Journal article

Switchable dissociation of excitons bound at strained CdTe/CdS interfaces

Florian Enders, Arne Budweg, Peng Zeng, Jannika Lauth, Trevor A Smith, Daniele Brida, Klaus Boldt

NANOSCALE | ROYAL SOC CHEMISTRY | Published : 2018

Abstract

Charge carrier dynamics of semiconductor nano-heterostructures are determined by band alignment and lattice mismatch of the adjacent materials. However, quantum efficiencies for the separation of excited charge carriers at such an interface are hard to predict and cannot yet be easily controlled. In this work we examine nanorods with a severely strained, axial CdTe/CdS interface using femtosecond transient absorption spectroscopy. We show that charge separation is mitigated by equal contributions of valence band distortion and formation of coulomb pairs across the interface. Left undisturbed such localised excitons relax rapidly via non-radiative recombination channels. By adding a competiti..

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University of Melbourne Researchers

Grants

Awarded by DFG


Awarded by Emmy Noether program of the German Research Foundation (DFG)


Awarded by Australian Research Council Centre of Excellence in Exciton Science


Funding Acknowledgements

This work was supported by the DFG project BO4516/3-1 and the DAAD-UAus project "Mapping ultrafast energy relaxation in semiconductor nanocrystals". K. B. is grateful for financial support by the Fonds der Chemischen Industrie via a Liebig Fellowship and the Zukunftskolleg Konstanz via a 5-year Marie Curie ZIF Research Fellowship. F. E. acknowledges financial support by the Fonds der Chemischen Industrie through a PhD scholarship. J. L. acknowledges funding by Toyota Motor Europe. D. B. acknowledges financial support from the Emmy Noether program (BR5030/1-1) of the German Research Foundation (DFG). T. A. S. and P. Z. acknowledge the support of the Australian Research Council Centre of Excellence in Exciton Science (CE170100026). The authors would like to thank Elena Sturm (nee Rosseeva) for Cs-corrected TEM micrographs, as well as Stefanie Breimaier, Niklas Unglaube, Lisa Winkler, and Samuel Monter for work assisting the development of the tipped nanorod synthesis.