title: Observation of the full exciton and phonon fine structure in CdSe/CdS dot-in-rod heteronanocrystals.
abstract: Light emission of semiconductor nanocrystals is a complex process, depending on many factors, among which are the quantum mechanical size confinement of excitons (coupled electron-hole pairs) and the influence of confined phonon modes and the nanocrystal surface. Despite years of research, the nature of nanocrystal emission at low temperatures is still under debate. Here we unravel the different optical recombination pathways of CdSe/CdS dot-in-rod systems that show an unprecedented number of narrow emission lines upon resonant laser excitation. By using self-assembled, vertically aligned rods and application of crystallographically oriented high magnetic fields, the origin of all these peaks is established. We observe a clear signature of an acoustic-phonon assisted transition, separated from the zero-phonon emission and optical-phonon replica, proving that nanocrystal light emission results from an intricate interplay between bright (optically allowed) and dark (optically forbidden) exciton states, coupled to both acoustic and optical phonon modes.
authors.affiliation: High Field Magnet Laboratory, Institute for Molecules and Materials, Radboud University Nijmegen , Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
authors.forename: Andrés
authors.initials: A
authors.lastname: Granados Del Águila
authors.forename: Bhawana
authors.initials: B
authors.lastname: Jha
authors.forename: Francesca
authors.initials: F
authors.lastname: Pietra
authors.forename: Esther
authors.initials: E
authors.lastname: Groeneveld
authors.forename: Celso
authors.initials: C
authors.lastname: de Mello Donegá
authors.forename: Jan C
authors.initials: JC
authors.lastname: Maan
authors.forename: Daniël
authors.initials: D
authors.lastname: Vanmaekelbergh
authors.forename: Peter C M
authors.initials: PC
authors.lastname: Christianen