Room-temperature near field microscope (RT-SNOM)

• Subject Area: Condensed Matter Physics
• Term: Funded in 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455095399

The applied for room-temperature near-field microscope allows to record near-field optical spectra in the frequency range of THz, infrared and optical with a lateral resolution between 10 and 50 nm. This resolution is significantly below the diffraction limit and thus allows unprecedented experimental progress. To this end, additionally to the main instrument, a CO2 laser source as well as an infrared spectrometer including a broad-band infrared source are applied for. The broad-band infrared source can additionally be used at the low-temperature near-field microscope applied for in parallel. To perform measurements in the THz, we will utilize the source applied for the in framework of the low-temperature near-field microscope, whereas this requires an upgrade. The funding possibility for this instrument has been granted in the framework of the basic funding for the call of Prof. Weitz to Göttingen, and is an essential tool for the building up of the group. With the microscope, we will be able to perform various highly innovative experiments in the area of modern solid-state research. For example, the tool will be used to localize topologically-protected states in bilayer graphene to allow their subsequent electrical characterization with the goal to e.g investigate their interplay with quantum-Hall states. Additionally, we are planning with the instrument to visualize novel topologically protected states in heterostructures composed of two-dimensional polymers and graphene. A further use-case of the novel instrument will be in the region of organic electronics. The unique capabilities of the instrument (which includes a customized symmetric Fabry-Perot interferometer) will allow the first-time nanoscopic investigations of local photocurrent spectroscopy at grain boundaries in organic semiconducting films to visualize local energy barriers at these defects. Furthermore, local morphology-dependent photocurrent measurements at nanoscopic organic p/n junctions will enable us to increase in the long run the efficiency of organic solar cells.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Raumtemperatur Nahfeldmikroskop (RT-SNOM)
• Instrumentation Group: 5091 Rasterkraft-Mikroskope
• Applicant Institution: Georg-August-Universität Göttingen
• Leader: Professor Dr. R. Thomas Weitz