Influence of a two-dimensional SiO2 nanorod structure on the extraction efficiency of ZnS:Mn thin-film electroluminescent devices

Abstract

To improve light extraction from thin-film electroluminescent (TFEL) devices, we have introduced a two-dimensional (2-D) SiO2 nanorod pattern into the glass substrate of a TFEL. This periodic modulation converts the guided waves in the high refractive index ZnS:Mn phosphor layers into leaked external waves. We used the finite-difference time-domain method to optimize the structural parameters of the 2-D nanorod pattern. Using a nanorod pattern with a depth of 300 nm, a lattice constant of 600 nm, and a radius of 180 nm, the extraction efficiency of the TFEL is theoretically predicted to increase by a factor of more than 4.8. We compare the calculated efficiency and that of the actual TFEL structure, with a view to decreasing diameter of nanorod.