Multi-colour emission from GaAs core-AlGaAs shell photonic nanowires

Semiconductor nanowires grown via the vapour-liquid-solid (VLS) mechanism are promising for miniaturisation of optoelectronic devices. Efficient optoelectronic devices require these nanowires to have high quantum efficiency. While optimizing the growth process to eliminate bulk defects and achieve perfect surface passivation is one approach to increase the quantum efficiency of nanowires¹, coupling the nanowires to resonant plasmonic structures to reduce the radiative lifetime of carriers in the semiconductor is an alternative approach. In this paper, we demonstrate increase in quantum efficiency of AlGaAs shell of GaAs core-AlGaAs shell-GaAs cap nanowires (Figure 1(a)) by coupling the nanowires to plasmonic nanoparticles deposited on their surface. Increase in quantum efficiency of the AlGaAs shell leads to multi-colour emission from the nanowires (from the band-edge of GaAs core and the AlGaAs shell). This approach to achieve multi-colour emission from the nanowires does not rely on the growth of quantum confined layers like quantum wells or quantum dots in the nanowires. In addition to achieving multi-colour emission, our approach also provides independent control on the polarization response of emission from the GaAs core and the AlGaAs shell of the nanowires².