Structural and photovoltaic properties of highly ordered ZnFe2O4 nanotube arrays fabricated by a facile sol–gel template method

Abstract Highly ordered ZnFe 2 O 4 nanotube arrays were successfully prepared using porous anodic aluminum oxide (AAO) template from sol–gel solution. The ZnFe 2 O 4 nanotubes are orderly arranged in parallel and each nanotube is composed of many agglutinating nanoparticles. The UV–vis absorption and surface photovoltage spectra of the ZnFe 2 O 4 nanotubes and gel powders have been compared. The photovoltaic response threshold of the ZnFe 2 O 4 nanotubes exhibited a blue-shift of about 150 nm with respect to that of the ZnFe 2 O 4 gel powder, which implies that the photogenerated charges in the nanotubes have a higher redox activity than that of the gel powder. Both materials behave like a p-type semiconductor with photogenerated electrons accumulated at their surface.