Dependence of the morphology evolution and crystal orientation of tellurium (Te) micro- and nanostructures on the growth temperature

Controlled Synthesis of Tellurium Nanowires

“…The effect of the gas carrier flow rate can then be understood by considering that moderate flow rates of 200 sccm led to an optimal concentration of Te near the seeds. At 80 sccm, on the other hand, an excessive Te concentration profile is formed around the seeds, causing overgrowth, and thus just a few nanostructures are produced [ 21 , 27 ]. Then, at 50 sccm, only large microstructures are formed, as seen in Figure S4 .…”

“…However, nanostructured Te can crystallize in the trigonal phase, and such trigonal Te exhibits high hole mobility (707 cm V −1 s −1 ) [ 17 ], high current density (1 A mm −2 ) [ 18 ], and has tunable energy bandgaps up to 1 eV [ 19 ], opening up additional research fields. Several studies have already shown the possibility of obtaining a variety of nanostructures, such as needle-like nanowires with a tip of 50–70 nm and a base of 150–200 nm [ 20 ], Te nanorods 300–500 nm in diameter and 3 μm in length [ 21 ], nanowires with a base of 200 nm and a conical tip with diameter of 20 nm [ 22 ], tubular nanowires with an inner size of 50 nm and an external size of 500 nm [ 23 ], and finally hexagonal nanowires with tunable dimensions with diameters of 50–3000 nm and lengths of 1–22 μm [ 24 ]. The most common production techniques are based on wet-chemistry processes, while few reports exist on other methods such as chemical vapour deposition (CVD), PVD, or sputtering techniques [ 11 , 20 ].…”

“…PVD has been shown to be suitable for tuning the morphology of Te micro- and nano-structures depending on the growth parameters (i.e., the source and deposition temperatures, pressure, and carrier gas flow rate) [ 20 , 21 ]. The guiding principle for vapour phase growth is to control the supersaturation of the vapours by properly tailoring the growing parameters such as the precursors, deposition temperatures, pressure, and carrier gas flow rate.…”

“…It has been previously reported by Sen, S. et al [ 20 ] and Hyung, J.H. et al [ 21 ] that the morphology of Te nanostructures is highly dependent on the growth temperature and gas flow rate. Even though the obtained nanostructures in both works have large diameters (≥200 nm), they provide an initial approach to understanding the control of the morphology, which is still far from ideal.…”

Preparation and Characterization of Thermoelectric PEDOT/Te Nanorod Array Composite Films

“…The increase in the intensity of the (011) peak with increasing GDR time indicated that the crystallinity increased as the GDR proceeded. In particular, the improvement in the intensity of the (003) peak implied a [001] orientation along the c-axis, which was perpendicular to the Si surface [ 26 ]. The growth along the [001] direction may be attributed to the highly anisotropic characteristic of Te, which has a hexagonal structure arising from the strong covalent bonding between the neighboring atoms of the same helical chain (intrachain bonding), and weaker interaction between neighboring atoms in adjacent chains (interchain bonding) [ 27 , 28 ].…”