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Electrical semiconductor characterization
Luminescence dating, research, dosimetry and more
Contamination monitor, beta-aerosol monitor, dose rate meter and more
for ultra-fast crystal orientation, crystal alignment in production, quality control, rocking curve measurements, material...
state-of-the-art XRD system for automatic single crystal ingot orientation, tilting and alignment for grinding
Wafer sorting, crystal orientation, resistivity, optical notch and flat determination
Flexible diffractometer for ultra-fast Omega Scan orientation determination
Smart diffractometer for ultra-fast Omega-scan of small samples.
Robust XRD equipment for fully automated in-line testing & alignment
for blanks, wafers & bars (AT, SC, TF, etc.)
three generations of X-ray engineers
in industrial production, R&D and more
discover the most convenient way of measuring orientation of single crystals
Mono- and Multi-crystalline wafer lifetime measurement device
Low cost table top lifetime measurement system for characterization of a variety of different silicon samples at different...
Mono- and Multi-crystalline wafer and brick lifetime measurement device
for production and quality control of monocrystalline Si ingots,bricks and wafers
Flexible OEM unit for lifetime measurements at a variety of different samples ranging from mono- to multicrystalline silicon...
for contactless and temperature dependent lifetime and LBIC measurements
High Resolution Resistivity Mapping Tool for process control and quality assurance measurements
The minority carrier life time is sensitive for all kinds of electrically active defects in semiconductors and is therefore...
MDP is an advanced technology with a so far unsurpassed combination of sensitivity, speed and resolution for fab and lab...
High sensitivity, high resolution surface photovoltage (SPV) measurement instrument
High sensitivity, high resolution surface photovoltage spectroscopy (SPS) instrument with a variable energy excitation source...
for quality control of bifacial PERC/PERC+ solar cells and more
portable in field PID tester for solar modules
user friendly and advanced operating software
The PIDcon devices are designed to investigate the PID susceptibility for production monitoring of solar cells as well as tests...
Learn more about the reasons for PID and the how the susceptibility of solar cells, mini modules and encapsulation materials can...
Our quality management system is an integrated process-oriented system with ISO 9001 certification.
Aim
Photocatalytic materials such as BiVO4 are of great interest, for example, for water splitting. Electronic defect states and surface passivation are important limiting factors. Photocatalytic materials can be applied as powders, porous layers or thin films what makes a simple and contactless photoelectric characterization of such materials still challenging.
Solution
SPV spectroscopy in the dc (Kelvin probe, measurement of the contact potential difference: DCPD) and ac (modulated) modes is a contactless and highly sensitive method allowing to detect very low SPV signals related to charge separation under excitation of defect states for powder, porous and thin film samples [1].
Application example
Figure 1 shows spectra of the modulated SPV amplitude for a BiVO4 thin film, porous layer and powder (see also [2]). The onset of the band gap of BiVO4 (2.5 eV), the energy parameters of exponential tails and transitions related to defects can be well measured. Figure 2 shows DCPD spectra of porous BiVO4 layers decorated with V13O15 with and without a passivating cobalt phosphate (Co-Pi) cocatalyst (see also [3]).
[1] Th. Dittrich, S. Fengler, “Surface photovoltage analysis of photoactive materials”, World Scientific, 2020.
[2] S. Fengler, et al., „Characterization of BiVO4 powders and cold gas sprayed layers by surface photovoltage techniques“, Catalysis Today 321 (2019) 34.
[3] H. Ren, et al., „Manipulation of charge transport by metallic V13O16 decorated on bismuth vanadate photoelectrochemical catalyst“, Adv. Mater. (2019) 1807204.
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