Macroscopic and microscopic charging effects of Si nanocrystals embedded in a SiO2 layer

Capacitance–voltage (C–V) and electrostatic force microscopy (EFM) measurements on Si nanocrystals (Si-NCs) formed by using the sonochemical method were carried out to investigate the charging effects of the Si-NCs. Transmission electron microscopy images and atomic force microscopy images showed that the Si-NCs were created inside the SiO2 layer. The C–V curve and the EFM image showed that the Si-NCs embedded in the SiO2 layer experienced charging effects. The macroscopic surface charge density determined from the C–V curve was in reasonable agreement with the microscopic local value obtained from the EFM image. The present results indicate that the EFM technique might provide a promising method for investigating charging effects in various kinds of nanocrystals embedded in the insulating layer.