****NON-TECHNICAL ABSTRACT***** This individual investigator award supports a project with a primary goal of providing an experimental test of recent predictions regarding the parameter that controls electrical properties of hydrogen when it is an impurity in semiconductors and other electronic materials. If the results confirm the theory, the research will establish a simple method to predict how the properties of new materials are impacted by hydrogen impurities. Hydrogen easily enters most materials and its defect chemistry is currently used in the semiconductor industry to extend the reliability of silicon based devices, but it can have very negative effects in some other materials, including a few being developed for use in next generation devices. Because hydrogen is highly reactive inside these materials and difficult to study, this research uses a short-lived artificially produced impurity that mimics hydrogen's behavior extremely well. An international research team will conduct these experiments at accelerator-based facilities in England, Canada and Switzerland. Undergraduates and MS students aiming for industrial careers, as well as PhD students, will receive training in research methods in the overlapping regions of physics, chemistry and materials engineering, and will gain valuable experience in a large-group research environment.
This individual investigator award supports a project seeking to establish thermodynamic energies for donor and acceptor defect-levels of hydrogen in a series of semiconductor materials. The results will provide a crucial test of recent predictions that the energy of H defects is universally pinned, and will determine that energy experimentally. The impact extends to new electronic materials and devices since H is crucial to device reliability when it passivates unwanted electrical activity of other defects, but can also introduce activity of its own. If universality is confirmed, placement of this H defect energy within the band structure of a given material is an excellent predictor of its electrical behavior. Because H is very reactive and difficult to study as an isolated impurity, this project uses its light pseudo-isotope Muonium. Experiments are conducted by an international team at accelerator-based muon-spin research facilities in the UK, Canada, and Switzerland. Undergraduate and MS students destined for industry, as well as PhD students, will receive training in research methods in overlap areas of physics, chemistry and materials engineering, and will gain valuable practical experience in a large-group environment.
