Spatially Correlated Charge Transport in Organic Thin Film Transistors

The hole mobility in organic ultrathin film field effect transistors was investigated as a function of the coverage. It was found that the charge carrier mobility rapidly increased with increasing coverage and saturated at a coverage of about two monolayers in the case of layered sexithienyl films. It was also found that the first two molecular layers next to the dielectric interface dominated the charge transport. Using a quantitative analysis it was shown that the second layer was crucial, as it provided efficient percolation pathways for carriers generated in both the first and the second layers.