title: Biexciton Auger Recombination in CdSe/CdS Core/Shell Semiconductor Nanocrystals.
abstract: A theoretical study of the positive and negative trion channels in the nonradiative Auger recombination of band-edge biexcitons (BXs) in CdSe/CdS core/shell nanocrystals (NCs) is presented. The theory takes into account the BX fine-structure produced by NC asymmetry and hole-hole exchange interaction. The calculations show that growth of CdS shell upon CdSe core suppresses the rate of the Auger recombination via negative trion channel, while the more efficient Auger recombination via positive trion channel shows much weaker dependence on the shell thickness. The demonstrated oscillatory dependence of the BX Auger rate on the core and shell sizes is explained qualitatively in terms of overlap of the ground and excited carrier wave functions. The calculations show that raise of temperature accelerates the Auger recombination in CdSe/CdS NCs due to reduction of the bulk energy gaps of CdSe and CdS.
authors.affiliation: George Mason University , Fairfax, Virginia 22030, United States.
authors.forename: Roman
authors.initials: R
authors.lastname: Vaxenburg
authors.affiliation: Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia.
authors.forename: Anna
authors.initials: A
authors.lastname: Rodina
authors.affiliation: Technion - Israel Institute of Technology , Haifa 32000, Israel.
authors.forename: Efrat
authors.initials: E
authors.lastname: Lifshitz
authors.affiliation: Naval Research Laboratory , Washington, D.C. 20375, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: L Efros
keywords: Auger recombination; CdSe/CdS; biexciton; core/shell; nanocrystal; quantum dot