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Structural and Electrostatic Complexity at a Pentacene/Insulator Interface
Author(s) -
Puntambekar K.,
Dong J.,
Haugstad G.,
Frisbie C. D.
Publication year - 2006
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200500816
Subject(s) - pentacene , materials science , organic semiconductor , kelvin probe force microscope , monolayer , electrostatic force microscope , optoelectronics , semiconductor , transistor , thin film transistor , nanotechnology , organic electronics , insulator (electricity) , grain boundary , microscopy , chemical physics , atomic force microscopy , optics , composite material , microstructure , voltage , chemistry , physics , layer (electronics) , quantum mechanics
The properties of organic‐semiconductor/insulator (O/I) interfaces are critically important to the operation of organic thin‐film transistors (OTFTs) currently being developed for printed flexible electronics. Here we report striking observations of structural defects and correlated electrostatic‐potential variations at the interface between the benchmark organic semiconductor pentacene and a common insulator, silicon dioxide. Using an unconventional mode of lateral force microscopy, we generate high‐contrast images of the grain‐boundary (GB) network in the first pentacene monolayer. Concurrent imaging by Kelvin probe force microscopy reveals localized surface‐potential wells at the GBs, indicating that GBs will serve as charge‐carrier (hole) traps. Scanning probe microscopy and chemical etching also demonstrate that slightly thicker pentacene films have domains with high line‐dislocation densities. These domains produce significant changes in surface potential across the film. The correlation of structural and electrostatic complexity at O/I interfaces has important implications for understanding electrical transport in OTFTs and for defining strategies to improve device performance.