Preparation of amorphous organic semiconductor thin films with polyperinaphthalene structure on temperature-controlled substrates by excimer laser ablation of 3,4,9,10-perylenetetracarboxylic dianhydride

Amorphous semiconducting organic thin films are prepared on temperature-controlled substrates by excimer laser ablation ELA.of 3,4,9,10-perylenetetracarboxylic dianhydride PTCDA.with 308 nm XeCl.beams. Drastic increase in electric conductivity and decrease in the FT-IR peak intensities related to the side groups of PTCDA monomers are observed for films prepared on substrates above 2008C. Electric conductivity of a film prepared on a substrate at 3008C comes up to 10y1 S cmy1. Raman spectroscopic measurement reveals that this film partially contains polyperinaphthalene PPN. structure. Structural change by increasing substrate temperature and film formation process are discussed. q1998 Elsevier Science B.V.