Preparation and characterization of thermally evaporated titanium phthalocyanine dichloride thin films

Titanium phthalocyanine dichloride (TiPcCl2) thin films are prepared on glass substrates by vacuum-sublimation technique. The optical constants of thin films are obtained by means of thin film spectrophotometry. Planar structures for the study of electrical properties are fabricated with TiPcCl2 as active layer and silver as the contact electrodes. The effects of post-deposition annealing on the optical band gap have been studied. The optical transition is found to be direct allowed in nature. The invariance in the optical band gap shows the thermal stability of the material. The activation energies are determined using the Arrhenius plots between electrical conductivity and inverse temperature. The variation in activation energy with post-deposition annealing is investigated. The unit cell dimensions of TiPcCl2 thin films are also determined by indexing the powder diffraction data. The variations of the surface morphology and grain size with annealing have also been studied.