Thermally evaporated of homogeneous nanostructured gallium-phthalocyanine-chloride films: Optical spectroscopy

Films of gallium-phthalocyanine-chloride (GaClPc) with various thicknesses were prepared by the vacuum thermal evaporating technique. The films' structural were studied by the X-ray diffraction pattern. It was found that GaClPc films with a thickness beyond 45 nm showed a single sharp peak at 2θ = 26.6°. The atomic force microscopy clarified that the grain size and the roughness increased as the film's thickness increased. The absorption exhibited a high linear transmittance in the region between 350 and 650 nm. Also, the values of the band gap energies are unaffected by the film thickness. The dielectric constants of GaClPc films at different thicknesses were evaluated. The first-order (χ⁽¹⁾) and the third-order (χ⁽³⁾) nonlinear susceptibility of GaClPc films were calculated. The values of (χ⁽³⁾) were increased as the film thickness was increased which may be due to the possible orientation of the molecular chains in unfavorable direction with the induced electric field as the film thickness increases. The optical limiter (OL) properties of GaClPc films have been discussed by the normalized power of two laser beams (the He–Ne laser of 638.2 nm and green diode laser of 533 nm). It was concluded that the GaClPc films can be used as a promised candidate OL material.