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.