Study of optical and electrical properties of ZnO/Cu/ZnO multilayers deposited on flexible substrate

Abstract

Transparent conducting oxide thin films have been extensively studied because they are essential elements in optoelectronic applications. In this communication, we report transparent conductive ZnO/Cu/ZnO multilayer films prepared by RF sputtering of ZnO and DC sputtering of Cu on flexible polyethylene naphthalate substrates. The optical and electrical properties of the multilayers were studied for different thicknesses of Cu and ZnO layers. Controlling the thickness of the ZnO layer for a specific Cu thickness affects the transmittance of the multilayer. Electrical properties are influenced by the thickness of ZnO and Cu layers. Sheet resistance of the stack rises with the decrease of Cu thickness and the increase of ZnO thickness. Repeated bending of the stack, after an initial 20% increase of sheet resistance, has no significant effect on the electrical performance of the multilayers.