Physics of photocatalysts

Abstract

When a semiconductor is band-gap excited by light absorption, electrons appear in the conduction band and holes are in the valence band. Some of the charge carriers, electrons and holes, migrate to the semiconductor surface, attach to adsorbed molecules, and then promote a desired reaction of the molecules. This series of physical and chemical events provide a photocatalytic reaction. It is still an open question how the carrier transport is affected by dopants in the bulk or by molecules at the surface. In this plenary talk, our experimental efforts to reveal the question using infrared absorption and scanning probe microscopy are reviewed.