Fabrication and characterization of DH-α6T monolayer film on silicon dioxide

Abstract

In this paper, we fabricated and characterized α, α′-dihexylsexithiophene (DH-α6T) monolayer film on silicon dioxide. The first layer is the mode of layer growth and from the second layer, the film mainly shows the mode of layer growth accompanying growth of little local island. On the other hand, the growth behavior of DH-α6T submonolayer as function of substrate temperature was investigated. DH-α6T submonolayer could be grown at low substrate temperatures although it has the high island density, and the high substrate temperatures of 100–120°C are optimal to grow large-size and high-quality DH-α6T films. These results imply that DH-α6T thin films are much longer range ordering than α6T, which originates from the self-assembly properties brought by alkyl groups in the α, α′ position. Thus DH-α6T is a more attractive material for fabricating both a high-quality DH-α6T monolayer film and a high-quality multimonolayer film. Furthermore, organic thin film transistor with a crystal-like DH-α6T 2.52 monolayer film as active layers realized high mobility of 0.239cm2/Vs.