We determined the effects of varying the array lattice parameters of the nanorods of a two-dimensional (2D) SiNx photonic crystal (PC) layer on the efficiency of extraction of photoluminescence (PL) of the Y2O3:Eu3+ thin films, in which the interface between the phosphor layer and the air was modified with a 2D SiNx PC pattern. The PL extraction was improved by a factor of over 3.7 compared to that of a conventional Y2O3:Eu3+ thin film by adding a PC array with a lattice constant of 600 nm, a height of 200 nm, and a filling ratio of 0.27. This improvement arises from the liberation of the photons trapped in the high-index guiding layers of the Y2O3:Eu3+ thin films. (c) 2006 The Electrochemical Society.