Proton Ion Irradiation on As<sub>40</sub>Se<sub>50</sub>Sb<sub>10</sub> Thin Films: Fluence-Dependent Tuning of Linear–Nonlinear Optical Properties for Photonic Applications
D. Sahoo, Satyaprakash Sahoo, D. Alagarasan, R. Ganesan, S. Varadharajaperumal, Ramakanta Naik
Abstract
The present work is focused on the impact of proton irradiation (30 keV) on the structural, optical, and morphological properties of thermally evaporated As40Se50Sb10 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 As40Se50Sb10. 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.