Electromechanical reliability of ITO/Ag/ITO multilayer coated pet substrate for optoelectronic application

Abstract

Successful design and fabricate flexible devices a Low sheet resistance, high optical transmittance, high mechanical reliability and low cost for electrode component are required. Aluminum-doped Zinc Oxide (AZO) film has been extensively used as an alternative promising candidate to Indium tin oxide (ITO) that are the predominant transparent conductive oxide (TCO) film in potential applications such as flexible organic light- emitting diodes, flat-panel displays, solar cells, and thin film transistors (TFTs). However AZO film are too brittle and their resistivity is rather high in some cases compared to ITO, can not completely meet flexible optoelectronic device requirements. In this work, AZO (35 nm)/Ag(12 nm)/AZO (35 nm) films was deposited on polyethylene naphthalate using RF magnetron sputtering system at room temperature. The mechanical behavior of continuous and patterned oxide film were investigated by means bending and twisting tests respectively. The change in the electrical resistance of the AZO/Ag/AZO multilayer was monitored in situ. In addition, failure mechanism of different pattern of AZO/Ag/AZO by using scanning electron microscopy after twisting test was investigated. Finite elements simulations will also be carried out to further understand the failure mechanisms of AZO/Ag/AZO under twisting deformation. In all shapes, cracks are observed to initiate from the pattern edges. Cracking and buckling delimitation failure modes were observed for all samples investigated at critical strains. Furthermore the buckling test demonstrated that the high failure strain of the ductile Ag layer lead to mechanical stability of multilayer compared to the single-layered AZO sample