Variation of Surface Nanostructures on (100) PbS Single Crystals during Argon Plasma Treatment

The nanostructuring of the (100) PbS single crystal surface was studied under varying argon plasma treatment conditions. The initial PbS single crystals were grown by high-pressure vertical zone melting, cut into wafer samples, and polished. Subsequently, the PbS single crystals were treated with inductively coupled argon plasma under varying treatment parameters such as ion energy and sputtering time. Plasma treatment with ions at a minimum energy of 25 eV resulted in the formation of nanotips with heights of 30–50 nm. When the ion energy was increased to 75–200 eV, two types of structures formed on the surface: high submicron cones and arrays of nanostructures with various shapes. In particular, the 120 s plasma treatment formed specific cruciform nanostructures with lateral orthogonal elements oriented in four <100> directions. In contrast, plasma treatment with an ion energy of 75 eV for 180 s led to the formation of submicron quasi-spherical lead structures with diameters of 250–600 nm. The nanostructuring mechanisms included a surface micromasking mechanism with lead formation and the vapor–liquid–solid mechanism, with liquid lead droplets acting as self-forming micromasks and growth catalysts depending on the plasma treatment conditions (sputtering time and rate).

Polymer-Templated Durable and Hydrophobic Nanostructures for Hydrogen Gas Sensing Applications

A simple and hands-on one-step process has been implemented to fabricate polymer-templated hydrophobic nanostructures as hydrogen gas sensing platforms. Topographic measurements have confirmed irregular hills and dips of various dimensions that are responsible for creating air bubble pockets that satisfy the Cassie–Baxter state of hydrophobicity. High-resolution field-emission scanning electron microscopy (FESEM) has revealed double-layer structures consisting of fine microscopic flower-like structures of nanoscale petals on the top of base nanostructures. Wetting contact angle (WCA) measurements further revealed the contact angle to be ~142.0° ± 10.0°. Such hydrophobic nanostructures were expected to provide a platform for gas-sensing materials of a higher surface area. From this direction, a very thin layer of palladium, ca. 100 nm of thickness, was sputtered. Thereafter, further topographic and WCA measurements were carried out. FESEM micrographs revealed that microscopic flower-like structures of nanoscale petals remained intact. A sessile drop test reconfirmed a WCA of as high as ~130.0° ± 10.0°. Due to the inherent features of hydrophobic nanostructures, a wider surface area was expected that can be useful for higher target gas adsorption sites. In this context, a customized sensing facility was set up, and H2 gas sensing performance was carried out. The surface nanostructures were found to be very stable and durable over the course of a year and beyond. A polymer-based hydrophobic gas-sensing platform as investigated in this study will play a dual role in hydrophobicity as well as superior gas-sensing characteristics.

Activation of two dopants, Bi and Er in δ-doped layer in Si crystal

Conventional doping processes are no longer viable for realizing extreme structures, such as a δ-doped layer with multiple elements, such as the heavy Bi, within the silicon crystal. Here, we demonstrate the formation of (Bi + Er)-δ-doped layer based on surface nanostructures, i.e. Bi nanolines, as the dopant source by molecular beam epitaxy. The concentration of both Er and Bi dopants is controlled by adjusting the amount of deposited Er atoms, the growth temperature during Si capping and surfactant techniques. Subsequent post-annealing processing is essential in this doping technique to obtain activated dopants in the δ-doped layer. Electric transport measurement and photoluminescence study revealed that both Bi and Er dopants were activated after post-annealing at moderate temperature.

Digital sovereignty of Russia based on the element base of topological nanostructures on a solid surface induced by laser radiation

The purpose of this work is to develop breakthrough technologies and technology transfer in the field of topological photonics, nanoelectronics and new materials with controlled functional and structural characteristics using a unique line of the Vladimir State University (VlSU) equipment (within the framework of the corresponding created structures - Centre of collective use, Center for Structural Materials Science and Breakthrough Engineering Physical Technologies, Center for Engineering Competencies, etc.) for carrying out work in the direction of high-tech industrial sectors. The report deals with the following issues on this topic: basic physical and scientific and technical principles, methods for measuring laser-induced structures on the surface of materials in real time, obtaining surface nanostructures on solid materials by deposition from colloidal systems using a two-stage scheme with laser ablation, modeling macroscopic quantum states in the functional properties of laser-induced 4d-topological nanoclusters in thin films on a solid surface and experimental demonstration of the work of real prototypes.

Electrochemical Synthesis of Unique Nanomaterials in Ionic Liquids

The review considers the features of the processes of the electrochemical synthesis of nanostructures in ionic liquids (ILs), including the production of carbon nanomaterials, silicon and germanium nanoparticles, metallic nanoparticles, nanomaterials and surface nanostructures based on oxides. In addition, the analysis of works on the synthesis of nanoscale polymer films of conductive polymers prepared using ionic liquids by electrochemical methods is given. The purpose of the review is to dwell upon an aspect of the applicability of ILs that is usually not fully reflected in modern literature, the synthesis of nanostructures (including unique ones that cannot be obtained in other electrolytes). The current underestimation of ILs as an electrochemical medium for the synthesis of nanomaterials may limit our understanding and the scope of their potential application. Another purpose of our review is to expand their possible application and to show the relative simplicity of the experimental part of the work.

Ablation-Free Laser Printing of Structural Colors in Reflection at 25,000 DPI

Using direct femtosecond laser patterning of metal-insulator-metal (MIM) sandwich designed to support Fabry-Perot mode in the visible spectral range we demonstrate new practically relevant strategy for high-resolution color printing. Irradiation of the MIM sandwich by tightly focused laser pulses allows to produce unique 3D surface nanostructures – hollow nanobumps and nanojets - locally modulating surface reflectivity. Laser processing parameters control the 3D shape of such nanostructures allowing to gradually tune the reflected color from reddish brown to pure green. Up-scalable ablation-free laser fabrication method paves the way towards various applications ranging from large-scale structural color printing to optical sensors and security labeling at a lateral resolution of 25,000 dots per inch.