Orientation and order of beta-tetrahexyl-sexithiophene molecules deposited by organic molecular beam deposition

Highly ordered and oriented deposition of substituted sexithiophene molecules is obtained on single crystal organic substrates. The study of X-ray diffraction and of the optical absorption of the films measured under different angles of incidence and with different directions of light polarization permits a complete structural model to be proposed. In addition, some interesting conclusions about the average molecular orientation with respect to the substrate are drawn.