Polar, semi- and non-polar nitride-based quantum dots: influence of substrate orientation and material parameter sets on electronic and optical properties

Abstract

In this work we present a detailed analysis of electrostatic built-in fields, electronic and optical properties of InGaN-based quantum dots grown on different crystallographic planes. The calculations are performed by means of a symmetry adapted $\mathbf {k}\cdot \mathbf {p}$ model. Special attention is paid to the influence of different effective mass and deformation potential parameter sets on the results. Our analysis reveals that the built-in potential profile is strongly dependent on the growth plane. These changes in the built-in potential affect the electronic structure and therefore the optical properties of semi-polar InGaN quantum dots significantly. For instance, while we observe a clear spatial separation of electron and hole ground state wave functions for quantum dots grown on the $(10\bar{1}3)$-plane, for the $(20\bar{2}1)$-plane our results indicate a strong spatial overlap. Furthermore, we show that the calculation of the degree of optical linear polarization in the considered semipolar InGaN quantum dot systems significantly depends on the chosen material parameter set for substrate incline angles of $0^\circ <\theta <58^\circ$. For instance, for growth on the $(10\bar{1}3)~(\theta =32^\circ)$-plane, the degree of optical linear polarization changes from 90 to 10 % when changing the input material parameter set.