Rubrene Thin Film Characteristics on Mica

Abstract

Rubrene thin films were deposited by Hot Wall Epitaxy on mica substrates. To optimise the growth conditions, the growth rate and the substrate temperature were changed systematically. The surface morphology of the grown rubrene layers was investigated by polarized optical microscopy (POM), electron microscopy (SEM) and atomic force microscopy (AFM). After an initial nucleation and coalescence stage a continuous amorphous layer is formed. In a later stage of growth, spherulites embedded in the amorphous matrix are found, which furthermore cover the whole surface. It could be proven that the spherulite consist of polycrystalline material, which could be used for the fabrication of organic field effect transistors.