Wafer-scale nanofabrication of telecom single-photon emitters in silicon.

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.

Nano-hillock formation on CaFdue to individual slow Au-cluster impacts.

We present a direct way to generate hillock-like nanostructures on CaF(111) ionic crystals by kinetic energy deposition upon Au-cluster irradiation. In the past, the formation of similar nanostructures has been observed for both slow highly charged ions and swift heavy ions. However, in these cases, potential energy deposition of highly charged ions or the electronic energy loss of fast heavy ions, respectively, first leads to strong electronic excitation of the target material before the excitation energy is transferred to the lattice by efficient electron-phonon coupling.

Imaging and milling resolution of light ion beams from helium ion microscopy and FIBs driven by liquid metal alloy ion sources.

While the application of focused ion beam (FIB) techniques has become a well-established technique in research and development for patterning and prototyping on the nanometer scale, there is still a large underused potential with respect to the usage of ion species other than gallium. Light ions in the range of = 1-28 u (hydrogen to silicon) are of increasing interest due to the available high beam resolution in the nanometer range and their special chemical and physical behavior in the substrate. In this work, helium and neon ion beams from a helium ion microscope are compared with ion beams such as lithium, beryllium, boron, and silicon, obtained from a mass-separated FIB using a liquid metal alloy ion source (LMAIS) with respect to the imaging and milling resolution, as well as the current stability.

Site-controlled formation of single Si nanocrystals in a buried SiO matrix using ion beam mixing.

For future nanoelectronic devices - such as room-temperature single electron transistors - the site-controlled formation of single Si nanocrystals (NCs) is a crucial prerequisite. Here, we report an approach to fabricate single Si NCs via medium-energy Si or Ne ion beam mixing of Si into a buried SiO layer followed by thermally activated phase separation. Binary collision approximation and kinetic Monte Carlo methods are conducted to gain atomistic insight into the influence of relevant experimental parameters on the Si NC formation process.

Magnetosensitive e-skins with directional perception for augmented reality.

Electronic skins equipped with artificial receptors are able to extend our perception beyond the modalities that have naturally evolved. These synthetic receptors offer complimentary information on our surroundings and endow us with novel means of manipulating physical or even virtual objects. We realize highly compliant magnetosensitive skins with directional perception that enable magnetic cognition, body position tracking, and touchless object manipulation.

Multiscale and luminescent, hollow microspheres for gas phase thermometry.

Recently developed laser-based measurement techniques are used to image the temperatures and velocities in gas flows. They require new phosphor materials with an unprecedented combination of properties. A novel synthesis procedure is described here; it results in hierarchically structured, hollow microspheres of Eu-doped YO, with unusual particle sizes and very good characteristics compared to full particles.

Ion-Beam-Induced Atomic Mixing in Ge, Si, and SiGe, Studied by Means of Isotope Multilayer Structures.

Crystalline and preamorphized isotope multilayers are utilized to investigate the dependence of ion beam mixing in silicon (Si), germanium (Ge), and silicon germanium (SiGe) on the atomic structure of the sample, temperature, ion flux, and electrical doping by the implanted ions. The magnitude of mixing is determined by secondary ion mass spectrometry. Rutherford backscattering spectrometry in channeling geometry, Raman spectroscopy, and transmission electron microscopy provide information about the structural state after ion irradiation.

Droplet-Confined Alternate Pulsed Epitaxy of GaAs Nanowires on Si Substrates down to CMOS-Compatible Temperatures.

We introduce droplet-confined alternate pulsed epitaxy for the self-catalyzed growth of GaAs nanowires on Si(111) substrates in the temperature range from 550 °C down to 450 °C. This unconventional growth mode is a modification of the migration-enhanced epitaxy, where alternating pulses of Ga and As4 are employed instead of a continuous supply. The enhancement of the diffusion length of Ga adatoms on the {11̅0} nanowire sidewalls allows for their targeted delivery to the Ga droplets at the top of the nanowires and, thus, for a highly directional growth along the nanowire axis even at temperatures as low as 450 °C.

Direct Depth- and Lateral- Imaging of Nanoscale Magnets Generated by Ion Impact.

Nanomagnets form the building blocks for a variety of spin-transport, spin-wave and data storage devices. In this work we generated nanoscale magnets by exploiting the phenomenon of disorder-induced ferromagnetism; disorder was induced locally on a chemically ordered, initially non-ferromagnetic, Fe60Al40 precursor film using  nm diameter beam of Ne(+) ions at 25 keV energy. The beam of energetic ions randomized the atomic arrangement locally, leading to the formation of ferromagnetism in the ion-affected regime.

Mapping the local elastic properties of nanostructured germanium surfaces: from nanoporous sponges to self-organized nanodots.

Due to their reduced dimensions, the mechanical properties of nanostructures may differ substantially from those of bulk materials. Quantifying and understanding the nanomechanical properties of individual nanostructures is thus of tremendous importance both from a fundamental and a technological point of view. Here we employ a recently introduced atomic force microscopy mode, i.

Taming of Ga droplets on DLC layers--size tuning and local arrangement with nanometer accuracy.

A new method for the fabrication of spherical gallium nanoparticles (Ga-NPs) on diamond-like carbon (DLC) layers with high precision in their desired diameter and positioning is presented. The basic principle is the pre-patterning of a DLC film by focused Ga(+) ion beam irradiation and subsequent annealing. During thermal treatment the evolution of single Ga-NPs with spherical shape on irradiated areas is driven by phase separation and surface segregation of Ga from the supersaturated DLC layer.

Pinhole interferometry with coherent hard X-rays.

This paper discusses the experimental realisation of two types of X-ray interferometer based on pinhole diffraction. In both interferometers the beam splitter was a thin metal foil containing micrometer pinholes to divide the incident X-ray wave into two coherent waves. The interference pattern was studied using an energy-dispersive detector to simultaneously investigate in a large spectral range the diffraction properties of the white synchrotron radiation.