Controlled Synthesis of Tellurium Nanowires

Abstract

One-dimensional tellurium nanostructures can exhibit distinct electronic properties from those seen in bulk Te. The electronic properties of nanostructured Te are highly dependent on their morphology, and thus controlled synthesis processes are required. Here, highly crystalline tellurium nanowires were produced via physical vapour deposition. We used growth temperature, heating rate, flow of the carrier gas, and growth time to control the degree of supersaturation in the region where Te nanostructures are grown. The latter leads to a control in the nucleation and morphology of Te nanostructures. We observed that Te nanowires grow via the vapour–solid mechanism where a Te particle acts as a seed. Transmission electron microscopy (TEM) and electron diffraction studies revealed that Te nanowires have a trigonal crystal structure and grow along the (0001) direction. Their diameter can be tuned from 26 to 200 nm with lengths from 8.5 to 22 μm, where the highest aspect ratio of 327 was obtained for wires measuring 26 nm in diameter and 8.5 μm in length. We investigated the use of bismuth as an additive to reduce the formation of tellurium oxides, and we discuss the effect of other growth parameters.

Magnetic properties of ferromagnetic nanoparticles of Fe x GeTe2 (x = 3, 5) directly exfoliated and dispersed in pure water

“…Figures 5(a), (d), (b) and (e) show the bulk (FNP) XPS data of F 3 GT and F 5 GT, respectively. The substantial increase of Teoxide peaks compared to Te 3d peaks from bulk to FNP indicates the formation of Te-oxide layers during the sonication process [37][38][39]. TEM data clearly shows the oxide layer at the edge of the crystal, while the inner region remains crystalline, which can be confirmed by the selected area diffraction pattern (figures 5(c) and (f) and supplementary figure 2).…”