Fabrication of gold nanostructures using wet lift-off without adhesion promotion

The use of an intervening adhesion layer is essential in reliable fabrication of noble metallic nanostructures for optical and electronic devices. However, many emerging applications such as plasmonics and transfer printing raise the demand of metallic structures without adhesion layers, either to mitigate the plasmon damping or to facilitate the transfer processes. In this work, we systematically investigate the fabrication reliability of adhesion-free lithographic gold nanostructures on Si wafers and gold-coated substrates using a wet lift-off process. According to a large amount of statistical results, we comprehensively evaluate the patterning behavior of metallic nanostructures without adhesion promotion. Analytical modelling and control experiments are carried out to characterize the mechanics of their failure behaviors as a function of morphology and surface property. Our work provides useful information to the nanofabrication community to obtain adhesion-free gold nanostructures for plasmonic and transfer printing applications.