Sulfur-doped zinc oxide (ZnO) Nanostars: Synthesis and simulation of growth mechanism

Abstract

We present a bottom-up synthesis, spectroscopic characterization, and ab initio simulations of star-shaped hexagonal zinc oxide (ZnO) nanowires. The ZnO nanostructures were synthesized by a low-temperature hydrothermal growth method. The cross-section of the ZnO nanowires transformed from a hexagon to a hexagram when sulfur dopants from thiourea [SC(NH 2 ) 2 ] were added into the growth solution, but no transformation occurred when urea (OC(NH 2 ) 2 ) was added. Comparison of the X-ray photoemission and photoluminescence spectra of undoped and sulfur-doped ZnO confirmed that sulfur is responsible for the novel morphology. Large-scale theoretical calculations were conducted to understand the role of sulfur doping in the growth process. The ab initio simulations demonstrated that the addition of sulfur causes a local change in charge distribution that is stronger at the vertices than at the edges, leading to the observed transformation from hexagon to hexagram nanostructures.

Nanoparticle shape anisotropy and photoluminescence properties: Europium containing ZnO as a Model Case

“…[44][45][46] Electronic and optical properties of ZnO can be controlled by specific anion or cation substitution in the sub-lattice, hereafter abbreviated as E@ZnO. [47][48][49][50][51][52][53][54] Special emphasis should be given here to ZnO nanomaterials doped with rare earth metal ions. [55][56][57][58] Those materials are promising candidates for potential applications in optical communication, 59 field emission displays (FEDs).…”

Dilute tin-doped CdS nanowires for low-loss optical waveguiding

“…It is this dilute doping concentration that allows for the co-existence of high crystalline quality and considerable trap-state emission in these nanowires, 13 which is entirely different from those heavily doped semiconductor nanostructures that usually suffer from high structural disorders and rough surfaces. [16][17][18]22 In this regard, these dilute doped nanowires are still excellent optical cavities, in spite of the presence of strong trap-state emission.…”

“…On one hand, pure single-crystalline semiconductor nanostructures can work as good optical cavities but their trap states are almost negligible. On the other hand, intentionally doping semiconductor nanostructures can oen lead to considerable trap states, but high structural disorder (rough surface, non-uniform diameter, small aspect ratio as well as high scattering concentration and interfaces) is easy to introduce simultaneously, [16][17][18] making it almost impossible to effectively transport the optical signal.…”

Enhanced moisture sensing properties of a nanostructured ZnO coated capacitive sensor

“…ZnO is a group II-VI, wide band gap (3.3 eV) semiconducting compound 14 with a stable wurtzite structure 15 and can be synthesized in various morphologies. [16][17][18][19] It exhibits distinctive properties and is widely applicable as an electrical generator, 20 or in light emitting diodes, 21 solar cells, 22 and different types of gas, as well as humidity, sensor. 18,23,24 Due to the high chemical stability, low cost, non-toxic nature, chemical sensitivity to gases, ease of doping and enhanced dielectric properties, ZnO nanoparticles were conceived to be benecial in gas sensing applications and moisture detection.…”