Direct imprinting of porous substrates: a rapid and low-cost approach for patterning porous nanomaterials.

This work describes a technique for one-step, direct patterning of porous nanomaterials, including insulators, semiconductors, and metals without the need for intermediate polymer processing or dry etching steps. Our process, which we call "direct imprinting of porous substrates (DIPS)", utilizes reusable stamps with micro- and nanoscale features that are applied directly to a porous material to selectively compress or crush the porous network. The stamp pattern is transferred to the porous material with high fidelity, vertical resolution below 5 nm, and lateral resolution below 100 nm. The process is performed in less than one minute at room temperature and at standard atmospheric pressure. We have demonstrated structures ranging from subwavelength optical components to microparticles and present exciting avenues for applications including surface-enhanced Raman spectroscopy (SERS), label-free biosensors, and drug delivery.