Long minority carrier lifetime in Au-catalyzed GaAs/Al(x)Ga(1-x)As core-shell nanowires

GaAs/AlxGa1-xAs core-shell nanowires were grown by metal organic chemical vapor deposition with optimized AlxGa1_xAs shell and twin-free Au-catalyzed GaAs cores. Time-resolved photoluminescence measurements were carried out on single nanowires at room temperature, revealing minority carrier lifetimes of 1.0260.43 ns, comparable to self-assisted nanowires grown by molecular beam epitaxy. The long minority carrier lifetimes are mainly attributed to improvement of the GaAs/AlxGa1-xAs interface quality. The upper limit of surface recombination velocity of the structure is calculated to be 1300 cm/s with the AlxGa1-xAs shell grown at 750C, which is comparable with planar double heterostructures.