Facile Process for Fabrication of Silicon Micro-Nanostructures of Different Shapes as Molds for Fabricating Flexible Micro-Nanostructures and Wearable Sensors

We report a method to fabricate silicon micro- nanostructures of different shapes by tuning the number of layers and the sizes of self-assembled polystyrene beads, which serve as the mask, and by tuning the reactive ion etching (RIE) time. This process is simple, scalable, and inexpensive without using any sophisticated nanomanufacturing equipment. Specifically, in this work, we demonstrate the proposed process by fabricating silicon micro-or nanoflowers, micro-or nanobells, nanopyramids, and nanotriangles using a self-assembled monolayer or bilayer of polystyrene beads as the mask. We also fabricate flexible micro- nanostructures by using silicon molds with micro-nanostructures. Finally, we demonstrate the fabrication of bandage-type electrochemical sensors with micro-nanostructured working electrodes for detecting dopamine, a neurotransmitter related to stress and neurodegenerative diseases in artificial sweat. All these demonstrations indicate that the proposed process provides a low-cost, easy to-use approach for fabricating silicon micro-nanostructures and flexible micro-nanostructures, thus paving a way for developing wearable micro-nanostructures enabled sensors for a variety of applications in an efficient manner.

Automated summary

We present a method for fabricating silicon micro-nanostructures of various shapes by manipulating the number and size of self-assembled polystyrene beads as a mask and adjusting the reactive ion etching time. This approach offers a simple, scalable, and cost-effective solution without requiring sophisticated nanomanufacturing equipment. The demonstration of this method includes the fabrication of silicon micro- or nanoflowers, micro- or nanobells, nanopyramids, and nanotriangles using polystyrene beads as a mask, as well as the creation of flexible micro- nanostructures using silicon molds. Furthermore, we showcase the fabrication of bandage-type electrochemical sensors for detecting dopamine in artificial sweat, indicating the potential of this method for developing wearable micro-nanostructure-enabled sensors.