The van der Pauw method is a technique for doing 4-probe resistivity and Hall effect measurements. In essence it provides an easy way to measure:
- Sheet resistivity/conductivity
- From this one can calculate the resistance/conductance provided the thickness of the sample is known
- Hall voltage
- Sheet carrier density
- From this one can calculate the carrier density provided the thickness of the sample is known
- Hall mobility
- The contacts are on the boundary of the sample (or as close to the boundary as possible)
- The contacts are infinitely small (or as close as possible)
- The sample is thin relative to the other dimensions
Measure Sheet Resistance
Eight measurements need to be made in order to calculate the sheet resistivity. A current must be forced through two adjacent contacts, and a voltage must be measured across the other two contacts. Let the current passing from contact i to contact j be denoted as: