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Free electron beams that carry high values of orbital angular momentum (OAM) possess large magnetic moments along the propagation direction. This makes them an ideal probe for measuring the electronic and magnetic properties of materials, as well as for fundamental experiments in magnetism. However, their generation requires the use of complex diffractive elements, which usually take the form of nano-fabricated holograms. Here, we show how the limitations of the current fabrication of such holograms can be overcome by using electron beam lithography. We demonstrate experimentally the realization of an electron vortex beam with the largest OAM value that has yet been reported to the first diffraction order (L = 1000 ℏ), paving the way for even more demanding demonstrations and applications of electron beam shaping

Suspended nanostructures (SNSs) are grown by electron beam-induced deposition (EBID) of Pt and tetra-ethyl-ortho-silicate (TEOS) gas precursors on nanopillar tips, by lateral shifting of a scanning electron microscope beam. Shape evolution of SNSs is characterized as a function of electron energy (5, 10, 15 keV) and electron charge deposited per unit length (CDL, 1–9 pC nm−1 range) along the beam track. Pt SNSs grow as single nanowires, evolving from thin (15–20 nm) and horizontal to thick (up to 70 nm) and inclined (up to 60°) geometry as CDL increases. TEOS SNSs consist of multiple nanowires arranged in a stack: horizontal and parallel along the beam shift direction and aligned on top of each other along the beam incidence axis. As the CDL increases, the number of nanowires increases and the top edge of the stack progressively inclines, taking the form of a hand-fan. Deposition yield and overall size of SNSs are found to be proportional to CDL and inversely proportional to electron energy for both Pt and TEOS precursors. As an example of 3D nanoarchitectures achievable by this lateral EBID approach, a ‘nano-windmill’ TEOS structure is presented.

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