Scanning Kelvin probe

Scanning Kelvin probeNot only can it measure the contact potential difference (CPD) of a single point in the sample, but it can also scan the entire surface of the sample.

Kelvin probes equipped with light sources can inspect the surface state of electrons in samples. The surface state of electrons plays an important role in charge transfer, which is crucial forScanning Kelvin probeEspecially in photovoltaic materials and photoelectrochemistry
Important.

The possibility of scanning the surface of the sample and examining its electrical properties can accurately evaluate the quality, uniformity, and other properties of the material. A series of CPD values collected for many points in the sample can be used for more accurate evaluation
Estimation function.

Electrostatic voltmeter

The measurement technology, analytical methods applied, and instrument design make this instrument unparalleled in testing charged dielectric surfaces, including dielectrics, where the measured potential is higher than the cumulative potential
The charge may reach several thousand volts!

The scanning Kelvin probe system can investigate:

• The work function of materials

• The position of the Fermi level relative to the edges of the conduction and valence bands,

• Types of semiconductors n or p

• The energy gap of semiconductors/

• Surface potential (SPV of flat band technology),

• The influence of surface adsorption and chemical adsorption on work function,

• Surface state density information/

• Surface charge discharge effect/

• Minority carrier diffusion length/

• Carrier recombination rate (especially in indirect bandgap semiconductors),

• Burial point interface information,

• The influence of temperature on the work function,

• The influence of humidity on the work function,

• The distribution of static charges on the surface.

Kelvin probe module

• The Kelvin probe set includes:

• Controller unit,

• Kelvin Probe instrument with probe,

• Faraday cage.

Kelvin Probe Instrument Equipment:

• The protective groove used for parking probes after the experiment,

• The laser pointer directly indicates the area,

• When the instrument is covered by a Faraday cage, it helps to process the light source of the sample,

• Laser barrier, used for precise detection of the distance between the probe and the sample,

• Golden probe,

• Sample rack,

• Electric XY worktable.

probe

The most important part of the Kelvin Probe instrument is the probe. The reference electrode is made of an Au mesh with a diameter of 2.5 mm. It provides high signal-to-noise ratio, even at a distance of 0.5 mm above the sample
The same goes for it. Therefore, whether the surface of the inspected sample is rough or polished is not important. The oscillation is generated by an electromagnet.

The probe is a component designed and manufactured by Instytut Fotonowy Sp. z o.o.

Sample rack

The standard Kelvin probe set includes two types of sample stages:

• Bottom contact frame for samples on conductive substrates,

• A top contact bracket for non-conductive substrates,

Faraday enclosure

The entire instrument is covered by a Faraday cage to protect the device from environmental light and electromagnetic fields.

Airtight Faraday enclosure with inert gas flow system

The scientific measurement of CPD is usually sensitive to environmental factors such as temperature, humidity, dust, and chemical pollutants. Kelvin probes can be placed in Faraday cages with inert gas flow systems
Within the sealed version.

Laser grating

The Kelvin probe is equipped with a laser barrier system. The system automatically detects the bottom of the sample

Liquid. Every time the probe approaches the tested sample, the accurate distance between the sample surface and the probe is measured with an accuracy of 20 μ m.

Sample lighting

During the measurement process, the sample may be illuminated by the optical fiber located above the probe. The probe allows light to pass through. The light at the fiber optic input end can be generated by LED rotator, xenon lamp, and grating
Provide any other type of required light source in combination.

routine

• Weight: 10 kg,

• Size: 40x40x45 centimeters,

• PC connection: USB 2.0

• Power supply: 230 V, 50 Hz or 115 V, 60 Hz,

• Measurement technology: 2-channel lock-in amplifier,

• Laser barriers can automatically detect substrates and prevent needle tips from entering the sample,

• Auxiliary sensors: humidity, temperature

• Small lamp/

• Laser indicators for surface indication of inspection points,

Sample rack:

• Free shaped solid with top contact bracket,

• Bottom contact bracket,

• Electrochemical scaffolds,

Faraday cage:

Standard/airtight, with inert gas flow system,

Measurement unit:

• Bias voltage range: -5 ÷ 5 V,

• Voltage measurement resolution: 0.15 mV,

• Current range: 300 nA, 30 nA, 3 nA, 300 pA

Probe:

• Probe type: Au mesh, diameter 2.5 mm,

• Vertical axis needle tip positioning resolution: 20 μ m,

• Automatic resonance frequency scanning/

• Adjustable oscillation amplitude/

• Automatically removed parasitic currents,

• Partial transparency of the light source,

• Typical CPD measurement distance: 0.2-1 mm,

XY Workbench:

• Electric, controlled by software,

• Size: 50 x 50 mm,

• Mobile range: 50 x 50 mm,

Demonstrative achievements

Aluminum surface

Potential distribution on the surface of the sample:

Environmental temperature during measurement:

Air humidity during the measurement process:

Metal surface samples with periodic pores

Potential distribution on the surface of the sample:

Environmental temperature during continuous measurement:

Air humidity during continuous measurement:

Charge distribution on the surface of dielectric:

PTFE on Aluminum Foil - Potential from Sample Surface Charge