Persistent photoconductivity in perovskite oxide semiconductors

The interaction of transparent oxide semiconductors with light is a central issue for a range of applications. Persistent effects could be exploited for holographic memory or optically defined circuits. They may also be detrimental to device operation. Large, room-temperature persistent photoconductivity (PPC) was discovered in strontium titanate (SrTiO₃, STO) after annealing in a hydrogen-containing atmosphere. Barium titanate (BaTiO₃, BTO), a ferroelectric material, was recently found to exhibit PPC. Recent results will also be presented on potassium tantalate (KTaO₃, KTO). The findings indicate that large PPC can occur in many materials and that hydrogen plays a central role.