Institute of Physical and Theoretical Chemistry

Working group of Prof. Gauglitz

Ellipsometry

Ellipsometry is an optical technique for the contactless and non-destructive determination of dielectric properties of thin films. The physical thickness as well as the refractive index can be probed simultaneously by measuring the change of polarization of light which is reflected at the thin film layer(s) of the sample. By this, information about morphology, composition and other surface properties of the thin layer(s) can be obtained. The samples can be measured in air and also in aqueous conditions, with physical thickness of the layer(s) ranging from tenths of nanometers to several micrometers.

In the working group of Prof. Gauglitz, there are two ellipsometers available: a spectroscopic and a single wavelength ellipsometer. These two setups are used for characterization of the prepared sensor surface modifications and comprehension of the layer systems that are built up during biomolecular interaction processes using Reflectometric Interference Spectroscopy (RIfS). With the gained information about physical thickness and refractive index, the surface chemistry can be optimized and adapted to special measuring problems. Also, simulations of the properties of thin films can be performed which are useful for determination of the optimal evaluation wavelength in the 1-lambda RIfS application.

Literature

  1. Raitza et al., Macromol. Chem. Phys. 2000, 201, 825-829
  2. Mutschler et al., Anal. Bioanal. Chem. 2002, 374(4), 658-664
  3. Busche et al., Prog. Colloid Polym. Sci. 2005, 132, 16-22