scholarly journals Resistive Switching of GaAs Oxide Nanostructures

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3451
Author(s):  
Vadim Avilov ◽  
Nikita Polupanov ◽  
Roman Tominov ◽  
Maxim Solodovnik ◽  
Boris Konoplev ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Experimental Studies ◽  
Nanoscale Structures ◽  
Oxide Nanostructures ◽  
Local Anodic Oxidation ◽  
Oxide Phases ◽  
Silicon Doped ◽  
Electronic Elements

The paper presents the results of experimental studies of the influence of the local anodic oxidation control parameters on the geometric parameters of oxide nanoscale structures (ONS) and profiled nanoscale structures (PNS) on the surface of epitaxial structures of silicon doped gallium arsenide with an impurity concentration of 5 × 1017 cm−3. X-ray photoelectron spectroscopy measurements showed that GaAs oxide consists of oxide phases Ga2O3 and As2O3, and the thickness of the Ga2O3 layer is 2–3 times greater than the thickness of As2O3 area—i.e., the oxidized GaAs region consists mainly of Ga2O3. The experimental studies of the influence of ONS thickness on the resistive switching effect were obtained. An increase in the ONS thickness from 0.8 ± 0.3 to 7.6 ± 0.6 nm leads to an increase in the switching voltage Uset from 2.8 ± 0.3 to 6.8 ± 0.9 V. The results can be used in the development of technological processes for the manufacturing of nano-electronic elements, such as ReRAM, as well as a high-efficiency quantum dot laser.

scholarly journals Investigation of resistive switching in gallium oxide nanostructures formed by local anodic oxidation

2019 ◽  
Vol 1410 ◽  
pp. 012233 ◽  
Author(s):  
R V Tominov ◽  
N A Polupanov ◽  
V I Avilov ◽  
M S Solodovnik ◽  
N V Parshina ◽  
...  
Keyword(s):  
Anodic Oxidation ◽  
Resistive Switching ◽  
Gallium Oxide ◽  
Oxide Nanostructures ◽  
Local Anodic Oxidation

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

scholarly journals Improved Synaptic Device Properties of HfAlOx Dielectric on Highly Doped Silicon Substrate by Partial Reset Process

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 772
Author(s):  
Seunghyun Kim ◽  
Osung Kwon ◽  
Hojeong Ryu ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Silicon Substrate ◽  
Photoelectron Spectroscopy ◽  
Random Access ◽  
Resistive Random Access Memory ◽  
Alloy Type ◽  
Switching Type ◽  
Neuromorphic System ◽  
Device Properties ◽  
Partial Reset

This work demonstrates the synaptic properties of the alloy-type resistive random-access memory (RRAM). We fabricated the HfAlOx-based RRAM for a synaptic device in a neuromorphic system. The deposition of the HfAlOx film on the silicon substrate was verified by X-ray photoelectron spectroscopy (XPS) analysis. It was found that both abrupt and gradual resistive switching could be implemented, depending on the reset stop voltage. In the reset process, the current gradually decreased at weak voltage, and at strong voltage, it tended to decrease rapidly by Joule heating. The type of switching determined by the first reset process was subsequently demonstrated to be stable switching by successive set and reset processes. A gradual switching type has a much smaller on/off window than abrupt switching. In addition, retention maintained stability up to 2000 s in both switching cases. Next, the multiple current states were tested in the gradual switching case by identical pulses. Finally, we demonstrated the potentiation and depression of the Cu/HfAlOx/Si device as a synapse in an artificial neural network and confirmed that gradual resistive switching was suitable for artificial synapses, using neuromorphic system simulation.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

scholarly journals High-Performance Resistive Switching in Solution-Derived IGZO:N Memristors by Microwave-Assisted Nitridation

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1081
Author(s):  
Shin-Yi Min ◽  
Won-Ju Cho
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electric Pulse ◽  
Chemical Species ◽  
Optical Absorption Coefficient ◽  
Microwave Assisted ◽  
Synthesis Strategy ◽  
Metal Insulator Metal ◽  
Switching Characteristics

In this study, we implemented a high-performance two-terminal memristor device with a metal/insulator/metal (MIM) structure using a solution-derived In-Ga-Zn-Oxide (IGZO)-based nanocomposite as a resistive switching (RS) layer. In order to secure stable memristive switching characteristics, IGZO:N nanocomposites were synthesized through the microwave-assisted nitridation of solution-derived IGZO thin films, and the resulting improvement in synaptic characteristics was systematically evaluated. The microwave-assisted nitridation of solution-derived IGZO films was clearly demonstrated by chemical etching, optical absorption coefficient analysis, and X-ray photoelectron spectroscopy. Two types of memristor devices were prepared using an IGZO or an IGZO:N nanocomposite film as an RS layer. As a result, the IGZO:N memristors showed excellent endurance and resistance distribution in the 103 repeated cycling tests, while the IGZO memristors showed poor characteristics. Furthermore, in terms of electrical synaptic operation, the IGZO:N memristors possessed a highly stable nonvolatile multi-level resistance controllability and yielded better electric pulse-induced conductance modulation in 5 × 102 stimulation pulses. These findings demonstrate that the microwave annealing process is an effective synthesis strategy for the incorporation of chemical species into the nanocomposite framework, and that the microwave-assisted nitridation improves the memristive switching characteristics in the oxide-based RS layer.

scholarly journals Resistive Switching Characteristics of Li-Doped ZnO Thin Films Based on Magnetron Sputtering

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1282 ◽  
Author(s):  
Zhao ◽  
Li ◽  
Ai ◽  
Wen
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Lattice Structure ◽  
Zno Thin Films ◽  
Bipolar Resistive Switching ◽  
X Ray ◽  
Doped Zno ◽  
Switching Characteristics

A kind of devices Pt/Ag/ZnO:Li/Pt/Ti with high resistive switching behaviors were prepared on a SiO2/Si substrate by using magnetron sputtering method and mask technology, composed of a bottom electrode (BE) of Pt/Ti, a resistive switching layer of ZnO:Li thin film and a top electrode (TE) of Pt/Ag. To determine the crystal lattice structure and the Li-doped concentration in the resulted ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. Resistive switching behaviors of the devices with different thicknesses of Li-doped ZnO thin films were studied at different set and reset voltages based on analog and digital resistive switching characteristics. At room temperature, the fabricated devices represent stable bipolar resistive switching behaviors with a low set voltage, a high switching current ratio and a long retention up to 104 s. In addition, the device can sustain an excellent endurance more than 103 cycles at an applied pulse voltage. The mechanism on how the thicknesses of the Li-doped ZnO thin films affect the resistive switching behaviors was investigated by installing conduction mechanism models. This study provides a new strategy for fabricating the resistive random access memory (ReRAM) device used in practice.

scholarly journals COHERENT PROPAGATION OF LASER BEAMS IN MCF FIBERS

2019 ◽  
Vol 47 (1) ◽  
pp. 21-23
Author(s):  
A.A. Balakin ◽  
S.A. Skobelev ◽  
A.V. Andrianov ◽  
E.A. Anashkina ◽  
A.G. Litvak
Keyword(s):  
Solid State ◽  
Optical Fibers ◽  
High Efficiency ◽  
Radiation Power ◽  
Experimental Studies ◽  
Pump Energy ◽  
Total Power ◽  
Beam Power ◽  
Self Focusing ◽  
Weakly Coupled

The successful development of fiber-optic technologies in recent decades has stimulated research on the replacement of components of solid-state laser systems with fiber components, which can drastically change the attractiveness of the corresponding applied developments. Yielding on the energy characteristics of solid-state systems, fiber lasers and nonlinear optical devices have high efficiency of conversion of pump energy to radiation energy associated with waveguide geometry, high quality of the spatial profile of the laser beam, as well as low cost, compactness, lack of alignment in work process. Note that the maximum achievable radiation power in a single fiber is limited primarily by the process of self-focusing, which leads to fiber damage. The use of a multi-core fiber (MCF), consisting of identical equidistant weakly coupled optical fibers, makes it possible to realize initially coherent propagation of laser radiation with a total power noticeably higher than it can be transmitted in a single optical fiber. However, as theoretical and experimental studies have shown, such systems have its own critical power (Balakin et al., 2016) whereby the self-focusing of the quasihomogeneous distribution of the wave field and its separation into a set of incoherent structures occurs. Therefore, we have considered a small-sized optical system of 2N identical weakly coupled optical fibers arranged in a ring (Balakin et. al., 2018). In such systems, it is possible to find stable distributions of intense wave beams, which allow coherent radiation transport over long distances. The total radiation power in the found distributions can significantly (up to 2N times) exceed the critical self-focusing power in continuous media. This manifests itself most clearly for the distribution of un ~ (-1)n with antiphase fields in neighboring waveguides, which is stable at an arbitrary wave beam power. Direct numerical simulation of a nonlinear wave equation confirms the stability of the field distributions found. The research was supported by the RAS Presidium Program «Nonlinear dynamics: fundamental problems and applications».

scholarly journals A Novel Piezoceramic-Based Sensing Technology Combined With Visual Domain Networks for Timber Damage Quantification

2021 ◽  
Vol 8 ◽  
Author(s):  
Haibei Xiong ◽  
Lin Chen ◽  
Cheng Yuan ◽  
Qingzhao Kong
Keyword(s):  
Time Domain ◽  
Damage Assessment ◽  
Structural Damage ◽  
High Efficiency ◽  
Experimental Studies ◽  
Stress Wave Propagation ◽  
Timber Structures ◽  
Sensing Technology ◽  
The Time Domain ◽  
Visual Domain

Early detection of timber damage is essential for the safety of timber structures. In recent decades, wave-based approaches have shown great potential for structural damage assessment. Current damage assessment accuracy based on sensing signals in the time domain is highly affected by the varied boundary conditions and environmental factors in practical applications. In this research, a novel piezoceramic-based sensing technology combined with a visual domain network was developed to quantitatively evaluate timber damage conditions. Numerical and experimental studies reveal the stress wave propagation properties in different cases of timber crack depths. Through the spectrogram visualization process, all sensing signals in the time domain were transferred to images which contain both time and frequency features of signals collected from different crack conditions. A deep neural network (DNN) was adopted for image training, testing, and classification. The classification results show high efficiency and accuracy for identifying crack conditions for timber structures. The proposed technology can be further integrated with a fielding sensing system to provide real-time monitoring of timber damage in field applications.

scholarly journals Fenton Degradation of Ofloxacin Using a Montmorillonite-Fe3O4 Composite

2020 ◽  
Vol 2 (1) ◽  
pp. 32
Author(s):  
Alamri Rahmah Dhahawi Ahmad ◽  
Saifullahi Shehu Imam ◽  
Wen Da Oh ◽  
Rohana Adnan
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Solar Irradiation ◽  
Precipitation Process ◽  
Wastewater Remediation ◽  
Solution Ph ◽  
X Ray ◽  
Subsequent Degradation ◽  
Co Precipitation

In this work, FeM composites consisting of montmorillonite and variable amounts of Fe3O4 were successfully synthesized via a facile co-precipitation process. They were characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), N2 adsorption-desorption, and Fourier transform infrared spectroscopy (FT-IR) techniques to explain the effect of Fe3O4 content on the physicochemical properties of the Fe3O4-montmorillonite (FeM) composites. The FeM composites were subsequently used as heterogeneous Fenton catalysts to activate green oxidant (H2O2) for the subsequent degradation of ofloxacin (OFL) antibiotic. The efficiency of the FeM composites was studied by varying various parameters of Fe3O4 loading on montmorillonite, catalyst dosage, initial solution pH, initial OFL concentration, different oxidants, H2O2 dosage, reaction temperature, inorganic salts, and solar irradiation. Under the conditions of 0.75 g/L FeM-10, 5 mL/L H2O2, and natural pH, almost 81% of 50 mg/L of OFL was removed within 120 min in the dark, while total organic carbon (TOC) reduction was about 56%. Moreover, the FeM-10 composite maintained high efficiency and was stable even after four continuous cycles, making it a promising candidate in real wastewater remediation.

Sign in / Sign up

Export Citation Format

Share Document