Photoluminescence of the single wurtzite GaAs nanowire with different powers and temperatures

High quality GaAs nanowires with wurtzite structure were grown by molecular beam epitaxy. The micro-photoluminescence from a single GaAs nanowire is carried out with different excitation powers to investigate both intrinsic and extrinsic emissions in wurtzite GaAs nanowires. The variation of emission energy of free exciton peak with temperature is also investigated. It is found that the electron-phonon interaction is weaker in wurtzite GaAs than that in its zinc-blende counterpart. The time-resolved photoluminescence is performed to study the life time of free exciton at last. By capping GaAs nanowires with an Al0.3Ga0.7As shell layer, the life time of free exciton increases significantly, which provides the possibility for the device application of the GaAs-based nanowires.