Atomic force microscopes
For the topological analysis of our samples we have two atomic force microscopes. The Veeco Bioscope II AFM and the Park XE 150 AFM. Both systems are attached to a Labram high-resolution spectrometer.
The Bioscope II sits on an inverted microscope connected to the Labram and is therefore well suited for the investigation of transparent samples. For such samples Raman and atomic force measurements can be performed simultaneously.
The Park AFM is equipped with a piezoelectric table to navigate on a sample with a precision of a few nanometer. Additionally, the navigation on a sample is further assisted by encoders. These encoders keep track of the table's absolute position to ensure that a region of interest of a sample can be found again.
With both systems we measure the topography of nano systems with high spatial resolution. In its simplest application this system aims at combining the topological information of a sample (where is the nano particle, is a nanotube straight or curved) with Raman scattering or luminescence link.
More advanced is the method of tip-enhanced Raman scattering. In the near field of a metallic tip the Raman signal is amplified by several orders of magnitude. Using this trick single e.g. molecules can be detected or the spatial resolution can be increased to be even below the light's wavelength. The coupling of atomic force microscopy with Raman microscopy is a new experimental method in the area of nano systems, biomaterials, etc..