NbN and NbS<SUB>2</SUB> Nanobelt Arrays: <I>In-Situ</I> Conversion Preparation and Field-Emission Performance

Abstract

NbN nanobelt arrays were prepared by an in-situ conversion of aligned NbS3 nanobelts in the flowing NH3 at 950 degrees C, meanwhile, NbS2 nanobelt arrays were produced by a pyrolysis of aligned NbS3 nanobelts in the flowing argon atmosphere. The morphology and size of those nanobelts are close to the NbS3 nanobelt precursors, having a reactangular section of about 11 x 250 - 520 x 3100 nm2, and a length of about 120 microm. The microstructures were characterized by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDX). Magnetic measurements showed that the NbN nanobelts have superconductivity below 14.1 K. Field-emission experiments showed that the turn-on and threshold fields of the NbN nanobelt arrays (which are defined to be the macroscopic field to produce a current density of 10 microA/cm2 and 1 mA/cm2, respectively) are 0.61 and 2.3 V/microm, respectively, whereas the turn-on and threshold fields of the NbS2 nanobelt arrays are 0.61 and 3.5 V/microm, respectively, suggesting that they are decent field emitters.

Thermal Stability of Quasi-1D NbS3 Nanoribbons and Their Transformation to 2D NbS2: Insights from in Situ Electron Microscopy and Spectroscopy

“…Certainly, Nb 1.2 S 2 is a known phase, but no definitive evidence for Nb 1.2 S 2 versus NbS 2 was provided by Danot and co-workers. Furthermore, according to ex situ studies, heating NbS 3 -I at 800 °C for 1.5 h leads to 2 H -NbS 2 . We also do not find evidence of Nb 1.2 S 2 , although our samples are not in the optimal orientation to detect Nb intercalation.…”

MoSx-coated NbS2 nanoflakes grown on glass carbon: an advanced electrocatalyst for the hydrogen evolution reaction

“…[16][17][18][19][20] NbS 2 has already been found as a promising material in several applications, such as battery, 21 hydrotreating catalyst, 22 and sensor. 23 At present, several effective approaches have been reported for synthesizing NbS 2 with different morphologies, for instance nanowires, 20 nanotubes, 24 nanobelt arrays, 25 and thin films. 26 However, the exploration of new applications for NbS 2 is still hampered by the lack of well-controlled sample preparation method.…”

A Method Toward Fabricating Semiconducting 3R-NbS2 Ultrathin Films

“…For different stoichiometric NbS 2 the corresponding morphologies differ. Various forms of NbS 2 including platelets, thin films, nanobelt arrays, nanowires, , nanoflakes, and nanocables have been synthesized using either physical or chemical routes.…”