Influence of Nb2O5 interlayer on permeability of oxide multilayers on flexible substrate

An oxide multilayer structure consisting of an indium zinc oxide (IZO) conductive layer, a silicon dioxide (SiO2) water vapor permeation barrier, and a niobium oxide (Nb2O5) interlayer coated on polyethylene naphthalate (PEN) is proposed as a transparent flexible substrate for display applications. In general, the properties of the multilayer, such as its mechanical, optical, and permeability attributes, are degraded considerably because of pinholes, grain boundaries, microcracks, intrinsic stress, and the refractive index. In order to improve the properties of the SiO2/Nb2O5/PEN film, a 30 nm-thick Nb2O5 interlayer was sputtered with an Ar ion beam prior to the SiO2 sputtering process. The SiO2/Nb2O5/PEN film showed good mechanical and permeability properties attributable to the effect of Ar ion bombardment on the thin film formation.