title: Detection of quantum well induced single degenerate-transition-dipoles in ZnO nanorods.
abstract: Quantifying and characterising atomic defects in nanocrystals is difficult and low-throughput using the existing methods such as high resolution transmission electron microscopy (HRTEM). In this article, using a defocused wide-field optical imaging technique, we demonstrate that a single ultrahigh-piezoelectric ZnO nanorod contains a single defect site. We model the observed dipole-emission patterns from optical imaging with a multi-dimensional dipole and find that the experimentally observed dipole pattern and model-calculated patterns are in excellent agreement. This agreement suggests the presence of vertically oriented degenerate-transition-dipoles in vertically aligned ZnO nanorods. The HRTEM of the ZnO nanorod shows the presence of a stacking fault, which generates a localised quantum well induced degenerate-transition-dipole. Finally, we elucidate that defocused wide-field imaging can be widely used to characterise defects in nanomaterials to answer many difficult questions concerning the performance of low-dimensional devices, such as in energy harvesting, advanced metal-oxide-semiconductor storage, and nanoelectromechanical and nanophotonic devices.
authors.affiliation: III. Institute of Physics, Georg-August-Universität-Göttingen, Friedrich-Hund-Platz 1, 37075 Göttingen, Germany. sghosh@physik3.gwdg.de.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India. ghoshiisc@gmail.com and Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Moumita
authors.initials: M
authors.lastname: Ghosh
authors.affiliation: IV. Institute of Physics, Georg-August-Universität-Göttingen, Freidrich-Hund-Platz 1, 37075 Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Seibt
authors.affiliation: Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India.
authors.forename: G Mohan
authors.initials: GM
authors.lastname: Rao