Fabrication of periodic nanostructures for SERS substrates using multi-tip probe-based nanomachining approach

Periodic nanostructures can be used in many fields such as SERS substrate and functional structures in biomedical and power generation devices. Recently, fabrication of periodic nanostructures efficiently has drawn increasing attentions owing to the aforementioned applications. In this study, periodic nanostructures include nanochannels and nanoindentations are machined by using atomic force microscopy (AFM) system with a dual-tip and four-tip probe, respectively. The machining efficiency was improved obviously compared with using conventional single-tip probe. Furthermore, the relationship between the machined depth and the period of the obtained nanostructure was explored in details. The effects of the machining parameters such as feed value and indentation angle on the nanostructure morphologies were also investigated. The Raman spectra of the Rhodamine 6G were measured based on the machined periodic nanostructures. The Raman intensity measured on the nanostructures that were machined with different feed values and depths were compared. Results show that the Raman intensity goes up with the increasing of the machined depth, which proves the SERS substrates are reliable. Our findings are significant for machining a periodic nanostructure with high machining efficiency and providing an approach to prepare SERS substrates.