****Technical Abstract**** A new type of spectroscopy combining optical-pumping of electrons with NMR detection, termed OPNMR, is being developed and applied to a series of important classes of direct-gap III-V semiconductors. OPNMR exploits the optically-oriented electrons, which couple to surrounding nuclear spins; enhanced NMR signals can then be observed. Defect sites and dopants related to optically-relevant defects will be spectroscopically identified. Polarization transfer schemes, whereby signal enhancements in one region travel via nuclear spin diffusion to other regions will be explored, opening up the possibility of new applications of OPNMR. Theory and experimental work will be closely coupled in this project with calculations of the bandstructure and spin-dependent optical transitions, and an industrial partner will assist in selection of heterostructure devices for analysis. Ancillary benefits of this research will include models of OPNMR phenomena for these methods to be applied to II-VI and Group IV semiconductors. Graduate students will be educated and trained in cutting-edge spectroscopy techniques, which enables them to pursue careers in a variety of areas including lasers, semiconductor devices, NMR/MRI spectroscopy, and it builds both knowledge and experience in chemistry, physics, and engineering. Experience working with an industrial partner will be invaluable to help students make informed career choices and to provide contacts for future research opportunities.
Cutting-edge spectroscopic tools are being developed that combine lasers with nuclear magnetic resonance, or NMR (a technique that is closely-related to MRI's used in medicine), to study semiconductors. Semiconductor materials are of enormous economic and industrial importance because these form the basic building blocks for electronic components and equipment. Semiconductors are a type of material that act as a "pipeline" for electrons, controlling where and how electrons flow inside the material, such as in computer chips or the pixels in digital cameras. By shining laser light onto the semiconductor, electrons are generated. Understanding how these photoexcited electrons behave is important to device performance, and the laser+NMR techniques are used to monitor the electron spins through their interactions with the surroundings. In this project, graduate students will be educated and trained in these advanced technologies, which enables them to pursue careers in a variety of areas (i.e., lasers, semiconductor devices, NMR/MRI spectroscopy), and it builds knowledge and experience in chemistry, physics, and engineering. The collaborative team includes an industrial partner thus offering real-world experience for our students, and a broader commercially-focused perspective to the senior (academic) personnel on this project.
