Scanning Kelvin Probe allows to measure the Contact Potential Difference (CPD) not only in a single point of the sample but the entire sample surface may be scanned.
Kelvin Probe equipped with a light source enables to examine surface states of electrons in the sample. Surface states of electrons play a significant role in electric charge transfer, which is especially important for photovoltaic materials and in photoelectrochemistry.
Possibility of scanning the sample surface and to examine its electrical properties enables precise assessment of the quality of the material, its homogeneity, etc. The series of CPD values collected for many points of the sample, may be used to evaluate Work Function more precisely.
The measurement technique, analytic methods applied and the design of the instrument makes the instrument unique and peerless in testing charged dielectric surfaces, including dielectrics where the measured potential above the accumulated charges may be as large as several kilovolts!
The Kelvin Probe set consists of:
The Kelvin Probe instrument is equipped with:
The most important part of the Kelvin Probe instrument is the Probe Tip. The reference electrode is made of Au mesh of 2.5 mm diameter. It provides high signal to noise ratio, even from a distance of 0.5 mm above the sample. Thus, it does not matter if the examined sample surface is rough or polished. The tip oscillations are generated with an electromagnet.
The Probe Tip is the component fully designed and manufactured by Instytut Fotonowy Sp. z o.o.
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The standard Kelvin Probe Set includes two types of sample stands:
The entire instrument is covered with the Faraday Cage, shielding the setup from the ambient light and electromagentic fields.
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Scince measurements of the CPD is often sensitive to environmental factors like temperature, humidity, dust and chemical contaminants, Kelvin Probe may be placed inside the hermetic version of the Faraday Cage with the inert gas flow system.
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The Kelvin Probe is equipped with the Laser barrier system. System automatically detects the sample sub-
strate. Each time the probe approaches the sample being examined, an accurate distance between the sample surface and the Probe Tip is measured with 20 µm precision.
The sample may be illuminated during the measurements from the optical fiber situated above the Probe Tip. The Probe Tip lets the light through. The light at optical fiber input may be provided by the LED Revolver, Xenon Lamp combined with the Monochromator or any other type of the light source desired.
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PTFE on alluminium foil – Electric potential from the surface charge of the sample
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