Optical and Spin Properties of Defect-Bound Excitons in Semiconductors

Abstract

The physical properties of semiconductor defects are highly relevant for future quantum technologies and current semiconductor device performance. Optical spectroscopy is a powerful tool for investigating a wide variety of defect properties, motivating us to develop a generalized theory of spontaneous emission from multi-carrier bound excitons. We apply this theory to the neutral-acceptor bound exciton, finding three distinct radiative lifetimes. Next, we utilize our knowledge of bound-exciton transitions to measure the spin lifetime of donor-bound electrons. These measurements motivate the use of shallow-dopant-bound spins as qubits for quantum information, and we explore possible pathways for isolating a single shallow donor or acceptor. Lastly, we investigate excitons bound to stacking faults, a common extended semiconductor defect, finding ultra-homogeneous linewidths and a giant exciton dipole moment. These feature imply that stacking faults could potentially be useful for studying many-body physics in strongly-interacting exciton gases.