Modeling of interfaces using electron force microscopy

The improvement achieved in the desired properties of a nanodielectric is primarily due to the preponderance of interfaces. There have been some studies that have attempted to indirectly detect and measure the interfacial region, in terms of thickness and/or modified relative permittivity. However, to date there has been no direct observation of this interfacial region. Interfaces may be imaged using Atomic Force Microscopy (AFM) and/or Electron Force Microscopy (EFM). In the current work, we develop a Finite Element Method (FEM) based computational model to computationally generate the EFM phase image at an interface of two dielectrics, based on the topological data and relevant material properties. The FEM model computes the electrostatic force on the cantilever as it scans the given surface, given material properties (permittivity and charge distribution). This is used to generate an EFM phase map of the surface computationally. The actual surface topology at and around an interface is obtained using AFM. The computed EFM phase image is matched with the experimentally-obtained EFM phase image. A simple interface between glass and epoxy is used to develop and validate the computational model. Further, this model is used to predict the EFM phase map around a single nanoparticle embedded in a polymer matrix.