Project Details
Projekt
Raman microscope
Subject Area
Condensed Matter Physics
Term
Funded in 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 556494758
We apply for a confocal Raman microscope working in the blue spectral range with highest spectral and spatial resolution. It will be used to investigate novel two-dimensional (2D) materials, nanotubes and nanoribbons (1D), and semiconductor nanoparticles. Our research objectives comprise the analysis of fundamental physical properties such as structure, number of layers, symmetry and phase transitions, strain, interface properties and doping. Moreover, we want to gain deep understanding of interaction processes like exciton-phonon coupling and interaction of optical excitations with defects. Furthermore, our aim is to modify the nanomaterials in a targeted manner, e.g. through detailed knowledge and control of spatial modifications like defects, edges, and covalent/ non-covalent functionalization. Raman spectroscopy is a versatile method to address these research questions. In particular, high-resolution Raman maps (hyperspectral images – a complete Raman spectrum per pixel) allow us to investigate microscopic structures and local modifications on a micrometer scale. Such local modifications can be formed by defects and chemical functionalization, but also by lateral variations in twist angle between twisted 2D materials, in interlayer distance in van-der-Waals heterostructures, electrical doping, and locally induced phase changes. For these investigations, the requested Raman microscope must provide fast lateral mapping with highest spatial and spectral resolution, and the possibility for preliminary analysis during scanning. The high spectral resolution is necessary to determine smallest frequency shifts resulting from strain or doping. The Raman microscope must offer flexibility to host samples in different environments (heating cell, Helium cryostat, cuvette or vacuum chamber). The measurement of very small phonon frequencies (~10-40 cm-1) requires a special filter to suppress the excitation laser line. The requested laser wavelengths are 405 nm (3.06 eV) and 473 nm (2.62 eV), being complementary to an existing setup. These wavelengths in the blue spectral range allow efficient excitation of large-bandgap materials as well as excitation of optical transitions above the fundamental bandgap in many 2D semiconductors.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Raman-Mikroskop
Instrumentation Group
1840 Raman-Spektrometer
Applicant Institution
Friedrich-Alexander-Universität Erlangen-Nürnberg
