KFM detection of charges injected by AFM into a thin SiO2 layer containing Si nanocrystals

Charge retention of Si nanocrystals elaborated by ultra-low energy ion implantation and thermal annealings into a thin SiO2 layer is characterized by atomic force microscopy (AFM) and Kelvin force microscopy (KFM). Electrons and holes are injected under ambient conditions by applying different bias to a conductive AFM tip in contact with the grounded sample. A surface potential mapping of the sample by KFM is continuously carried out after charge injection. The temporal decay of injected charges and their corresponding lateral spreading are quantified. The results show that the presence of Si nanocrystals leads to a strong charge confinement.