BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates i.e., Si (111) and SiC/graphene with Bi0.7Sb1.6Te1.8Se0.9 and ...Bi0.9Sb1.5Te1.8Se1.1, respectively. The crystallographic properties of BSTS films were investigated via X-ray diffraction, which showed the strongest reflections from the (0 0 l) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate. Polarization dependent Raman spectroscopy showed a weak appearance of the Ag mode in cross--polarized geometry. In contrast, a strong Eg mode was observed in both parallel and cross-polarized geometries which correspond to the rhombohedral crystal symmetry of BSTS films. A redshift of Ag and Eg modes was observed in the Raman spectra of BSTS films grown on the Si substrate, compared to those on SiC/graphene, which was directly associated with the unit cell parameter and composition of the films. Raman spectra showed four fundamental modes with asymmetric line shape, and deconvolution of the peaks resulted in additional modes in both the BSTS thin films. The sum of relative ratios of linewidths of fundamental modes (Ag and Eg) of BSTS films grown on Si substrate was lower, indicating a more ordered structure with lower contribution of defects as compared to BSTS film grown on SiC/graphene substrate.
BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates
, Si (111) and SiC/graphene with Bi
Sb
Te
Se
and Bi
Sb
Te
Se
, respectively. ...The crystallographic properties of BSTS films were investigated
X-ray diffraction, which showed the strongest reflections from the (0 0
) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate. Polarization dependent Raman spectroscopy showed a weak appearance of the A
mode in cross--polarized geometry. In contrast, a strong E
mode was observed in both parallel and cross-polarized geometries which correspond to the rhombohedral crystal symmetry of BSTS films. A redshift of A
and E
modes was observed in the Raman spectra of BSTS films grown on the Si substrate, compared to those on SiC/graphene, which was directly associated with the unit cell parameter and composition of the films. Raman spectra showed four fundamental modes with asymmetric line shape, and deconvolution of the peaks resulted in additional modes in both the BSTS thin films. The sum of relative ratios of linewidths of fundamental modes (A
and E
) of BSTS films grown on Si substrate was lower, indicating a more ordered structure with lower contribution of defects as compared to BSTS film grown on SiC/graphene substrate.
The results of the testing and operation of the Arktika-M highly elliptical orbit hydrometeorological space system are presented. The advantages of highly elliptical orbits, the main characteristics ...and tasks of the Arktika-M No. 1 satellite payload are considered. The description is given of the ground-based segment and resulting information products required to solve problems for the benefit of socioeconomic development of northern Russia.
BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates
i.e.
, Si (111) and SiC/graphene with Bi
0.7
Sb
1.6
Te
1.8
Se
0.9
and Bi
0.9
Sb
...1.5
Te
1.8
Se
1.1
, respectively. The crystallographic properties of BSTS films were investigated
via
X-ray diffraction, which showed the strongest reflections from the (0 0
l
) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate. Polarization dependent Raman spectroscopy showed a weak appearance of the A
g
mode in cross--polarized geometry. In contrast, a strong E
g
mode was observed in both parallel and cross-polarized geometries which correspond to the rhombohedral crystal symmetry of BSTS films. A redshift of A
g
and E
g
modes was observed in the Raman spectra of BSTS films grown on the Si substrate, compared to those on SiC/graphene, which was directly associated with the unit cell parameter and composition of the films. Raman spectra showed four fundamental modes with asymmetric line shape, and deconvolution of the peaks resulted in additional modes in both the BSTS thin films. The sum of relative ratios of linewidths of fundamental modes (A
g
and E
g
) of BSTS films grown on Si substrate was lower, indicating a more ordered structure with lower contribution of defects as compared to BSTS film grown on SiC/graphene substrate.
The sum of relative ratios of peak widths of A
g
and E
g
modes of BSTS film grown on Si substrate was lower which indicated more ordered structure with lower contribution of localized defects compared to SiC/graphene substrate.
The study presents methods and examples of using satellite-based products developed by the Planeta Research Center for Space Hydrometeorology to monitor natural hazards (floods, fires, tropical ...cyclones, environmental pollution, volcanic activity, etc.) on the territory of Russia.
Russia is currently developing the Meteor-3M space observation system of hydrometeorological and oceanographic service that operates through several space vehicles of Meteor-M type. In July, 2014 ...hydrometeorological satellite Meteor-M No. 2 was successfully launched to the sun-synchronized orbit. Given is general information on Meteor-M No. 2 onboard measurement system, the composition of its output products, and areas of their application. Described is the ground-based complex for the reception, processing, dissemination, and archiving of satellite data.
Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by ...employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir-Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 10
3
was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 10
4
. This is an important step towards the detection of the phonon spectrum from a single QD.
Electromagnetic enhancement of CdSe quantum dots in surface and tip-enhanced Raman scattering with improved sensitivity.
Discussed are the issues of the organization of work with distributed archives of satellite data and results of their processing in the Planeta Research Center for Space Hydrometeorology reception ...centers. It is tasked to design the system providing the uniform “transparent” work with the information resources regardless of their physical location. Considered are the general concept of such system as well as its main components and basic requirements. These components include uniform data processing subsystems, distributed data archiving subsystems, and data access subsystems which should be created in all Planeta centers. The special focus is made on the capabilities of the first operational stage of the system providing the access to and analysis of the data from various Russian and foreign operational satellite systems that are currently received and processed in the Planeta Research Center for Space Hydrometeorology. Given are the examples of the use of the system in hydrometeorology and disaster monitoring. In conclusion, the main courses of the development of the system are described.
The study provides the overview of the Russian and foreign Earth satellite observation systems used to monitor the Arctic region. The plans of development of Russian hydrometeorological constellation ...in the next years are outlined. A brief description of the Arktika-M satellite system is presented. The informational prospects are discussed of using IR data from MSU-IK-SRM scanning radiometer installed onboard Kanopus-V-IK satellite to monitor the Arctic sea ice. Various techniques of satellite data processing developed and used in the Planeta Research Center for Space Hydrometeorology are presented including the plotting of raster and vector Arctic sea ice maps, the maps of automated detection and classification of Arctic ice structures with multispectral imagery, sea ice drift, and sea ice boundaries in the Arctic region and its Russian sector. The long-term satellite datasets on Arctic sea ice mapping are analyzed, sea ice reduction is revealed. Map validation results for the Arctic sea ice boundaries obtained from Russian and foreign satellite data are presented.
We report on the study of surface enhanced infrared absorption (SEIRA) by steroid hormone cortisol molecules with different concentrations deposited on linear Au nanoantenna arrays. Localized surface ...plasmon resonances (LSPRs) arise in the nanoantennas under the influence of external electromagnetic radiation. LSPR frequency depends mainly on the nanoantenna length and can vary from the visible to the terahertz range. We establish the ratio between the structural parameters of nanoantenna arrays and LSPR frequencies based on the results of 3D electrodynamic simulations. Using nanolithography we fabricate nanoantenna arrays having LSPR frequencies close to the frequencies of the most intense absorption modes of steroid hormone cortisol. We deposit cortisol molecules onto the surface of nanoantenna arrays by drop- coating. SEIRA spectra of the nanoantenna arrays make it possible the determination of the presence of cortisol and establishing the sensitivity limit of this method. Thus, we show possibility of SEIRA application for cortisol concentration analysis.
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