One- and Two-Dimensional Spectral Diffusions in InP/InAs/InP Core–Multishell Nanowires

We report on the photoluminescence and time-resolved photoluminescence spectroscopy of wurtzite InP/InAs/InP core–multishell nanowires. Multiple peaks appeared in the photoluminescence spectra owing to the monolayer variation of InAs layers. Each photoluminescence peak has a broad photoluminescence band coming from the inhomogeneous broadening in a core–multishell single nanowire. Inhomogeneous broadening caused time-dependent red shift (spectral diffusion) at a constant energy-loss rate. The long-time-span (~10 ns) time-resolved photoluminescence measurement clarified that spectral diffusion takes place in two stages (initially at a fast rate and later at a slow rate). The fast one is ascribed to spectral diffusion on the side of the nanowire and the slow one is ascribed to spectral diffusion at the corner of the nanowire. This suggests that photoexcited excitons in a core–multishell nanowire move from the side of the nanowire toward the corner of the nanowire.