Modelling and technological expansion of nanowire surface-controlled contact printing
Final Report Abstract
The aim of the project was to further investigate the mechanisms of surface-controlled contact printing of bottom-up grown nanowires (here based on silicon nanowires) to improve the microtechnological fabrication of nanowire-based electronic devices. In this regard, it was also necessary to study possibilities for technological expansion. For experimental realisation, a system for contact printing was put into operation, which enables new degrees of freedom compared to the current state of research. This includes bidirectional printing on substrates up to 100 mm in diameter with simultaneous dynamic control of the contact printing. During the project, the system was additionally equipped with a UV light source and a stamp holder, so that nanowire contact printing, soft transfer printing and nanoimprint lithography can be carried out on a single microtechnological platform. In the area of nanowire contact printing, the mechanical behaviour and the interaction with the substrate of individual nanowires was described in further detail in numerical simulations to obtain an improved model-based description. The nanowire geometry, the substrate surface topography, friction parameters and the alignment of the nanowires on the original substrate were all taken into account. The measurement of the friction of individual nanowires was trialled, but was unable to provide convincing results, which is why these experiments were not further considered. As a result, an improved understanding of the mechanisms during nanowire contact printing could be derived, which also includes the influence of nanowire catcher structures and surface properties of the target substrate. Using dynamic, pressure-controlled contact printing, the project was able to show that nanowire density and arrangement can be controlled even without additional auxiliary structures such as nanowire catchers and resist elements, which significantly simplifies the process. It was also possible to successfully control the deposition angle in the target substrate plane and superimposed nanowire arrangements by means of multiple printing. By controlling the nanowire contact printing, nanowires were transferred aligned on different substrates. Successful deposition on microcantilevers was also demonstrated, which were ultimately implemented for the production of nanowire probes for atomic force microscopy. Conventional field-effect transistor configurations were also realised. To further control the density and positioning of nanowires while minimizing particle contamination, the use of soft transfer printing was researched in addition to contact printing. For this purpose, nanowires were deposited on a substrate with parallel alignment and then successfully transferred locally to a target substrate using soft, polymeric and microstructured stamps. With the help of the implemented UV light source and soft, transparent microstructured stamps, nanoimprint lithography was also realised on the same platform as mentioned above as an additional technological extension. Polymer nanowire catcher structures in different configurations could be produced and used. By using glass-polymer hybrid stamps, it was also possible to demonstrate the simultaneous generation of cross-scale structures, in this case from the micrometre to the millimetre range, within a single process step using nanoimprint lithography. The combination of pressure-controlled contact printing, soft transfer printing and nanoimprint lithography on a single technological platform expands and simplifies the realisation of nanowire-based devices. As a result of the research project, nanowire contact printing was modelled in accordance with the objectives of this research project gaining an improved understanding of nanowire contact printing and a significant technological expansion was achieved.
Publications
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“Combining Nanoimprint Lithography and Nanowire Contact Printing on a Single Platform”. 2020 GMM-Fachbericht 97: Mikro-Nano-Integration
P. Salimitari; S. Supreeti & S. Strehle
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Assembly of Single-nanowires by Combining Soft Transfer and Surface Controlled Contact Printing - Conference papers - VDE Publishing House,” in MikroSystemTechnik Kongress 2021.
P. Salimitari; C. Reuter; A. Kroetschl & S. Strehle
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Exploring nanowire regrowth for the integration of bottom-up grown silicon nanowires into AFM scanning probes. Journal of Micromechanics and Microengineering, 31(5), 055010.
Behroudj, A.; Salimitari, P.; Nilsen, M. & Strehle, S.
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Aligned deposition of bottom-up grown nanowires by two-directional pressure-controlled contact printing. Nanotechnology, 33(23), 235301.
Salimitari, P.; Behroudj, A. & Strehle, S.
