Grant: Discovery Grants Program - Individual

Silicon holds a central role in the continuously advancing electronic device technology, which enables the computing, communications, entertainment and other technologies upon whcih we rely. Silicon also holds a special place among semiconductors for the study of the physics of impurities, defects and excitations called excitons, thanks to the incredible purity and crystalline perfection available in silicon, resulting from the billions of dollars which have been invested in silicon technology over the past several decades. We study an even more perfect form of silicon, known as isotopically enriched silicon, and we have discovered surprising and unexpected new properties of this material which have already lead to new discoveries in semiconductor physics, and which may in future lead to new applications in quantum computing. Silicon, like most materials, has more than one stable isotope (different isotopes of the same element have the same chemical propoerties but differ slightly in mass since they contain different numbers of neutrons). By eliminating the randomness inherent in this mixture of isotopes, some of the properties of isotopically enriched silicon are remarkably better than what was thought possible based on normal silicon. In particular, this improves the optical properties which we study, and we can now observe phenomena which were thought to be impossible to see in any semiconductor, based on the properties of ordinary silicon. For example, we can measure and control the tiny nuclear spins of impurity atoms in isotopically enriched silicon using optical means, and this leads to many exciting new applications in the promising field of quantum computing. We can also study known, technologically important defects with incrediable new precision, and this has already led to a number of major surprises regarding the constituents of what were thought to be well-understood defects.