NT-MDT Spectrum Instruments

Using InSb/GaSb semiconductor quantum dots, we demonstrate the lateral spatial resolution of scattering apertureless near-field microscope equal to 10 – 15 nm at a wavelength of λ = 10.7 μm provided by a single-mode CO2 laser. The measurement conditions make it possible to undoubtedly exclude any artifacts caused by the sample topography and other similar factors. We identify the strongly localized in-plane near-field signal with a two-dimensional electron gas clamped on the InSb/GaSb interface of quantum dots.

Scanning probe lithography (SPL) is a versatile nanofabrication method that employs a scanning probe microscope (SPM) to generate patterns and nanoscale structures on surfaces. Typically, an atomic force microscope (AFM) is the preferred type of SPM for nanolithography and in situ characterization based on the probe–sample interaction. However, the maximum area of the existing SPL is mainly limited by scanner stroke of the AFM and usually less than 100 × 100 μm^2. Ultralarge-area nanofabrication can be achieved by using a “step and scan” manner but leading to stitching errors and low throughput. This article proposes a novel ultralarge-area stitchless SPL and high-throughput in situ characterization system utilizing a leaf spring-based nanomanipulator, which offers a maximum scanning area of 2 × 2 mm^2. Further, we propose a novel optimized passband loss filter for the repetitive control of the nanomanipulator to realize high-bandwidth and high-precision trajectory tracking. Experimental results indicate that the proposed control method achieves satisfactory tracking performance for a triangular wave with an amplitude of 500 μm. Compared with the existing SPL systems, we achieve stitchless nanolithography at a speed of ~ 2 mm/s and high-throughput in situ characterization in the range of 500 × 500 μm^2. This system opens up significant avenues for the research and application of ultralarge-area nanofabrication and in situ characterization.

Eumelanin, the brown-black member of the melanin biopigment family, is a prototype material for sustainable (green) organic electronics. Sepia eumelanin (Sepia) is a type of biosourced eumelanin extracted from the ink sac of cuttlefish. Electron microscopy and scanning probe microscopy images of Sepia show distinguishable near spherical granules with diameters of about 150–200 nm. We have recently reported on predominant electronic transport in printed films of Sepia formulated inks including the (insulating) binder Polyvinyl-butyral (PVB). In that work, we proposed that inter-granular percolative transport, observed for micrometric interelectrode distances, is promoted by the confining action of the PVB binder on the Sepia granules. Considering that inter-granular transport implies intra-granular transport, in this work we proceeded to a nanoscale study of Sepia granules by High Resolution Atomic Force Microscopy (HR-AFM) and Conductive-AFM (c-AFM). We have observed protrusions on the surface of the Sepia granules, suggesting sub-granular structures compatible with the hierarchical development of Sepia, as proposed elsewhere. For films of Sepia formulated inks deposited on gold-coated substrates, c-AFM revealed, for the very first time, a nanoscale electrical response. Nanoscale studies provide the key to structure–property relationships in biosourced materials strategic for sustainable organic electronics.

The atomic force microscopy (AFM) is an important tool capable of characterization, measurement, and manipulation at the nanoscale with a vertical resolution of less than 0.1 nm. However, the conventional AFMs' scanning range is around 100 µm, which limits their capability for processing cross-scale samples. In this study, it proposes a novel approach to overcome this limitation with an ultra-large scale stitchless AFM (ULSS-AFM) that allows for the high-throughput characterization of an area of up to 1 × 1 mm2 through a synergistic integration with a compliant nano-manipulator (CNM). Specifically, the compact CNM provides planar motion with nanoscale precision and millimeter range for the sample, while the probe of the ULSS-AFM interacts with the sample. Experimental results show that the proposed ULSS-AFM performs effectively in different scanning ranges under various scanning modes, resolutions, and frequencies. Compared with the conventional AFMs, the approach enables high-throughput characterization of ultra-large scale samples without stitching or bow errors, expanding the scanning area of conventional AFMs by two orders of magnitude. This advancement opens up important avenues for cross-scale scientific research and industrial applications in nano- and microscale.

Scanning probe lithography (SPL) is a promising technology to fabricate high-resolution, customized and cost-effective features at the nanoscale. However, the quality of nano-fabrication, particularly the critical dimension, is significantly influenced by various SPL fabrication techniques and their corresponding process parameters. Meanwhile, the identification and measurement of nano-fabrication features are very time-consuming and subjective. To tackle these challenges, we propose a novel framework for process parameter optimization and feature segmentation of SPL via machine learning (ML). Different from traditional SPL techniques that rely on manual labeling-based experimental methods, the proposed framework intelligently extracts reliable and global information for statistical analysis to fine-tune and optimize process parameters. Based on the proposed framework, we realized the processing of smaller critical dimensions through the optimization of process parameters, and performed direct-write nano-lithography on a large scale. Furthermore, data-driven feature extraction and analysis could potentially provide guidance for other characterization methods and fabrication quality optimization.

Scanning probe lithography (SPL) is a promising technology to fabricate high-resolution, customized and cost-effective features at the nanoscale. However, the quality of nano-fabrication, particularly the critical dimension, is significantly influenced by various SPL fabrication techniques and their corresponding process parameters. Meanwhile, the identification and measurement of nano-fabrication features are very time-consuming and subjective. To tackle these challenges, we propose a novel framework for process parameter optimization and feature segmentation of SPL via machine learning (ML). Different from traditional SPL techniques that rely on manual labeling-based experimental methods, the proposed framework intelligently extracts reliable and global information for statistical analysis to fine-tune and optimize process parameters. Based on the proposed framework, we realized the processing of smaller critical dimensions through the optimization of process parameters, and performed direct-write nano-lithography on a large scale. Furthermore, data-driven feature extraction and analysis could potentially provide guidance for other characterization methods and fabrication quality optimization.

Nanoarchitectures with promising properties have now been formed from many important biomolecules. However, the preparation of nanoparticles of vitamin B12 and its derivatives remains an ongoing research challenge. This paper describes the formation of supermolecular nanoentities (SMEs) of vitamin B12 derivatives, unique nanoparticles with strong noncovalent intermolecular interactions, emerging properties, and activity. These were created by a nanoarchitectonic approach using directed assembly of layers at the air-water interface as a link in the chain of evolution of the parent molecules under specially created conditions. Such layers can be represented as a nanocosm, where, at a critical density, the assemblies act as nanoreactors in which the transformation of the original material occurs. The discovered SMEs not only replicate the functioning of vitamin B12 assemblies with proteins in living organisms and act as vitamin B12-depended enzymes but also demonstrate important advantages over vitamin B12. They are more efficient in oxygen reduction/evolution reactions and in transformation into other forms. These SMEs, in performing advanced tasks, are an alternative to widely used materials based on noble metals for catalysis, medicine, and environment protection. Our findings open new perspectives both for the fabrication of novel SMEs of biomolecules and for a better understanding of the evolution of biomolecules in nature.

Currently, much research is devoted to the study of biological objects using atomic force microscopy (AFM). This method’s resolution is superior to the other non-scanning techniques. Our study aims to further emphasize some of the advantages of using AFM as a clinical screening tool. The study focused on red blood cells exposed to various physical and chemical factors, namely hemin, zinc ions, and long-term storage. AFM was used to investigate the morphological, nanostructural, cytoskeletal, and mechanical properties of red blood cells (RBCs). Based on experimental data, a set of important biomarkers determining the status of blood cells have been identified.

The nanoscale state for many substances differs significantly from the massive state. During the formation of arrays of silver nanoparticles by condensation on a cold substrate, the initial condensate is unstable. For the formation of stable arrays with a shape close to spherical, subsequent weak heat treatment is required. In this work the behavior of an array of silver nanoparticles during low-temperature annealing is shown. Using atomic force microscopy, the evolution of an array of silver nanoparticles formed on the SiO2 surface by vacuum-thermal evaporation onto an unheated substrate during in-situ heating to a temperature of 200°C is studied. A qualitative assessment of the effect of temperature on the geometry of nanoparticle arrays is obtained. It is experimentally shown that a sharp coarsening of silver nanoparticles and a decrease in their number on the surface take place in the narrow temperature range of 75 to 100°C, while in the temperature range of 100 to 200°C, there are no noticeable changes in the array of silver nanoparticles. After the statistical processing of the obtained data, the average size of the formed particles and their density per unit area at each stage of the experiment are determined. The corresponding dependences are obtained.

We used transmission electron microscopy, Raman, and photoluminescence spectroscopy to identify the effect of CuPt-type GaP-InP atomic ordering (AO) on the structural and emission properties of self-organized (SO) InP/GaInP2 Wigner molecule (WM) quantum dot (QD) structures. We found that the correlation of AO and SO growth results in the formation of InP/GaInP2 QD/AO-domain (QD/AOD) core-shell composites. This observation shows that intrinsic WMs in this system emerge due to a strong piezoelectric field generated by AODs, which induces QD doping and a built-in magnetic field. We found that the bond relaxation of AODs leads to a decrease in the emission energy of WMs of 80 meV. The photoluminescence spectra of single WMs having an emission energy ∼1.53 eV are presented here, the lowest one reported for this system.

This manuscript collects all the efforts of Russian Consortium, bottlenecks revealed in the course of the C-HPP realization and ways of their overcoming. One of the main bottlenecks in the C-HPP is the insufficient sensitivity of proteomic technologies, hampering the detection of low- and ultralow-copy number proteins formed the «dark part» of the human proteome. In the frame of MP-Challenge, to increase proteome coverage we suggest an experimental workflow based on a combination of shotgun technology and selected reaction monitoring with two-dimensional alkaline fractionation. Further, to detect proteins that cannot be identified by such technologies, nanotechnologies such as combined atomic force microscopy with molecular fishing and/or nanowire detection may be useful. These technologies provide a powerful tool for single molecule analysis, by analogy with nanopore sequencing during genome analysis. For the systematic analysis of the functional features of a number of proteins (CP50 Challenge), we created a mathematical model that predicts the number of proteins differing in amino acid sequence – proteoforms. According to our data, we should expect about 100 thousand different proteoforms in the liver tissue and a little more in the HepG2 cell line. The variety of proteins formed whole human proteome significantly exceeds these results due to PTMs. As PTMs determine the functional specificity of the protein, we propose using a combination of gene-centric transcriptome-proteomic analysis with preliminary fractionation by two-dimensional electrophoresis for chemically modified proteoforms identification. Despite the complexity of the proposed solutions, such integrative approaches could be fruitful for MP50 and CP50 Challenges in the framework of the C-HPP.

The low-temperature (T = 2 K) light reflectance spectra of organic semiconductor structures produced by depositing Langmuir–Blodgett films on a cadmium sulfide (CdS) crystal surface are studied. The spectra were studied in the region of the resonant frequency of the exciton state An = 1 in CdS. The spectra were analyzed within a multilayer medium model with allowance for the spatial dispersion and an exciton-free “dead” layer near the crystal surface contacting with the film. A conclusion is made that, as a result of the deposition of an organic film on a semiconductor crystal surface, the Wanier–Mott exciton is spatially localized near the film–crystal interface.

The CD spectra of dispersion particles with the “re-entrant” packing of ds DNA have been compared to the CD spectra of particles with the cholesteric ordering of these molecules. The intercalation of daunomycin (DAU) between base pairs of DNA leads to an appearance of new additional band in the CD spectra. The linking of DNA in the single particles by (DAU-copper) nanobridges transforms the “liquid-like” structures of the both particles into the “rigid” state. These effects prove the existence of the cholesteric structure in “re-entrant” DNA phase.

We report a realization of room temperature lasing threshold of 1 μW in GaInP microdisk containing a few self-aggregated InP/GaInP quantum dots (QDs) grown by metal-organic vapor phase epitaxy. InP/GaInP QD microdisk cavities emitting in the spectral range of 700–800 nm and having the size of ~2 μm, free spectral range of ~35 nm and quality factors Q ~ 4000 were formed by wet chemical etching. Low dot density (~2 μm–2) and large dot size (~150 nm), suggesting a single dot lasing and maximum overlap of QD and cavity mode, were achieved using deposition of 3 ML of InP layer at 700°C.

The work is devoted to the study of the surface of anti-friction aluminium alloys. The influence of alloying elements and heat treatment on the physical and mechanical properties of the surface, its thermal conductivity, and electrical conductivity was estimated. It is shown that the addition of a number of elements (Pb, Bi, Cd, and In) to the base alloy Al-5Si-4Cu and subsequent heat treatment lead to an increase in physical and mechanical properties (so, the greatest hardness value has an alloy with cadmium). Thermal conductivity at the macrolevel was estimated from the measurement of electrical conductivity; it is shown that doping and heat treatment in most cases bring to a little change of these parameters. A complex method of microscopy (scanning electron microscopy with elemental analysis and scanning probe microscopy) was used to study the surface of the samples. Various modes of scanning probe microscopy were used: topography, spreading currents, and surface temperature were measured independently. It is shown that the values of electrical conductivity and thermal conductivity measured at the microlevel are correlated well enough. A significant heterogeneity in the surface thermal conductivity of the cast sample is found, which correlates with the corresponding phase composition of the impurities.