An effective approach to grow boron nitride nanowires directly on stainless-steel substrates

When growing one-dimensional (1D) nanomaterials via the vapour–liquid–solid (VLS) model, the substrates usually need to be coated with a layer of catalyst film. In this study, however, an effective approach for the synthesis of boron nitride (BN) nanowires directly onto commercial stainless-steel foils has been demonstrated. Growth occurs by heating boron and zinc oxide (ZnO) powders at 1100 °C under a mixture of nitrogen and hydrogen gas flow (200 ml min−1). The stainless-steel foils played an additional role of catalyst besides substrate during the VLS growth of these BN nanowires. The as-synthesized nanowires emit strong photoluminescence (PL) bands at 515, 535 and 728 nm. In addition, we found that the gas flow rate and the hydrogen content in the gas mixture strongly affected the diameter and yield of the nanowires by changing the relative concentration of the nanowire growth species in the chamber.

Selective oxidation synthesis of MnCr2O4 spinel nanowires from Commercial stainless steel foil

For the first time, MnCr₂O₄ spinel single-crystalline nanowires were simply synthesized by heating commercial stainless steel foil (Cr_0.19Fe_0.70Ni_0.11) under a reducing atmosphere. The nanowires have an average diameter of 50 nm and a length of about 10 μm. Some nanowires are sheathed with a thin layer of amorphous silicon oxide. Photoluminescence measurements revealed that the nanowires exhibit an emission band at 435 nm, which resulted from the oxygen-related defects in the silicon oxide sheath. It was found that the reducing atmosphere plays a key role for the nanowire growth. In the reducing atmosphere, the Mn and Cr elements in the stainless steel could be selectively oxidized because of their higher affinity for oxygen than the Fe and Ni elements. The Fe and Ni elements in the stainless steel, however, acted as the catalyst for the vapor–liquid–solid (VLS) growth of the MnCr₂O₄ nanowires.

Controlled growth of zinc nanowires

Zinc nanowires have been synthesized by heating a mixture of boron and zinc oxide (ZnO) powders at 1050 °C under a nitrogen atmosphere. The influences of the gas flow rate and the substrate character on the nanowire formation were investigated. It was found that higher-flow rate of gas led to the formation of thinner nanowires; while lower-flow rate of gas produced thicker nanowires and even particles due to the higher partial pressure of Zn vapor in this case. Zn nanowires can be produced on alumina and quartz substrates, but not on a stainless-steel substrate under the same or different synthetic conditions. Photoluminescence measurements were conducted on Zn nanowires and particles and weak emission bands at 482 and 493 nm were observed, which may be contributed by the thin ZnO film on the nanowire surface.

Epitaxial growth of multi-structure sno2 by chemical vapor deposition

The nanowire and whisker heterostructures of tin dioxide were fabricated by the chemical vapor deposition technique. It was demonstrated that various structures of tin oxide can be obtained by controlling the thickness of gold layer and the partial pressure of source vapor at growing sites. 12.5 and 25 nm thicknesses are preferable for the epitaxial growth of nanowires and heterostructure through vapor-liquid-solid mechanism, respectively. The tin dioxide whiskers with core-shell structure were fabricated by vapor-solid mechanism. Meanwhile, the influences of various factors on the tin dioxide growth are also discussed.