Rubrene Thin Film Transistors

We report on the fabrication and characterization of field-effect transistors formed from rubrene thin films deposited on SiO$_{2}$/Si substrates by thermal evaporation. The growth and electrical properties of rubrene thin films are closely related. Rubrene thin film transistors have a lower saturation field effect mobility, $\sim $ 10$^{-4}$ cm$^{2}$/Vs, than single crystal devices and thin films of other materials. In comparison with pentacene, which initially forms 2D islands, atomic force microscopy shows that rubrene immediately forms circular multilayer islands. We discuss the electrical properties of rubrene transistors based on the geometry of rubrene islands.