Structural and electrical properties of Ag films sputter-deposited on HCl-doped and undoped polyaniline substrates

Ag films were sputter-deposited on HCl-doped polyaniline (HCl-PANI) and undoped polyaniline (PANI) substrates at 300 K. The 50 nm- and 200 nm-thick Ag films grown on HCl-PANI substrates convert respectively to the AgCl film and the AgCl-Ag composite film because Cl ions in the HCl-PANI substrate diffuse into the Ag films and the chemical reaction of Ag atoms with Cl ions occurs. The AgCl and AgCl-Ag composite films are porous. The Ag film grown on PANI substrate has a dense structure and its grain size increases with increasing film thickness. The conductance of the film grown on the PANI substrate does not change markedly with aging time. For the Ag film grown on the HCl-PANI substrate, however, the conductance decreases significantly with increasing aging time. After the aging time reached a threshold value, the conductance does not change with the aging time. The threshold time increases with increasing film thickness. The reaction controlled process dominates the formation of AgCl film on the HCl-PANI substrate.