LabAdviser/314/Microscopy 314-307/SEM/Nova/Micro 4-point probe: Difference between revisions
| Line 2: | Line 2: | ||
The electrical resistivity of metallic bulk and thin-film samples is usually measured by the 4-point probe technique. The classic arrangement, visible in Fig. 1, consists of four needle-like electrodes in a linear arrangement, with a current injected into the material via the outer two electrodes, while the resulting difference in electric potential is measured via the two inner electrodes. | The electrical resistivity of metallic bulk and thin-film samples is usually measured by the 4-point probe technique. The classic arrangement, visible in Fig. 1, consists of four needle-like electrodes in a linear arrangement, with a current injected into the material via the outer two electrodes, while the resulting difference in electric potential is measured via the two inner electrodes. | ||
[[:File:Picture2.png]] | |||
By using separate electrodes for the current injection and for the determination of the electric potential, the contact resistance between the metal electrodes and the material does not show up in the measured results. Since the contact resistance can be large and can strongly depend on the condition and materials of the electrodes, it is easier to interpret the data measured by the 4-point probe technique than from a 2-point probe system. If the sample has a finite size and if the spacing between the probes is | By using separate electrodes for the current injection and for the determination of the electric potential, the contact resistance between the metal electrodes and the material does not show up in the measured results. Since the contact resistance can be large and can strongly depend on the condition and materials of the electrodes, it is easier to interpret the data measured by the 4-point probe technique than from a 2-point probe system. If the sample has a finite size and if the spacing between the probes is | ||