Microwave Photoconductivity in Nanocrystalline Porous Titanium Oxide Subjected to Pulsed Laser Excitation

摘要

A contactless method of microwave photoconductivity was used to study the relaxation of photoexcited charge carriers in nanocrystalline porous titanium oxide. A decrease in the amplitude and a change in the microwave photoconductivity relaxation time is observed with reduction in the nanocrystal size, which is explained by localization of carriers due to dielectric confinement. Capture of holes by the traps on the TiO_2 surface increases the amplitude and prolongs the relaxation time of the microwave photoconductivity.