Persistent photocurrent and decay studies in CdS nanorods thin films

Abstract

Structural and electrical transport properties of thin films of CdS nanorods synthesized by solvothermal process are studied through x-ray diffraction, scanning electron microscopy, transmission electron microscopy, activation energy measurements, and decay of photoconductivity. The films show thermally activated conductivity, high photosensitivity, and persistent photoconductivity, which decays initially fast followed by slow decay. The decay time constant for fast decay are of the order of a few seconds, whereas for slow decay it is in the range of about 100 s. The electrical transport is similar to that in the polycrystalline material. The slow decay of excess conductivity has been attributed to the presence of defects and local potential fluctuations within the nanorods.