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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
Characterization of bulk polarization phenomena such as the bulk photo-voltaic effect (BPVE) in semiconductors requires the preparation of two electrical contacts on the sample, which inevitably introduces additional defects in the semiconductor-metal interface what is especially challenging for ultrawide bandgap semiconductors with high resistivity.
Solution
Surface photovoltage (SPV) spectroscopy using a Kelvin probe is used as a nondestructive, contactless method for characterizing the change of the contact potential difference (DCPD) in carbon doped GaN single crystals. By designing a unique setup capable of measuring DCPD up to ± 200 V, large photovoltages could be detected, without the need to deposit electrical contacts.
Application example
The band gap of GaN is 3.4 eV. As an example, figure 1 shows a spectrum of DCPD for a carbon doped GaN crystal (GaN:C). The corresponding SPV signal reached more than 13 V at 3 eV, i.e., under excitation of certain defect states, SPV signals were much larger than expected from the band gap (for more details see [1]). A change of the direction of DCPD and a signature in the derivative were found near the band gap. Under excitation with a laser diode (445 nm) at higher intensity, the maximum signal was obtained for GaN:C with a carbon concentration of 9×1018 cm-3 and amounted to about 23 V, far exceeding the band gap (figure 2).
[1] Levine, I., et al. "Bulk photovoltaic effect in carbon-doped gallium nitride revealed by anomalous surface photovoltage spectroscopy." Phys. Rev. B 101 (2020) 245205.
µPCD/MDP (QSS)
PID
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