PREPARATION OF POLYACENIC SEMICONDUCTIVE THIN-FILMS BY EXCIMER-LASER ABLATION

Polyacenic semiconductive thin films (PAS-TFs) were prepared onto a qu artz or a KBr substrate by excimer laser ablation at 308 nm of a bulk phenol-formaldehyde (PF) resin and the bulk of a PAS material which wa s obtained by heat treatment of the PF resin at 535 degrees C (pyrolyt ic PAS(535 degrees C)). These were homogeneous brown and/or dark brown thin films consisting of fine particles. The electric conductivities of the films thus prepared from PF resin and pyrolytic PAS(535 degrees C) were about 10(-8) and 10(-5) S cm(-1) at room temperature, respect ively. Remarkable increase of electric conductivities was achieved on increasing the substrate temperature during the deposition process. In particular, the conductivity of the film from pyrolytic PAS(535 degre es C) reached more than 10(-2) S cm(-1), which is comparable to that o f bulk PAS material prepared by pyrolytic treatment at 775 degrees C, when deposited on a substrate at 300 degrees C.