The performance of UV sensitive detectors has steadily increased over the last decades, and astronomical as well as terrestrial applications benefit from this evolution. These UV detectors have made possible the success of several solar missions and are n ow also finding application in the fabrication of user-friendly UV detectors for the prevention of skin cancer. However, the common Si-based UV-detectors exhibit some drawbacks that are difficult to overcome, including the issues of cooling and filtering to detect only a specific UV wavelength. These drawbacks can be resolved by using wide band-gap materials like GaN, SiC, ZnO and diamond. These materials can operate at elevated temperatures and, by a proper design, the detector requires no spectral filte ring via additional coatings. In particular, their wide band-gaps facilitate the construction of so-called daylight (solar) blind UV detectors which do not respond to radiation from the visible or infrared spectra but only to 'UV light'.
During the manufa cturing of UV detectors and in their operation afterwards, defects are introduced in them due to their exposure to energetic particles. In this project we intend comparing the introduction rates of defects in GaN, SiC, ZnO and diamond, during processing a s well as afterwards during controlled irradiation with high-energy particles. The results will show which of these four materials is the least affected by radiation. The radiation hardness of the materials will be assessed by, firstly, manufacturing UV d etectors on the four materials and, secondly, exposing them to MeV electrons, protons, He- and heavy-ions and then determining the defect introduction rates and free carrier removal rates. These results will be of great value both fundamentally and to the UV detector and spacecraft industries.
The project implies heavy involvement by both research teams and constitutes a good example of sustainable research co-operation on equal partnership.
S-AFRIKA-Program for forskningsamarbeid med Sør- Afrika