Tin Oxide Nanowires, Nanoribbons, and Nanotubes

Abstract

Nanowires, sandwiched nanoribbons, and nanotubes of SnO₂ are synthesized using elevated temperature synthesis techniques, and their structures are characterized in detail by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition to the normal rutile structured SnO₂, it has been possible to form an orthorhombic superlattice-like structure in the present study. The orthorhombic structure can form in a thin nanowire, coexist with the normal rutile structured SnO₂ in a sandwiched nanoribbon, or occur in the form of nanotubes. This result is distinct from that for bulk SnO₂ where pressures in excess of 150 kbar are required to form the orthorhombic form. The orientation relationship between the orthorhombic SnO₂ and the rutile structured SnO₂ is determined to be [001]_o || [102̄]_t and (100)_o || (010)_t for the nanowires and sandwiched nanoribbons, and [001]_o || [3 ]_t and (110)_o || (451)_t for the nanotubes. Although the growth direction of the rutile structured SnO₂ nanowires is along [101]_t, two growth directions are found to occur in the nanostructures having the orthorhombic SnO₂ structure. They are [010]_o for nanowires and [1̄10]_o for the sandwiched nanoribbons and nanotubes. The results in this study and the observation of orthorhombic SnO₂ may result from the formation of the products in an oxygen deficient environment.