CONDUCTION STUDIES ON POLYVINYL-ALCOHOL FILMS

Polyvinyl alcohol (PVA) films (pure, 0.5% and 2% iodine doped) are formed onto well cleaned glass slides by a solution growth technique. Al-PVA-Al sandwich structures of thin film capacitors are fabricated. d.c. and a.c. conduction studies are made at different frequencies (1 kHz-10 MHz) and temperatures (303-383 K) and the conductivity of PVA films is found to increase with iodine doping. The presence of iodine in the films is confirmed by optical absorption and RES studies. The conduction in these films is interpreted on the basis of the formation of charge transfer complexes. A Poole-Frenkel type of conduction is prevailing in pure and 0.5% iodine doped films, while a Schottky conduction mechanism is identified in 2% iodine doped films at high temperatures. The activation energy and metal-insulator work function (phi) for all films are calculated. Electronic hopping is found to be responsible for the a.c. conduction in these films.