Role of the interface on charge build-up in a low-density polyethylene: Surface roughness and nature of the electrode

The aim of this work is to better understand the impact of the nature of the metal and of the surface topology on the charge generation at a metal / dielectric interface. Conduction current and space charge measurements using the pulsed electro-acoustic method (PEA) have been carried out on low density polyethylene (LDPE-A) films with different metal electrodes (Au, Al, Ag, In) in order to evaluate the role of the carriers (hole, electron) injection barrier height on the charge build-up. The impact of the roughness of the interface has also been theoretically investigated. Experimental surface profiles have been introduced in a model able to simulate the surface roughness in two dimensions, and to calculate the electric field and the injection current.