Spectral diffusion of type-II excitons in InP/InAs/InP core-multishell nanowires

Spectral diffusion of type-II excitons in InP/InAs/InP core-multishell nanowires (CMNs) was studied at 5 K by means of time- and spectrally resolved photoluminescence. Up to 1.2 ns type-II excitons lose their energy slowly at the initial rate of 8×106eV/s and at the later rate of 3×106eV/s reflecting two-dimensional spectral diffusion in the quantum well region in CMNs. Acoustic-phonon-assisted migration of excitons to lower-energy-localized states leads to the spectral diffusion in two-dimension. Spectral diffusion of type-II excitons is discussed by extending the theory of spectral diffusion of type-I excitons.