Modeling of optical constants of diamond-like carbon

A new model of optical constants of diamond-like carbon parameterizing joint density of states (PJDOS) is introduced and compared with a previously published model based on the parameterization of density of states (PDOS). Both the models employ only six parameters: three parameters for π → π⁎ and three parameters for the σ → σ⁎ transitions. These parameters have a clear physical meaning. One describes the minimum energy needed for the band transition, i.e. band gap, the second is the maximum energy of transitions and the third is proportional to the total density of the corresponding electronic states. An inherent disadvantage of the PDOS model is in the necessity of a numerical calculation. On the other hand the PJDOS model is analytical and, therefore, it can be implemented in a simple manner. The efficiency of both the models for the study of DLC structure is demonstrated in several examples.