Photolithographic periodic patterning of gold using azobenzene-functionalized polymers

•A novel technique to fabricate periodic arrays of metal nanostructures is introduced.•Azobenzene-functionalized polymers replace conventional photoresists.•Surface relief gratings are used to form masks for dry etching of gold.•Metal stripe, disk and hole arrays that exhibit surface plasmon resonances are created.

Metal micro- and nanostructures for optical and electronic applications are typically fabricated by means of interferometric optical or electron-beam lithographies using conventional photo- or electron-beam resists. In this work, we report on fabrication of periodic nanostructures of gold by exploiting photoinduced surface-relief gratings in an azobenzene-functionalized polymer film as masks for reactive ion etching of the metal. The proposed technique provides a convenient, fast and flexible alternative to photoresist-based lithography for fabricating metal nanostructures of large surface area. Owing to the fact that the azo-polymer is sensitive to the polarization rather than the intensity modulation of the exposing light, the technique is particularly suitable for patterning highly reflective surfaces.