Memory effects in thin film organic transistor characteristics

Bottom gated field effect transistors were fabricated using spun films of peripherically substituted liquid-crystalline lutetium phthalocyanine (Lu(PcR(8))(2)) molecules as active layers and the electrical characteristics were found to be sensitive to the molecular orientations depending upon the post-deposition heat treatment of the films. High conductive states were attributed to the formation of a well ordered crystalline structure when as deposited Lu(PcR(8))2 films were annealed at 242 degrees C. Annealing at 125 degrees C produced a different crystalline of lower order, giving rise to low conductive states. The existence of these two well-defined conducting states makes Lu(PcR(8))(2) films suitable for the fabrication of storage-class memory devices.