Inter-particle Coulombic decay of highly excited resonance states: A study on competing relaxation mechanisms

Abstract

The interparticle Coulombic decay (ICD) is a nonradiative decay process, in which energy released by an electron’s transition within one species leads to the ionization of a neighboring species. Over the years, research has focused on ICD in quantum dots (QDs), whose size-dependent excitation makes them suitable to tailor ICD properties. This work introduces a more highly excited state in the relaxing QD, aiming to allow for several ICD pathways and to clarify their competition by energy and selection rules. As an unexpected result, it was found that the otherwise directive energetic ICD conditions alone are insufficient to predict behavior in an ICD setting with competing pathways. In general, the pathway with the higher-energy transition is found to be slower and, moreover, allowed due to the breaking of symmetry selection rules in the QD array. It could, hence, be used in time-resolved measurements of the electron dynamics in self-assembled QDs, where the state preparation via charging from a reservoir is straightforward.