In this work, the spectra of optical constants of epitaxial layers of cadmium telluride near the fundamental absorption edge are studied. For this purpose, ellipsometric measurements of the layers under study were carried out in a vacuum chamber in the temperature range from T = 38–275°C. A numerical algorithm has been developed for solving the inverse ellipsometry problem for the structures under consideration, with the help of which the spectral dependences of the refractive index n(λ) and absorption index k(λ) are determined in the wavelength range from 700 to 1000 nm. The parametric dependences of k(λ, T) in the fundamental absorption region and in the transparency region are presented. The presence of an extended absorption tail in the transparency region was established, presumably associated with imperfections in the crystal structure.

A solution to the direct ellipsometry problem is presented for a single-layer model of an isotropic substrate–anisotropic film in the case of the orientation of the film optical axis in the plane of incidence. Analytical expressions for calculating the ellipsometric parameters of such a structure are obtained. A simple numerical algorithm is proposed for determining the ordinary ( n_o ) and extraordinary ( n_e ) refractive indices of a bulk crystal under various measurement conditions. The inverse problem of determining n_o , n_e , and the film thickness d when changing the azimuth of the optical axis is considered. The correlation of the required parameters for such a problem is discussed.

The problems of in situ ellipsometric control during the growth of ZnTe and CdTe buffer layers intended for cadmium-mercury-tellurium epitaxy are considered. It has been established that for 20 nm ZnTe layers the spectral dependences of the optical constants near the absorption edge are smoothed, which indicates the presence of structural defects in the film. It has been shown that the microrelief of the CdTe growth surface is a criterion for the structural perfection of the layers and can be measured using an ellipsometer both at the early stages and during steady-state growth.

During the propagation of the Hinnamnor typhoon from September 5 to 6, 2022, swell waves were recorded that arrived at the recording point 20 h before the typhoon entered the Sea of Japan. While analyzing the field data of the laser meter of fluid pressure variation, it was possible to calculate the area of the formation of the main group of swell waves generated by the propagating typhoon and to localize the region of generation of forerunner waves and also to describe the mechanisms of their formation and propagation.

Представлено решение прямой задачи эллипсометрии для однослойной модели изотропная подложка - анизотропная плёнка в случае ориентации оптической оси плёнки в плоскости падения. Получены аналитические выражения для расчёта эллипсометрических параметров такой структуры. Предложен простой численный алгоритм определения обыкновенного ( no ) и необыкновенного (ne ) показателей преломления объёмного кристалла при различных условиях измерения. Рассматривается обратная задача определения no , ne и толщины плёнки d при изменении азимута оптической оси. Обсуждается проблема корреляции искомых параметров для такой задачи. A solution to the direct ellipsometry problem is presented for a single-layer model consisting of an isotropic substrate and an anisotropic film in the case of the orientation of the optical axis of the film in the plane of incidence. Analytical expressions for calculating the ellipsometric parameters of such a structure are obtained. A simple numerical algorithm is proposed for determining the ordinary ( no ) and extraordinary ( ne ) refractive indices of a bulk crystal under various measurement conditions. The inverse problem of determining no, ne, and film thickness d when changing the azimuth of the optical axis is considered. The correlation of the required parameters for such a problem is discussed.

Subject of study. An alternative substrate for the growth of a mercury-cadmium-telluride ternary compound is studied, which consists of silicon with CdTe and ZnTe layers deposited on it. Aim of study. . The aim is the construction of a model of the rough surface of CdTe films to create a technique for quality control of the growing structures. Method. Non-destructive methods with sufficient resolution are required as roughness measurement techniques. These conditions are satisfied by optical research methods. In this work, ellipsometry and interference profilometry were used. Main results. The roughness of CdTe films was studied using ellipsometry and interference profilometry. It is shown that these two methods perfectly complement each other and provide a more complete picture of the profile surface than each one separately. A two-scale model of the rough surface of CdTe buffer layers representing a slightly wavy surface with a small-scale relief superimposed on it has been constructed. It is shown that the ellipsometric measurements are affected by the small-scale relief. This result was used to develop a technique for controlling the process of epitaxial growth of buffer layers. Practical significance. The results of studying the surface roughness of CdTe films obtained in this work serve as the basis for the development of methods for controlling the parameters of CdTe layers suitable for growing high-quality photosensitive structures. (c) 2024 Optica Publishing Group

The energy structure of the size quantization levels in multiple Hg0.3Cd0.7Te/HgTe quantum wells grown via molecular beam epitaxy on a (013)GaAs substrate has been studied. Experimental and calculated energy positions of three size quantization levels are obtained.

В работе подтверждена сильная взаимосвязь пространственных свойств инфрагравитационных волн и характеристик волн зыби. Показано, что уровень энергии инфрагравитационных волн зависит от географических условий и местных особенностей. При обработке большого массива данных по вариациям гидросферного давления, полученных в ТОИ ДВО РАН с помощью лазерно-интерференционных донных измерительных систем, обнаружено, что поверхностные ветровые волны и зыбь в окрестностях мыса Шульца Японского моря усиливают амплитуды инфрагравитационных волн с периодами от 20 до 300 с. То есть, установлено соответствие возрастания амплитуды ветровых волн и зыби возрастанию амплитуды инфрагравитационных волн. Замечено, что это правило работает и в обратном порядке, т.е. снижение амплитуды ветровых волн и зыби соответствует снижению амплитуды инфрагравитационных волн. При этом рост амплитуды инфрагравитационных волн сопровождается возрастанием периода ветрового волнения. Данные инфрагравитационные волны распространяются в виде волновых цугов, границы которых практически не меняются со временем, при этом период отдельных волн внутри цугов может меняться, однако характер и параметры этих изменений не зависят от характеристик породивших их волн. В то же время обнаружено, что инфрагравитационные волны подвержены изменению своей спектральной структуры в случае влияния на них местных колебательных процессов. Так, в бухте Витязь инфрагравитационные волны имеют в спектре боковые максимумы, обусловленные модуляционным воздействием сейшевого колебательного процесса бухты. Периоды инфрагравитационных и ветровых волн, регистрируемых в бухте Витязь, могут быть промодулированы также приливно-отливными колебаниями, характеристики которых, очевидно, зависят от местных условий. Отмечено также, что спектральные максимумы, регистрируемых в бухте инфрагравитационных волн, имеют дискретную структуру, обусловленную модуляционным воздействием более низкочастотных волн. The work confirms the strong relationship between the spatial properties of infragravitational waves and the characteristics of swell waves. It is shown that the energy level of infragravitational waves depends on geographical conditions and local features. It was found that surface wind waves and swell in the vicinity of Cape Schulz in the Sea of Japan enhance the amplitudes of infragravitational waves with periods from 20 to 300 s. That is, the correspondence between the increase in the amplitude of wind waves and swell and the increase in the amplitude of infragravitational waves has been established. In this case, the increase in the amplitude of infragravitational waves is accompanied by an increase in the period of wind waves. These infragravitational waves propagate in the form of wave trains, the boundaries of which practically do not change with time, while the period of individual waves inside the trains can change, however, the nature and parameters of these changes do not depend on the characteristics of the waves that generated them. At the same time, it was found that infragravitational waves are subject to a change in their spectral structure if they are affected by local oscillatory processes. Thus, in the Vityaz Bay, infragravitational waves have side maxima in the spectrum, due to the modulation effect of the seiche oscillatory process of the bay. The periods of infragravitational and wind waves recorded in Vityaz Bay can also be modulated by tidal oscillations, the characteristics of which obviously depend on local conditions.

In situ temperature control is required to obtain HgCdTe layers of high crystalline perfection by molecular beam epitaxy. To solve this problem, we used spectroscopic ellipsometry. Various methods have been developed for measuring the temperature before the start of epitaxy. They are based on the analysis of different regions of the ellipsometric spectra of the CdTe buffer layer. An experimental comparison of the suggested methods shows that the temperature measurement accuracy is several degrees, and the sensitivity reaches fractions of a degree. At the stage of stationary growth of layers, it is possible to determine the change in temperature and composition from the kinetics of ellipsometric spectra. Ellipsometric measurements made during the growth of HgCdTe with a sharp change in the heating regime showed correlated changes in both temperature and composition.

An ellipsometric technique has been developed which makes it possible to observe changes in the composition and temperature of cadmium--mercury--tellurium layers during their growing by molecular beam epitaxy. The technique was tested for diagnostics the variations of the composition and the temperature during layer growth in the mode of constant power of the substrate heater and with its sharp change. It was found that the drop in power and a following decrease in the growth temperature were also accompanied by a monotonic decrease in the composition. In the case of a constant heater power, a slight increase in the sample temperature was observed with an almost unchanged composition of the growing layer. Keywords: ellipsometry, mercury--cadmium--telluride, in situ control, epitaxial growth, temperature.

The problem of in situ temperature control during the growth of epitaxial layers of HgCdTe by molecular beam epitaxy is considered. Various approaches to solving the problem using spectroscopic ellipsometry are proposed. They are based on the temperature dependence of the optical constants spectra of the CdTe buffer layer and the growing HgCdTe layer. The results of experimental testing of these methods are presented, which show that the temperature measurement accuracy is several degrees, and the sensitivity reaches fractions of a degree. At the stage of stationary growth, it is possible to determine the change not only in the temperature, but also in the composition of the growing layer from the ellipsometric spectra.

Influence storage and boiling in deionized water and heat treatments of epitaxial films CdxHg1-xTe on the Hall and ellipsometric parametres is investigated. Water treatment reduces refractive index of native CdxHg1-xTe oxide from 2.1 to 1.2-1.4. It means that matter with a lower refractive index, such as water, is introduced in the oxide. Boiling in water leads to formation of acceptors in CdxHg1-xTe with concentrations up to 1019 cm-3. Change of medium’s pH from alkaline to the acidic decreases the speed of acceptors formation. Heat treatments after storage in water also leads to formation of acceptors. The conclusion is made, that water medium or water absorbed by native oxide layer leads to formation of acceptors in CdxHg1-xTe. Concentration of acceptors grows with temperature of treatments and quantity of accessible water.

На основе проведeнных in situ и ex situ эллипсометрических измерений найдены спектральные зависимости температурной чувствительности оптических постоянных Hg1-xCdxTe --- dn(λ) и dk(λ) для серии образцов разного состава в диапазоне от 0.160 до 0.327. Эксперименты были проведены в процессе остывания выращенных образцов в вакуумной камере. Установлено, что полученные зависимости dn и dk хорошо аппроксимируются суммой трeх осцилляторов Лоренца с добавлением дисперсионных слагаемых формулы Коши. Предложена параметрическая модель, которая описывает чувствительности dn(λ) и dk(λ) для произвольного состава x в указанном диапазоне вблизи температуры роста. Проведенные ex situ температурные измерения вблизи комнатной температуры коррелируют с данными высокотемпературных измерений. Полученные результаты актуальны для разработки эллипсометрических методов контроля in situ процессов роста слоeв Hg1-xCdxTe. Ключевые слова: кадмий-ртуть-теллур, эллипсометрия, спектры оптических констант, температурная чувствительность, молекулярно-лучевая эпитаксия.

This article presents results on the development, creation, and application of a control system for long-base laser strain gauges intended for the study of geodynamic processes over a wide frequency range. The control system includes: a long base laser strain gauge employing test quadrature signals based on an unequal-arm Michelson laser interferometer, a recording apparatus, and a device for data collection and storage. A geophysical laser-interference complex is described which serves as a basis for constructing interregional spatially separated measurement systems. The efficiency of laser-interference measurement devices based on a Michelson interferometer is demonstrated in accounting for the influence of external factors during geophysical measurements employing laser strain gauges. A strain-gauge recording system based on a Michelson interferometer is described which yields high sensitivity and permits detection of high frequency oscillations (up to 2 kHz). The advantages of this monitoring system compared to the previous versions are noted: the optical scheme of the proposed interferometer contains fewer parts and the recording system is more reliable and consumes less power.

The modern tendencies of development of infrared detectors based on HgCdTe heterostructures are fabricating photoconductors and photodiodes type focal plane arrays (FPA). For producing of high quality FPA’s it is necessary to grow HgCdTe with high uniformity properties over the large surface area. The growth of HgCdTe heteroand nanostructures on GaAs and Si substrates allows to decrease the cost of HgCdTe material and essentially to simplify the technological process of FPA fabricating. The investigations of development of HgCdTe heteroand nanostructures growth on GaAs substrates are presented. Multi-chamber MBE installation for growth of HgCdTe epilayers on GaAs and Si substrates up to 4” in diameter with precise control of films quality in situ allows to solve many problems connected with the producing high uniformity MCT layer composition over the surface area and control the MCT composition throughout the thickness. The defects formation mechanisms, its nature, the parameters characterization allows are presented.The growth of HgCdTe heterostructures with different composition distribution throughout the thickness allows to prepare material with unique properties that lead to simplification of fabricating high quality IR detectors on their basis. The new fields of science are connected with different new physical phenomena studied on HgCdTe nanostructures such as single or multilayer quantum wells (QW). The results of HgCdTe based QW mostly HgTe QW growth with ellipsomentric control and parameters measurement are presented. The application of HgCdTe heterostructures for different IR detector type is presented. We presented the results of study of different HgTe QW in field of carrier transport, interaction with THz radiation, for laser radiation, 2D and 3D TI etc.

Low temperature in situ control in the technology of HgCdTe layers growing by MBE is a key requirement for obtaining structures of high quality. Spectroscopic ellipsometry seems to be one of the suitable technique for solving this problem. The present paper proposes ellipsometric methods for determining the temperature in the process of pre-epitaxial heat treatment of the samples. The proposed methods are based on the temperature dependence of the optical constants spectra of the CdTe buffer layer. The first method uses the temperature shift of the absorption edge, which is determined from the onset of interference oscillations. It turned out to be resistant to experimental errors and its accuracy proved to be 3-5 degrees C. The second method is based on comparing the measured and reference spectra. It is much more sensitive to the temperature, but depends strongly on the accuracy of ellipsometric measurements. The combined use of both methods ensures a temperature sensitivity of the order of 1 degrees C and an accuracy of 3-5 degrees C.

Разработана эллипсометрическая методика, позволяющая наблюдать за изменениями состава и температуры слоeв кадмий--ртуть--теллур в процессе их выращивания методом молекулярно-лучевой эпитаксии. Методика опробована для диагностики состава и температуры при выращивании слоeв в режиме постоянной мощности нагревателя подложки и при еe резком изменении. Установлено, что падение мощности и последующее уменьшение температуры роста сопровождается также монотонным уменьшением состава. В случае постоянной мощности нагревателя наблюдается незначительное увеличение температуры образца при практически неизменном составе растущего слоя. Ключевые слова: эллипсометрия, кадмий--ртуть--теллур, HgCdTe, состава, in situ контроль температуры, эпитаксиальный рост.

We provide a review of the current state, problems and their solutions, and potential possibilities to develop the technology of the Molecular Beam epitaxy (MBE) to obtain CdHgTe structures on various substrates for infrared detectors. We present the data about MBE supervacuum units control tools for growth processes, collected according to used substrates preparation processes for substrate surfaces, growth of buffer layers on alternating substrates, and growth and alloying of CdHgTe layers. We present main defects of structures (such as line defects and macrodefects) and their least achieved concentration levels limiting the quality of detectors. We consider the data about problems of the external alloying of CdHgTe layers by dopants and the obtained electrophysical parameters of such layers. We provide photoelectric parameters of IR-detectors, close to theoretical ones and showing that the MBE technology is ready to produce CdHgTe/Si structures on six-inch diameters. We demonstrate results of the research and development of the growth and alloying of CdHgTe structures on GaAs substrates and Si substrates of 76.2-mm diameters, implemented at the Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences.

Температура подложки при выращивании слоёв кадмий-ртуть-теллур (КРТ) в технологии молекулярно-лучевой эпитаксии является одним из ключевых параметров, который обеспечивает стабильный рост бездефектных эпитаксиальных плёнок с заданными характеристиками. Используемые в мировой практике методы контроля температуры, такие как пирометрия, спектроскопия края поглощения, термопарный либо малоэффективны, либо требуют дополнительной технической адаптации вакуумного оборудования.

By the analysis of the experimental data and model calculations, features of the propagation of hydroacoustic signals over a shelf of decreasing depth generated by a low-frequency hydroacoustic emitter at a frequency of 22 Hz and their transformations at the “water–bottom” interface into the Rayleigh waves recorded by a coastal laser strainmeter are studied. Energy estimates for the propagating hydroacoustic signals are presented at different points on the shelf; and such estimates for the transformed seismic–acoustic signals are obtained at the location of a laser strainmeter in the Earth’s crust.