Effect of γ-radiation on the conduction mechanism of thermal vacuum deposited Copper Phthalocyanine thin films

The dosimetry properties of thermally evaporated Copper Phthalocyanine (CuPc) thin films were investigated. The conduction mechanism of the as-deposited films was found to be space-charge-limited and their relative permittivity was within the range reported by others [ 1, 2. 3. 4]. The Poole-Frenkel effect became more dominant for the irradiated samples and they displayed large increase in permittivity and colour centre density, although the energies of their optical band gap and trapping levels did not change. The observed linear relationship between the absorbance at 615 nm and the gamma-radiation doses validated the use of CuPc as an optical sensor dosimeter especially for low radiation doses. Samples showed a higher radiation tolerance after being annealed for one hour at a temperature of only 323 K. Annealing also restored their initial electrical and optical properties.