Complete Kelvin Probe is an invention of Instytut Fotonowy that solves the 150 years old problem with Kelvin Probes: If you observe a CPD change, you don’t know whether it is a change of the sample’s Work Function or the change of the WF of the tip.
Complete Kelvin Probe is an ultimate Contact Potential Difference (CPD) measuring device. It can do whatever other Kelvin Probes can do but it also can measure
That lets the user clearly see what contribution to the sample-tip CPD comes from the sample and what from the tip.
Sample-Tip Contact Potential Difference (blue) with recorded ambient air temperature (green) and relative humidity (orange):
click the picture to enlargeSample-ground Contact Potential Difference (red) with recorded ambient air temperature (green) and relative humidity (orange). It represents only small fraction of the sample-tip variation:
click the picture to enlargeTip-ground Contact Potential Difference (gold) with recorded ambient air temperature (green) and relative humidity (orange). It shows that most of the CPD change is due to the change on the tips surface:
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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 in 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 such as 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. The system automatically detects the sample substrate. 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.
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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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