Direct Write Nanofabrication of Functional Substrates for Surface Enhanced Raman Spectroscopy
In recent years, the development, characterization and theoretical modelling of advanced substrates for Surface Enhanced Raman Spectroscopy (SERS) has become a focus of research at the FELMI-ZFE. The main strength of SERS is the enormous sensitivity down to single-molecule detection, providing unique chemical information. The basis for SERS are substrates with nanostructures made from certain metals (Au, Ag), which locally enhance the electric fields due to plasmonic excitations, leading to enhancement factors up to 1010. While traditional preparation (e.g. low content sputter coating) leads to stochastic distributions of shapes, dimensions and orientation of individual nanostructures, a defined nano-fabrication would not only increase the SERS performance even further but also would allow to study fundamental aspects of the enhancement processes. One technology, which meets the requirements, is Focused Electron Beam Induced Deposition (FEBID), which is a research focus for more than one decade at FELMI-ZFE. This technology relies on highly localized dissociation and immobilization of functional precursor molecules by a focused electron beam (see Figure top). By that, this technology allows direct-write fabrication of Au based nano-structures with widths below 15 nm in full-width-half-maximum (see Figure bottom-left). Such substrates can then be studied by Raman Microscopy (see Figure bottom-right), for gradual improvements towards both, a protocol for high-performance SERS substrates and a fundamental insight in their working principles.
By that, this thesis introduces the master student into both main technologies (FEBID and Raman microscopy) but also gives a comprehensive insight into atomic force microscopy (AFM) and scanning electron microscopy (SEM).
The ideal applicant has a strong interest in experimental work and will receive a financial support of € 3520,- (€ 440 for 8 months).
Addressed to Master students from the following fields:
Advanced Materials Science
Start: March 2019
Dr. Harald Fitzek
Institut für Elektronenmikroskopie und Nanoanalytik
Steyrergasse 17 / III
Phone: +43 (0)316 873 8333
Fax: 43 (0)316 873 108333