Abstract
Crystalline thin films of small organic molecules are actively studied for the application in transistors. Various techniques have been persued to improve the ordering and the crystallinity of microcrystals. We here report our approach to electronically excite the molecules and growing thin films by photo irradiation. One example is C_<60> grown on MoS_2 (0001) and another is the Alq3 grown on KCl (001). In the case of C_<60> which is known to photopolymerize, nucleation density is increased with threshold as a function of photo intensity, and the second layer is grown at the edge of the first layer. Alq3, a polar molecule widely used in electroluminescence devices, showed a distinct alignment effect, in which the needle crystal domains become aligned with the polarization of the laser.
