Frequently Asked Questions

Seebeck Coefficient/Electrical Conductivity

In the SBA 458 Nemesis®, the minimum sample length amounts to 12.7 mm or 10 mm (for square samples).

Samples thicknesses of smaller than 3 mm are possible. Hypothetically, the SBA 458 Nemesis® can handle sample thicknesses down to 100 nm; however, a precondition is that the sample possesses Ohmic transport (for electrical conductivity). Only in this case is a measurement possible. Furthermore, the sample should be placed on a carrier material (e.g., glass slide).

Please note, that not all thin film samples possess Ohmic transport (electrons). Our measurement method cannot be applied to samples with ballistic transport (scattering).

The SBA 458 includes a pressure control valve which opens at ~0.5 bar. Therefore, a measurement with pressure overload is not possible.

The lowest pressure that can be achieved amounts to 10-2 mbar.

With the SBA 458 Nemesis® setup, a broad variety of sample geometries can be measured. It is possible to test round samples, thin films, etc. or samples already prepared for LFA tests.

In the SBA 458 Nemesis® setup, the thermocouples and the current pins are in a fixed position.

The distance between the thermocouples and the current pins is very important for measurement/calculation of the electrical conductivity. Only the exact knowledge of the distance guarantees precise determination of the electrical conductivity.

This failure source is eliminated by the fixed positions of the thermocouples and pins and therefore, a distance determination is no longer required. Furthermore, the distance remains constant during the measurement.

Changing of the sample is easy and convenient.

The SBA 458 Nemesis® uses current pins (with a very low diameter) to supply the sample with the current. In this case, the current supply remains constant. With FEM simulation, we calculate the current supply (current flow lines) and also correction functions depending on the geometry of the sample. In addition, we consider the distance of the thermocouples and current pins (smoothing functions by Smits and Valdes). This allows for precise calculation of the electrical conductivity.