Synthesis of Sb-additivated SnO2 nanostructures and dependence of photoluminescence properties on Sb additivation concentration

Abstract

Single crystalline Sb-additivated SnO2 nanorods, beaklike nanorods, and nanoribbons were synthesized by an in situ catalyst-assisted thermal evaporation process on single-crystal Si substrates. As the Sb:Sn weight ratios were increased, the morphologies of Sb-additivated SnO2 nanostructures would progressively transform from nanorods to beaklike nanorods and to the mixture of nanowires and nanoribbons. The SnO2 nanorods grow along the [02¯0] direction and with lateral facets defining a square column consisting of {100} and {001} planes. The Sb-additivated SnO2 beaklike nanorods initially grow along the [01¯1¯] direction and then switch to the [031¯] direction to form the beak, while the nanoribbons grow along the [110] direction. The Sb atoms were found to uniformly distribute over the whole Sb-additivated SnO2 nanostructures and that it would not affect the single crystallinity of SnO2 nanostructures. The photoluminescence spectra of the nonadditivated and Sb-additivated SnO2 nanostructures exhibited multipeaks with peak positions centered at 403, 453, 485, 557, and 622 nm. When Sb atoms were additivated into SnO2 nanostructures, the luminescence intensities would significantly decrease and photoluminescence at 557 and 622 nm would almost disappear. These can be explained by the replacements of the six- and fivefold coordinated Sn atoms on low-index facets by five- and fourfold coordinated Sb atoms, respectively, leading to the cancellation of 100° tin coordinated on-plane oxygen bridging vacancies and 130° tin coordinated in-plane oxygen vacancies.