Influence of crystal structure on carrier transport in titanylphthalocyanine thin films

Titanylphthalocyanine (TiOPc) thin films were prepared by vacuum deposition at various substrate temperatures, and influence of crystallinity of the films on the carrier mobility was studied. The film crystallinity was evaluated by X-ray diffraction, TEM, SEM and STM observation. The carrier mobility perpendicular to the film plane was determined by time-of-flight method. Polycrystalline and amorphous films were obtained at the substrate temperatures of above 20°C and below 0°C, respectively. It was confirmed that the crystallinity of the TiOPc thin films increased with an increase in substrate temperature. The carrier mobility of the TiOPc thin films increased with an increase in substrate temperature, which could be explained by an increase in crystallinity.