Trapped carrier dynamics has been studied on Si3N4 nanodots grown by plasma enhanced chemical vapor deposition (PECVD) and on SiO2 nanodots grown by pulsed laser deposition (PLD) on Si wafers. Carrier dynamics can be explained with a model based on Coulomb interaction with the boundary conditions of the nanodot structure. The trapped charge can be estimated quantitatively from the measured trap dynamics, elucidating the electrostatic effect in a small dielectric system. (C) 2009 Elsevier B. V. All rights reserved.