Effect of nanosize metal overlayer on C₆₀ thin film optical parameters near fundamental absorption edge

Abstract

The effect of nanosize metal overlayer, both evaporated on C₆₀ films (Bi, In) and attached as nanoparticles of (Ag, Au), on the optical parameters of C₆₀ films near the fundamental absorption edge has been studied. The values of direct band gap (Eg), the optical gap (E₀) in the framework of Tauc model and the Urbach tail parameter (EU) were determined from the absorption coefficient (α) spectra plotted in coordinates (αhν)², (αhν)¹/² ln(α) vs hν, respectively. Parameters obtained testify diminishing the structural disorder in C₆₀ thin films with nanosize metal overlayer at optimal ratio of C₆₀ to metal layer thicknesses.