Four Point Probe

A four point probe measures sheet resistance (Ω/sq), resistivity and conductivity. Current flows through the two outer probes while the two inner probes measure the voltage drop; because almost no current passes through the voltage probes, contact resistance drops out of the result. This is why four-probe values are trusted for conductive films, ITO and FTO glass, PEDOT:PSS, metal and carbon coatings, and doped semiconductor layers.

Ossila Four Point Probe: specifications

  • Sheet resistance range 100 mΩ/sq – 10 MΩ/sq; current 1 μA – 200 mA; voltage 100 μV – 10 V.
  • Probe spacing 1.27 mm; samples from 5 mm up to 152.4 mm (6 inch) across and up to 8 mm thick.
  • Software calculates geometric correction factors, resistivity and conductivity (enter film thickness) and exports .csv. Positive and negative polarity measurements remove voltage offsets.

How to choose

  • Original (T2001A4/B4) runs from a PC over USB or Ethernet. Plus (T2001A5/B5) adds a built-in display, so it can be used without a PC, which is practical inside a glove box.
  • Soft-tipped head: gold-plated, spring-loaded rounded tips (0.24 mm radius, 60 g force) for organic layers and very thin films. Not suited to silicon or materials with a native oxide.
  • Sharp-tipped head: for harder surfaces and materials with a thin oxide layer. Configurations with both heads, and spare heads P2010A2 and P2010B1, are available.

Related: ITO and FTO substrates, spin coaters and other Ossila test and measurement instruments. Send us your sample type and expected resistance range via WhatsApp for a recommendation and a formal quotation.

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