Heiss, M.Fontana, Y.Gustafsson, A.Wuest, G.Magen, C.O'Regan, D. D.Luo, J. W.Ketterer, B.Conesa-Boj, S.Kuhlmann, A. V.Houel, J.Russo-Averchi, E.Morante, J. R.Cantoni, M.Marzari, N.Arbiol, J.Zunger, A.Warburton, R. J.Fontcuberta I. Morral, A.2013-10-012013-10-012013-10-01201310.1038/Nmat3557https://infoscience.epfl.ch/handle/20.500.14299/95448WOS:000317954800015Quantum dots embedded within nanowires represent one of the most promising technologies for applications in quantum photonics. Whereas the top-down fabrication of such structures remains a technological challenge, their bottom-up fabrication through self-assembly is a potentially more powerful strategy. However, present approaches often yield quantum dots with large optical linewidths, making reproducibility of their physical properties difficult. We present a versatile quantum-dot-innanowire system that reproducibly self-assembles in core-shell GaAs/AlGaAs nanowires. The quantum dots form at the apex of a GaAs/AlGaAs interface, are highly stable, and can be positioned with nanometre precision relative to the nanowire centre. Unusually, their emission is blue-shifted relative to the lowest energy continuum states of the GaAs core. Large-scale electronic structure calculations show that the origin of the optical transitions lies in quantum confinement due to Al-rich barriers. By emitting in the red and self-assembling on silicon substrates, these quantum dots could therefore become building blocks for solid-state lighting devices and third-generation solar cells.text::journal::journal article::research article