Observation of delayed fluorescence in CdSxSe1−x nanobelts by femtosecond time-resolved fluorescence spectroscopy

Abstract

The time-resolved fluorescence spectra as well as the decay kinetics for CdSxSe1−x single crystal nanobelts without and with the presence of structural disorders have been investigated by femtosecond time-resolved fluorescence spectrometer based on optical parametric fluorescence amplifier technique. The structural disorders in the crystal give rise to an inhomogeneous broadening of the steady-state fluorescence spectra and also to a distinct time-dependent redshift in the transient photoluminescence spectra, due to the carrier relaxation from the conduction band to the trapped states. The delayed fluorescence was observed and it can be attributed to several mechanisms including the electron-phonon interaction and the Auger effect.