DONOR BOUND EXCITONS CONFINED IN WURTZITE InGaN/GaN QUANTUM DOT NANOWIRE HETEROSTRUCTURES

Abstract

Within the framework of the effective-mass approximation, the donor bound exciton states and interband optical transitions in InGaN / GaN strained quantum dot (QD) nanowire heterostructures (NWHETs) are investigated using a variational method, in which the built-in electric field (BEF) effect due to the spontaneous and piezoelectric polarizations and the three-dimensional (3D) confinement of the electron and hole in the QD are considered. Our results show that the position of the ionized donor, the strong BEF, the In-composition and the QD structural parameters have a significant influence on the donor bound exciton binding energy, the electron interband optical transitions and the exciton oscillator strength. The donor bound exciton binding energy increases obviously if the donor position changes from the left-interface to the right-interface. The BEF reduces the bound exciton binding energy and the exciton oscillator strength. The donor bound exciton binding energy increases, if the In-fraction increases. The emission wavelength monotonically increases if the QD height and radius increase.