Short-Period Superlattice Structure of Sn-Doped In₂O₃(ZnO)₄ and In₂O₃(ZnO)₅ Nanowires

Two longitudinal superlattice structures of In₂O₃(ZnO)₄ and In₂O₃(ZnO)₅ nanowires were exclusively produced by a thermal evaporation method. The diameter is periodically modulated in the range of 50−90 nm. The nanowires consist of one In−O layer and five (or six) layered Zn−O slabs stacked alternately perpendicular to the long axis, with a modulation period of 1.65 (or 1.9) nm. These superlattice nanowires were doped with 6−8% Sn. The X-ray diffraction pattern reveals the structural defects of wurtzite ZnO crystals due to the In/Sn incorporation. The high-resolution X-ray photoelectron spectrum suggests that In and Sn withdraw the electrons from Zn and enhance the number of dangling-bond O 2p states, resulting in the reduction of the band gap. Photoluminescence and cathodoluminescence exhibit the peak shift of near band edge emission to the lower energy and the enhancement of green emission as the In/Sn content increases.