The objectives of this research are to understand the structures and properties of muonium defect centers in semiconductors. In turn this will provide a complementary picture of hydrogen in semiconductors, a common impurity which is difficult to study in unreacted form. The study of muonium permits us to learn about a variety of deep-level defect properties, such as metastability and bistability, local and long-range tunneling, carrier trapping, and pairing reactions. These topics are of considerable scientific and technological interest but are poorly understood. The powerful methods of muon spectroscopy together with the frequent occurrence of muonium centers makes this a powerful approach to these problems. %%% The research uses a sophisticated technique (involving a short- lived sub-atomic particle and its interactions with its surroundings) to probe the properties of defects in semiconductors. These defects are important determinants of the semiconductor properties and affect performance such as solar-cell efficiency. These topics are of considerable scientific and technological interest but are poorly understood.
