Research Information System
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, vol.131, no.10, 2025 (SCI-Expanded, Scopus)
Layered indium selenide (InSe) crystals were thoroughly examined using spectroscopic ellipsometry and optical transmission techniques to explore their linear and nonlinear optical behavior. The absorption edge analysis yielded direct band gap energy of 1.22 eV and Urbach energy of 19.7 meV, indicating the degree of structural disorder and electron-phonon coupling in the material. The dielectric function components, refractive index and extinction coefficient were modeled over a wide spectral range, and critical point transitions were extracted through second-derivative analysis of the dielectric spectra. Furthermore, the energy-dependent optical and electrical conductivities revealed prominent features corresponding to interband transitions. Nonlinear optical parameters, first- and third-order susceptibilities, were derived from the refractive index dispersion using established analytical relations. The findings confirm that InSe exhibits strong and tunable optical responses, emphasizing its potential in optoelectronic and photonic device applications.