Intellectual Merit: Ultraviolet (UV) lasers and light emitting diodes (LEDs) have potential applications in high-density optical storage, high-resolution laser printing, solid-state lighting and display. The investigators propose to utilize photonic band structures to reduce the threshold of UV lasers and to increase the efficiency of UV LEDs. The structural disorder introduced unintentionally during the fabrication process often limits the photonic band gap effects. The investigators propose a new approach, i.e. to utilize higher-order band structures. This approach increases the feature size and reduces the amount of lattice defects in the crystals. Owing to the large exciton binding energy, ZnO exhibits strong exciton emission even at room temperature. However, the non-directionality of exciton emission limits the efficiency of UV LEDs. The investigators propose to use two-dimensional photonic crystal to make ZnO exciton emission highly directional. Broader Impacts: The investigators envision that the success of their program will enrich the research and education environment of students, teachers, and their colleagues. The successful development of UV photonic crystal lasers and LEDs will have significant impact on the development of short-wavelength compact light sources. The investigators will be actively involved with the development of a dynamic, customized, web-based course for pre-college and first year undergraduate students in the area of light wave phenomena in nanostructured materials". They will post their research results in the Global Research Gallery of the NSF funded Materials World Network (MWN) for public viewing. Working with the National Center for Learning and Teaching in Nanoscale Science and Engineering, the investigators will develop an implementation plan to insert "nanophotonics" into modern physics courses. They will use Northwestern physics classes to develop a proto-type module.
