Synergy of photoinduced force microscopy and tip-enhanced Raman spectroscopy – a correlative study on MoS2
in: ACS Photonics (2019)
In this contribution, we combine for the first time tip-enhanced Raman spectroscopy (TERS) and photoinduced force microscopy (PiFM) synergistically and examine this instrumental approach on the 2D material molybdenum disulfide (MoS2). In a first step the PiFM technique was applied to map the electrical field distribution of the incident light field with nanometer resolution according to the plasmon resonance of the TERS tip. This experiment provides a fast and non-destructive characterization of the TERS tips focus interaction and is in good agreement with theoretical models. Subsequently, combined TERS and PiFM experiments on a MoS2 monolayer finally demonstrate a correlation of maximum TERS signal enhancement and the corresponding PiFM image with respect to the depth and lateral position of the focal laser spot. Hence, the results indicate a significantly improved route towards the alignment efficiency of TERS experiments and establish MoS2 as an outstandingly suitable TERS test sample.