Photolithography-assisted precise patterning of nanocracks for ultrasensitive strain sensors

Abstract

Nanocracking is an unconventional high-throughput nanofabrication technique for making a variety of nano materials and nano devices such as ultrasensitive sensors. However, this technique is yet to be practically applied because it is limited by the less controllability and low repeatability of the nanocrack pattern. Here we report a photolithography-assisted nanocrack patterning (PAnCP) method to precisely define the nanocrack pattern in a metal film. The strain distribution of the metal film was well structured as designed using standard photolithography, so arbitrary nanocrack patterns can be simply fabricated with a high repeatability, such as 50 mm-long parallel straight nanocracks with any desired densities, or various shaped patterns. We further developed a nanocrack-based strain sensor and achieved a gauge factor of ∼20 000 in 0–1.2% strain range, which is the highest ever reported in this strain range. The PAnCP method has great potential to be applied for mass production of various nanocrack-based materials and devices due to its superior simplicity, controllability and repeatability.