Ioffe Physical Technical Institute Research Articles

A Study of the Residual Gas Composition in the Vacuum System of the Cyclotron of the Ioffe Physical Technical Institute

A Study of the Residual Gas Composition in the Vacuum System of the Cyclotron of the Ioffe Physical Technical Institute

20th Russian Youth Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics

Editorial PrefaceThe 20th Russian Young Conference on Physics of Semiconductors and Nanostructures, Opto- and Nanoelectronics was held in Saint Petersburg on November 26 – 30, 2018. It was organized by Peter the Great St. Petersburg Polytechnic University.The program of the Conference included semiconductor technology, heterostructures with quantum wells and quantum dots, opto- and nanoelectronic devices and new materials. A large number of participants with more than 200 attendees from many regions of Russia provided a perfect platform for the valuable discussions between students and experienced scientists.Conference included two invited talks given by leading scientists devoted to actual problems and major advances in physics and technology. The keynote speakers were A.T. Burkov from Ioffe Physical Technical Institute (presentation “Thermoelectric effects and energy converters”) and K.V. Kavokin from Spin Optics Laboratory at St. Petersburg University (presentation “Spin physics: from semiconductors to birds”). Students, graduate and postgraduate students presented their results on plenary and poster sessions. The total number of accepted papers published in Russian (the official conference language) was 123. Here we publish 38 of them in English.List of Editors, Winners of the E.F. Gross Prize for the best presentation in semiconductor optics and Winners of the competition for the best report are available in this pdf.

Behavior of Capillary-Porous Systems with Liquid Lithium under Influence of Pulsed Deuterium Plasma

Capillary-porous systems (CPS) with liquid lithium are considered as a prospective alternative to traditional structural materials (W, Be, CFC) during the production of in-vessel elements contacting plasma of stationary thermonuclear reactors. The behavior of CPS with liquid lithium under the impact of pulsed deuterium plasma flows is considered. The basic processes determining the high stability of CPS against damage are revealed and the critical parameters defining the CPS resistance are specified. The behavior of the tungsten-lithium CPS after its interaction with atmospheric gases is studied in experiments on a plasma facility at the Ioffe Physical-Technical Institute. The irradiated samples of the CPS were studied by optical and scanning electronic microscopy and local X-ray spectral and X-ray diffraction analyses. The surface temperature was measured using a bicolored pyrometer during deuterium plasma irradiation. The outcome of the plasma effect on the heavily oxidized CPS surface substantially differs from that for a pure surface: there is damage to the CPS structure. The specific power of the plasma flow was 22–41 GW/m2, and the number of pulses per irradiated target was 100.

Interfacing of a Coordinate-Sensitive Detector Based on Charge-Coupled Devices for Recording Ions with a Portable Static Mass Spectrograph

An IDS 2030 IonCCD coordinate-sensitive detector (Analytical/CMS Field Products) is interfaced with a small-sized mass spectrograph developed at the Ioffe Physical Technical Institute, Russian Academy of Sciences. The measurement data obtained with the mass spectrograph using an IonCCD detector and a Magnum-5901-37029PS channel secondary electron multiplier (Photonics USA Inc., United States) are compared. The results of measurements are discussed, and the prospects for using the IonCCD coupled with a microchannel plate are assessed.

Сопряжение координатно-чувствительного детектора на основе приборов с зарядовой связью для регистрации ионов с портативным статическим масс-спектрографом

AbstractAn IDS 2030 IonCCD coordinate-sensitive detector (Analytical/CMS Field Products) is interfaced with a small-sized mass spectrograph developed at the Ioffe Physical Technical Institute, Russian Academy of Sciences. The measurement data obtained with the mass spectrograph using an IonCCD detector and a Magnum-5901-37029PS channel secondary electron multiplier (Photonics USA Inc., United States) are compared. The results of measurements are discussed, and the prospects for using the IonCCD coupled with a microchannel plate are assessed.

4th International School and Conference on Optoelectronics, Photonics, Engineering and Nanostructures “Saint Petersburg OPEN 2017”

Editorial PrefaceDear Colleagues,4th International School and Conference “Saint Petersburg OPEN 2017” on Optoelectronics, Photonics, Engineering and Nanostructures was held on April 3 - 6, 2017 at St. Petersburg Academic University. The School and Conference included a series of invited talks given by leading professors with the aim to introduce young scientists with actual problems and major advances in physics and technology. The keynote speakers wereAlexey Toropov (Ioffe Physical Technical Institute RAS, Russia)Leonid Karachinsky (Connector Optics LLC, Russia)Sergei Alexandrov (Peter the Great St Petersburg Polytechnic University, Russia)Sergey Morozov (Institute for Physics of Microstructures RAS, Russia)Alexander Marmaluk (JSC M. F. Stelmakh Research Institute “Polyus”, Russia)Nika Akopian (Technical University of Denmark, Denmark)Anatoly Evstrapov (Institute for Analytical Instrumentation RAS, Russia)Seppo Honkanen (University of Eastern Finland, Finland)During the poster session all undergraduate and graduate students attending the conference presented their works. Sufficiently large number of participants with 286 student attendees from all over the world allowed the Conference to provide a fertile ground for the fruitful discussions between the young scientists as well as to become a perfect platform for the valuable discussions between student authors and highly experienced scientists. The best student papers, which were selected by the Program Committee and by the invited speakers basing on the theses and their poster presentation, were awarded with diplomas of the conference and prizes.List of The head of Program Committee, The head of Organizing Committee, The invited speakers, Poster Session, Elevator speech session, Award ceremony are available in this PDF.

The development of thin-film photovoltaic applications based structures on cuinse2 within the triple helix model

This work concentrates on the rewiew of the study of the photoelectrical phenomena of thin films for solar cells and also show the search of a new physical effects, which may be the basis for the development of new technologies, diagnostic methods, new types of photoconverters, and devices on these multinary semiconductors. Solar cells which based on silicon or binary III–V semiconductor compounds and their solid solutions successfully fulfilled their role as the first energy sources in outer space in the 1950s–1990s. Since 1997, technological development has been carried out for amorphous Si, CdTe thin film polycristal and CuInSe2 (CIS) solar cells in the thin film solar cell family. Thin film solar cells based on CuInSe2 and the related materials heretofore have been studied only for the aims of creating efficiencies. Complex physical and technological studies of the thin film solar cells on the basis chalcogenide chalcopyrite materials have made it possible to create devices with high radiation hardness and efficiencies as high as 18% [1-4]. At the same time, basic studies aimed to speed up film deposition is conducted from the aspect of material and substrate technologies for further cost reductions. For CIS solar cells research and development efforts continue to establish both element technologies necessary for the improvement in product quality and efficiency and large-area film fabrication technologies as essential part of the solar cell production process. This study was supported by the contract “Research and Development of Deposition System for CIGS Solar Cell” signed by the Ioffe Physical Technical Institute (Russian Academy of Sciences).

Cigs Thin Film Solar Cells Fabricated on The Various Substrates

Solar cells which based on silicon or binary III–V semiconductor compounds and their solid solutions successfully fulfilled their role as the first energy sources in outer space in the 1950s–1990s. Concentrator cascade of solar cells formed as heterostructures, based on InGaAsP solid solutions grown on germanium substrates, ensured progress in improving their main parameters, such as power density, the ratio of power/weight, and the solar cells operating time, however, the cost of photoconverters drastically increased as a result of these improvements. Evidently, the observed steady increase in the number of launched artificial satellites and a tightening of requirements for the size, weight, and cost of space technology have stimulated a continuous increase in demand for high efficiency solar cells, which are fabricated by low cost technologies and, at the same time, feature low weight parameters.The results of measuring the first spectra of relative quantum efficiency for photoconversion in thin film ZnO/CdS/Cu(In, Ga)Se2/Mo solar cells (CIGS solar cells) fabricated on rigid (glass) and flexible (polyimide) substrates are reported. The character of interband transitions has been studied and the values of the band gap for direct and indirect transitions in thin Cu(In, Ga)Se2 films are determined. It is found that a shift of the maximal photosensitivity for the obtained solar cells to shorter wavelengths is observed as rigid substrates are replaced by flexible ones. It is concluded that thin film Cu(In, Ga)Se2 structures can be used as broad band photoconverters of solar radiation with low costs. This study was supported by the contract “Research and Development of Deposition System for CIGS Solar Cell” signed by the Ioffe Physical Technical Institute (Russian Academy of Sciences).

Small switches of high-power microsecond pulses on the basis of high-voltage integrated pulse thyristors and reverse switch-on dynistors

A high-voltage switch on the basis of a small unit of series-connected high-voltage integrated pulse thyristors (HVIPTs), which were developed at the Ioffe Physical Technical Institute, was designed and investigated. At a power voltage of 25 kV, current pulses of microsecond duration with an amplitude of 2.8 kA and a rise time of 0.8 μs were switched. The attained current density through an HVIPT (5.6 kA/cm2) appreciably exceeds the permissible current density for conventional thyristors. It is shown that the developed HVIPT unit can be used in the triggering circuit of a high-power assembly of reverse switch-on dynistors (RSDs) at an operating voltage of 25 kV, which consists of 14 series-connected dynistors with a diameter of their structures of 24 mm. The RSD switch with a triggering circuit on the basis of HVIPTs allowed switching of rapidly rising current pulses with an amplitude of 20 kA and a duration of 150 μs. The small dimensions of the HVIPT unit (4 × 10 × 32 cm) and the RSD assembly (7 × 7 × 34 cm) determine the wide prospects for using them in high-power pulse technology.

Temporal response of silicon EUV and soft X-ray detectors

A small-sized generator of picosecond electron beams is used to measure the temporal resolution of EUV and soft X-ray silicon detectors produced by the Ioffe Physical Technical Institute, Russian Academy of Sciences. The temporal resolution of the EUV and soft X-ray detectors based on silicon photodiodes is shown to be ∼1 ns. Preliminary experiments have been performed using these detectors with the aim of investigating the radiation characteristics of a soft X-ray source based on an X-pinch driven by a small-sized highcurrent generator with a current pulse amplitude of 250 kA. This source is used at the Institute of High Current Electronics for soft X-ray backlighting diagnostics of various plasmas.

A high-voltage pulse integrated thyristor

The results of investigations of a small-size integrated thyristor recently developed at the Ioffe Physical Technical Institute of the Russian Academy of Sciences are presented. The operating voltage of the thyristor is 3300 V. The thyristor shows high switching performance in the regime of commutation of short current pulses with a high rise rate. The amplitude of a current pulse with a duration of 600 ns reaches 3.3 kA, while the current density is ∼37 kA/cm2.

The Driving Conditions for Obtaining Subnanosecond High-Voltage Pulses From a Silicon-Avalanche-Shaper Diode

Silicon-avalanche-shaper (SAS) diodes are fast-closing switches capable of producing high-voltage pulses with a rise time of ~100 ps. The SAS can be driven by a positive, nanosecond scale, high-voltage pulse applied to its cathode where the magnitude of the driving pulse is correlated to the magnitude of the pulse at the SAS anode (output). Drift-step-recovery diodes (DSRDs) are fast-opening switches capable of producing high-voltage pulses with a rise time of the order of 1 ns. Thus, DSRDs are good candidates for driving SAS diodes. In this paper, the SAS output is studied with respect to its driving conditions. First, the SAS output is examined with respect to the magnitude and rise time of the driving pulse, utilizing three DSRDs to produce pulses with various rise times from 0.5 to 5 ns. In addition, the effect of the driving pulse repetition frequency (PRF) on the SAS output is studied. An experimental demonstration using a 1.5-kV SAS fabricated at the Ioffe Physical Technical Institute shows the advantage of driving the SAS with the short, 0.5 ns, pulses, and the degradation of performance due to high PRF, up to 10 MHz.

New-generation concentrator modules based on cascade solar cells: Design and optical and thermal properties

New-generation concentrator modules use III–V nanoheterostructure cascade solar cells the efficiency of which can be raised to 50% for the number of cascades exceeding three. To obtain a high overall efficiency of photovoltaic conversion in power plants and extend their service time, it is necessary that the design of the modules be optimal in terms of optics and thermal engineering. In this work, main challenges in designing solar modules, such as optical concentration of radiation and residual heat removal, are considered. The results of pilot works that have been recently done in the Ioffe Physical Technical Institute are primarily reported.

Report on the 21st international shock interaction symposium

The 21st International Shock Interaction Symposium (ISIS21) was held from August 3rd to August 8th, 2014, in Latvia. It was organized jointly by the Ioffe Physical-Technical Institute of the Russian Academy of Sciences (Saint-Petersburg, Russia) and the University of Latvia (Riga). The Ioffe Institute and the University of Latvia enjoy long-term scientific cooperation. For the majority of shock reflection researchers, Latvia was a new country. For this reason, we decided to suggest Latvia as a possible venue for this symposium at the ISIS-20 in Stockholm 2 years ago. We are very grateful to the International Advisory Committee for their trust. As a logo for the planned Symposium, we selected the auseklis—the Latvian symbol of the morning star. In Latvian folk tradition, it bears the meaning of good will, and thus we thought to express our wishes of good luck to the event and its participants. The Symposium started in the heart of Latvia’s capital city, Riga, in the University of Latvia main building. The importance of this event for the academic life of the country was noted in the welcome speech by Mr. Igor Pimenov, Member of Parliament of Latvia, Secretary of the European Affairs Committee of Saeima. The next speech by Prof. Indriķis Muižnieks, vice-rector for research, gave an insight into the past and present of the University as a flagship of higher education in Latvia. Just to mention a remarkable fact, the opening ceremony of ISIS-21 took place exactly 100 years after Friedrich Zander, known alongside Ernst Mach as the inventor of optical Mach-Zander interferometers, received his diploma of graduation from the University of Latvia (at that time known as Riga Polytechnic) in the walls of the very same building on 19 Raiņa boulevard, Riga.

Impact of climate change on the physiological condition of passerine birds during migration.

Interest of specialists to the problem of impact ofclimate on the biosphere is constantly growingthroughout the world [1, 2]. Longterm data onchange in the timing of seasonal events in variousorganisms, longterm dynamics of their numbers,range expansions and other ecological consequencesof climate change are published regularly [3–5]. However, there are few publications where longtermchanges in morphological or physiological parametersare analyzed, mainly because of scarcity of highquality data [6–8].At the Biological Station Rybachy of ZoologicalInstitute of the Russian Academy of Sciences, longterm monitoring of breeding and migrating populations of birds has been performed continuously since1958. Valuable data on biometrics, including bodymass, wing length, fat score, and other parameters,have been collected. In collaboration with Ioffe PhysicalTechnical Institute of the Russian Academy ofSciences, a unique database has been compiled, whichincludes 3

New Interest in Intermetallic Compound ZnSb

The intermetallic compound ZnSb has been known since the 1830s. It has semiconductor properties, but its mechanical, thermal, and chemical properties are very close to those of a metallic alloy. When thermoelectrics based on (BiSb)2(TeSe)3 solid solutions were created, interest in ZnSb subsided. However, the current situation is different, as tellurium has become expensive and rare. Moreover, its compounds are too toxic, and it is too difficult to produce such materials and devices from these solid solutions. Recently, n-type material based on Mg2(SnSi) solid solution was proposed in the Laboratory of Physics for Thermoelements of the Ioffe Physical-Technical Institute. This material together with ZnSb may form a promising couple for creating various thermoelectric modules. In this paper, various properties (Hall and Seebeck coefficients, electrical and thermal conductivities) are reported in the temperature range from 80 K to 797 K. Different acceptor impurities have been tested. The Hall concentration at room temperature varied from 1.5 × 1018 cm−3 to 2.7 × 1019 cm−3. Some features have been discovered in the behavior of the thermoelectric parameters of double-doped ZnSb samples at temperatures above 500 K. Their nature points to a temperature-dependent increase of the Hall concentration. The existence of two temperature ranges with additional doping is revealed by Hall coefficient and electrical conductivity measurements in the range from 80 K to 797 K. The experimental data are discussed based on a model of the energy spectrum with impurity and native defect states localized in the energy gap. It is shown that the dimensionless thermoelectric figure of merit of ZnSb: Cd, Ag, Sn is not less than 1.0 at 600 K.

Optical-fiber-tip temperature control system for fiber-coupled laser modules in medical equipment

An optical-fiber-tip temperature control device embedded into the power-supply unit of high-power laser diodes and modules (with fiber-optic output) used in medical laser equipment is proposed. As the sensing element, a III–V mid-infrared photodiode developed at the Ioffe Physical-Technical Institute is chosen from the photodiode class whose parameters are optimal for developing multipurpose thermal-radiation detectors (pyrometric sensors). The developed device allows temperature control at the working tip of the optical fiber of the laser “scalpel” in the range of 600–1100°C with an error no worse than 1% for a response time of 1 ms. The device has digital and analog temperature-signal outputs, which can be used to control the laser pump current, thus extending the functionality of medical laser equipment, increasing its efficiency, safety, and service life.

Simulation of the conditions of wave excitation for the optimization of the lower hybrid current drive in the Globus-M spherical tokamak

At present, the method of current drive by means of lower hybrid waves is not applied to low-aspect-ratio tokamaks, because, in the traditional approach, it would be necessary to use waves with a very high slowing-down factor. However, studies of new transparency regions for waves in a nonuniform magnetized plasma, performed earlier at the Ioffe Physical Technical Institute, Russian Academy of Sciences, made it possible to develop an approach in which slow waves are excited in the poloidal (rather than toroidal) direction. In this approach, moderately slowed-down waves first propagate in the poloidal direction, but then turn in the toroidalal direction and get into the dense plasma. In this work, this approach is further developed using numerical methods. In particular, the influence of the density profile in the edge plasma on the efficiency of wave excitation for given antenna parameters is studied in detail.

Вклад учёных в Великую Победу на примере ЛФТИ

Вклад учёных в Великую Победу на примере ЛФТИ

Challenges in astrophysics (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 25 January 2012)

On 25 January 2012, the scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS), entitled as “Challenges in astrophysics”, was held at the conference hall of the Lebedev Physical Institute, RAS. The following reports were put on the session agenda posted on the website www.gpad.ac.ru of the RAS Physical Sciences Division: (1) Stepanov A V (Central (Pulkovo) Astronomical Observatory, RAS, St. Petersburg) “Coronal seismology”; 2) Yakovlev D G (Ioffe Physical Technical Institute, St. Petersburg; St. Petersburg State Polytechnical University, St. Petersburg) “Superfluid neutron stars”. The papers written on the base of the oral reports are published below. • Coronal seismology, A V Stepanov, V V Zaitsev, V M Nakariakov Physics-Uspekhi, 2012, Volume 55, Number 9, Pages 929–935 • Superfluid neutron stars, P S Shternin, D G Yakovlev Physics-Uspekhi, 2012, Volume 55, Number 9, Pages 935–941