Polaron activation energy of nano porphyrin nickel(II) thin films

5,10,15,20-Tetraphenyl-21H, 23H-porphyrin nickel(II), NiTPP films were prepared by thermal evaporation method of mother powder material. Electrical as well as thermo-electric properties were investigated for the as-deposited and annealed NiTPP films. The effect of NiTPP film thickness (160-460 nm) and isochronal annealing in temperature range (300-348 K) on DC electrical properties were studied. Both bulk resistivity and the mean free path were determined; their values are 1.38 x 10(5) a"broken vertical bar cm and 0.433 nm, respectively. The electrical conductivity exhibits intrinsic and extrinsic conduction. The values of activation energy in extrinsic and intrinsic regions are 0.204 and 1.12 eV, respectively. Mott's parameters were determined at low temperature. Seebeck coefficient indicates p-type conduction of NiTPP films. Carrier density, mobility and holes concentration were determined. Seebeck coefficient decreases with the increasing of temperature, while the conductivity increases with the increasing of temperature. The difference between the conductivity and the thermoelectric power activation energies was attributed to the potential barrier grain boundaries.