Investigation of point or nanoscale defects in solids during in-situ ion irradiation and annealing. Dermining gas (hydrogen) distributions in solids after loading. On-line methods: Positron annihilation spectroscopy (PAS) for defect characterization or nuclear reaction analysis (NRA) for hydrogen depth profiling supported by XPS and other off-line methods. Most of studies can be performed in-situ.
Specific information on the method:
- Maximum information depth for PAS based defect analysis: Several 100 nm depending on the sample material
- Detection limits for open volume defects: 1016 – 1019 cm-3
- Maximum information depth for NRA based hydrogen depth profiling: About a few micrometer (depending on stopping cross section of the sample).
- Best depth resolution for hydrogen depth profiling: About 2-3 nanometers (near the surface).
- Sensitivity (detection limit) about 0.1% H.
Specific information on the equipment/instrumentation:
Sample size: 10x10x0.5 mm3, measurement in HV and UHV, sample heating up to 1000 K, in-situ ion irradiation up to 5 kV (can be extended to 30 kV), hydrogen loading in reactor at maximum 20 bar and 923 K, climate chamber at temperatures from 10°C to 95°C and relative humidity of 5% to 100%.
Suitable for thin films or solids, conductive samples as well as insulators,
Limitation: Samples stable under UHV conditions
Examples of typical analytical questions:
– How do atomic and nanoscale structural defects in a solid evolve during heating/annealing?
– How does hydrogen distribute inside a solid material?
– How does hydrogen decorate atomic or nanoscale structural defects?
Fields of research:
Structural defects in sustainable energy materials and their effect on functionality. Materials for gas (hydrogen) storage, detectors or gas separating membranes. High-performance structural materials and alloys.