Detection of Space Charge Limited Currents in Nanoscaled Titania

Abstract

Titania (TiO 2 ) exhibits widespread technical applications extending from photocatalysis for the oxidative degradation of organically polluted waste water up to photo-electrochemistry in novel solar cells. The abilities and advantages of photocatalytic titania (anatase) are widely made use of, but the microscopic physical properties, e.g. the mobility of electrons, the density of free charge carriers and the trap density are still objects of scientific research. In this paper, we report about the observation of space charge limited currents (SCLC) in nanoscaled pure and chromium doped titania. The electron transition times are measured and used to calculate the mobility of electrons. Furthermore, a determination of both free charge carrier density and trapped charge carrier density is given.