[摘要]：Photoluminescence (PL) studies of GaN/AlxGa1-xN 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. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3646389]
