ПОРИСТОЕ АНОДИРОВАНИЕ АЛЮМИНИЕВЫХ ПЛЕНОК С ИСПОЛЬЗОВАНИЕМ ФОТОЛИТОГРАФИЧЕСКОЙ МАСКИ ПРИ ВЫСОКИХ НАПРЯЖЕНИЯХ ФОРМОВКИ

The approach of aluminium porous anodisation has been proposed. Anodisation was realized under high forming voltages with Joule heat sink through aluminium tracks formed by a photolithographic mask. Record high forming voltages have been achieved leads to new tubular oxide structure with wide outer diameter of 50 - 400 nm and the high anodic process anisotropy up to 0,8. The results obtained can be explained by imposing the high electric field in the porous alumina barrier layer.Предложен метод локального электрохимического анодирования алюминиевых пленок при высоких напряжениях формовки с отводом выделяемого джоулева тепла через алюминиевые дорожки, граничащие с формируемым пористым оксидом алюминия. Предложенный метод позволяет проводить процесс при рекордно высоких напряжениях формовки, что, в свою очередь, приводит к достижению новых результатов, таких как формирование трубчатой структуры оксида с широким диапазоном внешнего диаметра трубок от 50 до 400 нм, а также обеспечивает высокую анизотропию анодного процесса со степенью анизотропии до 0,8. Отмеченные выше результаты могут быть объяснены реализацией процесса при высокой напряженности электрического поля внутри барьерного слоя пористого оксида алюминия

Mechanical impulse enhancement in a microsystem based on nanoporous silicon combustion

Nanostructured porous silicon impregnated by solid state oxidizer has been studied in order to provide the mechanical impulse for jet-propulsion microsystems. The system with jet-propulsion motion on a silicon chip has been tested for impulse measurements. The silicon chip has been fastened on a carrying platform through an elastic spacer. The elastic spacer promotes the combustion and prevents from explosion of porous silicon fast oxidation. It is shown that such a microsystem gains the impulse up to 200-220 mN•s

Porous Silicon for Accumulation and Generation of Hydrogen

Porous silicon layers have been formed by electrochemical anodization of p- and n-type Si substrates. The volume of hydrogen desorbed from the surface of porous silicon after the anodic treatment was measured to be as large as 4 wt.%. Regeneration of hydrogen can be achieved by porous silicon reanodization

Superconducting properties of Nb thin films deposited on porous silicon templates

Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependence of the superconducting resistive transition width at H=1 Tesla. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.Comment: accepted for publication on Journal of Applied Physic

Formation of alumina nanotubes and jet effect during high voltage local anodization of aluminum

Using an improved heat sink from the barrier layer, the voltage of anodic electrochemical oxidation of aluminum in sulfuric electrolytes is successfully increased from the conventional limit of about 40 to 200 V. This is done by localization of the anodized regions within the windows in the niobium thin film masks with the diameters of 0.3 μm to 2.5 mm. High-voltage anodization in water solutions of sulfuric acid is observed to be accompanied by a reproducible formation of densely packed alumina nanotubes and intense gas propulsion from the pores of the forming alumina. The latter is proposed and experimentally confirmed for use as an efficient driving agent in micro- and nanoengines. Test samples are accelerated to the velocities up to 1 cm s−1, demonstrating a thrust-to-weight ratio of about 1000

Forming of nanostructured anti-reflective coating on titanium elements of optical devises

Technological approach for anti-reflective coatings on refractory metal surfaces has been proposed. Specular reflection coefficient of anti-reflective coatings created on titanium samples was as low as 0,1–0,33 % for the visible range. Coatings with similar properties can be created using different refractory metals. Developed approach can be used to decrease unwanted reflection of the digital camera elements on earth imaging satellites.Антиотражающие покрытия представляют интерес для разработки и создания оптоэлектронных и дисплейных устройств. Одна из бурно развивающихся сфер применения данных покрытий – снижение светового загрязнения изображений отражениями от элементов оптоэлектронных систем и их носителей. Многие современные антиотражающие покрытия имеют органическую основу или созданы на основе массивов углеродных нанотрубок и, как следствие, неустойчивы в условиях высоких температур и механических нагрузок. Для создания наиболее бюджетных антиотражающих покрытий на металлических поверхностях применяются, как правило, методики микроструктурирования поверхности путем механической обработки (шлифовка, пескоструйная обработка и другие технологии абразивной обработки). Подобная обработка позволяет снизить коэффициент зеркального отражения поверхности титанового изделия до уровня полутора-двух процентов

3D Silicon Photonic Structures Based on Avalanche LED with Interconnections through Optical Interposer

Design and manufacturing technology of 3-D silicon photonic structures with optical interconnections through microchannel vias interposers were developed. Silicon chips placed over each other were separated by the silicon microchannel vias interposer served as a light waveguide. Light emitting diodes and photodiodes were formed at the inner surfaces of silicon chips from nanostructured silicon clusters embedded into alumina matrix. The developed structure is characterized by the current conversion efficiency of 0.1 % and can operate in the GHz frequency range

ВЛИЯНИЕ ТЕРМООБРАБОТКИ НА СТРУКТУРУ И СОСТАВ ПОРИСТЫХ ПЛЕНОК АНОДНОГО ОКСИДА АЛЮМИНИЯ, СФОРМИРОВАННЫХ ПРИ РАЗЛИЧНЫХ НАПРЯЖЕНИЯХ ФОРМОВКИ

A fabrication of porous alumina films by electrochemical anodization of aluminium foils and aluminium films deposited on silicon wafers is presented. Anodization process was held in the 2 % sulphuric acid aqueous solution at different forming voltages. It was shown that thermal treatment at 450 °С and 950 °С leads to increase of anodic alumina film porosity and decrease of volume expansion factor. It was also defined that embedding of electrolyte components in anodic alumina during anodization in sulphuric acid solutions intensifies with the increase of forming voltage value.Представлены результаты исследования электрохимического анодирования алюминиевой фольги и тонких алюминиевых пленок, осажденных на кремниевые пластины, в 2 % водном растворе серной кислоты при различных напряжениях формовки. Показано, что термообработка при температурах 450 °С и 950 °С увеличивает пористость пленки анодного оксида алюминия и приводит к снижению значения коэффициента увеличения объема. Также установлено, что встраивание компонентов электролита в анодный оксид при анодировании в растворах серной кислоты интенсифицируется с ростом напряжения формовки

A highly sensitive silicon nanowire array sensor for joint detection of tumor markers CEA and AFP

Liver cancer is one of the malignant tumors with the highest fatality rate and increasing incidence, which has no effective treatment plan. Early diagnosis and early treatment of liver cancer play a vital role in prolonging the survival period of patients and improving the cure rate. Carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) are two crucial tumor markers for liver cancer diagnosis. In this work, we firstly proposed a wafer-level, highly controlled silicon nanowire (SiNW) field-effect transistor (FET) joint detection sensor for highly sensitive and selective detection of CEA and AFP. The SiNWs-FET joint detection sensor possesses 4 sensing regions. Each sensing region consists of 120 SiNWs arranged in a 15 × 8 array. The SiNW sensor was developed by using a wafer-level and highly controllable top-down manufacturing technology to achieve the repeatability and controllability of device preparation. To identify and detect CEA/AFP, we modified the corresponding CEA antibodies/AFP antibodies to the sensing region surface after a series of surface modification processes, including O2 plasma treatment, soaking in 3-aminopropyltriethoxysilane (APTES) solution, and soaking in glutaraldehyde (GA) solution. The experimental results showed that the SiNW array sensor has superior sensitivity with a real-time ultralow detection limit of 0.1 fg ml−1 (AFP in 0.1× PBS) and 1 fg ml−1 (CEA in 0.1× PBS). Also, the logarithms of the concentration of CEA (from 1 fg ml−1 to 10 pg ml−1) and AFP (from 0.1 fg ml−1 to 100 pg ml−1) achieved conspicuously linear relationships with normalized current changes. The R2 of AFP in 0.1× PBS and R2 of CEA in 0.1× PBS were 0.99885 and 0.99677, respectively. Furthermore, the sensor could distinguish CEA/AFP from interferents at high concentrations. Importantly, even in serum samples, our sensor could successfully detect CEA/AFP. This demonstrates the promising clinical development of our sensor

Effect of anodic voltage on parameters of porous alumina formed in sulfuric acid electrolytes

Local porous aluminum anodizing with a photolithography mask has been carried out at anodic voltages varying from 15 to 200 V in sulfuric acid electrolytes. Record anodic voltages at room temperature have been achieved leading to new parameters of porous alumina such as interpore distance up to 320 nm, forming cell factor up to 1.2 nm/V, thickness expansion factor up to 3.5, porosity up to 1%, sulfur concentration up to 7.7 at.%. A central angle of porous alumina cells has been measured in concave points as well as in peak points of porous alumina cells at the border with aluminum. The measurements have shown that central angles can reach 90° at anodic voltages larger than 100 V. The electric field distribution in porous alumina cells has been simulated for different central angles. It is found that the electric field reaches 2.7×1010 V/m in the layers with a porosity of 1% in growing alumina