Structural and Transport Properties of Copper Phthalocyanine (CuPc) Thin Films

Thin films of CuPc of various thicknesses have been deposited onto
clean glass substrates using thermal evaporation technique at room
temperature. The structural studies, using X-ray diffractometry and IR spectral
analysis, showed that the films are mainly of β- form with preferential
orientation of the plane (100). The dark electrical resistivity and the
thermoelectric power measurements were carried out at different temperatures
in the range 300-450 K. Room temperature current density-voltage
characteristics showed ohmic conduction in the lower voltage range and spacecharge-
limited – conductivity (SCLC) in the relatively high voltage. The SCLC
are controlled by an exponential distribution of traps above the valence band
edge. The temperature dependence of current density allows the calculations of
some essential parameters such as the hole mobility, the relative permittivity,
the trap concentration, the characteristic temperature and the trap density