No abstract

The photosensitivity of amorphous chalcogenide thin films brings out light-induced changes in the nonlinear and linear optical parameters upon sub-bandgap and bandgap laser irradiation.

The present work is focused on the impact of proton irradiation (30 keV) on the structural, optical, and morphological properties of thermally evaporated As 40 Se 50 Sb 10 thin films. The fluence-induced linear and nonlinear optical parameters were calculated from the transmittance, reflectance, and absorbance data obtained from UV−vis spectroscopy in the range of 550−1100 nm. The increase in transmittance suggests that the material is getting more transparent upon proton irradiation. The change in absorption edge, optical band gap, and refractive index represents the post-irradiation effect. The disorder in the film influenced the density of defect states in the localized state region, which led to the changes in the optical band gap. The variation of dispersion and dielectric parameters such as dispersion energy, oscillator energy, dielectric constant, plasma frequency, and real and imaginary optical conductivities upon proton irradiation displays the tuning capabilities of As 40 Se 50 Sb 10 . The higher values of nonlinear optical parameters with proton irradiation are essential for cutting-edge photonic applications. The X-ray diffraction reveals the amorphous nature of the films after proton irradiation, and the microstructural changes were noticed from the Raman spectra. The composition of the films was verified by energy-dispersive X-ray analysis, and the surface morphology pictures were taken by field emission scanning electron microscopy and atomic force microscopy.

The present work shows the effect of annealing conditions on the linear and nonlinear optical properties of two-year-old thermally evaporated 800 nm As40Se50Ge10 thin films.