Determination of the localization times of electrons and holes in the HgS well in a CdS/HgS/CdS quantum dot–quantum well nanoparticle

Markus Braun, Stephan Link, Clemens Burda, and Mostafa El-Sayed
Phys. Rev. B 66, 205312 – Published 11 November 2002
PDFExport Citation

Abstract

The femtosecond time-resolved electron-hole dynamics of the CdS/HgS/CdS quantum dot–quantum well system (QDQW) was investigated as a function of excitation energy. In the transient absorption spectra four bleach bands and a stimulated emission signal in the visible spectral range between 450 and 780 nm were resolved. By using an IR probe pulse at 4.7 μm a transient induced absorption due to intraband transitions was found. The decay and rise times of these signals were measured when the CdS core or the HgS well of the nanoparticles was excited by the pump pulse. After excitation within the HgS well the transient signals rise within the resolution of our pump pulse, while after core excitation slower rise times were measured. From the 1.5 ps rise time of the stimulated emission originating from the HgS well and the intraband hole IR absorption (150 fs) after excitation into the CdS core, the electron localization time (transfer time from the core to the well) is found to be 1.5 ps while that of the hole is ∼150 fs. This large difference in the observed dynamics of the electron and hole in crossing the CdS/HgS interface is discussed.

  • Received 1 July 2002

DOI:https://doi.org/10.1103/PhysRevB.66.205312

©2002 American Physical Society

Authors & Affiliations

Markus Braun*, Stephan Link, Clemens Burda, and Mostafa El-Sayed

  • School of Chemistry and Biochemistry, LDL, Georgia Institute of Technology, Atlanta, Georgia 30332

  • *Present address: Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, D-80538 München, Germany.
  • Present address: Chemistry Department, Case Western Reserve University, Cleveland, OH 44106.
  • Author to whom correspondence should be addressed.

References (Subscription Required)

Click to Expand
Issue

Vol. 66, Iss. 20 — 15 November 2002

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×