Effect of layer-by-layer electrostatic assemblies on the surface potential and current voltage characteristic of metal-insulator-semiconductor structures.

In the present Article, the Kelvin probe method for surface potential measurement is introduced to study polyelectrolyte multilayer coatings deposited on silicon plates. Metal−insulator−semiconductor (MIS) structures with polyelectrolyte layers as insulator were fabricated. The polyelectrolyte layer deposition on the surface of silicon plates led to a change of the current−voltage characteristics connected with resistance changes of the MIS structures. Poly(ethylenimine) (PEI) monolayer formation resulted in resistance decrease, and the following increase of the polyelectrolyte layer number led to MIS structure resistance increase. The results are interpreted as an interplay between accumulation of majority carriers (electrons) near the semiconductor surface and resistance increase due to insulating polyelectrolyte adsorption, and both effects can be discriminated by varying the polyelectrolyte layer thickness.