Date of Award
Doctor of Philosophy (PhD)
Chair and Committee
Sophia E Hayes
Since its inception, nuclear magnetic resonance (NMR) has been a key technique for sample characterization. One significant limitation of NMR is an inherent lack of sensitivity, making it extremely difficult to probe systems with low spin densities (≤ 1017 nuclei). Optically pumped NMR (OPNMR) provides one method to get around this sensitivity barrier by utilizing the high electronic polarizations that can be generated through the application of polarized light.
Semiconducting materials are the fundamental building blocks of important components in most aspects of modern society, including solar cells, optical detectors, and diodes and transistors in electronic circuits. Because of this prevalence, accurate and comprehensive characterization of a sample is necessary to gauge the ability of the sample to perform the necessary role. Extremely small concentrations of defects in a sample can have substantial effects on the performance of a device, so characterization techniques must have a high degree of sensitivity. OPNMR aims to provide a path to characterize these defects.
Recent work in our lab has focused on probing the underlying mechanisms occurring in OPNMR, including the source of nuclear polarization and the nature of the hyperfine coupling that occurs between nuclear spins and nearby electrons. This dissertation examines the theory of optical pumping, polarization transfer, and experimental applications. Also included are observations of perturbations to the nutation and echo behavior of GaAs under optical pumping conditions.
Wheeler, Dustin D., "Measurement and Modeling of OPNMR Phenomena in GaAs Semiconductors" (2014). All Theses and Dissertations (ETDs). 1363.