Analyzing the Nanogranularity of Focused-Electron-Beam-Induced-Deposited Materials by Electron Tomography

Abstract

Nanogranular material systems are promising for a variety of applications in research and development. Their physical properties are often determined by grain sizes, shapes, mutual distances and by the chemistry of the embedding matrix With focused electron beam induced deposition arbitrarily shaped nanocomposite materials can be designed, where metallic, nanogranular structures are embedded in a carbonaceous matrix. Using "post-growth" electron beam curing, these materials can be tuned for improved electric transport or mechanical behavior.Such an optimization necessitates a thorough understanding and characterization of the internal changes in chemistry and morphology, which is where conventional projection based imaging techniques fall short. Here, we apply scanning transmission electron tomography to get a comprehensive picture of the distribution and morphology degree of embedded Pt nanograins after initial fabrication, and we demonstrate the impact of electron beam curing, which leads to condensed regions of interconnected metal nanograins.

Direct Writing of Cobalt Silicide Nanostructures Using Single-Source Precursors

“…The effects of electron beam curing can be manifold, such as (i) providing reactive species by fragmentation, e.g., atomic oxygen from initially incorporated CO, which could alter the electronic and magnetic properties of the metallic grains, 29 (ii) completing phase formation/crystallization, 22 (iii) a completion of hydrogen abstraction from partially noncomplete silyl fragmentation, which would be similar to the C−H bond cleavage, 43 (iv) graphitization of the carbon content, 39 and (v) changing the microstructure in the deposit. 44 A more in-depth characterization of the magnetic properties and how they can be related to the microstructure will be the focus of a follow-up study.…”

Mechanical Properties of 3D Nanostructures Obtained by Focused Electron/Ion Beam-Induced Deposition: A Review

“…For comparison, bulk metal elastic moduli are shown in the top line of the diagram: Pt, 174 GPa; W, 396 As for the carbon pillars discussed in Section 2.1., core-shell structures may also arise for pillar deposition in metal FEBID [103] and FIBID, and care should be taken to tune deposition conditions and gas delivery for homogeneous pillar material deposition or to carefully investigate the internal structure for proper interpretation of the results, especially when mechanical properties are studied. Due to the nanometer scale size of FEBID and FIBID structures, the pillar characterization with respect to radial and axial uniformity is very challenging and requires analysis methods with sophisticated preparation, such as transmission electron microscopy ( [102], see Figure 14), FIB cross-sectioning [103], and an atom probe [104].…”

“…After high-dose e-beam curing at 30 keV/150 pA, the grain growth (average by 25 rel.%) is clearly evident, while the partial percolation characteristics remain, as shown by the different colors in (c). Images have been adapted from reference[102].…”

Focused Electron Beam-Based 3D Nanoprinting for Scanning Probe Microscopy: A Review

“…For example, the functional properties can be tuned via post-growth electron beam exposure, denoted as e-beam curing (EBC) [78]. EBC initiates two processes: (1) the dissociation of incompletely dissociated precursor molecules, which release target atoms, leading to slight grain-growth [22,23,[78][79][80]; and (2) the modification and cross-linking of the carbon matrix (sp 3 to sp 2 ) [21,29,80,81]. The former effect allows precise tuning of the electrical conductivity [78] and even enables a controlled insulator-metal transition, as demonstrated for Pt und Au [18,22,23,78].…”