Quaternary Layers Research Articles

Quaternary Layered Li[Ni0.89Co0.05Mn0.05Al0.01]O2 (NCMA) Cathode for High-Energy Density Lithium-Ion Batteries

Li[Ni1-x-y CoxAl z ]O2 (NCA) and Li[Ni1-x-y Co x Mn y ]O2 (NCM) cathodes have been the archetypes of current high-energy density cathodes for Li-ion batteries. A hybrid of NCA and NCM cathodes, a quaternary system consisting of Li[Ni0.89Co0.05Mn0.05Al0.01]O2 (NCMA) was benchmarked against NCM and NCA with similar Ni contents. The quaternary NCMA cathode delivered a capacity of 228 mAh g-1 and outperformed the benchmarking cathodes in long-term cycling stability (85% after 1000 cycles). The reduction in the volume change during deintercalation and the enhanced intrinsic mechanical strength confirmed by the single particle compression test suppressed the microcrack nucleation and propagation. Microcrack suppression was important because microcracks serve as channels for electrolyte infiltration and lead to the subsequent surface degradation of internal surfaces. The proposed NCMA cathode provides extra cycling stability which is essential for electric vehicles, which require a long battery life and improvs the thermal stability of the cathode, which contributes to a safer battery. Myung et al. ACS Energy Lett. 2017, 2, 196-223.Kim et al. Energy Environ. Sci. 2018, 11, 1271-1279.Yoon et al. Electrochem. Soc. 2015, 162, A2483-A2489.Kim et al. ACS Energy Lett. 2017, 2, 1848-1854.

Interfacial Engineering for the Fast Carrier Tunneling Channel by a Novelty Quaternary Layered Photoanode

Developing an advanced photoanode structure to decrease the charge recombination is a mandatory requirement to enhance charge separation and transfer for photoelectrochemical reactions. Herein, we report an interfacial engineering design of quaternary layered Bi2S3/Bi2Mo2O9/Bi2S3/Bi2Mo2O9 by using a successive ionic layer absorption and reaction method. The synergistic effect of double p–n junctions combined with the Z-scheme system by band structure matching is the key point for this novelty design. The double p–n junctions can reinforce the charge separation when the semiconductor absorbs photons. The third ultrathin interlayer Bi2Mo2O9 sandwiched between two Bi2S3 layers plays a role as a carriers’ tunneling channel thanks to the Z-scheme system, which can accelerate the directional flowing of the electron and hole in the bilayer Bi2S3. Such a quaternary layered structure will be a “highway” for the electron transfer to the bulk, and the transfer of holes is to the surface where water oxidation takes p...

The power conversion efficiency optimization of the solar cells by doping of (Au:Ag) nanoparticles into P3HT:PCBM active layer prepared with chlorobenzene and chloroform solvents

We report to enhance the power conversion efficiency of organic solar cells by embedding of (Au:Ag) nanoparticles (NPs) into P3HT:PCBM active layer of the organic solar cells. Furthermore, the effect of solvents based on chlorobenzene and chloroform on the P3HT:PCBM active layer has been investigated for comparison. As known, the performance of organic solar cells based on the blend of regioregular P3HT:PCBM is strongly influenced by blend composition. For this purpose, ITO/PEDOT:PSS/P3HT:PCBM/(Au:Ag)NPs/LiF/Al quaternary hybrid solar cells were fabricated. Absorption, AFM, SEM and XRD measurements of the quaternary hydride active layers prepared with chlorobenzene (CB) and chloroform (CF) solvents were obtained. The optical energy band gap of the hybrid active layer was calculated. The highest PCE values were obtained for 1.2% Au: 0.3% Ag NPs ratios and the study has been focused on these values. (Au:Ag) NPs in the active layer increased the power conversion efficiency (PCE) of the device from 2.11% to 3.29% and to 2.27% for prepared with CB and CF solvents, respectively. This increase was explained by the scatter of the incident light from the NPs and an enhancement of light absorption in the active layer of the solar cell, increasing the optical path distance.

High-breakdown-voltage AlGaN-channel metal-insulator-semiconductor heterostructure field-effect transistors employing a quaternary AlGaInN barrier layer and an Al2O3 gate insulator

In this study, Al2O3-gate-insulated metal-insulator-semiconductor (MIS) heterostructure field-effect transistors (HFETs) were fabricated using an Al0.61Ga0.37In0.02N/Al0.18Ga0.82N two-dimensional-electron-gas heterostructure, and their electrical properties were characterized. It was confirmed that the thermally stable quaternary AlGaInN barrier layer contributed to a good ohmic contact resistance of 10.5 Ω mm. This value seemed to be considerably small as an AlGaN-channel heterostructure. The fabricated MIS-HFETs showed good pinch-off characteristics and exhibited a maximum drain current (IDSmax) of approximately 180 mA/mm at the gate bias of +2 V. A high off-state breakdown voltage of 2.5 kV was obtained for the device with a gate-to-drain length of 20 μm.

High-gain leaky surface acoustic wave amplifier in epitaxial InGaAs on lithium niobate heterostructure

Active surface acoustic wave components have the potential to transform RF front ends by consolidating functionalities that currently occur across multiple chip technologies, leading to reduced insertion loss from converting back and forth between acoustic and electronic domains in addition to improved size and power efficiency. This letter demonstrates a significant advance in these active devices with a compact, high-gain, and low-power leaky surface acoustic wave amplifier based on the acoustoelectric effect. Devices use an acoustically thin semi-insulating InGaAs surface film on a YX lithium niobate substrate to achieve exceptionally high acoustoelectric interaction strength via an epitaxial In0.53Ga0.47As(P)/InP quaternary layer structure and wafer-scale bonding. We demonstrate 1.9 dB of gain per acoustic wavelength and power consumption of 90 mW for 30 dB of electronic gain. Despite the strong intrinsic leaky propagation loss, 5 dB of terminal gain is obtained for a semiconductor that is only 338 μm long due to state-of-the-art heterogenous integration and an improved material platform.

Effect of In composition on electrical performance of AlInGaN/GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si

Al x In y Ga ( 1 − x − y ) N / GaN heterostructures were grown on 4-in. p-type Si wafers to investigate the effect of In composition in the quaternary nitride layer on the electrical performance of Al2O3/AlInGaN/GaN-based normally-ON metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs). From the comparative study of the electrical measurements, it was observed that the transport properties of the devices were relatively poor in the presence of higher In composition in the quaternary-N layer. The deterioration of the electrical characteristics of MIS-HEMTs originated from the formation of deep pits on the AlInGaN epilayer surface caused by the segregation of In atoms during epitaxial growth. However, the formation of such pits was reduced for the quaternary epilayer with lower In content and exhibited better transport performance. A maximum current density (Id,max) of 780 mA/mm with a specific ON-resistance of 0.71mΩcm2 was observed for the device fabricated on the wafer with an In composition of 9% in the AlInGaN epilayer. We have achieved a high breakdown voltage of 793 V with a device with the gate-to-drain distance (Lgd) of 20μm under the off-state condition.

Terahertz pulse emission from GaInAsBi

Quaternary GaInAsBi alloy epitaxial layers were grown on InP substrates with 6% Bi. It was found that the thick layers remain fully strained. The measured carrier lifetimes were of the order of a few picoseconds. The terahertz (THz) emission was investigated using a GaInAsBi layer as an unbiased surface emitter and as a substrate for photoconductive antenna. It was observed that fabricated THz emitters were sensitive to the optical pulses with wavelengths longer than 2 μm. The demonstrated spectral characteristics of THz pulses obtained when using an Er-doped fiber laser for photoexcitation were comparable with those observed in other emitters used for THz-time-domain spectroscopy systems.

Trap state characterization of Al2O3/AlInGaN/GaN metal-insulator-semiconductor heterostructures

Frequency-dependent conductance measurements were carried out to investigate the trap states in Al2O3/AlInGaN/GaN metal-insulator-semiconductor (MIS) heterostructures. From the electrical measurements, an improvement in trap state characteristics was observed for the device fabricated with lower In composition in quaternary nitride layers. In the presence of higher In composition, segregation of In atoms was observed in AlInGaN layers. Because of this In-segregation, surface quality of the quaternary-N deteriorated that led to the formation of trap states at and near the oxide/semiconductor interface. Therefore, in the presence of lower In composition, an improvement in trap characteristics was observed for the AlInGaN/GaN-based MIS devices.

3D geological modeling of Gareb-Bouareg basin in northeast Morocco

The Gareb-Bouareg region located in northeastern Morocco is characterized by a semi-arid climate with low rainfall. The unconfined aquifer of this region supplies water for agricultural and industrial activities. This study aims to develop a 3D model of the geology that adequately describes the observed structure and geometry of the aquifer in this coastal region. The geological formations considered during modeling are of Quaternary and Miocene ages. The input parameters include data from (i) 70 boreholes, (ii) four geological maps, and (iii) a digital terrain model. After processing, the data were subjected to a Geographic Information System (GIS) platform and 3D modeling software. The geological model comprises three geological Quaternary age layers (thin silt, limestone, and gravels silts) and two Miocene layers (marls and volcanic rock). The Quaternary geologic formations constitute the unconfined aquifer of the Gareb-Bouareg basin, while Miocene marls form the bedrock of the aquifer. The piezometric map shows that the water table lies at the following depths: 1.4 m from the ground in the vicinity of Nador Lagoon in the north of the region, 3.5 m at Mount Arouit in the center of the region, and 98 m north of the foothills of Kebdana in the south. The map also reveals the flow of groundwater from the south and southwest to the north and northeast.

SQL: Superpixels via quaternary labeling

This paper formulates superpixel segmentation as a pixel labeling problem and proposes a quaternary labeling algorithm to generate superpixel lattice. It is achieved by seaming overlapped patches regularly placed on the image plane. Patch seaming is formulated as a pixel labeling problem, where each label indexes one patch. Once the optimal seaming is completed, all pixels covered by one retained patch constitute one superpixel. Further, four kinds of patches are distinguished and assembled into four layers correspondingly, and the patch indexes are mapped to the quaternary layer indexes. It significantly reduces the number of labels and greatly improves labelling efficiency. Furthermore, an objective function is developed to achieve optimal segmentation. Lattice structure is guaranteed by fixing patch centers to be superpixel centers, compact superpixels are assured by horizontal and vertical constraints enforced on the smooth terms, and coherent superpixels are achieved by iteratively refining the data terms. Extensive experiments on BSDS data set demonstrate that SQL algorithm significantly improves labeling efficiency, outperforms the other superpixel lattice methods, and is competitive with state-of-the-art methods without lattice guarantee. Superpixel lattice allows contextual relationships among superpixels to be easily modeled by either MRFs or CNN.

Quality Evaluation and Applicability Analysis of TRD Method in Sand Stratum of Subway Station

Trench re-mixing and cutting deep method (TRD) construction is a rising method for building waterproof curtains in deep foundation pits, providing the advantages of large construction depth, widespread applicability to soil layers, and high quality of the cement-soil wall. Against the background of the Miaotou subway station foundation pit project through the quaternary system watery sand layer containing cohesive soil in Qingdao, the applicability of cement-soil wall constructed by the TRD method in Qingdao’s soft soil was researched. A comprehensive testing method which can evaluate the quality of the cement-soil wall was proposed. A series of field detection and laboratory tests that include borehole water pressure tests, borehole television imaging, electromagnetic wave borehole radar, and unconfined compressive strength test of the drilling core was completed. The test results show that the cement-soil wall had good integrity and continuity without weak tectonic zones. The average strength of the cement-soil wall ranged from 0.94 to 1.21 MPa, and the strength of the cement-soil wall at different depths existed large discreteness. However, it still met the design requirements of no less than 0.8 MPa. Test results showed that the permeability of the clay layer decreased from 10−5 to 10−7 cm/s and the permeability of the sand layer decreased from 10−2 to 10−7 cm/s. Both strength and permeability of the wall satisfied the design requirements for a watertight screen. The research results may provide reference for pit waterproof curtain engineering in similar sand stratum.

Quantification of the Quaternary Geological Structure Using Geological Cross-Sections in a Selected Part of the Moravian-Silesian Region for Geotechnical Purposes

The article deals with the quantification of the Quaternary geological structure of a selected part of the Moravian-Silesian region for geotechnical purposes (Ostrava glacigenous basin). The geological structure was quantified using the existing Quaternary cross-sections from various sources. The Quaternary cross-sections were vectorised and quantified in terms of the surface of section, horizontal length and using average thickness (average vertical length). All the data were processed for the first Quaternary layer from the ground surface. Next, data were processed for the whole Quaternary geological structure. Both the types of data are important for engineering geology, particularly for civil engineering purposes. In total, 60 cross-sections of 444 599 km in length were processed. The disadvantage of quantification is the fact that the real spatial structure is not reflected. On the contrary, the advantage is the reference quantified information on the basic types of geological environment for engineering-geological purposes for designers, engineering geologists and geotechnicians. At the same time, this resulted in the review of the existing Quaternary cross-sections. It is important to have reference quantified data on the basic geological environments in selected regions, in this case a selected part of the Moravian-Silesian Region and its Ostrava glacigenous basin.

Design and material growth of AlGaN-channel two-dimensional-electron gas heterostructures employing strain-controlled quaternary AlGaInN barrier layers

In order to improve the thermal stability in AlGaN-channel two-dimensional electron gas (2DEG) heterostructures, we newly designed strain-controlled quaternary AlGaInN barrier layers, and then we grew them by metalorganic chemical vapor deposition. A 2DEG density as high as 2.5 × 1013 cm−2 and a good surface morphology were obtained for an (Al0.64Ga0.36)0.976In0.024N/Al0.19Ga0.81N heterostructure, in which in-plane tensile strain in the barrier layer was estimated to be 0.51%. It was also confirmed that the (Al0.64Ga0.36)0.976In0.024N/Al0.19Ga0.81N heterostructure showed an excellent thermal stability in its 2DEG properties even at high temperatures up to 900 °C. As a result of their thermal stability improvement, we were also able to confirm that the contact resistance was improved by applying high-temperature annealing.

Interfacial Mixing Analysis for Strained Layer Superlattices by Atom Probe Tomography

Quantum wells and barriers with precise thicknesses and abrupt composition changes at their interfaces are critical for obtaining the desired emission wavelength from quantum cascade laser devices. High-resolution X-ray diffraction and transmission electron microscopy are commonly used to calibrate and characterize the layers’ thicknesses and compositions. A complementary technique, atom probe tomography, was employed here to obtain a direct measurement of the 3-dimensional spatially-resolved compositional profile in two InxGa1−xAs/InyAl1−yAs III-V strained-layer superlattice structures, both grown at 605 °C. Fitting the measured composition profiles to solutions to Fick’s Second Law yielded an average interdiffusion coefficient of 3.5 × 10−23 m2 s−1 at 605 °C. The extent of interdiffusion into each layer determined for these specific superlattices was 0.55 nm on average. The results suggest that quaternary active layers will form, rather than the intended ternary compounds, in structures with thicknesses and growth protocols that are typically designed for quantum cascade laser devices.

Review Article: Atomic layer deposition for oxide semiconductor thin film transistors: Advances in research and development

This article is a review of recent research and development advances in oxide thin film transistors (TFTs) fabricated by atomic layer deposition (ALD) processes. The ALD process is remarkable as it offers accurate control of film thickness and composition as well as the ability to achieve excellent uniformity over large areas at relatively low temperatures. Firstly, an introduction to n-type oxide TFTs is provided with a focus on the development of active-layer material combinations from binary oxide active layers, like zinc oxide and indium oxide, to ternary and quaternary oxide active layers formed by doping with elements such as gallium or tin to achieve high mobility and high device stability for TFTs. Secondly, ALD p-type channel oxide TFTs are also introduced, which are required for the realization of many types of low-power circuits, such as complementary metal oxide semiconductor devices.

Quantitative Analysis and Band Gap Determination for CIGS Absorber Layers Using Surface Techniques.

Recently, Cu(InXGa(1−X))Se2 (CIGS) absorber layers have been extensively studied by many research groups for thin-film solar cell technology. CIGS material is particularly promising due to its exceptionally high absorption coefficient and large band gap range, which is adjustable as a function of alloy stoichiometry. To enhance the conversion performance of CIGS solar cells, understanding the CIGS structure and composition is a crucial challenge. We conducted a quantitative study to determine the bulk composition of the major elements such as Cu, In, Ga, and Se of four different CIGS photovoltaic cells. The compositional information was obtained by X-ray fluorescence (XRF), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and femtosecond laser ablation inductively coupled plasma mass spectrometry (fs-LA-ICP-MS). Then, the XRF concentration ratio was compared with the intensity ratio of fs-LA-ICP-MS to investigate the potential of accurate and rapid analysis using the fs-LA-ICP-MS technique. In contrast to the bulk information, the surface techniques can supply detailed information about the chemical composition across the depth profile. Here, elemental depth distributions of CIGS thin films were investigated using magnetic sector secondary ion mass spectrometry (SIMS) and Auger electron spectroscopy (AES). The atomic distributions of four different CIGS absorber layers exhibited a good agreement although they were obtained using two different surface instruments, AES and SIMS. Comparative analysis results of different CIGS absorber layers using SIMS, AES, and fs-LA-ICP-MS provide us with the appropriate technique for the information of accurate composition in a rapid analysis time. Thanks to a simple approach using the Ga/(In + Ga) ratio, the optical band gap energy of the Cu(InXGa(1−X))Se2 quaternary layer was monitored in the entire CIGS layer. The elemental distribution and the band gap determination were then used to elucidate their relationship to the corresponding CIGS cell efficiency result.

Long Term Hydrodynamic Effects in a Semi-Arid Mediterranean Multilayer Aquifer: Campo de Cartagena in South-Eastern Spain

The Mediterranean basin contains many semi-arid environments where aquifers are subject to intensive exploitation, generally to meet irrigation demands. The Campo de Cartagena aquifer is a clear example from such a semi-arid environment, and its hydrodynamic effects have aroused great scientific interest. The main objective of this study is to evaluate the hydrodynamic effects that have occurred in the last century of anthropogenic activity in this aquifer system. This aquifer is subject to intensive exploitation and shows clear deficits in times of drought, with recharge by irrigation playing an important role. This study’s methodology includes groundwater modelling to reconstruct the transient evolution of the aquifer system during the last century, to generate water balances and to illustrate how the evolution of irrigation has, in many ways, changed the aquifer’s groundwater flow pattern. The results delineate the hydraulic communication of the aquifer stratums through specific geological structures, as well as the flow transfer from the Quaternary layer to the Mar Menor and the Mediterranean Sea. The reconstruction of the entire system’s temporal evolution shows a fragile water balance that is supported by surface-water contributions.

Study of dark current in mid-infrared InAsSb-based hetero n-i-p photodiode

In this work, we study the dark current characteristics in middle-wavelength infrared photodiodes with a heterojunction n-i-p architecture. The photodiode includes wide bandgap and quaternary layers to reduce the bulk dark current. Photodiodes with square mesa size varying from 500–20 µm are fabricated and their dark currents are characterized at temperatures from 77 K to room temperature (293 K). Surface leakage current is found to be negligible under normal operational conditions. Based on the study of activation energy, when the magnitude of reverse bias is smaller than 0.1 V and the temperature is larger than 255 K, the bulk dark current is found to be dominated mainly by the diffusion process. The contribution from the Shockley–Read–Hall and tunneling process will become significant when the temperature is below 255 K or the magnitude of reverse voltage bias is larger than 0.1 V. At −0.1 V bias, the observed dark current density is as small as 0.605 A · cm−2 at room temperature, and decreases to 6.6 × 10−2 A · cm−2 at 255 K and 1.16 × 10−3 A · cm−2 at 185 K for a typical square mesa diode with a size of 50 µm. Room-temperature performance of the photodiode demonstrates a cutoff wavelength of 5 µm and a blackbody detectivity of 1.5 × 109 cm · Hz1/2 W−1.

Liquid-Phase Exfoliated Indium-Selenide Flakes and Their Application in Hydrogen Evolution Reaction.

Single- and few-layered InSe flakes are produced by the liquid-phase exfoliation of β-InSe single crystals in 2-propanol, obtaining stable dispersions with a concentration as high as 0.11 g L-1 . Ultracentrifugation is used to tune the morphology, i.e., the lateral size and thickness of the as-produced InSe flakes. It is demonstrated that the obtained InSe flakes have maximum lateral sizes ranging from 30 nm to a few micrometers, and thicknesses ranging from 1 to 20 nm, with a maximum population centered at ≈5 nm, corresponding to 4 Se-In-In-Se quaternary layers. It is also shown that no formation of further InSe-based compounds (such as In2 Se3 ) or oxides occurs during the exfoliation process. The potential of these exfoliated-InSe few-layer flakes as a catalyst for the hydrogen evolution reaction (HER) is tested in hybrid single-walled carbon nanotubes/InSe heterostructures. The dependence of the InSe flakes' morphologies, i.e., surface area and thickness, on the HER performances is highlighted, achieving the best efficiencies with small flakes offering predominant edge effects. The theoretical model unveils the origin of the catalytic efficiency of InSe flakes, and correlates the catalytic activity to the Se vacancies at the edge of the flakes.

Mid-infrared GaSb-based resonant tunneling diode photodetectors for gas sensing applications

We present resonant tunneling diode-photodetectors (RTD-PDs) with GaAs0.15Sb0.85/AlAs0.1Sb0.9 double barrier structures combined with an additional quaternary Ga0.64In0.36As0.33Sb0.67 absorption layer covering the fingerprint absorption lines of various gases in the mid-infrared wavelength spectral region. The absorption layer cut-off wavelength is determined to be 3.5 μm, and the RTD-PDs show peak-to-valley current ratios up to 4.3 with a peak current density of 12 A/cm−2. The incorporation of the quaternary absorption layer enables the RTD-PDs to be sensitive to illumination with light up to the absorption lines of HCl at 3395 nm. At this wavelength, the detector shows a responsivity of 6.3 mA/W. At the absorption lines of CO2 and CO at 2004 nm and 2330 nm, respectively, the RTD-PDs reach responsivities up to 0.97 A/W. Thus, RTD-PDs pave the way towards high sensitive mid-infrared detectors that can be utilized in tunable laser absorption spectroscopy.