Abstract

The origins of the green emission (GE) from ZnO nanostructures remain highly controversial despite extensive studies. Herein, transient absorption spectroscopy (TAS) revealed a small Stokes shift of ~180 meV between the GE-centers (located at ~0.7 eV above the valence band) and the GE peak – yielding the first experimental evidence of the GE originating from charge transitions of the ZnO di-vacancies proposed recently in density functional calculations. TAS also uncovered an ultrafast Auger-type hole-trapping process to V_ZnO that occurs in a sub-ps timescale

© 2013 Optical Society of America