Simulation-Based Analysis of Electro-Optical Properties in ITO/Ultrathin-Oxide/ITO Multilayer Structures: A Comparative Study with Metal Interlayers

This study presents a simulation-based analysis of the electro-optical performance of indium tin oxide (ITO) multilayer structures incorporating ultrathin dielectric interlayers, with a focus on aluminum oxide (Al₂O₃), zinc oxide (ZnO), and titanium dioxide (TiO₂). The aim is to assess their potential as alternatives to conventional metallic interlayers such as copper (Cu) and silver (Ag), which, despite enhancing conductivity, often degrade optical transparency and long-term stability. Multilayer configurations of ITO/X/ITO (X = Al₂O₃, ZnO, TiO₂) with interlayer thicknesses ranging from 1 to 5 nm were modeled and compared against previously reported ITO/Cu/ITO and ITO/Ag/ITO systems. Unlike most previous studies that evaluate metallic or oxide interlayers separately, this work provides a unified simulation framework comparing both classes under identical optical–electrical assumptions. The ITO/ZnO/ITO configuration demonstrated the best overall compromise, achieving transmittance of 81–86% at 550 nm together with sheet resistance values as low as 13 Ω/sq at 5 nm interlayer thickness, whereas Ag-based stacks reduced sheet resistance to 3–12 Ω/sq but at the expense of significantly lower transparency . Notably, the ITO/ZnO/ITO configuration demonstrated the best overall performance, combining low resistivity with superior transparency. Furthermore, the dielectric interlayers exhibited enhanced thermal and chemical stability, making them attractive for long-term and flexible device applications. This comparative investigation highlights the viability of oxide interlayers in transparent conductive systems and provides insights for the development of next-generation optoelectronic devices.