The Van der Pauw Method
Taking Measurements
Measurements require four ohmic contacts on the sample
The contacts are placed on or as close to sample boundary as possible
The contacts are infinitely small.
The error in measurement is given by D/L
D = average diameter of contact
L = distance between contacts
All four contacts need to be same material
Actual sheet resistance is related to these resistances by the van der Pauw formula:
In van der Pauw resistivity measurements, the current is measured on adjacent nodes and the
voltage is measured on opposing adjacent nodes