Visualizing charge transport in silicon nanocrystals embedded in SiO2 films with electrostatic force microscopy

Abstract

In this work, we report a mapping of charge transport in silicon nanocrystals (nc-Si) embedded in SiO2 dielectric films with electrostatic force microscopy. The charge diffusion from chargednc-Si to neighboring uncharged nc-Si in the SiO2 matrix is found to be the dominant mechanism for the decay of the trapped charge in the nc-Si. The trapped charge and the charge decay have been determined quantitatively from the electrical force measurement. An increase in the area of the charge cloud due to the charge diffusion has been observed clearly. In addition, the blockage and acceleration of charge diffusion by the neighboring charges with the same and opposite charge signs (i.e., positive or negative), respectively, have been observed.