Raith (Germany)

Freestanding micro-nanodevices stand out as excellent candidates for the next generation of neural interfaces. Their wireless nature, coupled with their subcellular dimensions, promises to enable minimally invasive neuromodulation with high spatial resolution within three-dimensional tissues. Nevertheless, their practical implementation is hindered by technical challenges. Specifically, fabricating and harvesting freestanding devices with subcellular sizes proves exceedingly difficult, and characterizing their functionality in a representative freestanding configuration presents an even greater challenge. In this work, we present a comprehensive framework for fabricating, collecting, and characterizing freestanding micro-nanodevices to advance progress in neural interfaces. We developed three distinct micro-nanofabrication methods tailored for manufacturing freestanding micro-nanodevices with varying characteristics. These methods include a very large-scale integration process for manufacturing and manipulating freestanding microdevices (2-200 µm) with high throughput, a cell-friendly approach utilizing only biocompatible materials and solvents for rapid microdevice production, and a protocol for fabricating and handling freestanding devices with even smaller size scale (200 nm to 3 µm). We subsequently devised an effective approach to rapidly characterize the electrical modulation capabilities of freestanding micro-nanodevices in a cell-like environment, employing artificial bilayer lipid membranes. We showcased this method by studying the variation of bilayer lipid membrane transmembrane potential in response to a light stimulus when sprinkled with organic semiconductor devices. Ultimately, we established an analytical model of the characterization system to translate experimental findings made with bilayer lipid membrane into single cells. By overcoming the technical limitations hindering the fabrication, manipulation, and characterization of freestanding micro-nanodevices, we hope that our research efforts will contribute to accelerating progress in the development of next-generation neural interfaces and unlock the full potential of neuromodulation technologies in fundamental and clinical research.

Focused ion beam (FIB) processing has been established as a well-suited and promising technique in R&D in nearly all fields of nanotechnology for patterning and prototyping on the micrometer scale and below. Liquid metal alloy ion sources (LMAISs) represent an alternative to expand FIB application fields beyond all other source concepts. In particular, ions from the rare earth (RE) element Dy are very interesting for local modification of magnetic properties like RE-induced damping in metallic alloys. In this article, various alloys for source preparation were investigated. A promising solution was found in a Cu30Dy70 based LMAIS, which will be introduced in more detail.

Optical control of electronic spins is the basis for ultrafast spintronics:\ncircularly polarized light in combination with spin-orbit coupling of the\nelectronic states allows for spin manipulation in condensed matter. However,\nthe conventional approach is limited to spin orientation along one particular\norientation that is dictated by the direction of photon propagation. Plasmonics\nopens new capabilities, allowing one to tailor the light polarization at the\nnanoscale. Here, we demonstrate ultrafast optical excitation of electron spin\non femtosecond time scales via plasmon to exciton spin conversion. By\ntime-resolving the THz spin dynamics in a hybrid (Cd,Mn)Te quantum well\nstructure covered with a metallic grating, we unambiguously determine the\norientation of the photoexcited electron spins which is locked to the\npropagation direction of surface plasmon-polaritons. Using the spin of the\nincident photons as additional degree of freedom, one can orient the\nphotoexcited electron spin at will in a two-dimensional plane.\n

It is reported an enhancement of the transverse magneto-optical Kerr effect (TMOKE) in the vicinity of the excitonic and hybrid plasmon-exciton modes. Such modes are excited in quantum well in the bare diluted semiconductor thin films and in the plasmonic semiconductor nanostructures. Two-order enhancement of the TMOKE is observed in bare semiconductor films in the spectral region of the excitonic resonances. In plasmonic semiconductor nanostructures with quantum wells we also observe the hybridization of the TMOKE spectrum due to excitation of plasmon-exciton modes.

Nano device prototyping (NDP) is essential for realizing and assessing ideas as well as theories in the form of nano devices, before they can be made available in or as commercial products. In this review, application results patterned similarly to those in the semiconductor industry (for cell phone, computer processors, or memory) will be presented. For NDP, some requirements are different: thus, other technologies are employed. Currently, in NDP, for many applications direct write Gaussian vector scan electron beam lithography (EBL) is used to define the required features in organic resists on this scale. We will take a look at many application results carried out by EBL, self-organized 3D epitaxy, atomic probe microscopy (scanning tunneling microscope/atomic force microscope), and in more detail ion beam techniques. For ion beam techniques, there is a special focus on those based upon liquid metal (alloy) ion sources, as recent developments have significantly increased their applicability for NDP.

Miniaturization is the central theme in modern fabrication technology. Many of the components used in modern products are becoming smaller and smaller. The applicability of the standard lithographic technologies to processing the new functional materials is crucial for their successful wide implementation in practice. Recently we have reported experimental design and test of the new generation for nano-mecanical devices like nano-tweezers based on original bilayer Ti 2 NiCu/Pt composite structures. In the present paper it is demonstrated that standard ion beam nano-fabrication technology is quit suitable for full cycle of production operational stages of practical nano-tweezers production. The technological experiments were done on realizing by usage of a novel focused ion beam instrument Raith ionLiNE™ device. This device is a novel focused ion beam instrument for low dose nanolithography and nano-fabrication. ionLiNE™ Raith was applied for experimental composite nano-tweezers production on the base of Ti 2 NiCu/W with length - 30 µm, gap width 0.9 µ. The tests showed high quality of reproduction and long term operation under thermal control at temperature change only 14 K