Advanced Methods for Nano-Characterisation

• Applicant: Professor Dr. Dietrich R. T. Zahn, since 12/2014
• Subject Area: Microsystems
• Term: from 2011 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 195215523

The application of the methods for nano-characterisation developed during the first funding period and their further improvement are essential for the overall success of the SMINT project. Results obtained so far are very promising and TERS as well as c-AFM/KPFM shall be employed for the characterization of refined sensor structures. The results will contribute to the optimization of these structures and the refined structures will vice versa allow more precise measurements to be performed; e.g. if CNTs of only one chirality form the sensor then effects induced by strain or temperature variation can be determined with higher accuracy. Special attention will be devoted to measuring sensors under operating conditions.Further experimental methods will broaden the spectrum of nano-characterisation. Amongst those are scanning tunneling microscopy (STM) with sub-nanometer resolution and spectroscopic ellipsometry with a lateral resolution of 1 m (-SE). With -SE anisotropic optical properties of CNTs deposited by dielectrophoresis can be determined. Corresponding results deliver the input for the modelling of the optical properties. -SE can also be applied during the operation of the sensors so that changes of the optical properties e.g. due to strain can be measured. Moreover, the ellipsometry setup allows other methods to be implemented, e.g. Raman spectroscopy. For this purpose the remote head of an existing Raman spectrometer will be modified so that the same sample position can be investigated with comparable lateral resolution using spectroscopic ellipsometry as well as Raman spectroscopy. This combination is particularly interesting for studies of functionalized CNTs, since the functionalization with nanoparticles will alter the optical properties markedly and induce SERS in the Raman spectra via the metallic nanoparticles. Finally this combination of -SE and Raman spectroscopy will also be applied to rolled-up smart tubes. Here the optical properties can be monitored as a function of tube filling with high lateral resolution.The project aims can be summarized as follows:Application and further optimization of the methods for nano-characterisation which were developed during the project phase, namely TERS and c-AFM/KPFM, with special attention devoted to the application during sensor operation (in situ analytics).Integration of STM as a further component of the scanning probe techniques for the nanocharacterisation of CNTs and sensors/structures based on them with resolution down to the sub-nanometer region.Determination of anisotropic optical Properties of CNT structures and smart tubes using the combination of -SE and Raman spectroscopy.

• DFG Programme: Research Units
• Subproject of: FOR 1713: Sensoric Micro- and Nanosystems
• Ehemaliger Antragsteller: Professor Dr. Michael Hietschold, until 12/2014