Experiment and Model Studies of Ge10Se90 Sample

Abstract

Ge₁₀Se₉₀ is a Group IV–VI semiconductor glassy material synthesized by the melt-quenching technique. Its optical properties were studied using UV–Visible spectroscopy. The optical band gap of the sample was found to be 1.95 eV. The increase in band gap compared to the bulk value indicates quantum confinement effects, confirming the nano-dimensional nature of the material. The wavelength dependence of the refractive index was analyzed using the Wemple–DiDomenico single-oscillator model. From this model, parameters such as the single-oscillator energy (E₀) and dispersion energy (E_d) were determined, and their values reflect the influence of nano-dimensional effects. The Sellmeier model was also applied to obtain parameters such as oscillator strength and average oscillator wavelength. The Abbe number of the glass was calculated to be 17.21, which is smaller than that of flint glass (Abbe number ≈ 25). The lower Abbe number indicates higher chromatic dispersion. The material exhibits normal dispersion behavior, as the first derivative of the refractive index with respect to wavelength (dn/dλ) is less than zero.