Synthesis and characterization of high-purity SnO2(ZnO:Sn)m superlattice nanowire arrays with broad-spectrum emissions

Abstract

SnO₂(ZnO:Sn)_m is a new phase recently found in the diagram of a ZnO–SnO₂ binary system in the form of a one-dimensional nanowire, which is a new group of superlattice oxide besides the widely known M₂O₃(ZnO)_m (M = trivalent elements, such as In, Ga, and Al, and m = integer). Thereafter, more comprehensive structural and physical properties of SnO₂(ZnO:Sn)_m are still quite lacking due to the difficulties in high purity synthesis. In this study, we demonstrate a rational design for the growth of SnO₂(ZnO:Sn)_m superlattice nanowire arrays using a home-built double-tube chemical vapor deposition (CVD) system for the first time. The atomic microstructure of the nanowire array was investigated by Cs-corrected scanning transmission electron microscopy (STEM), and a phenomenon of unsaturated Sn occupation in Sn–O octahedral layers was observed. Two new vibrational modes at 276 cm⁻¹ and 698 cm⁻¹ were found in Raman measurement. The photoluminescence (PL) spectrum of SnO₂(ZnO:Sn)_m superlattice nanowires displays an interesting broad-spectrum emission in the range of around 380–570 nm. Kelvin probe force microscopy reveals that the average work function of SnO₂(ZnO:Sn)_m nanowires is in the range of 4.05–4.32 eV.