Photoluminescence from colloidal CdS-CdSe-CdS quantum wells

摘要

We report investigations of CdS-CdSe-CdS (core-well-shell) nanostructures by photoluminescence (PL) spectroscopy at temperatures between 77 and 300 K. PL intensity measurements show a transition from a pump-rate-limited regime at low excitation intensity to the range determined by a spontaneous emission lifetime at a high excitation limit. PL intensity changes as a function of temperature. Also, the temperature dependences of the PL linewidth and PL peak energy are all determined experimentally. The PL linewidth is narrower for thicker quantum wells and becomes broader when the temperature increases owing to longitudinal-optical (LO) phonon scattering. The LO phonon scattering strength is around 30 meV, which is independent of the well thickness, and is much smaller than the value for bulk CdSe. © 2005 Optical Society of America.