Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by germanium doping

We report on electrostatic screening of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures with germanium-doped GaN nanodiscs embedded between AlN barriers. The incorporation of germanium at concentrations above 1020 cm–3 shifts the photoluminescence emission energy of GaN nanodiscs to higher energies accompanied by a decrease of the photoluminescence decay time. At the same time, the thickness-dependent shift in emission energy is significantly reduced. In spite of the high donor concentration, a degradation of the photoluminescence properties is not observed.