scholarly journals Digging gold: keV He+ ion interaction with Au

2013 ◽  
Vol 4 ◽  
pp. 453-460 ◽  
Author(s):  
Vasilisa Veligura ◽  
Gregor Hlawacek ◽  
Robin P Berkelaar ◽  
Raoul van Gastel ◽  
Harold J W Zandvliet ◽  
...  
Keyword(s):  
Ion Beam ◽  
Normal Incidence ◽  
Sample Surface ◽  
Primary Energy ◽  
Periodic Surface ◽  
Helium Bubbles ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Helium Implantation ◽  
Ion Microscopy

Helium ion microscopy (HIM) was used to investigate the interaction of a focused He+ ion beam with energies of several tens of kiloelectronvolts with metals. HIM is usually applied for the visualization of materials with extreme surface sensitivity and resolution. However, the use of high ion fluences can lead to significant sample modifications. We have characterized the changes caused by a focused He+ ion beam at normal incidence to the Au{111} surface as a function of ion fluence and energy. Under the influence of the beam a periodic surface nanopattern develops. The periodicity of the pattern shows a power-law dependence on the ion fluence. Simultaneously, helium implantation occurs. Depending on the fluence and primary energy, porous nanostructures or large blisters form on the sample surface. The growth of the helium bubbles responsible for this effect is discussed.

Nanostructures from Hydrogen and Helium Implantation of Aluminum

2010 ◽  
Vol 1264 ◽  
Author(s):  
Markus D. Ong ◽  
Nancy Yang ◽  
Ryan J. Depuit ◽  
Bruce R. McWatters ◽  
Rion A. Causey
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Mobility ◽  
Transmission Electron ◽  
Helium Ion ◽  
Fusion Applications ◽  
Helium Implantation ◽  
Bicontinuous Structure ◽  
Nanoporous Structures

AbstractThis study investigates a pathway to nanoporous structures created by hydrogen and helium implantation in aluminum. Previous experiments for fusion applications have indicated that hydrogen and helium ion implantations are capable of producing bicontinuous nanoporous structures in a variety of metals. This study focuses specifically on implantations of hydrogen and helium ions at 25 keV in aluminum. The hydrogen and helium systems result in remarkably different nanostructures of aluminum at the surface. Scanning electron microscopy, focused ion beam, and transmission electron microscopy show that both implantations result in porosity that persists approximately 200 nm deep. However, hydrogen implantations tend to produce larger and more irregular voids that preferentially reside at defects. Implantations of helium at a fluence of 1018 cm-2 produce much smaller porosity on the order of 10 nm that is regular and creates a bicontinuous structure in the porous region. The primary difference driving the formation of the contrasting structures is likely the relatively high mobility of hydrogen and the ability of hydrogen to form alanes that are capable of desorbing and etching Al (111) faces.

scholarly journals Building with ions: towards direct write of platinum nanostructures using in situ liquid cell helium ion microscopy

Nanoscale ◽  
2017 ◽  
Vol 9 (35) ◽  
pp. 12949-12956 ◽  
Author(s):  
Anton V. Ievlev ◽  
Jacek Jakowski ◽  
Matthew J. Burch ◽  
Vighter Iberi ◽  
Holland Hysmith ◽  
...  
Keyword(s):  
Ion Beam ◽  
Direct Write ◽  
High Chemical ◽  
Liquid Precursor ◽  
Helium Ion ◽  
Liquid Cell ◽  
Chemical Purity ◽  
Ion Microscopy

Direct write with liquid precursor using an helium ion beam, allows fabrication of nanostructures with sub-15 nm resolution and high chemical purity.

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

2012 ◽  
Vol 3 ◽  
pp. 507-512 ◽  
Author(s):  
Gregor Hlawacek ◽  
Vasilisa Veligura ◽  
Stefan Lorbek ◽  
Tijs F Mocking ◽  
Antony George ◽  
...  
Keyword(s):  
High Performance ◽  
High Surface ◽  
Thin Layers ◽  
Light Elements ◽  
Ion Channeling ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Contrast Mechanism ◽  
Assembled Monolayers ◽  
Ion Microscopy

Background: Helium ion microscopy is a new high-performance alternative to classical scanning electron microscopy. It provides superior resolution and high surface sensitivity by using secondary electrons. Results: We report on a new contrast mechanism that extends the high surface sensitivity that is usually achieved in secondary electron images, to backscattered helium images. We demonstrate how thin organic and inorganic layers as well as self-assembled monolayers can be visualized on heavier element substrates by changes in the backscatter yield. Thin layers of light elements on heavy substrates should have a negligible direct influence on backscatter yields. However, using simple 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.

scholarly journals Channeling in helium ion microscopy: Mapping of crystal orientation

2012 ◽  
Vol 3 ◽  
pp. 501-506 ◽  
Author(s):  
Vasilisa Veligura ◽  
Gregor Hlawacek ◽  
Raoul van Gastel ◽  
Harold J W Zandvliet ◽  
Bene Poelsema
Keyword(s):  
Secondary Electron ◽  
Geometric Model ◽  
Particle Beam ◽  
Surface Layers ◽  
Charged Particle Beam ◽  
Surface Information ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Ion Microscopy ◽  
Unique Surface

Background: The unique surface 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 images. Secondary electron images can be used to extract crystallographic information from bulk samples as well as from thin surface layers, in a straightforward manner.

Organic pore structure characterization of shale: a comparison between scanning electron microscopy and helium ion microscopy

2020 ◽  
Author(s):  
Junliang Zhao ◽  
Wei Zhang ◽  
Dongxiao Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pore Structure ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Structure Characterization ◽  
Depth Of Field ◽  
Helium Ion ◽  
Ion Microscopy ◽  
Scanning Electron

<p>Scanning electron microscopy (SEM) and helium ion microscopy (HIM) are two of the fundamental tools in the study of the microstructures of shale. A comprehensive comparison of these two techniques in the application of organic pore structure characterization is presented in this work. Owing to the small wavelength of the helium ion, the spot size of the ion beam is not restricted by diffraction aberration, and the convergence angle of helium ion beam can be much smaller than of the electron beam. The microscopic images and reconstruction models indicate that HIM has higher spatial resolution and increased depth of field than SEM. The pores below 10 nm and inner structures of pore networks can be observed via HIM images. The advantages shown in the focused ion beam/helium ion microscopy (FIB/HIM) results are similar to the 2-D HIM images. Smaller pores whose size is beyond the resolution of focused ion beam/scanning electron microscopy (FIB/SEM) can be found, which suggests the connection possibility of the big pores. However, to get reliable pictures, the ion-induced damage on organic matters should be avoided. To lower the beam current and to shorten the dwell time are two effective ways to reduce the beam damage.</p>

scholarly journals Ion Beam Induced Current Measurements of Solar Cells with Helium Ion Microscopy

2017 ◽  
Vol 23 (S1) ◽  
pp. 2084-2085
Author(s):  
Alex Belianinov ◽  
Songkil Kim ◽  
Cannon Buechley ◽  
Matthew Burch ◽  
Olga Ovchinnikova ◽  
...  
Keyword(s):  
Solar Cells ◽  
Ion Beam ◽  
Induced Current ◽  
Helium Ion ◽  
Ion Microscopy

Contrast Mechanisms and Image Formation in Helium Ion Microscopy

2009 ◽  
Vol 15 (2) ◽  
pp. 147-153 ◽  
Author(s):  
David C. Bell
Keyword(s):  
Imaging System ◽  
Ion Source ◽  
Ion Imaging ◽  
Small Surface ◽  
Surface Sensitivity ◽  
Helium Ion ◽  
Contrast Mechanisms ◽  
Ion Microscopy ◽  
Imaging Instrument ◽  
Enhanced Surface

AbstractThe helium ion microscope is a unique imaging instrument. Based on an atomic level imaging system using the principle of field ion microscopy, the helium ion source has been shown to be incredibly stable and reliable, itself a remarkable engineering feat. Here we show that the image contrast is fundamentally different to other microscopes such as the scanning electron microscope (SEM), although showing many operational similarities due to the physical ion interaction mechanisms with the sample. Secondary electron images show enhanced surface contrast due the small surface interaction volume as well as elemental contrast differences, such as for nanowires imaged on a substrate. We present images of nanowires and nanoparticles for comparison with SEM imaging. Applications of Rutherford backscattered ion imaging as a unique and novel imaging mechanism are described. The advantages of the contrast mechanisms offered by this instrument for imaging nanomaterials are clearly apparent due to the high resolution and surface sensitivity afforded in the images. Future developments of the helium ion microscope should yield yet further improvements in imaging and provide a platform for continued advances in microscope science and nanoscale research.

scholarly journals Aging Analysis of Reference Sample Surface Using Helium Ion Microscopy

2021 ◽  
Vol 64 (9) ◽  
pp. 424-429
Author(s):  
Keiko ONISHI ◽  
Shoko NAGANO ◽  
Daisuke FUJITA ◽  
Taro YAKABE ◽  
Akiko ITAKURA
Keyword(s):  
Reference Sample ◽  
Sample Surface ◽  
Helium Ion ◽  
Ion Microscopy

Field ion microscopy

1988 ◽  
Vol 46 ◽  
pp. 434-435
Author(s):  
Gert Ehrlich
Keyword(s):  
Low Temperature ◽  
Sample Surface ◽  
Low Pressure ◽  
Radius Of Curvature ◽  
Field Ion Microscopy ◽  
Phosphor Screen ◽  
Ion Microscopy ◽  
Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

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