New optical dispersion models for the accurate description of the electrical permittivity in direct and indirect semiconductors

Abstract We propose new optical dispersion models to describe the imaginary part of electrical permittivity dielectric and semiconductor materials in fundamental absorption region. work out our procedure based on well-known structure semi-empirical Tauc–Lorentz model band-fluctuations approach derive a five-parameter formula that describes Urbach, Tauc high-absorption regions direct indirect semiconductors. Main features are self-consistent generation exponential Urbach tail below bandgap incorporation Lorentz oscillator behavior due electronic transitions above apply test these data (MAPbI 3 , gallium arsenide indium phosphide), (gallium phosphide crystalline silicon), amorphous hydrogenated silicon semiconductors, accurately describing spectra permittivity. Lastly, we compare results with other similarly inspired assess bandgap, central resonance energy.