The epitaxial growth technique of InGaAs photodiode structures based on a digital InGaAs/GaAs metamorphic buffer layer by metalorganic chemical vapor deposition has been developed. The spectral dependence of the photocurrent of photodiodes based on the produced structures has a maximum at the 1.16 µm wavelength. The photosensitivity range at 10% of peak is 0.99 - 1.33 µm at room temperature. The current-voltage characteristics in the temperature range 9–300 K were investigated. It is shown that the dark current consists of generation-recombination and tunneling components. The dark current density at room temperature was 8×10 -5 A/cm 2 with a reverse bias of -5 V.

Pulsed laser deposition in vacuum at 220°C of GaAs layers heavily doped with Mn and/or Bi has been used to form nanostructures on i-GaAs (100) substrates. It is shown that, for the electrical activation of manganese, it is expedient to use subsequent annealing with an excimer laser pulse with a wavelength of 248 nm and a duration of 30 ns. The structures show an anomalous Hall effect with a hysteresis loop on the magnetic field dependence up to a Curie temperature of about 70 K. Negative magnetoresistance is observed up to temperatures of ≈150 K. Bismuth does not prevent the activation of Mn atoms during annealing and contributes to an increase in the coercive field of the GaMnAs ferromagnetic semiconductor.

Abstract A new method for depositing carbon films by the thermal decomposition of carbon tetrachloride (CCl_4) in a hydrogen flux in a reactor for metal-organic chemical vapor deposition (MOCVD) at atmospheric pressure is developed. From the results obtained by Raman spectroscopy, it can be conceived that the carbon layers produced by this method are the disordered nanocrystalline graphite. It is shown that such carbon layers can be used in the technological cycle of the production of gallium-arsenide optoelectronic device structures (among them spin light-emitting diodes with a CoPt injector).

A new method for depositing carbon films by the thermal decomposition of carbon tetrachloride (CCl4) in a hydrogen flux in a reactor for metal-organic chemical vapor deposition (MOCVD) at atmospheric pressure is developed. From the results obtained by Raman spectroscopy, it can be conceived that the carbon layers produced by this method are the disordered nanocrystalline graphite. It is shown that such carbon layers can be used in the technological cycle of the production of gallium-arsenide optoelectronic device structures (among them spin light-emitting diodes with a CoPt injector).

The results of studying GaInAs/GaInP/GaAs photodiode structures grown by metal–organic vapor-phase epitaxy are reported. A procedure for the diagnostics of such multilayer structures is developed. The procedure is based on the application of Raman spectroscopy in combination with photoluminescence spectroscopy in the mode of the lateral scanning of transverse cleavages. The compositions of the GaInAs and GaInP solid solutions are determined.

AbstractThe results of studying GaInAs/GaInP/GaAs photodiode structures grown by metal–organic vapor-phase epitaxy are reported. A procedure for the diagnostics of such multilayer structures is developed. The procedure is based on the application of Raman spectroscopy in combination with photoluminescence spectroscopy in the mode of the lateral scanning of transverse cleavages. The compositions of the GaInAs and GaInP solid solutions are determined.

The capabilities of a technique based on combined photoluminescence and Raman-spectroscopy measurements upon lateral scanning across the cleaved edge of heterostructures for monitoring the strain profile and the thickness of epitaxial layers are demonstrated. The characteristics of a laser heterostructure with InGaAs/GaAsP quantum wells are investigated by this technique. It is shown that photoluminescence from different layers of the structure can be recorded separately. It is established that both the frequency of the InP-like phonon mode and the photoluminescence energy can be used to determine the composition of the In x Ga 1– x P alloy. The two methods yield close results.

С целью повышения концентрации электрически-активного Mn в слоях полупроводников A3B5 : Mn выполнены эксперименты по лазерному отжигу. Использован эксимерный лазер LPX-200 на KrF с длиной волны 248 nm и длительностью импульса ~30 ns. Экспериментально показано, что при энергии импульса эксимерного лазера >230 mJ/cm2 концентрация дырок в слоях GaAs : Mn увеличивается до 3·1020 cm-3. Отрицательное магнетосопротивление и аномальный эффект Холла с петлей гистерезиса для отожженных образцов GaAs : Mn сохраняются вплоть до 80-100 K. Аналогичные изменения в результате лазерного отжига наблюдаются и для слоев InAs : Mn. Работа выполнена в рамках реализации государственного задания (проект N 8.1751.2017/ПЧ) Минобрнауки России и Программы фундаментальных исследований ОФН РАН II.4 Спиновые явления в твердотельных наноструктурах и спинтроника" (тема 31). DOI: 10.21883/FTT.2017.11.45049.12k

Laser annealing experiments were performed in order to increase the concentration of electrically active manganese in the layers of A 3 B 5 : Mn semiconductors. An LPX-200 KrF excimer laser with a wavelength of 248 nm and a pulse duration of ~30 ns was used. It is shown experimentally that at a pulse energy of an excimer laser of >230 mJ/cm 2 , the hole concentration in GaAs: Mn layers increases to 3 × 10 20 cm –3 . The negative magnetoresistance and the anomalous Hall effect with a hysteresis loop for annealed GaAs: Mn samples remain the same up to 80–100 K. Similar changes are observed for InAs: Mn layers as a result of laser annealing.

Показана возможность комплексного применения фотолюминесценции и спектроскопии комбинационного рассеяния в режиме латерального сканирования поперечных сколов гетероструктур для контроля распределения напряжений, определения толщины эпитаксиальных слоев и состава твердых растворов. Указанным способом исследованы свойства лазерной гетероструктуры с квантовыми ямами InGaAs/GaAsP. Продемонстрирована возможность дифференцированно регистрировать фотолюминесцентное излучение от различных слоев структуры. Установлено, что определение состава твердого раствора InxGa1-xP по частотному положению InP-подобной моды и по энергии фотолюминесценции дает близкие значения. DOI: 10.21883/FTP.2017.11.45101.15

Методом сканирующей конфокальной спектроскопии комбинационного рассеяния света исследована кристаллическая структура GaAs, облученного ионами Mn+ с последующим импульсным лазерным отжигом. Сканирование поперечного скола образцов показало, что в результате лазерного отжига она полностью восстанавливается на всю глубину имплантации. Обнаружено рассеяние на связанной фонон-плазмонной моде, свидетельствующее об электрической активации примеси при дозах марганца выше 1·1016 см-2. На примере данных исследований продемонстрированы возможности метода сканирующей конфокальной спектроскопии комбинационного рассеяния света при исследовании поперечного скола структур, а на тестовом образце c delta-слоем углерода установлено, что латеральное разрешение метода составляет 300 нм.

Confocal micro-Raman spectroscopy was used to measure cross-section linescans of the cleaved edge of heterostructures involving a GaMnAs layer. The investigations revealed a shift of the TO mode in the compressed GaMnAs layer to high frequencies relative to the TO GaAs mode in the substrate and to low frequencies in the tensile GaMnAs layers. These results are in agreement with the different manifestations of the anomalous Hall effect in the GaMnAs layers, with either compressive or tensile strains. It is shown that Raman spectroscopy is an appropriate method for the investigation of cross-sectional semiconductor heterostructures whose total thickness is comparable to the size of the analyzing laser spot.

Scanning confocal Raman spectroscopy is used to study the crystal structure of GaAs irradiated with Mn + ions with subsequent pulse laser annealing. The scanning of cleaved cross sections of samples shows that the structure completely recovers over the depth of implantation after the annealing. Scattering in the coupled phonon–plasmon mode is revealed, which is indicative of electrical activation of the impurity at Mn doses above 1 × 10 16 cm –2 . The study shows the possibilities of using scanning confocal Raman spectroscopy in investigations of cleaved cross sections of structures. Using a test structure with a single δ-doped C layer, we show that the lateral resolution of the technique is 300 nm.

The results of complex studies of InGaAs/GaAs nanoheterostructures δ-doped with Mn are reported. The structures are grown by metal-organic vapor-phase epitaxy in combination with laser deposition. By confocal Raman spectroscopy, it is shown that the low-temperature δ-doped GaAs cap layers are of higher crystal quality compared to uniformly doped layers. Scattering of light in the coupled phonon-plasmon mode is observed. The appearance of this mode is conditioned by the diffusion of manganese from the δ-layer. The thickness of the cap layer is found to be d c ≈ 9–20 nm, optimal for attainment of the highest photoluminescence intensity of the quantum well and the highest layer concentration of holes by doping with manganese.

t is reported about fabrication by laser deposition in a gaseous environment of epitaxial layers of ferromagnetic semiconductors GaMnSb and InMnSb. Investigations of x-ray diffraction and Raman scattering showed reasonably good crystal quality of GaMnSb and InMnSb layers. Magnetic properties were investigated by magneto-optical transversal Kerr effect and Hall effect. It is established, that GaMnSb layers are ferromagnetic at room temperature. In contrast, InMnSb samples demonstrate the ferromagnetic properties only at low temperatures (< 70 K).

The structural, optical, and galvanomagnetic properties of (Ga, Mn)Sb layers grown by the laser sputtering of solid targets in H2 flow are n studied. It is shown that at a growth temperature of 400°C, (Ga, Mn)Sb layers are single-crystal up to high Mn concentrations. The magnetic field dependence of the Hall resistance at measuring temperatures of 10–300 K contains a hysteresis loop; i. e., the layers are ferromagnetic semiconductors.

Photoluminescence, infrared Fourier spectroscopy, Raman scattering, transmission electron microscopy, and electron diffraction were used to study the luminescent, optical, and structural properties of aluminum oxide layers (sapphire and films of Al 2 O 3 deposited on silicon) implanted with Si + to produce silicon nanocrystals. It is established that, in both cases, a high-temperature annealing of heavily implanted samples brings about the formation of silicon nanocrystals. However, the luminescent properties of the nanocrystals are strongly dependent on the type of pristine matrix; namely, nanocrystals in Al 2 O 3 films emit light in the spectral range typical of Si quantum dots (700–850 nm), whereas in sapphire this photoluminescence is not observed. This difference is interpreted as being due to the fact that local stresses arise in the nanocrystal/sapphire system and break chemical bonds at the interface between the phases, whereas in Al 2 O 3 films stresses are relaxed.

The formation of defects at the surfaces of semiconductors in the course of chemical, radiation, and other treatment can be studied with the help of quantum-well structures. Quantum-well heterostructures, embedded near a surface, have been used as probes to detect defects. This method can be used to determine the width and profile of the defective region, the concentration of photoelectrically active defects, and certain other characteristics of defect formation. A GaAs/In0.3Ga0.7As heterostructure was used to study defect formation in the course of anodic oxidation and bombardment of a GaAs surface by argon ions.

A simple highly sensitive photoelectric method is proposed for the determination of the impurity optical absorption coefficient of semiinsulators. The method is based on the normalized spectral dependence of the transverse photoconductivity of a sample subjected to additional illumination. It is shown that this method can be used to determine not only the photoactive, but also the nonphotoactive components of the absorption coefficient. The method was tested by application of semiinsulating GaAs.