Analysis and fragmentation of organic samples by (low‐energy) dynamic SIMS

Ngo, Khanh Q.; Philipp, Patrick; Jin, Y.; Morris, Steven E.; Shtein, Max; Kieffer, John; Wirtz, Tom

doi:10.1002/sia.3533

Cited by 7 publications

(8 citation statements)

References 21 publications

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“…The odd–even effect for the ToF‐SIMS C n ‐ peaks for n = 1 … 6 and the steady decrease in intensity for the n ≥ 6 peaks. While negative ion SIMS of CNTs has been reported, there does not appear to have been any recognition or discussion of this effect, although odd–even effects of secondary ions from other carbon‐containing materials are known The valence band spectrum of CNTs taken with X‐radiation (Al Kα) does not appear to have been reported.As has previously been reported for highly ordered pyrolytic graphite and CNTs, the C 1 s peak is asymmetric .…”

Section: Discussionmentioning

confidence: 93%

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Jensen

Kanyal

Madaan

et al. 2013

Surface & Interface Analysis

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We apply a suite of analytical tools to characterize materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy. Materials characterized include: the Si(100) substrate with native oxide: Si/SiO 2 , alumina (35 nm) deposited as a diffusion barrier on the Si/SiO 2 : Si/SiO 2 /Al 2 O 3 , iron (6 nm) thermally evaporated on the Al 2 O 3 : Si/SiO 2 /Al 2 O 3 /Fe, the iron film annealed in H 2 to make Fe catalyst nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP)/CNT. The Fe films and nanoparticles appear in an oxidized state. Some of the analyses of the CNTs/CNT forests appear to be unique: (i) the CNT forest appears to exhibit an interesting 'channeling' phenomenon by RBS, (ii) we observe an odd-even effect in the SIMS spectra of C n -species for n = 1 -6, with the n ≥ 6 ions showing a steady decrease in intensity, and (iii) valence band characterization of CNTs using X-radiation is reported. Initial analysis of the CNT forest by XPS shows that it is 100 at.% carbon. After one year, only ca. 0.25 at.% oxygen is observed. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of 'The Blind Men and the Elephant'. The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

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Section: Discussionmentioning

confidence: 93%

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Jensen

Kanyal

Madaan

et al. 2013

Surface & Interface Analysis

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“…For organic optoelectronic devices, cluster ion bombardment is not the only possibility for depth profiling. Under low-energy Cs + bombardment, the fragmentation is less prevalent than for kiloelectronvolt bombardment, , and stable secondary ion intensities of small characteristic fragments are obtained under steady-state conditions . The successful depth profiling of metal–organic multilayered samples and the ability to extract information on the interface morphology have been reported previously.…”

Section: Introductionmentioning

confidence: 66%

Silver Diffusion in Organic Optoelectronic Devices: Deposition-Related Processes versus Secondary Ion Mass Spectrometry Analysis Artifacts

et al. 2015

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The development of organic optoelectronic devices relies on controlling interfaces during thin-film deposition and requires an accurate characterization of the film composition at these interfaces. Dynamic secondary ion mass spectrometry (SIMS) is widely used to investigate multilayer thin-film structures. Routine analysis protocols are well established for classical semiconductor samples, but for organic or mixed metallic−organic samples the limitations of the technique are less well established. In the current work, low-energy dynamic SIMS is used on metal−organic multilayered model structures similar to those in organic optoelectronic devices to study the origin of diffusion of metal into the organic layer (e.g., irradiation-induced diffusion during SIMS analysis or during the deposition process). Samples contain silver and organic compounds sequentially deposited by thermal evaporation in vacuum onto a Si substrate. They are analyzed using a 250 eV to 1 keV Cs + primary ion beam. It is found that the mixing of silver into the organic layer depends on the impact energy and the conditions for sample preparation. This irradiation effect can be minimized by a back-side depth profiling approach, which was developed in this work. By applying this method, it is shown that some silver is likely to diffuse into the organic layers during the deposition process.

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“…For the negative secondary ion mode, we selected characteristic fragments leading to high secondary ion yields4 as well as atomic ions of interest, i.e. O − , Si − , C n − , C n Cs − , C n N m − , CuN m − , CuC n N m − .…”

Section: Resultsmentioning

confidence: 99%

“…The fragmentation of C 60 and CuPC have also been studied as a function of the impact energy by looking at the abundance distributions of C n − , C n Cs − and C n N m − cluster ions in the negative secondary ion mode. These results are reported in a separate paper 4. Here, these distributions are used to select characteristic secondary ions of each molecule and facilitate the interpretation of the depth profile in the negative mode.…”

Section: Introductionmentioning

confidence: 92%

Analysis of organic multilayered samples for optoelectronic devices by (low‐energy) dynamic SIMS

Ngo¹,

Philipp²,

Jin

et al. 2011

Surface & Interface Analysis

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aThe increasing sophistication of optoelectronic devices requires molecular-level dimensional control in the fabrication of multilayered structures with specifically engineered interfaces. However, the effectiveness of growth and doping strategies devised to achieve the desired device structures often remains unverified due to the lack of adequate characterization techniques. This is particularly true for devices based on conjugated organic compounds, which find increasing use in energy applications (e.g. organic light emitting diodes and organic photovoltaic cells, etc.). The buried interfaces are simply inaccessible or suffer damage when using conventional characterization techniques. In a current project, we address this challenge by advancing the development of low-energy (LE) SIMS for the analysis of organic-based optoelectronic materials systems.In the present study, multilayered organic thin films have been analyzed, varying experimental conditions such as the impact energies for Cs + bombardment in the MCs x + and M − mode on a Cameca Sc-Ultra instrument to investigate the ionization mechanisms as well as the atomic mixing at the interfaces between layers, and the degradation of the organic information. Low-energy dynamic SIMS proved to be a reliable tool for the characterization of organic multilayered optoelectronic devices: MCs x + secondary ions provide information about the distribution of elements within the samples, while negative fragments that are characteristic for the different molecules give information about the structure.

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Analysis and fragmentation of organic samples by (low‐energy) dynamic SIMS

Cited by 7 publications

References 21 publications

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Multi‐instrument characterization of the surfaces and materials in microfabricated, carbon nanotube‐templated thin layer chromatography plates. An analogy to ‘The Blind Men and the Elephant’

Silver Diffusion in Organic Optoelectronic Devices: Deposition-Related Processes versus Secondary Ion Mass Spectrometry Analysis Artifacts

Analysis of organic multilayered samples for optoelectronic devices by (low‐energy) dynamic SIMS

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