High Performance Field Emitters.

The field electron emission performance of bulk, 1D, and 2D nanomaterials is here empirically compared in the largest metal-analysis of its type. No clear trends are noted between the turn-on electric field and maximum current density as a function of emitter work function, while a more pronounced correlation with the emitters dimensionality is noted. The turn-on field is found to be twice as large for bulk materials compared to 1D and 2D materials, empirically confirming the wider communities view that high aspect ratios, and highly perturbed surface morphologies allow for enhanced field electron emitters.M.T.C. thanks the Oppenheimer Trust, Cambridge University, for generous financial support. This work was supported by an EPSRC Impact Acceleration grant and an Innovate UK Advanced Materials Feasibility Study award. CC thanks the EPSRC Centre for Doctoral Training in Ultra Precision.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/advs.20150031

Growth and characterization of PbO Nanorods grown using facile oxidation of lead sheet

PbO nanorods were synthesized by oxidation of lead sheets under an oxygen ambiance with different temperatures at 330, 400, 450 and 550ºC in a tube furnace. Scanning electron microscope (SEM) results showed that the nanorods started growing on the sheet that was placed at 330ºC. On the other hand, by increasing of the temperature to 550°C more nanorods appeared on the Pb sheet, which were lied on the lead sheet. X-ray diffraction pattern (XRD) indicated that the nanorods had α-PbO structures. However, a few β-PbO phases also appeared for the nanorods. Raman measurements confirmed the XRD results and indicated two Raman active modes that belonged to α-PbO phase for the nanorods. In addition, the Raman spectrum of the nanorods showed a weak peak of the β-PbO structure. The optical properties of the products were characterized using a room temperature photoluminescence (PL) technique. The PL result indicated a band gap for the PbO nanorods in the visible region

Growth and Optical properties investigation of undoped and Ag-doped ZnO nanostructures by sol-gel method

Undoped and Ag-doped ZnO nanoparticles with different percentage of Ag (2%, 4%, and6%) were synthesized by a sol-gel method using a gelatin media as a polymerization agent. Zinc nitrate and silver nitrate were used as raw materials for reaction. The obtained nanoparticles were characterized by TEM, XRD, UV-vis, and PL. The TEM results showed that, the sizes of the nanoparticles were the same approximately. The XRD patterns indicated hexagonal structure for all samples and incorporation silver ions in to the ZnO lattice. The UV-vis and PL results revealed that, the optical properties of the undoped ZnO nanoparticles were better than the Ag-doped ZnO nanoparticles