Synthesis and Characterization of Nanoporous SnO2 Thin Film

SnO₂ is a kind of typical n-type semiconductor material. Due to its excellent performance in conductivity, optics, thermal stability and corrosion resisting, it has been widely applied in fields of gas sensor, solar cell, chemical electrode materials. A novel synthesis route, originated from dealloying of Sn-Zn alloys films in hydrochloric acid (HCl) solution and then thermal treating, has been developed for the preparation of SnO₂ films with three-demensional (3D) nanoporous. The influences of the HCl solution concentration and immersion time on crystal structure and morphology have been investigated. Porous structure and fracture surface morphology of the samples were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results indicated that the corrosion weight loss of Zn increased with the increasing of immersion time in HCl solution。An average pore diameter of the porous SnO₂ films is 50~200nm after heat treatment at 500°C for 2 hours. XRD patterns show that the films are SnO₂ with rutile structure.