Absorption Features of Symmetric Molecular Nanofilms
American Scientific Publishers
Electronic components are used today in extreme physical conditions and in that sense, ultrathin dielectric crystalline films could be used as surface layers for electronic component protection. Calculating dynamical permittivity by the single-pole Green’s functions it was shown that the threshold of light absorption can be moved along frequencies, changing the film thickness and the intensity of boundary perturbations. We study the basic micro and macroscopic physical characteristics of symmetric ultrathin molecular crystalline films and one can see that essential optical properties of these systems arise with perturbation conditions, which appear at their surface layers. Depending on the values of the parameters of surface interactions, certain energy levels can lie outside the energy band of the ideal crystal, so there appear the surface localized states of excitons. Characteristic resonant peaks appear in the dependence of dielectric permittivity and absorption index (extinction coefficient) of ultrathin film on frequency of external electro-magnetic field.