Ultralow-energy amorphization of contaminated silicon samples investigated by molecular dynamics

• Grégoire R. N. Defoort-Levkov,
• Alan Bahm and
• Patrick Philipp

Beilstein J. Nanotechnol. 2023, 14, 834–849, doi:10.3762/bjnano.14.68

• strong interaction with silicon, we can assume that free oxygen will tend to pair extremely quickly with silicon, whereas hydrogen can travel deeper into the sample, because of its low mass and via channeling processes. Contaminants tend to remain closer to the surface than argon. Because the water

Is the Ne operation of the helium ion microscope suitable for electron backscatter diffraction sample preparation?

• Annalena Wolff

Beilstein J. Nanotechnol. 2021, 12, 965–983, doi:10.3762/bjnano.12.73

• the ion image contrast occur with darker patches forming in the irradiated area in the ion channeling images. A detailed discussion on channeling contrast and the effect of grain orientation on milling speed can be found in [35]. The different stages of dark patch formation are shown in Figure 5a–c

• grains can easily be distinguished in SEM images due to their significant height differences. The Ga peak can be clearly identified in the measurements on the slower milling grain suggesting a significantly higher amount of incorporated Ga in those grains. A careful assessment of the ion channeling

• different times. This result is in good agreement with the observed dark patch growth in the ion channeling images. The kernel average misorientation map and grain boundary map overlay (Figure 7c) shows a higher local misorientation and low-angle grain boundaries within the topographically higher regions

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• the varying crystal orientations cause a variation in the local sputter rate due to ion channeling [24]. If one of the symmetry axes of the crystal lattice is oriented along the beam direction, the ion penetration depth is larger, which, in turn, reduces the sputter rate. The resulting surface

Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector

• Eduardo Serralta,
• Nico Klingner,
• Olivier De Castro,
• Michael Mousley,
• Santhana Eswara,
• Serge Duarte Pinto,
• Tom Wirtz and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2020, 11, 1854–1864, doi:10.3762/bjnano.11.167

• also detect channeling-related contrast on polycrystalline silicon, thallium chloride nanocrystals, and single-crystalline silicon by comparing the signal transmitted at different directions for the same data set. Keywords: bright-field; channeling; dark-field; delay line detector; helium ion

• , thereby creating easier directions for the penetration of the projectile atom. If the projectile atom reaches the crystal at an angle smaller than the critical angle for such an axial or planar channeling direction, the projectile will be steered along this direction and will experience a reduced

• probability of undergoing large-angle scattering. Hence, it will have a smaller energy loss per distance compared to random directions. This phenomenon is called the channeling effect and has been described for megaelectronvolt ions in detail in [17]. When compared to a random orientation, the channeling

Stationary beam full-field transmission helium ion microscopy using sub-50 keV He⁺: Projected images and intensity patterns

• Michael Mousley,
• Santhana Eswara,
• Olivier De Castro,
• Olivier Bouton,
• Nico Klingner,
• Christoph T. Koch,
• Gregor Hlawacek and
• Tom Wirtz

Beilstein J. Nanotechnol. 2019, 10, 1648–1657, doi:10.3762/bjnano.10.160

• revealed that these samples charge significantly under He+ ion irradiation. The spot patterns obtained in the THIM experiments are explained as artefacts related to sample charging. The results presented here indicate that factors other than channeling, blocking and surface diffraction of ions have an

• thickness fringes seen in transmission electron microscopy (TEM) have been observed in a HIM and have possible explanations involving diffraction [19] or inelastic scattering [23] of He+ ions. This observation led to computational work investigating coherent scattering, channeling and diffraction of He

• + ions in crystals to explore the possibilities to obtain atomic-resolution images in a HIM [23]. Hence, experimental investigation of the intensity distribution of transmitted He+ ions can provide valuable insights related to ion–solid interaction such as channeling, blocking and diffraction [23][24][25

Fabrication of phase masks from amorphous carbon thin films for electron-beam shaping

• Lukas Grünewald,
• Dagmar Gerthsen and
• Simon Hettler

Beilstein J. Nanotechnol. 2019, 10, 1290–1302, doi:10.3762/bjnano.10.128

• transition between SixNy and aC was observable. This procedure leaves a free-standing aC thin film with slight inhomogeneities (Figure 3a), which are attributed to an inhomogeneous, grain-orientation-dependent sputter rate of the nanocrystalline Pt due to ion-channeling effects [30]. The second method uses

Site-controlled formation of single Si nanocrystals in a buried SiO₂ matrix using ion beam mixing

• Xiaomo Xu,
• Thomas Prüfer,
• Daniel Wolf,
• Hans-Jürgen Engelmann,
• Lothar Bischoff,
• René Hübner,
• Karl-Heinz Heinig,
• Wolfhard Möller,
• Stefan Facsko,
• Johannes von Borany and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2018, 9, 2883–2892, doi:10.3762/bjnano.9.267

• ) [37]. The ion beam incident angle was kept at 7° to avoid channeling. A thermocouple was clipped to the sample during the irradiation to monitor that the temperature does not exceed 423 K. The fluence is measured by a Faraday corner-cup setup. Focused beam irradiation Focused ion beam (FIB

Optimization of the optical coupling in nanowire-based integrated photonic platforms by FDTD simulation

• Nan Guan,
• Andrey Babichev,
• Martin Foldyna,
• Dmitry Denisov,
• François H. Julien and
• Maria Tchernycheva

Beilstein J. Nanotechnol. 2018, 9, 2248–2254, doi:10.3762/bjnano.9.209

• between an LED and a photoconductive detector both based on GaN NWs [29]. The communication took place in free space. Using NWs located close to each other, the authors demonstrated a correlation between the LED on/off switching and the photodetector current variations. A waveguide for light channeling is

High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography

• Kahraman Keskinbora,
• Umut Tunca Sanli,
• Margarita Baluktsian,
• Corinne Grévent,
• Markus Weigand and
• Gisela Schütz

Beilstein J. Nanotechnol. 2018, 9, 2049–2056, doi:10.3762/bjnano.9.194

• . Figure 2b and Figure 2c show some hard Au grains remained relatively unharmed by the ion beam due to the strong dependence of the ion beam damage on the crystal orientation concerning anisotropic sputter yield and channeling effects [42]. These grains have a random spatial distribution, which renders

A terahertz-vibration to terahertz-radiation converter based on gold nanoobjects: a feasibility study

• Kamil Moldosanov and
• Andrei Postnikov

Beilstein J. Nanotechnol. 2016, 7, 983–989, doi:10.3762/bjnano.7.90

• longitudinal phonon, the setup will be given for channeling the relaxation process into an emission of a THz photon. In GNR (Figure 3b), the compression waves run along the cyclic contour, to which the phonon momentum nvmq is tangential. Similarly to the case of GNB, the momentum of an excited electron stands

Focused particle beam-induced processing

• Michael Huth and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2015, 6, 1883–1885, doi:10.3762/bjnano.6.191

• nanofabrication. Along the same path, Gregor Hlawacek, Bene Poelsema and coworkers focused on the interaction of helium ions with metal surfaces (gold in particular) [13][14][15]. In a series of three distinct articles, they concentrate on ion channeling, crystal mapping, and finally, ion-induced modification of

Scanning reflection ion microscopy in a helium ion microscope

• Yuri V. Petrov and
• Oleg F. Vyvenko

Beilstein J. Nanotechnol. 2015, 6, 1125–1137, doi:10.3762/bjnano.6.114

• were examined in the field of material science [15][17][18][19][20][21][22][23] as well as in biology [15][16][24][25][26]. Different techniques such as secondary electron energy filtering [27], helium ion channeling contrast [28][29][30], helium ion transmission microscopy [31], secondary ion mass

• that the reflection coefficient is independent of the polar incident angle, φ1, that is, η = η(Θ1,φ1,Θ2,φ2) = η(Θ1,Θ2,φ2). This assumption is valid for amorphous materials and in the absence of ion channeling in crystalline materials. Ion channeling can cause the reflection coefficient to become

• strongly dependent on the angle in the vicinity of the channeling critical angles [28][30] and can be eliminated by a proper choice of the angle between the incident beam and crystal atomic planes [38]. The RI signal is the number of SEs per second measured by the ET detector as the flux of SEs from the Pt

Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

• Pravin Kumar,
• Udai Bhan Singh,
• Kedar Mal,
• Sunil Ojha,
• Indra Sulania,
• Dinakar Kanjilal,
• Dinesh Singh and
• Vidya Nand Singh

Beilstein J. Nanotechnol. 2014, 5, 1864–1872, doi:10.3762/bjnano.5.197

• IUAC, New Delhi. The backscattering yield was measured using a surface barrier detector mounted at 10º in the irradiation chamber with respect to the beam direction. The vacuum inside the chamber during irradiation was ≈10−4 Torr. He+ irradiation was carried out at 7° to avoid ion channeling in the

Characterization of electroforming-free titanium dioxide memristors

• John Paul Strachan,
• J. Joshua Yang,
• L. A. Montoro,
• C. A. Ospina,
• A. J. Ramirez,
• A. L. D. Kilcoyne,
• Gilberto Medeiros-Ribeiro and
• R. Stanley Williams

Beilstein J. Nanotechnol. 2013, 4, 467–473, doi:10.3762/bjnano.4.55

• contrast mainly dominated by the local atomic mass. In addition, the BF imaging has a major electron-phase contribution and channeling effect, which are more appropriate for probing the switching process. Nonetheless, no evidence of a switching effect was observed from a careful analysis along the junction

Digging gold: keV He⁺ ion interaction with Au

• Vasilisa Veligura,
• Gregor Hlawacek,
• Robin P. Berkelaar,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2013, 4, 453–460, doi:10.3762/bjnano.4.53

• done to the surface and bulk of the gold grains, their crystalline nature is still evident. The blisters have equilateral triangles on top. The same triangles are also observed in the BSHe images, hinting at the channeling nature of the contrast. We attribute these dark triangles and rings to

• channeling along the planes of the FCC crystal. The crystalline shell of the blister is bent (see Figure 1c) due to the high internal gas pressure. As a consequence the surface vector locally tilts. This leads to a local channeling condition with the planes along sections of the blister, resulting in the

• dark bands on the blister surface. The contrast changes with variation of the beam incidence angle, the channeling condition is no longer fulfilled and the dark stripes move or even vanish entirely [8]. The orientations of the sides of the triangles in Figure 2e and Figure 2i help to determine the

Imaging ultra thin layers with helium ion microscopy: Utilizing the channeling contrast mechanism

• Gregor Hlawacek,
• Vasilisa Veligura,
• Stefan Lorbek,
• Tijs F. Mocking,
• Antony George,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 507–512, doi:10.3762/bjnano.3.58

• geometric calculations of the opaque crystal fraction, the contrast that is observed in the images can be interpreted in terms of changes in the channeling probability. Conclusion: The suppression of ion channeling into crystalline matter by adsorbed thin films provides a new contrast mechanism for HIM

• . This dechanneling contrast is particularly well suited for the visualization of ultrathin layers of light elements on heavier substrates. Our results also highlight the importance of proper vacuum conditions for channeling-based experimental methods. Keywords: channeling; contrast mechanism; helium

• crystal orientation. Channeling along low index directions affects SE as well as BSHe images [3][4]. Here, we discuss how channeling can be utilized to gain unexpected contrast in BSHe images on ultrathin surface layers. HIM already provides superior surface sensitivity in SE-based images. The described

Channeling in helium ion microscopy: Mapping of crystal orientation

• Vasilisa Veligura,
• Gregor Hlawacek,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 501–506, doi:10.3762/bjnano.3.57

• sensitivity and the high resolution that can be achieved with helium ion microscopy make it a competitive technique for modern materials characterization. As in other techniques that make use of a charged particle beam, channeling through the crystal structure of the bulk of the material can occur. Results

• : Here, we demonstrate how this bulk phenomenon affects secondary electron images that predominantly contain surface information. In addition, we will show how it can be used to obtain crystallographic information. We will discuss the origin of channeling contrast in secondary electron images, illustrate

• this with experiments, and develop a simple geometric model to predict channeling maxima. Conclusion: Channeling plays an important role in helium ion microscopy and has to be taken into account when trying to achieve maximum image quality in backscattered helium images as well as secondary electron