In this paper, we fabricated and characterized alpha, alpha'-dihexylsexithiophene (DH-alpha 6T) 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-alpha 6T submonolayer as function of substrate temperature was investigated. DH-alpha 6T submonolayer could be grown at low substrate temperatures although it has the high island density, and the high substrate temperatures of 100-120 degrees C are optimal to grow large-size and high-quality DH-alpha 6T films. These results imply that DH-alpha 6T thin films are much longer range ordering than alpha 6T, which originates from the self-assembly properties brought by alkyl groups in the alpha, alpha' position. Thus DH-alpha 6T is a more attractive material for fabricating both a high-quality DH-alpha 6T monolayer film and a high-quality multimonolayer film. Furthermore, organic thin film transistor with a crystal-like DH-alpha 6T 2.52 monolayer film as active layers realized high mobility of 0.239 cm(2)/V S. (c) 2013 Elsevier B.V. All rights reserved.