The starting point of this project is the PI's recent findings that electron injection into p-type GaN leads to considerable changes in the material's electronic properties, in particular longer minority carrier diffusion length. The intellectual merit of this three-year project is in exploration of the novel electron injection-induced effects in the wide range of p-type Mg-doped AlxGa1-xN (x 0.35) and AlxGa1-xN/GaN superlattices. In addition, the electron injection effects in III-Nitrides doped with impurities other than Mg (manganese or iron, for example) and III-N alloys and superlattices other than AlxGa1-xN and AlxGa1-xN/GaN (InxGa1-xN and InxGa1-xN/GaN, for example) will be studied. To fully understand the novel electron injection-induced effects and to achieve control over device performance, systematic electrical and optical studies will be carried out in the representative range of III-Nitride-based structures. Electrical measurements, which include Deep Level Transient Spectroscopy and Electron Beam Induced Current, will be performed before and after electron injection. These measurements will be complemented with cathodoluminescence, photoresponse, as well as photoconductivity measurements able to provide critical information on optical and optoelectronic properties. The broader impact of this project is in integration of research and education at the graduate and undergraduate levels as well as in partnership with industry (SVT Associates). Two other aspects of the project's broader impact are in participation of a female Ph.D. student and undergraduates from a Historically Black (Bethune-Cookman) College in the proposed research. Finally, the international dimension of the project is in close collaboration of the PI with a group at the Walter Schottky Institute of Munich Technical University in Germany. The practical significance of this research is in long-term, several-fold enhancement of quantum efficiency for III-Nitride ultra-violet detectors. This is because the increased diffusion length improves minority carrier collection and eliminates the "dead space" where carriers recombine before they are collected.
