A Micropowered Chemoresistive Sensor Based on a Thin Alumina Nanoporous Membrane and SnxBikMoyOz Nanocomposite

This work presents and discusses the design of an efficient gas sensor, as well as the technological process of its fabrication. The optimal dimensions of the different sensor elements including their deformation were determined considering the geometric modeling and the calculated moduli of the elasticity and thermal conductivity coefficients. Multicomponent SnxBikMoyOz thin films were prepared by ionic layering on an anodic alumina membrane and were used as gas-sensitive layers in the sensor design. The resistance of the SnxBikMoyOz nanostructured film at temperatures up to 150 ◦C exceeded 106 Ohm but decreased to 104 Ohm at 550 ◦C in air. The sensitivity of the SnxBikMoyOz composite to concentrations of 5 and 40 ppm H2 at 250 ◦C (10 mW) was determined to be 0.22 and 0.40, respectively

Multicomponent Sn–Mo–O-containing films formed in anodic alumina matrixes by ionic layer deposition

Multicomponent metal oxide compounds of the composition Sn–Mo–O, Sn–Ni–Mo–O and Sn–Bi–Mo–O were formed by successive ionic layer adsorption and reaction (SILAR) method deposition into anodic alumina matrixes. The growth mechanism of the Sn–Mo–O-containing films in the porous anodic alu- mina was investigated. It was found that the degree of pore filling, specific thickness and surface mor- phology of the deposited layer depend not only on the number of cycle’s treatment, but also on the composition of the used solutions. The morphology of Sn–Mo–O and Sn–Ni–Mo–O surfaces had granular structures, while Sn–Bi–Mo–O layer had flake-like structure. The differences in microstructure and depo- sition of the layers on the surface of the matrixes can be explained by the insufficient activation of anodic alumina pores before deposition. The investigations of the formed layers composition by the electron- probe X-ray spectral microanalysis showed that the ratio of tin to molybdenum in tin-molybdenum con- taining oxides changes. The Sn/Mo atomic ratio for Sn–Mo–O layer is 1.29/2.72; for Sn–Ni–Mo–O layer is 5.83/4.85; for Sn–Bi–Mo–O layer is 0.60/0.87. The using of SILAR method allows forming multicomponent films in the anodic alumina matrixes, which have great potential to applicate in high-sensitivity gas sensors

Controlled integrated vacuum elements on niobium field cathodes for microdisplays

The paper presents the methods of creation and research results of matrices of electronic elements on field cold cathodes with given geometric and electrophysical parameters. The developed controlled matrices are small-sized, highly efficient sources of electron beams with low energy consumption for microelectronic devices, such as microdisplays. Field emission elements with nanostructured cathodes in the triode and diode configurations are implemented based on original structural and technological methods for the electrochemical formation of vertically oriented arrays of metal oxide niobium nanostructures, compatible with the latest nanotechnologies used in the manufacture of promising optoelectronic and nanoelectronic products

Autoelectronic cathodes based on arrays of niobium-oxide columnar nanostructures for field emission displays

В статье обсуждаются перспективы создания управляемых матриц автоэлектронных катодов на основе массивов столбиковых оксидных ниобиевых наноструктур для полевых эмиссионных дисплеев. Разработаны и исследованы геометрические модели автоэлектронных катодов и вакуумных элементов на их основе. Получены распределения электрического поля в вакуумном устройстве при различных расстояниях между катодом и анодом, приложенных напряжениях между ними, форме и микрогеометрии катодов. На основании результатов моделирования рассчитаны оптимальные геометрические параметры наноструктурированных автоэлектронных катодов и матриц на их основе. Разработан технологический маршрут изготовления матриц автоэлектронных катодов на основе массивов ниобиевых металлоксидных столбиковых наноструктур, формируемых электрохимическим анодированием тонкопленочной системы Al/Nb. Изготовлены образцы управляемых матриц автоэлектронных катодов и исследованы их вольт-амперные характеристики при межэлектродном зазоре 2, 5 и 10 мкм в различных электрических режимах при изменении напряженности электрического поля от 3 до 85 В/мкм. При 2 мкм зазоре между анодом и катодом эмиссия возникает при минимальных пороговых напряжениях, однако характеризуется ограниченными значениями токов. Увеличение межэлектродного зазора позволяет увеличить эмиссионные токи, однако при этом повышаются пороговые напряжения. В импульсном режиме достигаются большие значения эмиссионных токов. При зазоре 5 мкм между катодом и анодом пороговое напряжение составило 9,16 В, максимальные токи достигали 350 мкA при напряжении 22,5 В. В импульсном режиме эмиссия возникала при 11,06 В, максимальный ток достигал 1500 мкА при 40 В

АВТОЭЛЕКТРОННЫЕ КАТОДЫ НА ОСНОВЕ МАССИВОВ НИОБИЕВЫХ ОКСИДНЫХ СТОЛБИКОВЫХ НАНОСТРУКТУР ДЛЯ ПОЛЕВЫХ ЭМИССИОННЫХ ДИСПЛЕЕВ

The article discusses the prospects of creating controlled field-effect cathodes based on arrays of columnar oxide niobium nanostructures for field emission displays. Geometrical models of field-emission cathodes and vacuum elements have been developed and investigated. The distribution of the electric field in the vacuum device at various distances between the cathode and the anode, the applied voltages between them, the shape and microgeometry of the cathodes were obtained. The optimal geometric parameters of nanostructured autoelectronic cathodes and matrices of these were calculated based on the simulation. The technological route has been developed for the production of autoelectronic cathode matrices based on arrays of niobium-oxide columnar nanostructures formed by electrochemical anodization of Al/Nb thin-film system. The samples of controlled arrays of autoelectronic cathodes were fabricated and the current-voltage characteristics with interelectrode gap of 2, 5 and 10 μm in various electric modes with change in the electric field strength from 3 to 85 V/μm were studied. At 2 μm gap between the anode and cathode, the emission occurs at minimum threshold voltages, but it is characterized by limited current values. The increasing in the interelectrode gap allows rising the emission currents, however, the threshold voltages increase. In the pulsed mode, the large emission currents are achieved. The threshold voltage of autoelectronic cathode matrices with interelectrode gap of 5 μm was 9.16 V, the maximum currents reached 350 μA at voltage of 22.5 V. In the pulsed mode, the emission arose at 11.06 V, the maximum current reached 1500 μA at 40 V.В статье обсуждаются перспективы создания управляемых матриц автоэлектронных катодов на основе массивов столбиковых оксидных ниобиевых наноструктур для полевых эмиссионных дисплеев. Разработаны и исследованы геометрические модели автоэлектронных катодов и вакуумных элементов на их основе. Получены распределения электрического поля в вакуумном устройстве при различных расстояниях между катодом и анодом, приложенных напряжениях между ними, форме и микрогеометрии катодов. На основании результатов моделирования рассчитаны оптимальные геометрические параметры наноструктурированных автоэлектронных катодов и матриц на их основе. Разработан технологический маршрут изготовления матриц автоэлектронных катодов на основе массивов ниобиевых металлоксидных столбиковых наноструктур, формируемых электрохимическим анодированием тонкопленочной системы Al/Nb. Изготовлены образцы управляемых матриц автоэлектронных катодов и исследованы их вольт-амперные характеристики при межэлектродном зазоре 2, 5 и 10 мкм в различных электрических режимах при изменении напряженности электрического поля от 3 до 85 В/мкм. При 2 мкм зазоре между анодом и катодом эмиссия возникает при минимальных пороговых напряжениях, однако характеризуется ограниченными значениями токов. Увеличение межэлектродного зазора позволяет увеличить эмиссионные токи, однако при этом повышаются пороговые напряжения. В импульсном режиме достигаются большие значения эмиссионных токов. При зазоре 5 мкм между катодом и анодом пороговое напряжение составило 9,16 В, максимальные токи достигали 350 мкA при напряжении 22,5 В. В импульсном режиме эмиссия возникала при 11,06 В, максимальный ток достигал 1500 мкА при 40 В

Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing

The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10 −3 K −1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively. At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity, which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and low power consumption

AUTOELECTRONIC CATHODES BASED ON ARRAYS OF NIOBIUM-OXIDE COLUMNAR NANOSTRUCTURES FOR FIELD EMISSION DISPLAYS

The article discusses the prospects of creating controlled field-effect cathodes based on arrays of columnar oxide niobium nanostructures for field emission displays. Geometrical models of field-emission cathodes and vacuum elements have been developed and investigated. The distribution of the electric field in the vacuum device at various distances between the cathode and the anode, the applied voltages between them, the shape and microgeometry of the cathodes were obtained. The optimal geometric parameters of nanostructured autoelectronic cathodes and matrices of these were calculated based on the simulation. The technological route has been developed for the production of autoelectronic cathode matrices based on arrays of niobium-oxide columnar nanostructures formed by electrochemical anodization of Al/Nb thin-film system. The samples of controlled arrays of autoelectronic cathodes were fabricated and the current-voltage characteristics with interelectrode gap of 2, 5 and 10 μm in various electric modes with change in the electric field strength from 3 to 85 V/μm were studied. At 2 μm gap between the anode and cathode, the emission occurs at minimum threshold voltages, but it is characterized by limited current values. The increasing in the interelectrode gap allows rising the emission currents, however, the threshold voltages increase. In the pulsed mode, the large emission currents are achieved. The threshold voltage of autoelectronic cathode matrices with interelectrode gap of 5 μm was 9.16 V, the maximum currents reached 350 μA at voltage of 22.5 V. In the pulsed mode, the emission arose at 11.06 V, the maximum current reached 1500 μA at 40 V

Ring gyroscope sensitive element based on nanoporous alumina

The paper aims to present new technological approaches of manufacturing of micromechanical gyroscope ring-sensitive element based on the nanoporous anodic alumina instead of traditional silicon technology. Simulation and the operation analyses of such elements have been performe

Low-power gas sensor on nanostructured dielectric membrane

The article presents a technology for manufacture of a gas sensor with a two-layer nanostructured dielectric membrane on a silicon substrate and its characteristics. Selection of the correct mathematical model ensures a good correlation between the experimental and calculated current-voltage characteristics of the sensor and makes it possible to evaluate the effect of porosity of the dielectric membrane on the value of the sensor’s power consumption, temperature of its sensitive layer and the related thermomechanical stresses. It demonstrates that the temperature range (150—350 °C) of the sensor’s sensitive layer, where the sensor’s response to 1 ppm CO is detected, is ensured due to power consumption from 5,0 mW up to 15,5 mW

Low-power gas sensor on nanostructured dielectric membrane

The article presents a technology for manufacture of a gas sensor with a two-layer nanostructured dielectric membrane on a silicon substrate and its characteristics. Selection of the correct mathematical model ensures a good correlation between the experimental and calculated current-voltage characteristics of the sensor and makes it possible to evaluate the effect of porosity of the dielectric membrane on the value of the sensor’s power consumption, temperature of its sensitive layer and the related thermomechanical stresses. It demonstrates that the temperature range (150—350 °C) of the sensor’s sensitive layer, where the sensor’s response to 1 ppm CO is detected, is ensured due to power consumption from 5,0 mW up to 15,5 mW