Electrical study of polyelectrolyte self-assembled films using mercury probe

A non-destructive technique of a mercury probe was employed for studying electrical characteristics of polyelectrolyte self-assembled films. A series of I–V and C–V tests were performed on polyallylamine/polysterenesulfonate (PAA/PSS) multilayers deposited onto silicon wafers. C–V characteristics of the structure p-Si/(PAA/PSS)/Hg did not show any polarisation behaviour related to either ion movement or dipole orientation. The observed hysteresis of C–V curves is caused by recharging the surface states of the density of about 5×1014 m−2. The value of 1.73±0.16 was found for the relative dielectric permittivity of PAA/PSS films. DC conductivity of PAA/PSS films was found to be thickness dependent. The mechanism of conductivity transforms from the surface limited conductivity for thin films to the bulk limited for thicker films.