Strong suppression of internal electric field in GaN/AlGaN multi-layer quantum dots in nanowires
Résumé
Photoluminescence (PL) studies of GaN/Al(x)Ga(1-x)N quantum dots (QDs) in nanowires demonstrate an efficient carrier confinement, resulting in thermally stable decay times up to 300 K. The evolution of the PL transition energy as a function of both the QD height and the Al mole fraction in the barriers, as well as the evolution of the decay time as a function of the QD height, point out that a built-in electric field is significantly smaller than the value expected from the spontaneous polarization discontinuity. This is explained by the uniaxial compressive strain resulting from the spontaneously formed Al-rich shell that envelops the QD stack