Electrical compensation mechanism in fluorine-doped SnO2

Abstract

We report first-principles results for the electrical compensation mechanism in fluorine-doped SnO2 (SnO2:F), a widely used transparent conductor. We show that interstitial fluorine, which has traditionally been invoked as the source of compensation, has a high formation energy and hence cannot be responsible for compensation. Instead, we attribute compensation to complexes involving two fluorine atoms sharing an oxygen site. Formation of these complexes can explain the puzzling reduction (rather than a simple saturation) in the carrier concentration observed at high F concentrations.