ToF-ERDA/RBS analysis of annealed TiO2 nanotubes grown onto FTO glass

Abstract

Different semiconductors have been studied as photoanode material for solar cells. Among them, TiO2 has been shown to be the best material due to its chemical stability and good charge transport capability. It is usually deposited onto FTO glass (F-SnO2), and then heated at high temperature in order to obtain inter-crystalline electric contact for improving electron conductivity. The focus of this research was chemical analysis of the TiO2 nanotubes (NTs) obtained by anodization of titanium film on FTO glass using NH4F in ethylene glycol electrolyte. There are only few studies suggesting that the electrolyte is a source of N dopant in TiO2, but also Sn diffusion from FTO support was reported. This study aims to show the chemical distribution of elements of interest along the nanotubes depth. For that purpose the time-of-flight elastic recoil detection analysis (ToF-ERDA) and Rutherford backscattering (RBS) methods were used as complementary techniques for chemical analysis of both light, such is N, and heavy elements, such is Sn. The TiO2 NTs films were annealed at different temperatures (450– 630 °C) and the impact of the heating temperature on the chemical distribution was followed.