Well-crystalline ultrathin GaS nanobelts have been successfully synthesized on silicon substrates by a simple thermal evaporation process. The GaS nanobelts were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), and energy dispersive X-ray analysis (EDAX). The XRD pattern indicates formation of well-crystalline hexagonal phase GaS nanostructures. The SEM image shows uniformly distributed GaS nanostructures covering the entire substrate surface. The TEM results reveal that the GaS nanostructures are "nanobelts" of widths 20 to 50 nm and lengths up to several microns, and some of them are L-shaped. The growth mechanism and formation of GaS straight and L-shaped nanobelts has been explained. The field emission studies revealed that the threshold field required to draw an emission current of ∼1 nA is to be 2.9 V/µm, and a current density of ∼5.7 µA/cm 2 can be drawn at an applied field of 6.0 V/µm. The Fowler-Nordheim plot, derived from the observed current densityapplied field characteristics depicts nonlinear behavior over the entire range of applied field. The field enhancement factor is estimated to be ∼2.0 × 10 4 . The emission current stability investigated over a duration of more than 2 h at the preset value ∼4.0 µA shows initial increment followed by stabilization to a higher value ∼6.0 µA. The average emission current at the stabilized value is seen to be fairly constant with current fluctuations within (10%. The results suggest the use of GaS nanobelts as a promising electron source for applications in field emission based devices.

Here, we demonstrate the synthesis of aligned CdS nanowires by a solvothermal process where the alignment of the nanowires was controlled by tuning the reaction conditions. The normal and photoassisted field emission properties of the aligned CdS nanowires were studied. The turn-on field is found to be 0.68 V/μm which is much lower than the reported values. From the I-t plot, it is shown that the emission current remains nearly constant over 4 h at preset current value of 5 μA. Upon illumination, the photofield emission current shows a reproducible switching property with a rise in the current level of almost 50% of the initial value. The field emission properties indicate promising applications in field emission based devices.

High-quality self-assembled V(2)O(5) nanofiber-bundles (NBs) are synthesized by a simple and direct hydrothermal method using a vanadium(v) hydroxylamido complex as a vanadium source in the presence of HNO(3). The possible reaction pathway for the formation of V(2)O(5) NBs is discussed and demonstrated that HNO(3) functions both as an oxidizing and as an acidification agent. V(2)O(5) NBs are single-crystals of an orthorhombic phase that have grown along the [010] direction. A bundle is made of indefinite numbers of homogeneous V(2)O(5) nanofibers where nanofibers have lengths up to several micrometres and widths ranging between 20 and 50 nm. As-prepared V(2)O(5) NBs display a high electrochemical performance in a non-aqueous electrolyte as a cathode material for lithium ion batteries. Field emission properties are also investigated which shows that a low turn-on field of ∼1.84 V μm(-1) is required to draw the emission current density of 10 μA cm(-2).

Here, we report the synthesis of vertically aligned gallium sulfide (GaS) nanohorn arrays using simple vapor-liquid-solid (VLS) method. The morphologies of GaS nano and microstructures are tuned by controlling the temperature and position of the substrate with respect to the source material. A plausible mechanism for the controlled growth has been proposed. It is important to note that the turn-on field value of GaS nanohorns array is found to be the low turn-on field 4.2 V/μm having current density of 0.1 μA/cm(2). The striking feature of the field emission behavior of the GaS nanohorn arrays is that the average emission current remains nearly constant over long time without any degradation.

The field-emission properties of SnO(2):WO(2.72) hierarchical nanowire heterostructure have been investigated. Nanoheterostructure consisting of SnO(2) nanowires as stem and WO(2.72) nanothorns as branches are synthesized in two steps by physical vapor deposition technique. Their field emission properties were recorded. A low turn-on field of ~0.82 V/μm (to draw an emission current density ~10 μA/cm(2)) is achieved along with stable emission for 4 h duration. The emission characteristic shows the SnO(2):WO(2.72) nanoheterostructures are extremely suitable for field-emission applications.