The work performed in PROMISES can be split in two parts. The first part deals with the analysis of nanomaterials by advanced TEM and related techniques. Numerous material systems have been investigated and the main results are summarized in the following: From the MLC material system class, nanotubes made of SrxCoO2-CoO2 have been analyzed and identified as promising candidates as interconnect material due to an extraordinary high ampacity. In a similar material, stable layered CoO2 nanoscrolls could be observed. The nanoscrolls are noteworthy as layered CoO2 is unstable in bulk form. A novel class of quaternary chalcogen-based MLC nanotubes (Sm,Y)S-TaS2 was studied. Related to MLCs, the study of nanotubes from the ternary system W(S,Se)2 showed that the band gap of the nanotubes can be tuned by the S/Se alloying degree, which could be useful for optoelectronic applications. A study of the epitaxial growth conditions of WS2 on sapphire showed that a metal pre-seeding step leads to the formation of an WO3 interface that facilitates the large-scale growth of WS2.
The second part of the work focused on methodological development of TEM. The combination of aberration correction with Zernike phase plates was successfully studied, a very promising technique to enhance contrast and improve interpretability of TEM images of nanomaterials. The main methodological development was focused on in-situ TEM analysis, especially electrical characterization studies. The thermoelectrical characterization of (nano)materials by in-situ TEM was explored. Proof-of-principle experiments show the induction of a thermo-voltage and the general possibility of such analyses. One of the main challenges for in-situ TEM is a clean preparation and contacting of the sample on the in-situ chip, especially for nanomaterials, whose structure has to be preserved throughout the process. A support-based transfer process was elaborated that provides a high reproducibility at minimum damage and contamination of the material. The process was sent as an investigation result to the office of technology transfer. The technique was tested on various different nanomaterials, which subsequently were studied by in-situ TEM. Results have been obtained on the stability of LaS-TaS2 MLC under high electrical currents, which allows to study the breakdown mechanism. This breakdown mechanism differs largely between materials as have shown similar experiments on carbon-based materials.
In addition to the publication of 6 scientific articles in peer-reviewed journals, the results have been presented at five scientific conferences or seminars. Moreover, several dissemination activities during PROMISES aimed for the non-scientific public, including newspaper articles, the participation at the European Researchers’ Night and the 2021 edition of Science is Wonderful. Worth special mentioning is the creation of a song and movie on Misfit nanotubes published on Youtube.
