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The origin of micrometeorites (MMs) from asteroids and comets is well-established, but the relative contribution from these two classes remains poorly resolved. Likewise, determining the precise origin of individual micrometeorites is an open challenge. Here, cosmic-ray exposure ages are used to resolve the spatial origins of twelve MMs collected from urban areas and Antarctica. Their 26Al and 10Be concentration, produced during cosmic-ray irradiation in space, were measured by accelerator mass spectrometry. These data are compared to results from a model simulating the transport and irradiation of the MM precursors in space. This model, for the first time, considers a variety of orbits, precursor particle sizes, compositions, and densities and incorporates non-isotropic solar and galactic cosmic-ray flux profiles, depth-dependent production rates, as well as spherical evaporation during atmospheric entry. While the origin for six MMs remains ambiguous, two MMs show a preferential tendency towards an origin in the Inner Solar System (Near Earth Objects to the Asteroid Belt) and four towards an origin in the Outer Solar System (Jupiter Family Comets to the Kuiper Belt). These findings challenge the notion that dust originating from the Outer Solar System is unlikely to survive long-term transport and delivery to the terrestrial planets.

The focused ion beam (FIB) is a powerful tool for fabrication, modification, and characterization of materials down to the nanoscale. Starting with the gallium FIB, which was originally intended for photomask repair in the semiconductor industry, there are now many different types of FIB that are commercially available. These instruments use a range of ion species and are applied broadly in materials science, physics, chemistry, biology, medicine, and even archaeology. The goal of this roadmap is to provide an overview of FIB instrumentation, theory, techniques, and applications. By viewing FIB developments through the lens of various research communities, we aim to identify future pathways for ion source and instrumentation development, as well as emerging applications and opportunities for improved understanding of the complex interplay of ion–solid interactions. We intend to provide a guide for all scientists in the field that identifies common research interest and will support future fruitful interactions connecting tool development, experiment, and theory. While a comprehensive overview of the field is sought, it is not possible to cover all research related to FIB technologies in detail. We give examples of specific projects within the broader context, referencing original works and previous review articles throughout.

The focused ion beam (FIB) is a powerful tool for fabrication, modification, and characterization of materials down to the nanoscale. Starting with the gallium FIB, which was originally intended for photomask repair in the semiconductor industry, there are now many different types of FIB that are commercially available. These instruments use a range of ion species and are applied broadly in materials science, physics, chemistry, biology, medicine, and even archaeology. The goal of this roadmap is to provide an overview of FIB instrumentation, theory, techniques, and applications. By viewing FIB developments through the lens of various research communities, we aim to identify future pathways for ion source and instrumentation development, as well as emerging applications and opportunities for improved understanding of the complex interplay of ion–solid interactions. We intend to provide a guide for all scientists in the field that identifies common research interest and will support future fruitful interactions connecting tool development, experiment, and theory. While a comprehensive overview of the field is sought, it is not possible to cover all research related to FIB technologies in detail. We give examples of specific projects within the broader context, referencing original works and previous review articles throughout.

The ongoing miniaturization has reached a point where dopants, impurities or active impurities reach the quantum limit, making deterministic single ion implantation (SII) indispensable. Moreover, applications in quantum computing, spintronics, and magnonics require at the same time, a very precise spatial placement of these implants. Other requirements for such an implantation system would be a wide range of available ion species, the ability to implant at extremely low fluence as well as low voltage operation. Our new system, named Tibussii, is expected to address all of these requirements. It will be the first UHV system to include a liquid metal alloy ion source (LMAIS) focused ion beam (FIB) column, a plasma FIB, and a scanning electron microscope (SEM). The 4-nm SEM will be used for damage-free navigation, orientation and inspection. Both FIB columns are mass-separated columns with three Einzellenses, a chicane for neutral particles, and additional blankers and features optimized for single ion implantation. We will show the current status of the system, which is currently being installed and further developed by HZDR and Orsay Physics. To verify the implantation of single ions, we are currently developing a secondary electron (SE) detection system with a sensitivity close to unity. It will be based on a semiconductor detector and is expected to surpass the detection efficiency of existing systems based on electron multiplication, such as channeltrons or microchannel plates.

The focused ion beam (FIB) is a powerful tool for fabrication, modification, and characterization of materials down to the nanoscale. Starting with the gallium FIB, which was originally intended for photomask repair in the semiconductor industry, there are now many different types of FIB that are commercially available. These instruments use a range of ion species and are applied broadly in materials science, physics, chemistry, biology, medicine, and even archaeology. The goal of this roadmap is to provide an overview of FIB instrumentation, theory, techniques, and applications. By viewing FIB developments through the lens of various research communities, we aim to identify future pathways for ion source and instrumentation development, as well as emerging applications and opportunities for improved understanding of the complex interplay of ion–solid interactions. We intend to provide a guide for all scientists in the field that identifies common research interest and will support future fruitful interactions connecting tool development, experiment, and theory. While a comprehensive overview of the field is sought, it is not possible to cover all research related to FIB technologies in detail. We give examples of specific projects within the broader context, referencing original works and previous review articles throughout.

Broad ion beams have shown their wide applications for materials modification. Focused ion beams can be used in a similar way while simultaneously providing process monitoring. Here, we demonstrate this on a new kind of ion-induced structural evolution. Sub-micrometer Sn spheres were irradiated in a helium ion microscope with a sub-nm beam of 30 keV He ions. Above a fluence of ~10^17/cm², Sn extrusions appeared on the surface of the spheres, which were imaged using the secondary electron signal. Initially, small, pyramid-like faceted extrusions form at the equator of the spheres (north pole pointing to the ion source). Later, each sphere becomes completely covered by the extrusions. A model was developed that assumes that each He ion generate ~70 Frenkel pairs. The implanted helium atoms, interstitials, and vacancies will be confined by the oxide skin of the spheres. Some He atoms will occupy vacancies, which partially prevent their recombination with interstitials. Furthermore, the ion irradiation leads to erosion and opening of the SnO skin. The interstitials can now escape from the interior of the Sn sphere and form an epitaxial regular Sn lattice on the exterior. Transmission electron microscopy, Auger electron spectroscopy as well as TRI3DYN [1] and 3D kinetic lattice Monte Carlo [2] simulations support these findings. In addition, we provide a perspective on focused ion beams from our in-house development and production of liquid metal alloy ion sources, which can be used for applications from self-organized patterning, over altering magnetic or electrical properties, to quantum photonics and computation [3]. [1] Möller, Nucl. Instr. Meth. B 322 (2014) 23 [2] Strobel et al., Phys. Rev. B 64 (2001) 245422 [3] www.hzdr.de/fib

Laterally resolved polymoprh conversion in Galliumoxide using Focused Ion Beams

We present results for direct maskless magnetic patterning of ferromagnetic nanostructures using a special liquid metal alloy ion source for focused ion beam (FIB) systems. We used a Co36Nd64 alloy as the FIB source [1]. A Wien mass filter allows for quick switching between the ion species in the alloy without changing the FIB source. A 5000×1000×50 nm3 permalloy strip served as the sample. Using the FIB we implanted a 300-nm-wide track with Co ions (see Fig.1). We observed the Co-induced changes by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. This allows for easy magnetic modification of edge-localized spin waves. In another set of samples, we implanted Dy ions to locally increase the damping in a stripe pattern of ~120-nm-wide strips with 400 nm periodicity on a total area of 1×1 mm². Thus, the Gilbert damping parameter can be easily increased by one order of magnitude with a lateral resolution of about 100 nm. In contrast to electron beam lithography in combination with broad-beam ion implantation, the maskless FIB process does not require the cumbersome and difficult removal of the ion-hardened resist if optical measurements like BLS or TR-MOKE are needed.

RBS as one of the most widely used IBA methods requires a rather high beam fluence due to the small backscattering cross-section. Although the lack of measurement statistics can be compensated by a longer measurement time, this can only be applied to macroscopic beam spots and is not possible for sensitive samples or in a micro beam setup. Larger detectors are an easy means to increase the covered solid angle, however this is limited in terms of kinematic broadening and decreasing energy resolution due to increasing detector capacitance [1]. Multi-detector setups overcome this limitation and are attracting increasing interest in various laboratories. Geometric constraints, mechanical robustness, the cost of multiple MCA systems, as well as the difficulty of simultaneously analyzing data from the individual detectors make this a difficult but worthwhile endeavor. In this contribution, we report on our recently commissioned setup - namely, the "RBS hedgehog" located at the 3 MV tandem accelerator of the HZDR’ Ion Beam Center. The setup is equipped with 78 independent RBS detectors arranged in 5 concentric rings with backscattering angles from 165° to 105° covering a total solid angle of 680 msr - equivalent to 34% of the total backscatter angle. The 78 independent MCA systems can handle up to 8 Mega counts per second. The presentation will start with an introduction to RBS technique, it’s advantages and disadvantages. It will be followed by a theoretical design study of the influence of different detector configurations on the kinematic broadening for different energies and ion species. We then introduction the used in-house designed and fabricated PIPS detectors and MCA systems and present initial experimental results for various projectiles and energies. Finally, we will illustrate its power at a future application of ion beam induced phase transformation in Ga2O3 [2]. [1] Klingner, N., et al. (2013), Optimizing the Rutherford Backscattering Spectrometry setup in a

High-entropy alloys (HEAs) are a relatively new class of metal alloys composed of several principal elements, usually at (near) equiatomic ratios. Our goal is to understand how such a multicomponent alloy behaves under irradiation. The FeCoCrNiV HEA exhibits both a face-centred cubic (fcc) and a body-centred tetragonal (bct) phase, thus allowing us to specifically study the influence of crystalline structure at very similar chemical composition. We irradiated both phases with a focussed He beam provided by a helium ion microscope (HIM) at temperatures between room temperature and 500∘C. The irradiation fluence was varied between 6× 1017 ions/cm2 and 1× 1020 ions/cm2. High-resolution images of the irradiated areas were taken with the same HIM. Selected irradiated areas were additionally studied by TEM in combination with EDXS. Under irradiation, pores start to be generated in the material with pore sizes differing significantly between the two phases. At higher fluences and above a critical temperature, a tendril structure forms in both phases. We found that the critical temperature depends on the phase and is lower for fcc. TEM images reveal that the tendrils span the whole depth of the irradiated area, and are accompanied by bubbles of various sizes. Scanning TEM-based EDXS of these structures indicates a He-induced change in composition.

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many approaches lack the required spatial placement accuracy and Si technology compatibility required for many of the envisioned applications. Here, we present a method to place single or few SPEs emitting in the telecom O-band1. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit for which this work lays the foundations. To achieve our goal, we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabrication methods have been irradiated with Si++ 40 keV ions in a spot pattern of 6 to 500 ions per spot. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom with a zero phonon lines (ZPL) at 1278 nm have been created in carbon rich SOI wafers. In ultra clean SOI wafers W-centers, a tri-interstitial Si complex has been created with a ZPL at 1218 nm. The achieved lateral SPE placement accuracy is below 50 nm in both cases and the success rate of SPE formation is more than 50%. Finally, we give an overview on possible other applications and give an outlook on future projects and instrumentation developments. 1Hollenbach, M., Klingner, N., Jagtap, N.S. et al. Wafer-scale nanofabrication of telecom single-photon emitters in silicon. Nature Communications 13, 7683 (2022). https://doi.org/10.1038/s41467-022-35051-5

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many approaches lack the required spatial placement accuracy and Si technology compatibility required for many of the envisioned applications. Here, we present a method to place single or few SPEs emitting in the telecom O-band1. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit for which this work lays the foundations. To achieve our goal, we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabrication methods have been irradiated with Si++ 40 keV ions in a spot pattern of 6 to 500 ions per spot. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom with a zero phonon lines (ZPL) at 1278 nm have been created in carbon rich SOI wafers. In ultra clean SOI wafers W-centers, a tri-interstitial Si complex has been created with a ZPL at 1218 nm. The achieved lateral SPE placement accuracy is below 50 nm in both cases and the success rate of SPE formation is more than 50%. Finally, we give an overview on possible other applications and give an outlook on future projects and instrumentation developments. 1Hollenbach, M., Klingner, N., Jagtap, N.S. et al. Wafer-scale nanofabrication of telecom single-photon emitters in silicon. Nature Communications 13, 7683 (2022). https://doi.org/10.1038/s41467-022-35051-5

Single photon emitters (SPE) are the starting point and foundation for future photonic quantum technologies. We present the laterally controlled fabrication of single G and W centers in silicon that emit in the telecom O-band. We utilized home built gold-silicon liquid metal alloy ion sources (LMAIS) in a focused ion beam (FIB) system to perform mask-free implantation of 40 keV Si ions from 6 to 500 ions per spot. Analysis and confirmation of SPEs has been done in a home-build cryo-photoluminescence setup. We will demonstrate a success rate of more than 50% and upscaling to wafer-scale. We will also provide an insight and overview on the LMAIS technology and an outlook on other potential applications of FIB implantation.

I will present some recent results on the high fluence irradiation of metals using gas field ion source (GFIS) based helium ion microscope (HIM)1 . High entropy alloys (HEAs) are a relatively new class of metal alloys composed of several principal elements, usually at (near) equiatomic ratios. Here, our goal is to understand how such a multicomponent alloy behaves under irradiation. The FeCoCrNiV HEA exhibits both a face-centred cubic (fcc) and a body-centred tetragonal (bct) phase, thus allowing us to specifically study the influence of crystalline structure at very similar chemical composition. We irradiated both phases with a focussed He beam provided by a HIM at temperatures between room temperature and 500 ∘ C. The irradiation fluence was varied between 6 × 1017 ions cm−2 to 1 × 1020 ions cm−2 . High-resolution images of the irradiated areas were taken with the same HIM. Selected irradiated areas were additionally studied by transmission electron microscopy (TEM) in combination with energy dispersive X-ray spectroscopy (EDXS). Under irradiation, pores start to be generated in the material with pore sizes differing significantly between the two phases. At higher fluences and above a critical temperature, a tendril structure forms in both phases. We found that the critical temperature depends on the phase and is lower for fcc. TEM images reveal that the tendrils span the whole depth of the irradiated area, and are accompanied by bubbles of various sizes. Scanning TEM-based EDXS of these structures indicates a He-induced change in composition. In the second part I want to present an intriguing observation shedding light on the fundamental processes related to interstitial diffusion during irradiation. I will show how epitaxial growth of tin extrusions on tin-oxide-covered tin spheres can be induced and simultaneously observed by implanting helium using a HIM2 . Calculations of collision cascades based on the binary collision approximation (BCA) and 3D-lattice-kine

In this study, we propose the development of a purely silicon-based photonic enhanced single photon emitter that can be optically or electrically pumped. Its design is based on an introduction of near-infrared (NIR) single photon emitting color centers in silicon photonic resonators and diodes by focused ion beams and high energy ion implantation. Color centers will deterministically be implanted in positions of guided high-Q modes to ensure an efficient optical coupling and to enhance the single photon purity, photon indistinguishability and brightness of the device. Implanted species to be tested in the experiments are C and Si that create various NIR single photon emitting centers in silicon.

Since the first reports on intrinsically magnetic two-dimensional (2D) materials in 2017 [1,2], the price-to-pay for accessing their monolayers is still the lack of ambient stability. Recently, we demonstrated weak ferromagnetism in 2D Fe:talc at room temperature and proposed iron-rich phyllosilicates as a promising platform for air-stable magnetic monolayers [3]. Since these minerals are rather rare and since phyllosilicates are hard to synthesize, we suggest here as an alternative ion implantation to tailor the magnetic properties of the phyllosilicates. Nonmagnetic, single-crystalline bulk talc crystals [4] were implanted with 50 keV iron and cobalt ion beams at different substrate temperatures. In all cases, ultra-thin layers could be exfoliated indicating that the layered crystal structure is maintained after ion irradiation. For both ion species, the Mg-OH Raman peak showed a triplet formation implying a successful substitution of Mg by Fe or Co in the talc layers. [1] Gong, C., et al., Nature 546, 265 (2017). [2] Huang, B., et al., Nature 546, 270 (2017). [3] A. Matković, et al., npj 2D Mat. Appl. 5, 94 (2021). [4] B. Vasić, et al., Nanotechnology 32, 265701 (2021).

The ongoing miniaturization has reached a point where dopants, impurities or active impurities reach the quantum limit, making deterministic single ion implantation (SII) indispensable. Moreover, applications in quantum computing, spintronics, and magnonics require at the same time, a very precise spatial placement of these implants. Other requirements for such an implantation system would be a wide range of available ion species, the ability to implant at extremely low fluence as well as low voltage operation. Our new system, named Tibussii, is expected to address all of these requirements. It will be the first UHV system to include a liquid metal alloy ion source (LMAIS) focused ion beam (FIB) column, a plasma FIB, and a scanning electron microscope (SEM). The 4-nm SEM will be used for damage-free navigation, orientation and inspection. Both FIB columns are mass-separated columns with three Einzellenses, a chicane for neutral particles, and additional blankers and features optimized for single ion implantation. We will show the current status of the system, which is currently being installed and further developed by HZDR and Orsay Physics. To verify the implantation of single ions, we are currently developing a secondary electron (SE) detection system with a sensitivity close to unity. It will be based on a semiconductor detector and is expected to surpass the detection efficiency of existing systems based on electron multiplication, such as channeltrons or microchannel plates.

The focused ion beam (FIB) is a powerful tool for fabrication, modification, and characterization of materials down to the nanoscale. Starting with the gallium FIB, which was originally intended for photomask repair in the semiconductor industry, there are now many different types of FIB that are commercially available. These instruments use a range of ion species and are applied broadly in materials science, physics, chemistry, biology, medicine, and even archaeology. The goal of this roadmap is to provide an overview of FIB instrumentation, theory, techniques, and applications. By viewing FIB developments through the lens of various research communities, we aim to identify future pathways for ion source and instrumentation development, as well as emerging applications and opportunities for improved understanding of the complex interplay of ion–solid interactions. We intend to provide a guide for all scientists in the field that identifies common research interest and will support future fruitful interactions connecting tool development, experiment, and theory. While a comprehensive overview of the field is sought, it is not possible to cover all research related to FIB technologies in detail. We give examples of specific projects within the broader context, referencing original works and previous review articles throughout.

The ongoing miniaturization has reached a point where dopants, impurities or active impurities reach the quantum limit, making deterministic single ion implantation (SII) indispensable. Moreover, applications in quantum computing, spintronics, and magnonics require at the same time, a very precise spatial placement of these implants. Other requirements for such an implantation system would be a wide range of available ion species, the ability to implant at extremely low fluence as well as low voltage operation. Our new system, named Tibussii, is expected to address all of these requirements. It will be the first UHV system to include a liquid metal alloy ion source (LMAIS) focused ion beam (FIB) column, a plasma FIB, and a scanning electron microscope (SEM). The 4-nm SEM will be used for damage-free navigation, orientation and inspection. Both FIB columns are mass-separated columns with three Einzellenses, a chicane for neutral particles, and additional blankers and features optimized for single ion implantation. We will show the current status of the system, which is currently being installed and further developed by HZDR and Orsay Physics. To verify the implantation of single ions, we are currently developing a secondary electron (SE) detection system with a sensitivity close to unity. It will be based on a semiconductor detector and is expected to surpass the detection efficiency of existing systems based on electron multiplication, such as channeltrons or microchannel plates.

Gallium oxide is a novel ultra-wide band gap material, and the rationale for the current research project is that its thin film fabrication technology is immature. In particular, the metastability conditions are difficult to control during sequential deposition of different polymorphs with existing techniques. However, the polymorphism may turn into a significant advantage if one can gain control over the polymorph multilayer and nanostructure design. Our objective is to develop a method for the controllable solid state polymorph conversion of gallium oxide assisted by ion irradiation. This fabrication method may pave the way for several potential applications (e.g. in power electronics, optoelectronics, thermoelectricity batteries) and we will test the corresponding functionalities during the project. Thus, we envisage multiple positive impacts and potential benefits across a wide range of stakeholders. I will introduce the aims and objectives of project paying specific attention to the planned methodology to gain spatial control over the polymorph conversion. In the second half I will present the first results obtained in the last 5 month. This includes broad beam irradiation which confirms the successful polymorph conversion independent of primary ion species and the related exceptional radiation tolerance of the formed g-Ga2 O3 layer. Further I will report the first spatially resolved focused ion beam (FIB) induced b- to g-Ga2 O3 polymorph conversion. For this result different FIBs—available at the Ion Beam Center—have been used. These are in particular the Helium Ion Microscope (HIM) using Neon ions, a conventional Gallium liquid metal ion source (LMIS) based FIB as well as a liquid metal alloy ion source (LMAIS) FIB using Co ions. The confirmation of the latter result also required the test and optimization of an electron backscatter diffraction (EBSD) based analysis method. I will end with an outlook on experiments foreseen for the rest of the project duratio

Radiation tolerance is determined as an ability of crystalline materials to withstand the accumulation of the radiation induced disorder. Based on the magnitudes of such disorder levels, semiconductors are commonly grouped into the low- or high-radiation tolerant. Nevertheless, upon exposing to sufficiently high fluences, in all cases known by far, it ends up with either extremely high disorder levels or amorphization. Here we show that gamma/beta double polymorph Ga2O3 structures exhibit unprecedently high radiation tolerance. Specifically, for room temperature experiments, they tolerate a disorder equivalent to hundreds of displacements per atom, without severe degradations of crystallinity; in comparison with, e.g., Si amorphizable already with the lattice atoms displaced just once. We explain this behavior by an interesting combination of the Ga- and O-sublattice properties in gamma-Ga2O3. In particular, O-sublattice exhibits a strong recrystallization trend to recover the face-centered-cubic stacking despite high mobility of O atoms in collision cascades compared to Ga. Concurrently, the characteristic structure of the Ga-sublattice is nearly insensitive to the accumulated disorder. Jointly it explains macroscopically negligible structural deformations in gamma-Ga2O3 observed in experiment. Notably, we also explained the origin of the beta-to-gamma Ga2O3 transformation, as a function of increased disorder in beta-Ga2O3 and studied the phenomena as a function of the chemical nature of the implanted atoms. As a result, we conclude that gamma-beta double polymorph Ga2O3 structures, in terms of their radiation tolerance properties, benchmark a new class of universal radiation tolerant semiconductors.

We present results of direct maskless magnetic patterning of ferromagnetic nanostructures using a cobalt focused ion beam (FIB) system. The liquid metal ion source of the FIB was made of a Co36Nd64 alloy. A Wien mass filter allows for selecting the ion species. Using the FIB, we implanted narrow tracks of Co ions into a nominal 5000×1000×50 nm3 permalloy strip. We observed the Co-induced changes of the magnetic properties by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Regions as small as 50 nm can be implanted up to concentrations of at.-10 % near the surface. This allows for easy magnetic modification of edge-localized spin waves with a lateral resolution otherwise hard to reach. The direct-write maskless FIB process is quick and convenient for optical measurement techniques, as it does not involve the virtually impossible removal of ion-hardened resist masks one would face when using lithography with broad-beam ion implantation

A review of single photon emitters in silicon based on ion-induced defects is provided. Fabrication methods and current state of the art are discussed.

Single-photon emitters (SPEs) are one of the elementary building blocks for photonic quantum information and optical quantum computing. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements, and single-photon detection on a silicon chip in a controllable manner. Particularly, fully integrated SPEs on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits. The major challenge in realizing a fully monolithic, photonic integrated circuitry lies in the development of a quantum light source in silicon since the indirect nature of the small energy bandgap does not allow for efficient PL emission. Nevertheless, below-bandgap light emission can be used for good advantage by exploiting extrinsic and intrinsic point defects acting as SPEs. Indeed, the isolation of SPEs, such as G-, W-, and T-centers, in the optical telecommunication O-band has been recently realized in silicon.. In all these cases, however, SPEs were created uncontrollably in random locations, preventing their scalability. We present mask-free nanofabrication involving a quasi-deterministic creation of single G- and W-centers in silicon wafers using focused-ion beam (FIB) writing. We also implement a scalable, broad-beam implantation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabricate telecom SPEs at desired positions on the nanoscale.

Single-photon emitters (SPEs) are one of the elementary building blocks for photonic quantum information and optical quantum computing. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements, and single-photon detection on a sili- con chip in a controllable manner. Particularly, fully integrated SPEs on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits. The major challenge in realizing a fully monolithic, photonic integrated circuitry lies in the development of a quantum light source in silicon since the indirect nature of the small energy bandgap does not allow for efficient PL emission. Nev- ertheless, below-bandgap light emission can be used for good advantage by exploiting extrinsic and intrinsic point defects acting as SPEs. Indeed, the isolation of SPEs, such as G-, W-, and T-centers, in the optical telecom- munication O-band has been recently realized in silicon [1-4]. In all these cases, however, SPEs were created uncontrollably in random locations, preventing their scalability. We present mask-free nanofabrication involving a quasi-deterministic creation of single G- and W-centers in silicon wafers using focused-ion beam (FIB) writing. We also implement a scalable, broad-beam implan- tation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabri- cate telecom SPEs at desired positions on the nanoscale [5]. [1] M. Hollenbach et al., Optics Express 28, 26111 (2020) [2] W. Redjem et al., Nature Electronics 3, 738 (2020) [3] Y. Baron et al., ACS Photonics 9, 2337 (2022) [4] D. B. Higginbottom et al., Nature 607, 266 (2022) [5] M. Hollenbach et al., Nat. Commun. 13, 7683 (2022)

EBSD data and irradiation parameters

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many ap- proach lack the required spatial placement accuracy and Si tech- nology compatibility required for many of the envisioned applica- tions. Here, we present a method to fabricate at will placed single or few SPEs emitting in the telecom O-band in Silicon [1] . The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way to- ward a monolithic, all-silicon-based semiconductor-supercon- ductor quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabri- cation methods have been irradiated with a spot pattern. 6 to 500 Si2+ ions have been implanted per spot using an energy of 40 keV. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom are confirmed by measurements of zero phonon lines (ZPL) at the expected wave length of 1278 nm for the case of carbon rich SOI wafers. In the case of ultra clean SOI wafers and high ion fluxes emission from tri-interstitial Si complexes is observed. The SPE nature of these so called W-centers has also been confirmed by ZPL measurements at 1218 nm. The achieved lateral SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than 50%. After a discus- sion of the formation statistic we also present an approach how our FIB based approach can be upscaled to wafer-scale nanofabrication of telecom SPEs compatible with complementary metal oxide semiconductor (CMOS) technology for very large scale integration (VLSI).

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many ap- proach lack the required spatial placement accuracy and Si tech- nology compatibility required for many of the envisioned applica- tions. Here, we present a method to fabricate at will placed single or few SPEs emitting in the telecom O-band in Silicon [1] . The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way to- ward a monolithic, all-silicon-based semiconductor-supercon- ductor quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabri- cation methods have been irradiated with a spot pattern. 6 to 500 Si2+ ions have been implanted per spot using an energy of 40 keV. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom are confirmed by measurements of zero phonon lines (ZPL) at the expected wave length of 1278 nm for the case of carbon rich SOI wafers. In the case of ultra clean SOI wafers and high ion fluxes emission from tri-interstitial Si complexes is observed. The SPE nature of these so called W-centers has also been confirmed by ZPL measurements at 1218 nm. The achieved lateral SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than 50%. After a discus- sion of the formation statistic we also present an approach how our FIB based approach can be upscaled to wafer-scale nanofabrication of telecom SPEs compatible with complementary metal oxide semiconductor (CMOS) technology for very large scale integration (VLSI).

Most approaches to implant single or few ions for quantum applications require the use of focused ion beams (FIB). In addition to the detection of ion implantation and laterally precise placement, the first consideration should also be the species as well as the emittance of the ion beam itself. While elements that are gaseous at room temperature can mainly provided by Gas Field Ion Sources or Plasma Ion Sources, most of the metals and semimetals afford the utilization of Liquid Metal Ion Sources (LMIS). Gallium has established in industry and science as easiest and most stable type of LMIS. For quantum applications other ion species like Li, B, C, N, Al, Si, P, Sb, Bi or the rare earth elements became from higher interest [1-6]. We give an overview about published metal alloys for FIBs and give an insight into the development and production of new sources. Finally, we give an outlook on current and future applications and activities. [1] L. Bischoff, et al., Micro Eng. 13, 367 (1991), 10.1016/0167-9317(91)90113-R [2] P. Mazarov, et al., JVST B 27, L47-L49 (2009), 10.1116/1.3253471 [3] L. Bischoff, et al., Appl. Phys. Rev. 3, 021101 (2016), 10.1063/1.4947095 [4] W. Pilz, et al., JVST B 37, 021802 (2019), 10.1116/1.5086271 [5] L. Bischoff, et al., JVST B 38, 042801 (2020), 10.1116/6.0000073 [6] N. Klingner, et al., BJNANO 11, 1742 (2020), 10.3762/bjnano.11.156

We present results for direct maskless magnetic patterning of ferromagnetic nanostructures using a special liquid metal alloy ion source for focused ion beam (FIB) systems. We used a Co36Nd64 alloy as the FIB source [1]. A Wien mass filter allows for quick switching between the ion species in the alloy without changing the FIB source. A 5000×1000×50 nm3 permalloy strip served as the sample. Using the FIB we implanted a 300-nm-wide track with Co ions (see Fig.1). We observed the Co-induced changes by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. This allows for easy magnetic modification of edge-localized spin waves. In another set of samples, we implanted Dy ions to locally increase the damping in a stripe pattern of ~120-nm-wide strips with 400 nm periodicity on a total area of 1×1 mm². Thus, the Gilbert damping parameter can be easily increased by one order of magnitude with a lateral resolution of about 100 nm. In contrast to electron beam lithography in combination with broad-beam ion implantation, the maskless FIB process does not require the cumbersome and difficult removal of the ion-hardened resist if optical measurements like BLS or TR-MOKE are needed.

Broad ion beams have shown their wide applications for materials modification. Focused ion beams can be used in a similar way while simultaneously providing process monitoring. Here, we demonstrate this on a new kind of ion-induced structural evolution. Sub-micrometer Sn spheres were irradiated in a helium ion microscope with a sub-nm beam of 30 keV He ions. Above a fluence of ~10^17/cm², Sn extrusions appeared on the surface of the spheres, which were imaged using the secondary electron signal. Initially, small, pyramid-like faceted extrusions form at the equator of the spheres (north pole pointing to the ion source). Later, each sphere becomes completely covered by the extrusions. A model was developed that assumes that each He ion generate ~70 Frenkel pairs. The implanted helium atoms, interstitials, and vacancies will be confined by the oxide skin of the spheres. Some He atoms will occupy vacancies, which partially prevent their recombination with interstitials. Furthermore, the ion irradiation leads to erosion and opening of the SnO skin. The interstitials can now escape from the interior of the Sn sphere and form an epitaxial regular Sn lattice on the exterior. Transmission electron microscopy, Auger electron spectroscopy as well as TRI3DYN [1] and 3D kinetic lattice Monte Carlo [2] simulations support these findings. In addition, we provide a perspective on focused ion beams from our in-house development and production of liquid metal alloy ion sources, which can be used for applications from self-organized patterning, over altering magnetic or electrical properties, to quantum photonics and computation [3]. [1] Möller, Nucl. Instr. Meth. B 322 (2014) 23 [2] Strobel et al., Phys. Rev. B 64 (2001) 245422 [3] www.hzdr.de/fib

We present results for direct maskless magnetic patterning of ferromagnetic nanostructures using a special liquid metal alloy ion source for focused ion beam (FIB) systems. We used a Co36Nd64 alloy as the FIB source [1]. A Wien mass filter allows for quick switching between the ion species in the alloy without changing the FIB source. A 5000×1000×50 nm3 permalloy strip served as the sample. Using the FIB we implanted a 300-nm-wide track with Co ions (see Fig.1). We observed the Co-induced changes by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. This allows for easy magnetic modification of edge-localized spin waves. In another set of samples, we implanted Dy ions to locally increase the damping in a stripe pattern of ~120-nm-wide strips with 400 nm periodicity on a total area of 1×1 mm². Thus, the Gilbert damping parameter can be easily increased by one order of magnitude with a lateral resolution of about 100 nm. In contrast to electron beam lithography in combination with broad-beam ion implantation, the maskless FIB process does not require the cumbersome and difficult removal of the ion-hardened resist if optical measurements like BLS or TR-MOKE are needed.

Single-photon sources are one of the elementary building blocks for photonic quantum information and optical quantum computing [1]. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements and single-photon detection on a silicon chip in a controllable manner. Particularly, fully integrated single-photon emitters on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits [2]. This work presents a mask-free nanofabrication method involving a quasi-deterministic creation of scalable extrinsic color centers in silicon emitting in the optical telecom O-band [3] on a commercial silicon-on-insulator platform using focused ion beam writing. We also show the local writing of an intrinsic color center in silicon, which is linked to a tri-interstitial complex and reveals quantum emission close to the telecom band [4]. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars [5] and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit. [1]D. D. Awschalom et al.,Nature Photonics 12,516 (2018) [2]J. C. Adcock et al.,IEEE, 27, 2, (2021) [3]M. Hollenbach et al.,Optics Express 28,26111 (2020) [4]Y. Baron et al.,arXiv:2108.04283 (2021) [5]M. Hollenbach et al.,arXiv:2112.02680 (2021)

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many ap- proach lack the required spatial placement accuracy and Si tech- nology compatibility required for many of the envisioned applica- tions. Here, we present a method to fabricate at will placed single or few SPEs emitting in the telecom O-band in Silicon [1] . The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way to- ward a monolithic, all-silicon-based semiconductor-supercon- ductor quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabri- cation methods have been irradiated with a spot pattern. 6 to 500 Si2+ ions have been implanted per spot using an energy of 40 keV. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom are confirmed by measurements of zero phonon lines (ZPL) at the expected wave length of 1278 nm for the case of carbon rich SOI wafers. In the case of ultra clean SOI wafers and high ion fluxes emission from tri-interstitial Si complexes is observed. The SPE nature of these so called W-centers has also been confirmed by ZPL measurements at 1218 nm. The achieved lateral SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than 50%. After a discus- sion of the formation statistic we also present an approach how our FIB based approach can be upscaled to wafer-scale nanofabrication of telecom SPEs compatible with complementary metal oxide semiconductor (CMOS) technology for very large scale integration (VLSI).

Most approaches to implant single or few ions for quantum applications require the use of focused ion beams (FIB). In addition to the detection of ion implantation and laterally precise placement, the first consideration should also be the species as well as the emittance of the ion beam itself. While elements that are gaseous at room temperature can mainly provided by Gas Field Ion Sources or Plasma Ion Sources, most of the metals and semimetals afford the utilization of Liquid Metal Ion Sources (LMIS). Gallium has established in industry and science as easiest and most stable type of LMIS. For quantum applications other ion species like Li, B, C, N, Al, Si, P, Sb, Bi or the rare earth elements became from higher interest [1-6]. We give an overview about published metal alloys for FIBs and give an insight into the development and production of new sources. Finally, we give an outlook on current and future applications and activities. [1] L. Bischoff, et al., Micro Eng. 13, 367 (1991), 10.1016/0167-9317(91)90113-R [2] P. Mazarov, et al., JVST B 27, L47-L49 (2009), 10.1116/1.3253471 [3] L. Bischoff, et al., Appl. Phys. Rev. 3, 021101 (2016), 10.1063/1.4947095 [4] W. Pilz, et al., JVST B 37, 021802 (2019), 10.1116/1.5086271 [5] L. Bischoff, et al., JVST B 38, 042801 (2020), 10.1116/6.0000073 [6] N. Klingner, et al., BJNANO 11, 1742 (2020), 10.3762/bjnano.11.156

A highly promising route to scale millions of qubits is to use quantum photonic integrated circuits (PICs), where deterministic photon sources, reconfigurable optical elements, and single-photon detectors are monolithically integrated on the same silicon chip. The isolation of single-photon emitters, such as the G centers and W centers, in the optical telecommunication O-band, has recently been realized in silicon. In all previous cases, however, single-photon emitters were created uncontrollably in random locations, preventing their scalability. Here, we report the controllable fabrication of single G and W centers in silicon wafers using focused ion beams (FIB) with a probability exceeding 50%. We also implement a scalable, broad-beam implantation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabricate single telecom emitters at desired positions on the nanoscale. Our findings unlock a clear and easily exploitable pathway for industrial-scale photonic quantum processors with technology nodes below 100 nm.

Enhanced interstitial diffusion in tin is a phenomenon often observed during ion-beam irradiation and in lead-free solders. For the latter, this not very well understood, strain-driven mechanism results in the growth of whiskers, which can lead to unwanted shorts in electronic designs. In ion-beam physics, this phenomenon is often observed as a result of the enhanced formation of Frenkel pairs in the energetic collision cascade. Here, we show how epitaxial growth of tin extrusions on tin-oxide-covered tin spheres can be induced and simultaneously observed by implanting helium using a helium ion microscope. Calculations of collision cascades based on the binary collision approximation and 3D-lattice-kinetic Monte Carlo simulations show that the implanted helium will occupy vacancy sites, leading to a tin interstitial excess. Sputtering and phase separation of the tin oxide skin, which is impermeable for tin atoms, create holes and will allow the epitaxial overgrowth to start. Simultaneously, helium accumulates inside the irradiated spheres. Fitting the simulations to the experimentally observed morphology allows us to estimate the tin to tin-oxide interface energy to be 1.98 J m−2 . Our approach allows the targeted initiation and in situ observation of interstitial diffusion-driven effects to improve the understanding of the tin-whisker growth mechanism observed in lead-free solders.

Enhanced interstitial diffusion in tin is a phenomenon often observed during ion-beam irradiation and in lead-free solders. For the latter, this not very well understood, strain-driven mechanism results in the growth of whiskers, which can lead to unwanted shorts in electronic designs. In ion-beam physics, this phenomenon is often observed as a result of the enhanced formation of Frenkel pairs in the energetic collision cascade. Here, we show how epitaxial growth of tin extrusions on tin-oxide-covered tin spheres can be induced and simultaneously observed by implanting helium using a helium ion microscope. Calculations of collision cascades based on the binary collision approximation and 3D-lattice-kinetic Monte Carlo simulations show that the implanted helium will occupy vacancy sites, leading to a tin interstitial excess. Sputtering and phase separation of the tin oxide skin, which is impermeable for tin atoms, create holes and will allow the epitaxial overgrowth to start. Simultaneously, helium accumulates inside the irradiated spheres. Fitting the simulations to the experimentally observed morphology allows us to estimate the tin to tin-oxide interface energy to be 1.98 J m−2 . Our approach allows the targeted initiation and in situ observation of interstitial diffusion-driven effects to improve the understanding of the tin-whisker growth mechanism observed in lead-free solders.

We investigate differential evolution optimization to fit Rutherford back-scattering data. The algorithm helps to find, with very high precision, the sample composition profile that best fits the experimental spectra. The capabilities of the algorithm are first demonstrated with the analysis of synthetic Rutherford back-scattering spectra. The use of synthetic spectra highlights the achievable precision, through which it becomes possible to differentiate between the counting statistical uncertainty of the spectra and the fitting error. Finally, the capability of the algorithm to analyze large sets of experimental spectra is demonstrated with the analysis of the position-dependent composition of a SrxTiyOz layer on a 200 mm silicon wafer. It is shown that the counting statistical uncertainty as well as the fitting error can be determined, and the reported total analysis uncertainty must cover both.

Metal nanoparticles grafted within inert and porous wide-area supports are emerging as recyclable, sustainable catalysts for modern industry applications. Here, we develop gold nanoparticle-anchored supported catalysts by utilizing the natural metal binding and reductive potential of natural eggshell. Variable hand-recyclable wide-area catalysts between ~(80±7) and (0.5±0.1) cm2 are generated by varying the support dimensions. The catalyst possesses high-porosity (17.1 Å) and stability against high-temperatures (300°C), polar and non-polar solvents, electrolytes, acids and bases, facilitating compatible ultra-efficient catalysis. As validated by large-volume (2.8 liters) sewage-dye detoxification, gram-scale hydrogenation of nitroarenes and synthesis of propargylamine. Moreover, persistent-recyclability, monitoring of reaction kinetics and product intermediates are possible due to retrievability and interchangeability of the catalyst. Finally, the bio-nature of support permits ~76.9% recovery of noble gold simply by immersing in royal solution. Our naturally-created, low-cost, scalable, hand-recyclable and resilient supported mega-catalyst dwarfs most challenges for large-scale metal-based heterogeneous catalysis.

Quantitative nanoscale imaging using transmission He ion channelling contrast: Proof-of-concept and application to study isolated crystalline defects

We present results for direct maskless magnetic patterning of ferromagnetic nanostructures using a special liquid metal alloy ion source for focused ion beam (FIB) systems. We used a Co36Nd64 alloy as the FIB source [1]. A Wien mass filter allows for quick switching between the ion species in the alloy without changing the FIB source. A 5000×1000×50 nm3 permalloy strip served as the sample. Using the FIB we implanted a 300-nm-wide track with Co ions (see Fig.1). We observed the Co-induced changes by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. This allows for easy magnetic modification of edge-localized spin waves. In another set of samples, we implanted Dy ions to locally increase the damping in a stripe pattern of ~120-nm-wide strips with 400 nm periodicity on a total area of 1×1 mm². Thus, the Gilbert damping parameter can be easily increased by one order of magnitude with a lateral resolution of about 100 nm. In contrast to electron beam lithography in combination with broad-beam ion implantation, the maskless FIB process does not require the cumbersome and difficult removal of the ion-hardened resist if optical measurements like BLS or TR-MOKE are needed.

Broad ion beams have shown their wide applications for materials modification. Focused ion beams can be used in a similar way while simultaneously providing process monitoring. Here, we demonstrate this on a new kind of ion-induced structural evolution. Sub-micrometer Sn spheres were irradiated in a helium ion microscope with a sub-nm beam of 30 keV He ions. Above a fluence of ~10^17/cm², Sn extrusions appeared on the surface of the spheres, which were imaged using the secondary electron signal. Initially, small, pyramid-like faceted extrusions form at the equator of the spheres (north pole pointing to the ion source). Later, each sphere becomes completely covered by the extrusions. A model was developed that assumes that each He ion generate ~70 Frenkel pairs. The implanted helium atoms, interstitials, and vacancies will be confined by the oxide skin of the spheres. Some He atoms will occupy vacancies, which partially prevent their recombination with interstitials. Furthermore, the ion irradiation leads to erosion and opening of the SnO skin. The interstitials can now escape from the interior of the Sn sphere and form an epitaxial regular Sn lattice on the exterior. Transmission electron microscopy, Auger electron spectroscopy as well as TRI3DYN [1] and 3D kinetic lattice Monte Carlo [2] simulations support these findings. In addition, we provide a perspective on focused ion beams from our in-house development and production of liquid metal alloy ion sources, which can be used for applications from self-organized patterning, over altering magnetic or electrical properties, to quantum photonics and computation [3]. [1] Möller, Nucl. Instr. Meth. B 322 (2014) 23 [2] Strobel et al., Phys. Rev. B 64 (2001) 245422 [3] www.hzdr.de/fib

Magnetic nanostructures needed for magnonics and spintronics are usually processed by conventional lithography techniques in combination with lift-off or broad-beam ion etching. However, it has been shown [1] that the quality and shape of the structures’ edges play an important role for the magnetization dynamics as structures become smaller and smaller. Furthermore, regarding optical measurement techniques, hard-to-remove resist masks that become hardened by ion etching are problematic. Direct-writing focused ion beams (FIB) do not have these issues. In addition, using non-standard ion species opens various paths for local magnetic patterning, i.e., influencing the magnetic properties locally. I will present results for maskless magnetic patterning of ferromagnetic nanostructures using He and Ne ions as well as a few liquid metal alloy ion sources (LMAIS) for FIB systems. He/Ne FIBs are well established and commercially available. Irradiation of (paramagnetic) FeAl films by Ne ions creates local ferromagnetic nanostructures caused by disorder that are embedded in a paramagnetic matrix [2]. The precise Ne FIB also enables us to trim the edges of magnetic nanostructures enhancing their magnetic fidelity and creating certain localized magnon states at the edges of the samples. Using specifically developed LMAIS, like e.g., Co36Nd64, CoDy, or CuDy [3,4] in combination with a Wien mass filter offers further new paths for magnetic patterning. I will present results on the modification of Ni80Fe20 (permalloy) strip samples. Using the CoNd LMAIS a narrow track of Co ions was implanted. The induced magnetic changes were measured with microresonator ferromagnetic resonance (FMR) before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. Using Dy ions one can locally increase the Gilbert damping parameter of the magnetization dynamics

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many ap- proach lack the required spatial placement accuracy and Si tech- nology compatibility required for many of the envisioned applica- tions. Here, we present a method to fabricate at will placed single or few SPEs emitting in the telecom O-band in Silicon [1] . The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way to- ward a monolithic, all-silicon-based semiconductor-supercon- ductor quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabri- cation methods have been irradiated with a spot pattern. 6 to 500 Si2+ ions have been implanted per spot using an energy of 40 keV. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom are confirmed by measurements of zero phonon lines (ZPL) at the expected wave length of 1278 nm for the case of carbon rich SOI wafers. In the case of ultra clean SOI wafers and high ion fluxes emission from tri-interstitial Si complexes is observed. The SPE nature of these so called W-centers has also been confirmed by ZPL measurements at 1218 nm. The achieved lateral SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than 50%. After a discus- sion of the formation statistic we also present an approach how our FIB based approach can be upscaled to wafer-scale nanofabrication of telecom SPEs compatible with complementary metal oxide semiconductor (CMOS) technology for very large scale integration (VLSI).

Single-photon sources are one of the elementary building blocks for photonic quantum information and optical quantum computing [1]. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements and single-photon detection on a silicon chip in a controllable manner. Particularly, fully integrated single-photon emitters on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits [2]. This work presents a mask-free nanofabrication method involving a quasi-deterministic creation of scalable extrinsic color centers in silicon emitting in the optical telecom O-band [3] on a commercial silicon-on-insulator platform using focused ion beam writing. We also show the local writing of an intrinsic color center in silicon, which is linked to a tri-interstitial complex and reveals quantum emission close to the telecom band [4]. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars [5] and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit. [1]D. D. Awschalom et al.,Nature Photonics 12,516 (2018) [2]J. C. Adcock et al.,IEEE, 27, 2, (2021) [3]M. Hollenbach et al.,Optics Express 28,26111 (2020) [4]Y. Baron et al.,arXiv:2108.04283 (2021) [5]M. Hollenbach et al.,arXiv:2112.02680 (2021)

Single photon emitters (SPE) are fundamental building blocks for future quantum technology applications. However, many ap- proach lack the required spatial placement accuracy and Si tech- nology compatibility required for many of the envisioned applica- tions. Here, we present a method to fabricate at will placed single or few SPEs emitting in the telecom O-band in Silicon [1] . The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with sub-micrometer precision paves the way to- ward a monolithic, all-silicon-based semiconductor-supercon- ductor quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi liquid metal alloy ion sources (LMAIS) and an Orsay Physics CANION M31Z+ focused ion beam (FIB). Silicon-on-insulator substrates from different fabri- cation methods have been irradiated with a spot pattern. 6 to 500 Si2+ ions have been implanted per spot using an energy of 40 keV. For the analysis and confirmation of the fabrication of true SPEs a home build photo luminescence setup has been used. G-centers formed by the combination of two carbon atoms and a silicon atom are confirmed by measurements of zero phonon lines (ZPL) at the expected wave length of 1278 nm for the case of carbon rich SOI wafers. In the case of ultra clean SOI wafers and high ion fluxes emission from tri-interstitial Si complexes is observed. The SPE nature of these so called W-centers has also been confirmed by ZPL measurements at 1218 nm. The achieved lateral SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than 50%. After a discus- sion of the formation statistic we also present an approach how our FIB based approach can be upscaled to wafer-scale nanofabrication of telecom SPEs compatible with complementary metal oxide semiconductor (CMOS) technology for very large scale integration (VLSI).

We present results for direct maskless magnetic patterning of ferromagnetic nanostructures using a special liquid metal alloy ion source for focused ion beam (FIB) systems. We used a Co36Nd64 alloy as the FIB source [1]. A Wien mass filter allows for quick switching between the ion species in the alloy without changing the FIB source. A 5000×1000×50 nm3 permalloy strip served as the sample. Using the FIB we implanted a 300-nm-wide track with Co ions (see Fig.1). We observed the Co-induced changes by measuring the sample with microresonator ferromagnetic resonance before and after the implantation. Structures as small as 30 nm can be implanted up to a concentration of 10 % near the surface. Such lateral resolution is hard to reach for other lithographic methods. This allows for easy magnetic modification of edge-localized spin waves. In another set of samples, we implanted Dy ions to locally increase the damping in a stripe pattern of ~120-nm-wide strips with 400 nm periodicity on a total area of 1×1 mm². Thus, the Gilbert damping parameter can be easily increased by one order of magnitude with a lateral resolution of about 100 nm. In contrast to electron beam lithography in combination with broad-beam ion implantation, the maskless FIB process does not require the cumbersome and difficult removal of the ion-hardened resist if optical measurements like BLS or TR-MOKE are needed.

The helium ion microscope (HIM) is an instrument for high-resolution imaging, composition analysis, and materials modification at the nanoscale. Ion transmission experiments could further improve the analytical capabilities of this technique, and multiple contrast modes are possible. We explore the latter at keV ion energies using a HIM in a scanning transmission approach as well as a broad beam in combination with a time-of-flight (ToF) set-up. Both systems employ positionsensitive detectors allowing for analysis of angular distributions. In the ToF-system, we find a strong trajectory-dependence of the measured specific energy loss attributed to charge-exchange events in close collisions. Channelling and blocking of transmitted ions allows for mapping of intensity as well as different energy loss moments. In the HIM we demonstrate different contrasts, e.g., due to orientation of nanocrystals, channelling in single-crystalline membranes and material contrast for layered films.