In Situ Direct-Write Materials Processing Methods in Electron Microscopes

Focused beam induced processing holds great promise for advanced nanoscale device design and prototyping but often has severe limitations in material quality, purity and compatibility. In particular focused electron beam induced deposition (FEBID) can create 3D nanostructures of extremely complex geometries, but the deposited material purity is often very low (< 10% metal). Ex situ functionalization processes, such as sputter coating, do not conformally coat the nanostructures but instead apply pure material from the top down. Here, a laser based photothermal coating method leveraging the geometry-dependent thermal transport properties is used to apply high-quality pure material conformally coat the exposed nanostructures and is not limited to a specific nanostructure or substrate material. Additionally, focused electron beam induced etching (FEBIE) is used to investigate a low damage, chemical etching process of the transition metal dichalcogenide MoS₂ [Molybdenum disulfide] in contrast to more common, but much more damaging physical methods like focused ion beam (FIB) patterning. Experimental techniques such as scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS/EDX), Raman and photoluminescence spectroscopy are used to fully characterize the investigated processes and materials. Additionally, finite element modeling (FEM) and automated SEM video analysis are employed to investigate the time dependent dynamics of the processes.