Spatially Correlated Charge Transport in Organic Thin Film Transistors

FRANCO DINELLI, MAURO MURGIA, PABLO LEVY,* MASSIMILIANO CAVALLINI, AND FABIO BISCARINI†

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2004 vol. 92 p. 116802 - 116802

0031-9007

Hole mobility in organic ultrathin film field-effect transistors is studied as a function of the coverage. For layered sexithienyl films, the charge carrier mobility rapidly increases with increasing coverage and saturates at a coverage of about two monolayers. This shows that the first two molecular layers next to the dielectric interface dominate the charge transport. A quantitative analysis of spatial correlations shows that the second layer is crucial, as it provides efficient percolation pathways for carriers generated in both the first and the second layers. The upper layers do not actively contribute either because their domains are smaller than the ones in the second layer or because the carrier density is negligible.DOI: 10.1103/PhysRevLett.92.116802 PACS numbers: 73.61.Ph, 68.37.–d, 68.55.–a, 81.07.Nb