Gamma radiation-induced changes on the structural and optical properties of aluminum phthalocyanine chloride thin films

Abstract Thin films of aluminum phthalocyanine chloride (AlPcCl) were prepared by thermal evaporation technique under high vacuum at room temperature. The prepared films were divided into two groups for study; the first was the as – deposited films, the second group was irradiated in gamma cell type 60Co source in air at room temperature with different absorbed doses (20–60 kGy). The surface morphology of γ-irradiated film was observed with a higher aggregation compared with as-deposited film with an average particles size of (10–28 nm). The optical parameters were obtained using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in wavelengths range of 200–2500 nm. The type of optical transition was found to be an indirect allowed transition, the band gaps decrease with increasing γ-irradiation doses. The calculated dispersion parameters of AlPcCl films decreased with increasing the γ-irradiation dose. The disagreement between the obtained values of e ∞ and e L may be attributed to the lattice vibration and free carrier contribution.