Silver nanostructures embedding in polymethyl methacrylate patterns fabricated using proton beam writing

Proton beam writing (PBW) on polymethyl methacrylate (PMMA) followed by embedding of biosynthesized silver nanoparticles (AgNPs) was investigated. This is the first demonstration of the use of 3 MV Tandetron accelerator at iThemba LABS for fabricating patterns using PBW technique. The irradiation of PMMA was carried out using 3.0-MeV proton beam focused down to micrometer spot size. The fluence of protons was counted as electrical charge per unit monitored by exposure time, beam current, and irradiated area. As expected, the PMMA behaved as a positive resist because of chain scissioning induced from the interaction with proton beam. Morphological characterization using scanning electron microscope (SEM) revealed fabrication of square-like patterns, and atomic force microscopy (AFM) provided the possibility of observing the presence of AgNPs that stood out of the PMMA matrix.