Preparation of polyacenic semiconductive thin films by excimer laser ablation

Polyacenic semiconductive thin films (PAS-TFs) were prepared onto a quartz 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 was obtained by heat treatment of the PF resin at 535 °C (pyrolytic PAS (535 °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 °C) were about 10−8 and 10−5 S cm−1 at room temperature, respectively. 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 °C) reached more than 10 −2 S cm−1, which is comparable to that of bulk PAS material prepared by pyrolytic treatment at 775 °C, when deposited on a substrate at 300 °C.