Versatile Direct Laser Writing Lithography Technique for Surface Enhanced\nInfrared Spectroscopy Sensors

Abstract

A challenge\nfor design, testing, and fabrication of nanostructured\nchemical sensors is the fabrication of mm² size arrays\nof nanostructures in a reasonable time. Herein, we introduce and show\nhow direct laser writing (DLW) in positive-tone photoresists, followed\nby lift-off process, can be used for fast fabrication (up to three\ntimes faster than a comparable electron beam lithography system) of\narrays of nanoscale plasmonic structures with a great level of control\nover the design and dimensions of the nanostructures. We demonstrate\nthe function of nanostructured arrays, fabricated by various DLW approaches,\nwith surface enhanced infrared absorption (SEIRA) detection of nine\nvibrational modes of PMMA. We also discuss the tunability of the plasmonic\nresonanceand hence the spectral detection rangeby\nalteration of the size and array parameters of the nanostructures,\nand demonstrate the flexibility of this fabrication method by showing\ndevices made of various substrate and antenna materials.