Properties of nanosized ΖnO: Ho films deposited using explosive evaporation

The properties of nanosized ZnO:Ho thin films deposited by explosive evaporation method have been studied. This work is aimed at studying the effect of high deposition rate on the oxide characteristics interesting from the viewpoint of photocatalysis, namely: morphology and structure, electrical and optical properties, lifetime of charge carriers. Explosive deposition of films defines the novelty of this work as compared to majority of previous studies devoted to nanosized ZnO:Ho photocatalysts, which used equilibrium methods for their synthesis. Methods of scanning electron microscopy, XRD analysis, photoluminescence, and Raman scattering have shown that in ZnO:Ho films deposited using explosive evaporation, with increasing holmium content, amorphization of their structure and morphology are observed. It is related with random incorporation of holmium atoms into the crystalline lattice of ZnO as well as with the fact that the ionic radius of Ho3+ exceeds that of Zn2+. It is accompanied by a shift of the edge of ZnO absorption toward the long-wave (blue) spectral range, the decrease of the bandgap as well as an increase in the resistivity and lifetime of charge carriers. All these changes are favourable for the photocatalytic process involving nanostructures based on ZnO:Ho

Laser Printing of Plasmonic Nanosponges

Three-dimensional porous nanostructures made of noble metals represent novel class of nanomaterials promising for nonlinear nanooptics and sensors. Such nanostructures are typically fabricated using either reproducible yet time-consuming and costly multi-step lithography protocols or less reproducible chemical synthesis that involve liquid processing with toxic compounds. Here, we combined scalable nanosecond-laser ablation with advanced engineering of the chemical composition of thin substrate-supported Au films to produce nanobumps containing multiple nanopores inside. Most of the nanopores hidden beneath the nanobump surface can be further uncapped using gentle etching of the nanobumps by an Ar-ion beam to form functional 3D plasmonic nanosponges. The nanopores 10–150 nm in diameter were found to appear via laser-induced explosive evaporation/boiling and coalescence of the randomly arranged nucleation sites formed by nitrogen-rich areas of the Au films. Density of the nanopores can be controlled by the amount of the nitrogen in the Au films regulated in the process of their magnetron sputtering assisted with nitrogen-containing discharge gas.

Laser Printing of Plasmonic Nanosponges

Three-dimensional porous nanostructures made of noble metals represent novel class of nanomaterials promising for nonlinear nanooptics and sensors. Such nanostructures are typically fabricated using either reproducible yet time-consuming and costly multi-step lithography protocols or less reproducible chemical synthesis that involve liquid processing with toxic compounds. Here, we combined scalable nanosecond-laser ablation with advanced engineering of the chemical composition of thin substrate-supported Au films to produce nanobumps containing multiple nanopores inside. Most of the nanopores hidden beneath the nanobump surface can be further uncapped using gentle etching of the nanobumps by an Ar-ion beam to form functional 3D plasmonic nanosponges. The nanopores 10-150~nm in diameter were found to appear via laser-induced explosive evaporation/boiling and coalescence of the randomly arranged nucleation sites formed by nitrogen-rich areas of the Au films. Density of the nanopores can be controlled by the amount of the nitrogen in the Au films regulated in the process of their magnetron sputtering assisted with nitrogen-containing discharge gas.

Features of the Implementation of the Vegard’s Law in Thin Films of Rare Earth Elements Compounds

In this work, the fulfillment of Vegard's law in thin polycrystalline films Sm1-xGdxS and Sm1-xEuxS, obtained by the method of explosive evaporation of the powder in vacuum, is investigated. It is shown that compliance with the Vegard law in the manufacture of thin-film structures based on Sm1-xEuxS solid solutions is possible only with the same technological parameters of film deposition, in particular, the substrate temperature. In the case of the Sm1-xGdxS solid solutions, the law is observed only in the metal phase of the solid solutions, with x> 0.12.

Study on the Structure and Morphology of Iron Nanopowders Obtained by the Method of Electric Explosion of Wires

This article presents the results of comprehensive study on the structure and<br />morphology of iron nanopowders synthesized by electric explosive evaporation of<br />metal wire. The results of scanning and transmission electron microscopy showed<br />that nanoclusters have a spherical shape with an average diameter of 65 nm. It<br />was revealed based on the analysis of the diffraction patterns that nanoparticles of<br />nanopowders obtained in electric explosion have a crystal lattice with a parameter<br />less than a standard cell. The results of computer experiments are in good agreement<br />with the findings of X-ray analysis. However, the question about the reasons of<br />distortion of the crystal lattice of nanoclusters remains controversial.