Measurement of resistivity and Hall voltage The resistivity of PV cell materials can be measured by four-pin detection method 3 by loading a current source and measuring the voltage. Four-point collinear detection technology or Vanderborg method can be used.
When using the four-point collinear detection technology for measurement, two probes are used to connect the current source, and the other two probes are used to measure the voltage drop on the photovoltaic material. When the thickness of the PV material is known, the volume resistivity (ρ) can be calculated according to the following formula:
ρ = (π / ln2) (V / I) (tk)
Among them, ρ = volume resistivity, unit is Ωcm, V = measured voltage, unit is V, I = source current, unit is A, t = sample thickness, unit is cm, k = correction coefficient, depends on the probe Ratio to wafer diameter and ratio of wafer thickness to probe pitch.