Title: Signatures of energy transfer and multi-exciton states on exciton Rabi oscillation in semiconductor nanocrystals

Authors: Ameenah N. Al-Ahmadi

Addresses: Physics Department, Umm Al-Qura University, P.C. 21955, P.O. Box 715, Makkah, KSA

Abstract: The theory of coherent energy transfer in nanocrystal (NC) systems is generalised for multi-exciton states. We study the effect of the Forster coupling between two individual semiconductor nanocrystals on the pump and induced Rabi oscillations (ROs). The relevant excitonic states in an isolated NC can be described by an effective four-state system, consisting of the ground state, the exciton state, the biexciton state and the triexciton state. The dynamics of a single donor-acceptor pair is described using a density matrix approach that incorporates dipole coupling to multi-exciton states. Our study shows that for short pulse the multi-exciton states play an important role in the dynamics. We also show that the amplitude and the period of the ROs in both dots are heavily influenced by Forster coupling strength. The quality factor of the induced ROs in the acceptor yields information on the energy transfer rate between the two dots. We present result for a variety of sample materials and realistic structure parameters.

Keywords: quantum dots; QDs; energy transfer; Rabi oscillation; multi-exciton states; semiconductor nanocrystals; Forster coupling; nanoparticles; nanotechnology.

DOI: 10.1504/IJNP.2009.028786

International Journal of Nanoparticles, 2009 Vol.2 No.1/2/3/4/5/6, pp.497-501

Published online: 30 Sep 2009 *

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