Самоорганізовані метал-напівпровідникові мікро- та наноструктури Au-GaAs для застосування у плазмонній фотовольтаїці

Au-GaAs metal-semiconductor composite microstructures have been prepared by an anisotropic etching of n-GaAs (100) wafers doped with Te (1016 to 1017 cm-3) with subsequent photostimulated chemical deposition of noble metal (Au) on formed semiconductor quasigratings. The microrelief topology of GaAs surface is controlled by the anisotropic etching conditions. Au metal was deposited on the structured GaAs surface as randomly placed nanoparticles of various shape and size and/or nanowires on the top of the hills of formed semiconductor microstructure. As the number of Au nanoparticles increases, they tend to localize on the ledges of the GaAs microrelief forming a system of approximately parallel nanowires. Obtained periodic structures with submicron to microns periods without Au nanoparticles and with deposited nanoparticles have been studied by means of scanning electron microscopy, optical spectroscopy (photoluminescence spectroscopy at room temperature), and photoelectric measurements. The decrease of the relative intensity of main photoluminescence band for samples with Au nanostructures compared to ones without nanoparticles deposition and simultaniously changes of the shape of photocurrent spectra of Au-GaAs microstructures have been observed. Such correlation in behaviour of measured spectra make formed Au-GaA metal-semiconductor microstructures perspective for the application in plasmonic photovoltaics. Pages of the article in the issue: 139 - 142 Language of the article: EnglishМетал-напівпровідникові композитні мікроструктури Au-GaAs були отримані шляхом анізотропного травлення з подальшим фотостимульованим хімічним осадженням благородного металу (Au) на сформовані напівпровідникові квазігратки. Золото наносилося на структуровану поверхню GaAs у вигляді хаотично розміщених наночастинок металу та/або нанодротів на вершинах пагорбів напівпровідникової мікроструктури. Сформовані структури вивчаються за допомогою скануючої електронної мікроскопії, оптичної спектроскопії та фотоелектричних вимірювань. Створені метал-напівпровідникові мікроструктури Au-GaAs є перспективними для застосування в плазмонній фотовольтаїці, що підтверджується поведінкою спектрів фотолюмінесценції та змінами форми спектрів фотоструму

Influence of complex defects on electrophysical properties of GaP light emitting diodes

In order to estimate the role of complex defects on GaP light emitting diodes (LED) operation, luminescent and electrical characteristics of GaP LEDs irradiated with reactor neutrons have been studied. It has been stated that nonradiative levels of radiation defects affect electroluminescence quenching. From the analysis of the tunnel current, the density of dislocations in the depleted part of the p–n junction was obtained. Neutron induced disorder regions do not change the tunnel component of the direct current of red diodes, increasing the dislocation density, because the carrier flow along the “tunnel shunts” is blocked

Local plasmons contribution into photocurrent of Au/GaAs surface barrier structure with Au nanoparticles on interface

Au/SiO₂ core-shell nanoparticles have been used to increase the photocurrent in the surface barrier structure Au/GaAs. The method for theoretical calculation of interaction between light and the system of ordered nanoparticles placed on the surface barrier structures has been proposed. Local plasmons excited in the nanoparticles produce additional carriers due to scattering, prolonged interaction with semiconductor and enhanced evanescent electromagnetic field, thus they increase the photocurrent

ZnO as a conductive layer prepared by ALD for solar cells based on n-CdS/n-CdTe/p-Cu₁.₈S heterostructure

ZnO films with high conductivity are obtained by atomic layer deposition for application in solar cells based on n CdS/ n CdTe / p Cu₁.₈S heterostructure. The parameters of solar cells with ZnO electrode are calculated from light and dark currentvoltage characteristics and compared with those obtained for structures with Mo contact. The advantages of ZnO electrode are discussed

СКРИНИНГ НОВЫХ ХИМИОТЕРАПЕВТИЧЕСКИХ СРЕДСТВ ДЛЯ БОРЬБЫ С БОЛЕЗНЯМИ РЫБ, ВЫЗЫВАЕМЫМИ ПАРАЗИТИЧЕСКИМИ ДИПЛОМОНАДИДАМИ (DIPLOMONADIDA WENYON, 1926)

Objective of research. The purpose of the study – screening of new chemotherapeutic agents for the treatment of hexamita ornamental fish. Materials and methods. The test drugs were performed on juveniles of the discus Symphysodon discus a body mass of 15 g, spontaneously infested hexamitidae (Diplomonadida). 35 discus of the infected individuals were divided into 7 groups of 5 copies of the Fish 1, 2, 3, 4, 5, and 6th groups were appointed in the composition of granulated feed, respectively pyrimethamine at a dose of 50 mg/kg albendazole – 50, fenbendazole – 50, mebendazole – 10, magnesium sulfate – 500 and metronidazole in a dose of 50 mg/kg for 5 days. Fish 7 the first group was control and received feed without the drug. The effectiveness was considered after 5 days after the last Dachi medicated feed. Fish were dissected, the intestines were isolated, which were released from the food pulp, homogenized, and were studied by optical microscopy at a magnification of 180 times. Results and discussion. The number of examined in treated fish compared with the control decreased after the application of metronidazole by 95.5 %, mebendazole – 77.8, magnesium sulfate, which is 74.5, fenbendazole – by 56.6, albendazole – 50.5 and pyrimethamine – 24.4 %. Advanced for further testing are mebendazole, magnesium sulphate, fenbendazole and albendazole. The most effective was a basic drug – metronidazole. During the test degradation of fish were noted. Food activity was moderate at the level of 2% of ichthyomass. In fish treated with metronidazole, mebendazole and magnesium sulfate, have improved the condition.Цель исследования – скрининг новых химиотерапевтических средств для лечения гексамитоза декоративных рыб. Материалы и методы. Испытание препаратов проводили на молоди дискуса Symphysodon discus массой тела 15 г, спонтанно инвазированных гексамитидами (Diplomonadida). 35 зараженных особей дискуса разделили на 7 групп по 5 экз. Рыбам 1, 2, 3, 4, 5 и 6-й групп назначали в составе гранулированного корма соответственно пириметамин в дозе 50 мг/кг, альбендазол – 50, фенбендазол – 50, мебендазол – 10, сульфат магния – 500 и метронидазол – в дозе 50 мг/кг в течение 5 сут. Рыба 7-й группы была контролем и получала корм без препарата. Эффективность препаратов учитывали через 5 сут после последней дачи лечебного корма. Рыбу вскрывали, выделяли кишечник, который освобождали от кормовых масс, гомогенизировали и микроскопировали при увеличении в 180 раз. Результаты и обсуждение. Число гексамитид у леченой рыбы по сравнению с контролем снизилось после применения метронидазола на 95,5 %, мебендазола – на 77,8, сульфата магния – на 74,5, фенбендазола – на 56,6, альбендазола – на 50,5 и пириметамина – на 24,4 %. Перспективными для дальнейших испытаний являются мебендазол, сульфат магния, фенбендазол и альбендазол. Наиболее эффективным оказался базовый препарат – метронидазол. В период испытания ухудшения состояния рыб не отмечали. Пищевая активность была умеренной, на уровне 2 % от ихтиомассы. У рыб, леченных метронидазолом, мебендазолом и сульфатом магния, улучшилось состояние здоровья