Sheet resistance
Resistance of a thin layer per square, independent of its size.
Useful forConductive films, TCOs, coatingsElectrical, Magnetic & Electrochemical
Electrical Conductivity
Four Probe Method
The four-probe method passes a current through the outer two of four in-line probes and reads the voltage across the inner two. It gives sheet resistance, resistivity and conductivity without contact-resistance errors.
1 test optionSheet resistance & resistivityFilms, wafers and pelletsTypical turnaround 3–5 working days
Electrical Conductivity measurement principleIllustrative
01 / Overview
What is Electrical Conductivity?
Four equally spaced probes are pressed onto the sample in a straight line. A known current flows between the outer pair while a high-impedance voltmeter reads the voltage across the inner pair. Geometric correction factors turn this into sheet resistance and, with the thickness, into resistivity and conductivity.
Because almost no current flows through the voltage probes, contact and lead resistance drop out of the result, unlike a simple two-probe measurement. It is quick, needs only a flat surface, and suits thin films, semiconductor wafers, conductive coatings and pressed powder pellets.
02 / How it works
How it works
- 01
Sample is placed flat
The film, wafer or pellet sits on an insulating stage with the measured side facing up.
- 02
Probes touch down
Four equally spaced, spring-loaded probes are lowered onto the surface in a straight line.
- 03
Current flows, voltage is read
A known current passes through the outer probes while the inner pair measures the voltage drop.
- 04
Resistivity is calculated
V/I is corrected for sample size and thickness to give sheet resistance, resistivity and conductivity.
03 / What it measures
What it measures
Resistivity
A material property, from sheet resistance and known thickness.
Useful forWafers, pellets, bulk sheetsConductivity
The reciprocal of resistivity, reported in S/cm or S/m.
Useful forConductive polymers, composites, ceramicsUniformity
Compare readings at several points on the same sample.
Useful forDeposited films, wafersEffect of processing
Compare samples before and after annealing, doping or coating.
Useful forProcess and recipe optimisation04 / Test options
Choose the Electrical Conductivity options you need
1 option · none added yet
05 / Sample requirements
Sample requirements
- Accepted forms
- Films on insulating substrates, wafers, sheets, pressed pellets
- Size
- Flat piece at least ~10 × 10 mm; pellets ~10–20 mm diameter
- Thickness
- State film or pellet thickness; it is needed for resistivity
- Powders
- Send as a pressed pellet, or discuss pelletising first
- Flat, clean surface on the measured side
- Films deposited on an insulating substrate (e.g. glass, quartz)
- Note film or pellet thickness, if known
- No films on conductive substrates without discussing first
- No soft, sticky, wet or crumbling samples
Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.
06 / Results & turnaround
Results & turnaround
What you receive
- Sheet resistance (Ω/sq)
- Resistivity (Ω·cm) and conductivity (S/cm), with thickness
- V–I data for each reading
- Multi-point readings, when requested
- Report PDF
Turnaround & pricing
Typically 3–5 working days after samples reach the lab.
Price confirmed in your quotation, depending on user type, options and number of samples.
07 / Limitations
When Electrical Conductivity isn't the right fit
Highly insulating or dielectric samples
Electrochemical or redox behaviour
Conductivity mapped at the nanoscale
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