Swift-Heavy Ion-Induced Effects on Optical and Dielectric Properties of Ge_7As_(39)Se_(54) Thin Films

摘要

Present work applies 100 MeV Ag swift-heavy ions irradiation to optical and dielectric properties of amorphous Ge_7As_(39)Se_(54) chalcogenide thin films. Five different fluences (3 × 10~(10), 1 × 10~(11), 3×10~(11), 1 × 10~(12), 3×10~(12) ions/cm~2) of 100 MeV Ag swift-heavy ions are used to irradiate thin film samples. Optical transmission is used for determination of linear optical parameters using Swanepoel method in the wavelength range 300-900 nm. Wemple-DiDomenico relation is used to determine dispersion in thin film samples. Dielectric constants and dielectric loss factor are determined from linear optical parameters. Scanning Electron Microscope measurements indicate that surface destruction due to ion irradiation starts at fluence 3 × 10~(12) ions/cm~2 in the thin film samples. The study reveals that 3 × 10~(11) ion/cm~2 is the most suitable dose for optical applications at which refractive index increases significantly and optical/dielectric losses are minimized. Optimization in optical and dielectric properties is understood in terms of structural rearrangement upon ion irradiation.