Annealing effect on Dy: (GeSe2)80(In2Se3)20 thin films - Oscillator, dielectric, absorption and nonlinear parameters

Rare earth doping increases the emission range and is an attractive candidate for sensing applications because of its good infrared properties. Here (Dy) doped (GeSe2)80(In2Se3)20 thin films have been deposited via thermal evaporation and then annealed at different temperatures in order to investigate its effect on various parameters. Refractive index, calculated by drawing lower and upper envelopes, has been used to calculate the Wemple DiDomenico and Sellmeier oscillator parameters. The calculation of dielectric parameters shows a decrease in the loss of electromagnetic energy. Optical energy bandgap (Eg) values increase from 1.86 eV to 2.10 eV. To a good approximation, E0 and Eg follow Tanaka's relation: E0/Eg ≈ 2. The electric modulus and complex impedance have been interpreted to give information about the relaxation phenomenon in the films. The calculated nonlinear refractive index values vary from 5.74 × 1011 esu to 3.45 × 1011 esu which are far higher than the silica glasses.