title: Temperature dependent radiative and non-radiative recombination dynamics in CdSe-CdTe and CdTe-CdSe type II hetero nanoplatelets.
abstract: We investigate the temperature-dependent decay kinetics of type II CdSe-CdTe and CdTe-CdSe core-lateral shell nanoplatelets. From a kinetic analysis of the photoluminescence (PL) decay and a measurement of the temperature dependent quantum yield we deduce the temperature dependence of the non-radiative and radiative lifetimes of hetero nanoplates. In line with the predictions of the giant oscillator strength effect in 2D we observe a strong increase of the radiative lifetime with temperature. This is attributed to an increase of the homogeneous transition linewidth with temperature. Comparing core only and hetero platelets we observe a significant prolongation of the radiative lifetime in type II platelets by two orders in magnitude while the quantum yield is barely affected. In a careful analysis of the PL decay transients we compare different recombination models, including electron hole pairs and exciton decay, being relevant for the applicability of those structures in photonic applications like solar cells or lasers. We conclude that the observed biexponential PL decay behavior in hetero platelets is predominately due to spatially indirect excitons being present at the hetero junction and not ionized e-h pair recombination.
authors.affiliation: Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany. alexander.achtstein@tu-berlin.de.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Scott
authors.affiliation: Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany. alexander.achtstein@tu-berlin.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kickhöfel
authors.affiliation: Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany. alexander.achtstein@tu-berlin.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Schoeps
authors.affiliation: Institute of Physico Chemical Problems, Belarussian State University, Leningradskaya str. 14, 220030 Minsk, Belarus.
authors.forename: Artsiom
authors.initials: A
authors.lastname: Antanovich
authors.affiliation: Institute of Physico Chemical Problems, Belarussian State University, Leningradskaya str. 14, 220030 Minsk, Belarus.
authors.forename: Anatol
authors.initials: A
authors.lastname: Prudnikau
authors.affiliation: CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia - San Sebastian, Spain and Ikerbasque, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain.
authors.forename: Andrey
authors.initials: A
authors.lastname: Chuvilin
authors.affiliation: Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany. alexander.achtstein@tu-berlin.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Woggon
authors.affiliation: Institute of Physico Chemical Problems, Belarussian State University, Leningradskaya str. 14, 220030 Minsk, Belarus.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Artemyev
authors.affiliation: Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany. alexander.achtstein@tu-berlin.de.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Achtstein