This book reports experimental work delivering a route to the successful isotopic enrichment of 28-silicon for providing a solid-state spin vacuum platform suitable for quantum computing. The levels of isotopic purification achieved reduce the nuclear spin carrying 29-silicon isotope to below 3 parts-per-million (ppm), while also reducing 30-silicon to below 1 ppm and removing other impurities. The book also presents the first reported electrically detected magnetic resonance spectroscopy study of the magnetic clock transition in 75-arsenic doped silicon. This is of interest to those developing donor-based qubit systems for quantum technologies as these transitions show reduced sensitivity to otherwise deleterious magnetic field fluctuations. Overall, the thesis represents a significant advance in the state-of-the-art relating to advanced semiconductor platforms for quantum technologies.

Ravi Acharya attended the University of Manchester, including a year abroad at the University of Illinois at Urbana-Champaign, and received an M.Phys. (Hons) degree in 2021. He subsequently began a joint Ph.D. program between the University of Melbourne and University of Manchester, focusing on the development and characterization of materials for semiconductor spin-based quantum computing. His doctoral research investigated methods for producing highly coherent group-V donor spin qubits in silicon, specifically the generation of high purity 28-silicon and the exploitation of donor magnetic clock transitions, both of which reduce the magnetic noise affecting the donor spin. He was awarded a joint DPhil degree from both institutes in June 2025.