Exciton states and interband optical transitions in wurtzite InGaN/GaN quantum dot nanowire heterostructures

摘要

Within the framework of the effective-mass approximation, the exciton states and interband optical transitions in In_xGa_(1-x)N/CaN strained quantum dot (QD) nanowire heterostructures are investigated using a variational method, in which the important built-in electric field (BEF) effects, dielectric-constant mismatch and three-dimensional confinement of the electron and hole in In_xGa_(1-x)N/CaN QDs are considered. We find that the strong BEF gives rise to an obvious reduction of the effective band gap of QDs and leads to a remarkable electron-hole spatial separation. The BEF, QD height and radius, and dielectric mismatch effects have a significant influence on exciton binding energy, electron interband optical transitions, and the exciton oscillator strength.