Perspectives in the characteristics and applications of Tauc-Lorentz dielectric function model

We explore inherent characteristics of Tauc-Lorentz (TL) dielectric function model [Appl. Phys. Lett. <Emphasis Type="Bold">69, 371 (1996)] on the basis of relevant optical-constant data in the literature. It is found that the (single or multiple) TL model is strongly related to the one-oscillator Wemple-DiDomenico (WD) model [Phys. Rev. B <Emphasis Type="Bold">3, 1338 (1971)]. New physical significance has been attached to the transition energy parameter of the TL model in terms of the WD model. We have also attempted to extend the applications of the TL model to evaluating specific bond density in various semiconductors, proposing a criterion for judging whether the quantum size effect is prominent or not within crystalline/amorphous mixed-phase materials, and obtaining information about mass density and coordination number of the samples investigated. These perspectives directly provide the possibility of deeper and wider usage of the TL model in many other covalent and ionic materials. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2005