Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 84: Scanning Probe Techniques: Method Developments

O 84.10: Talk

Thursday, March 10, 2016, 17:30–17:45, S054

Tip-enhanced Raman spectroscopy: comparison between AFM and STM feedback mechanism performance — •Jana Kalbacova, Raul D. Rodriguez, Axel Fechner, and Dietrich R.T. Zahn — Semiconductor Physics, Technische Universität Chemnitz, 09126 Chemnitz, Germany

Tip-enhanced Raman spectroscopy (TERS) is a relatively young technique, with the first experimental reports around the year 2000. This technique combines features of two distinct methods - Raman spectroscopy that can e.g. provide details on the chemical composition of a sample, while the metallic tip acts as a nano-antenna enhancing the sample signal only beneath the tip apex. In this way, the chemical information can be resolved at the nanoscale. The way to control the position of the tip apex is the feedback mechanism of the scanning probe microscope. In this contribution, we first review the pros and cons of the atomic force microscopy (AFM) and scanning tunnelling microscopy (STM) feedback loop in TERS. For experimental part of this comparative study, we prepared a sample comprised of single-walled carbon nanotubes and graphene oxide deposited on a gold substrate. An etched gold tip was employed for TERS imaging in both modes. We demonstrate TERS in ambient conditions with sub-10 nm spatial resolution for both approaches (AFM and STM) showing the availability of various working conditions that can be chosen to accommodate different samples with STM, as a feedback loop, displaying better spatial resolution.