW structure. However, the potential drop significantly decreases with decreasing dDD. In addition, the potential drop in QDs is found to depend on the lower-boundary barrier thickness dB1 and is shown to decrease with decreasing dB1. On the other hand, the dB1 dependence of the potential drop is not as large as its dDD dependence, which means that a detailed knowledge of barrier thickness dependences of the internal potential is important in designing vertically arranged InGaN-based QD structures.