Effective Thickness Research Articles

Relationship between orbital moment anisotropy, magnetocrystalline anisotropy, and Dzyaloshinskii-Moriya interaction in W/Co/Pt trilayers

We have studied the Co layer thickness dependences of magnetocrystalline anisotropy (MCA), Dzyaloshinskii-Moriya interaction (DMI), and orbital moment anisotropy (OMA) in W/Co/Pt trilayers, in order to clarify their correlations with each other. We find that the MCA favors magnetization along the film normal and monotonically increases with decreasing effective magnetic layer thickness (teff). The magnitude of the Dzyaloshinskii-Moriya exchange constant (|D|) increases with decreasing teff until teff∼1 nm, below which |D| decreases. The MCA and |D| scale with 1/teff for teff larger than ∼1 nm, indicating an interfacial origin. The increase of MCA with decreasing teff continues below teff∼ 1 nm, but with a slower rate. To clarify the cause of the teff dependences of MCA and DMI, the OMA of Co in W/Co/Pt trilayers is studied using x-ray magnetic circular dichroism. We find nonzero OMA when teff is smaller than ∼0.8 nm. The OMA increases with decreasing teff more rapidly than what is expected from the MCA, indicating that factors other than OMA contribute to the MCA at small teff. The teff dependence of the OMA also suggests that |D| at teff smaller than ∼1 nm is not related to the OMA at the interface. We propose that the growth of Co on W results in a strain and/or texture that reduces the interfacial DMI, and, to some extent, MCA at small teff. Published by the American Physical Society 2024

The Effective Elastic Thickness of the Lithosphere Reveals Tectonic Process and Lithospheric Rheology of the Eurasian Basin

ABSTRACTWe obtained the effective elastic thickness of the lithosphere (Te) in the Eurasian Basin using the fan‐shaped wavelet method. For ultraslow spreading ridges, the magmatic heat input is insufficient to form continuous quasisteady‐state magma lenses along the axis, resulting in significant variability in the rheological strength of the lithosphere. We suggested that the tectonic inheritance resulted in the different lithospheric rheology of WVZ and SMZ, consequently leading to distinct tectonic‐magmatic activities. The SMZ with less magmatic activity has a weaker lithosphere than that of the EVZ with extensive magmatism. We propose that the lithospheric rheology and thermal structure of ultraslow spreading ridge may be influenced not by the amount of magma supply but by the mode of magma emplacement.

Effect of powder properties, process parameters, and recoating speed on powder layer properties measured by in-situ laser profilometry and part properties in laser powder bed fusion

In laser-based powder bed fusion of metals (PBF-LB/M), the powder layer is the link between the powder properties and the resulting part quality. Powder layer quality is a key metric related to powder spreadability and ultimately part quality, yet it is still unclear how it can be quantified. This is due to the difficulty of studying powder layer properties during the process. This study investigates the influence of powder properties, process parameters, and recoating speed on the surface roughness of the powder layer and the part, as well as on the effective thickness of the powder layer and solidified layer, and the resulting relative part density. Utilizing in-situ laser profilometry, high-resolution topographical data of the powder layer and the part surface were acquired, with minimal interference to the PBF-LB/M process. Six AlSi10Mg powders with varying particle size distribution, morphology, and flowability were processed using a wide range of recoating speeds and scan speeds to create powder layers with a wide range of properties. The results reveal a strong correlation between energy input and the effective powder layer thickness where lower scan speed results in an increased effective powder layer thickness due to material losses. Additionally, faster recoating decreases the powder layer density, which is moderated by the median particle size where the effect is strongest for fine powders. The surface roughness of the powder layer and top part surface are influenced by the recoating speed, energy input, and particle size, and they are strongly linked to each other. This highlights the importance of considering realistic substrate surface roughnesses in both powder spreading experiments and simulations. Finally, layer properties affect the process stability, resulting in small differences in relative part density.

Fabrication of polydopamine doped helical/chiral porous carbon fiber (HPCFs@PDA) and N-doped carbon layers (HPCFs@NCLs) for their application as wave absorber with ultrawide EAB

A new class of wave absorbing materials HPCFst@PDA and HPCFst@NCLs (where HPCFs describes helical/chiral porous carbon fiber, t refers to carbonization 700, 800 °C, PDA ascribed to poly (dopamine), and NCLs corresponds to nitrogen doped carbon layers) with helical/chiral, hierarchical, multi-layered structural morphology containing different heterostructures was triumphantly constructed through single-step carbonization of HPCFst. The HPCFst biomass fiber was go through self-polymerization of dopamine and we get HPCFs700@PDA, HPCFs800@PDA as an intermediate product. Finally, the PDA doped HPCFs biomass (HPCFs700@PDA, HPCFs800@PDA) was effectively transformed into NCLs from inside toward outside (HPCFs700@NCLs, HPCFs800@NCLs) through carbonization. Notably, HPCFs exhibit helical/chiral, hierarchical porous morphology with hetero-interfaces (such as dipole interfaces) that improve dielectric loss, while PDA and NCLs ameliorate wave absorber conductivity, through generation of polarization centers, heterointerfaces and resulting in considerable dielectric loss. Moreover, HPCFs with such unique structural morphology provide additional loss mechanism through cross-polarization that improve dissipation/attenuation of microwave. The microwave absorption mechanism of HPCFst@PDA(1–3), HPCFst@NCLs(1–3) (where 1, 2, 3 refer to filler content 27.50, 30.00, 32.50%wt PDA derived absorber and 20.00, 22.50, 25.00%wt NCLs filler) and their structure active relationship are further elucidated. Evidently, HPCFs700@PDA2 gained reflection loss (RL) of −51.60 dB at 13.60 GHz, across the broad spectrum of frequencies (EAB, RL ≤ −10 dB) covers 6.70 GHz (11.30–18.00 GHz) at 2.70 mm thickness. The EAB ameliorate to the value of 7.20 GHz (10.70–18.00 GHz) at thickness of 2.80 mm. While HPCFs700@NCLs2 RL was improved to −63.00 dB at 2.40 mm thickness with EAB 5.10 GHz (11.40–16.50) at 13.30 GHz frequency. Likewise, HPCFs800@PDA2 RL elevates to the value of −53.40 dB with adequate EAB covering 12.80–18.00 GHz (5.20 GHz) at higher values of 14.40 GHz and 2.10 mm thickness. For HPCFs800@NCLs2, the RL is as high as −65.40 dB at 9.90 GHz, with an effective thickness of 3.20 mm covering 7.50–11.20 GHz (3.20 GHz) EAB. At matching thickness of 2.00 mm the EAB covers 13.80–18.00 (4.20 GHz). Their top-notch microwave absorption capabilities with widened EAB at lower matching thickness demonstrate potentially promising prospects of HPCFst@PDA and HPCFst@NCLs as wave absorbing materials.

Gas Production Prediction Model of Volcanic Reservoir Based on Data-Driven Method

Based on on-site construction experience, considering the time-varying characteristics of gas well quantity, production time, effective reservoir thickness, controlled reserves, reserve abundance, formation pressure, and the energy storage coefficient, a data-driven method was used to establish a natural gas production prediction model based on differential simulation theory. The calculation results showed that the average error between the actual production and predicted production was 12.49%, and the model determination coefficient was 0.99, indicating that the model can effectively predict natural gas production. Additionally, we observed that the influence of factors such as reserve abundance, the number of wells in operation, controlled reserves, the previous year’s gas production, formation pressure, the energy storage coefficient, effective matrix thickness, and annual production time on the annual gas production increases progressively as the F-values decrease. These insights are pivotal to a more profound understanding of gas production dynamics in volcanic reservoirs and are instrumental in optimizing stimulation treatments and enhancing resource recovery in such reservoirs and other unconventional hydrocarbon formations.

Developing Correction Methods by Revisiting the Concept of Effective Thickness in Attenuated Total Reflection Spectroscopy.

We propose a new way of deriving the effective thickness in attenuated total reflection (ATR) spectroscopy, initially introduced by Hansen and Harrick in 1965. While following Hansen's approach, our derivation is more straightforward and includes an intermediate approximation that more closely aligns with results derived from Fresnel's equations, particularly for organic and biological materials. Using this intermediate approximation, we present improved estimations for the effective thicknesses with s- and p-polarized light. These estimations enabled us to enhance a recently developed ATR correction scheme that relies on effective thickness. Additionally, we examined the wavelength dependence of the product of wavenumber and effective thickness, observing that it bears a resemblance to the refractive index function of the sample. This similarity increases with the angle of incidence and the refractive index of the ATR crystal. Based on this observation, we introduce a simple correction scheme using the Kramers-Kronig transformed absorbance. This correction has the potential to address spectral shifts, facilitating applications in pattern recognition and spectra identification.

Dietary sodium sulfate supplementation improves eggshell quality, uterine ion transportation and glycosaminoglycan synthesis in laying hens.

This study evaluated the effects of dietary sodium sulfate (Na2SO4) supplementation on eggshell quality, uterine ion transportation, and glycosaminoglycan (GAG) synthesis. A total of 432 48-wk-old Hy-line Brown laying hens were randomly divided into 6 dietary treatments with 8 replicates of 9 birds each. The experimental laying hens were fed the corn-soybean meal diets (containing 0.15% NaCl) supplemented with 0.22%, 0.37%, 0.52%, 0.68%, 0.83%, or 0.99% Na2SO4 for 12 weeks. Results showed that the eggshell breaking strength and eggshell ratio significantly increased in the 0.68% Na2SO4 group at the end of wk 56 and wk 60 (P < 0.05). In addition, eggshell thickness and weight significantly increased in the 0.68% Na2SO4 group at the end of wk 60 (P < 0.05). Eggshell calcium (Ca) content in the 0.68% Na2SO4 group was higher than that of 0.22% and 0.99% groups (P < 0.001). The concentrations of K+ and Ca2+ in the uterine fluid were significantly greater in the 0.68% group than in the other groups (P < 0.05). Dietary Na2SO4 increased the gene expression of SLC8A1, SCNN1A, ATP1B1, and KCNMA1 quadratically in the uterus (P < 0.05), and higher values were observed in 0.68% group. Additionally, the GAG contents of the eggshell, and ATP-S, SULT, CS, and DS contents of the isthmus increased linearly with the increment of dietary Na2SO4 (P < 0.05). There was a remarkable reduction in mammillary knob width, mammillary thickness, and the percentage of the mammillary layer (P < 0.05), and an increment in mammillary knob density, effective thickness, and total thickness in the 0.68% group compared with the 0.22% and 0.99% groups (P < 0.05). Overall, there was no dose-related difference with the increment of dietary Na2SO4 levels. The addition of 0.68% Na2SO4 in the corn-soybean basal diet (0.15% Cl) regulated uterine ion transport, increased GAG contents of eggshell, and improved eggshell ultrastructure and quality.

Testing Cloud Adjustment Hypotheses for the Maintenance of Earth's Hemispheric Albedo Symmetry With Natural Experiments

AbstractEarth's Northern and Southern Hemispheres reflect essentially equal amounts of sunlight. How—and whether—this hemispheric albedo symmetry is maintained remains a mystery. We decompose Earth's hemispheric albedo symmetry into components associated with the surface, clear‐sky atmosphere, and different cloud types as defined by cloud effective pressure and optical thickness. Climatologically, greater reflection by the surface, aerosols, and high clouds in the Northern Hemisphere is balanced by greater low and mid‐level cloudiness in the Southern Hemisphere. Both hemispheres have darkened at similar rates over the past two decades; whether the darkening from more rapidly declining aerosol in the Northern Hemisphere is causing a departure from all‐sky symmetry remains uncertain. Natural experiments including long‐term trends, sea ice loss, and volcanic eruptions provide strong evidence against the hypothesis that extratropical low clouds compensate changing clear‐sky asymmetries on annual‐to‐decadal timescales but some evidence that tropical high cloud shifts may do so.

A Methodology to Quantify the Effective Vertical Thickness of Prephonatory Vocal Fold Medial Surface

ObjectiveThe shape of the vocal fold medial surface, particularly its vertical thickness, has been shown in computational and physical modeling studies to be highly influential in regulating glottal closure during phonation. However, because of the difficulty to quantify the vertical thickness in real vocal folds, this influence has often been overlooked in clinical contexts. Therefore, the goal of this study is to present a method to calculate an effective vertical thickness of the medial surface that is predictive of the glottal closure pattern during phonation. MethodsAn effective vertical thickness of the medial surface is calculated as a weighted integral of the medial surface contour along the vertical dimension. The weight is one for the part of the medial surface within a fixed threshold distance from the most medial point, and decays exponentially otherwise. The influence of the threshold distance value on the effective thickness value is investigated. Additionally, the sensitivity of the calculated effective thickness to slight misidentification of the vertical glottal midline is also studied. The methodology is validated on the vocal fold medial surface data from a canine hemilarynx at different levels of thyroarytenoid muscle activation. ResultsFor most threshold distances, the thickness follows an expected sigmoid-like trend with respect to the thyroarytenoid muscle activation level. A threshold distance of 0.05 mm appears optimal as it produced thickness changes in a range comparable to previous computational and experimental studies. The methodology is relatively robust to slight misidentification of the vertical glottal midline. ConclusionsA methodology to estimate the effective vocal fold vertical thickness from medial surface contours is proposed. The methodology can be applied in future studies to correlate medial surface shape to relevant parameters characterizing vocal fold vibration as well as clinical evaluation of treatment effectiveness.

Simulation model to enhance Bragg reflector assisted GeSn SACM-SPAD performance for 1550 nm LIDAR applications in autonomous vehicles

A safe 3-D lidar sensor for autonomous vehicle creates a high demand on 1550 nm SPADs detectors. Due to the limitation of the energy band gab and absorption coefficient of Si and Ge, their photodetectors have low efficiency at the 1550 nm wavelength. Doping Ge with Sn reduces its bandgap and enables higher efficiency in this range while adding Bragg reflector represents a smart way to increase absorption area effective thickness. Here a simulation model for Ge(1-x)Snx SACM SPAD is proposed to work as a 1550 nm laser detector. Two Bragg reflectors are built using Si\\SiGe and Si\\SiGeSn layers. Results show a significant enhancement on detector optical properties. PDP reaches 38 % at room temperature and the increase in Pdp due to Bragg reflector reaches 66 %. Although DCR also increases, it can be handled with proper dead time configuration.

The effective elastic thickness along the Emperor Seamount Chain and its tectonic implications

Summary The Hawaiian-Emperor Seamount Chain, a pre-eminent example of a hotspot-generated intraplate seamount chain, provides key constraints not only on the kinematics of plates but also on their rigidity. Previous studies have shown that the effective elastic thickness, Te, a proxy for the long-term strength of the lithosphere, changes abruptly at the Hawaiian-Emperor ‘bend’ from low values (∼16 km) at the Emperor Seamounts to high values (∼27 km) at the Hawaiian Ridge. To better constrain Te along the poorly explored Emperor Seamounts we have used a free-air gravity anomaly and bathymetry gridded data set, together with fully 3-dimensional elastic plate (flexure) models, to estimate the continuity of Te and volcano load and infill densities along 1000 profiles spaced 2 km apart of the chain. Results show that Te generally decreases northward along the chain. The decrease is most systematic between Ojin and Jimmu guyots where Te depends on the age of the lithosphere at the time of volcano loading and is controlled by the 340°C and 400°C oceanic isotherms. The largest variation from these isotherms occurs at the northern and southern ends of the chain where Te is smaller than expected suggesting the influence of pre-existing, older, loads. We use these results to constrain the subsidence, flexural tilt, rheological properties, and tectonic setting along the seamount chain. We found an excess subsidence in the range 1.2-2.4 km, a tilt as large as 2-3°, oceanic lithosphere that is weaker than it is seaward of the weak zone at subduction zones, and a tectonic setting at Detroit and Koko seamounts that, despite their forming an integral part of the hotspot generated seamount chain, retains a memory of their proximity to earlier loads associated with plume influenced mid-oceanic ridges.

Research on Evaluation Method of Natural Gas Hydrate Resources Based on Probability Distribution Model

Natural gas hydrate, as a highly efficient and clean energy source, has garnered significant attention from both developed and energy-deficient nations. However, to achieve industrial application, several technical challenges must be addressed, including resource exploration, spatial positioning, resource assessment, economic production evaluation, and climate change impact assessment. Currently, our exploration and evaluation system for gas hydrate resources remains immature. This study aims to determine the probability distribution of effective thickness, porosity, and saturation of natural gas hydrate resource parameters in the study area and their variations. Utilizing probability statistics theory, we calculated specific values for all gas hydrate resource parameters from open-source data of 14 exploration well locations, determined their probability distributions, and conducted distribution detection to identify specific distributions. Data analysis was performed using linear graphs and bar charts to summarize patterns. Subsequently, by applying the mathematical formula Q = A×Z×∅×S×E, we categorized natural gas hydrate resource parameters, calculated gas hydrate resources at each effective depth, determined the probability distribution of each obtained data point, and ultimately solved for the total natural gas hydrate resources, yielding a final solution of 31875763695.08.

A method for structural framework variation of a multilayer field associated with complicated geology

Background. During the probabilistic resource base estimation, the largest uncertainties are associated with the wide range of the gross rock volume. In the course of the formation area work, the resulting maps of gross thickness are constructed incorrectly. Objective. To take into account facies zoning when varying the structural framework if working with the Achimov strata of a multilayer field. Materials and methods. The applied approach implies accounting of the errors in structural constructions in proportion to the power depending on facies zones. The authors proposed an additional stage of mapping using proportion maps to avoid obtaining geologically unrealistic local power anomalies. Results. A set of modified maps of the total thickness of clinocyclites was obtained, reflecting the key features of the geological structure of the modeling object, particularly facies differentiation and related lateral heterogeneity. Conclusions. The chosen approach to constructing maps of gross thickness allowed to obtain geologically realistic maps of effective thickness, which, in turn, formed the basis for mapping of productive volume.

Tunnel silicon oxynitride phase transformation for n-type polysilicon passivating contacts in crystalline silicon solar cells

The study investigates the fabrication and characterization of tunnel oxynitride (TON) layers produced using Plasma-Enhanced Chemical Vapor Deposition (PECVD) at different pressure and power variations. The aim is to explore TON layers as potential substitutes for conventional SiO2 in Tunnel Oxide Passivated Contact (TOPCon) solar cells. Foe this purpose, an effective oxide thickness (EOT) of 1.1–1.2 nm and 1.5–1.6 nm has been achieved by treating the TON samples with NH3 and N2 gas plasma, respectively. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed critical variations in the chemical bonding within TON layers, which exhibit different properties based on the deposition conditions. The presence of nitrogen-nitrogen and nitrogen–hydrogen bonds is prominently influenced by changes in the PECVD parameters, directly affecting the layer’s optical and electronic properties. Notably, the presence of hydroxyl (O–H) and amino (NH2) groups within the TON structure suggests an improvement in surface passivation, essential for optimizing solar cell performance and durability. A lifetime of 737 and 823 μs has been recorded for N2 and NH3 samples, compared to the NAOS 710 μs reference sample. NH3 plasma-treated samples show an improved iVoc of 736 mV, indicating better phase transformation and passivation quality than N2 plasma treatment and the NAOS reference sample.

Phased optimization of multi-thermal fluid flooding for enhanced oil recovery

Multi-thermal fluid flooding has become a critical technique in heavy oil reservoirs and is widely applied in China. Owing to the complexity of the displacement process and the involvement of multiple injection media, conventional optimization methods are unable to achieve economic and efficient development of heavy oil. In this study, an efficient phased parametric optimization method for multi-thermal fluid flooding was developed using horizontal wells in heavy oil reservoirs. This method utilizes particle swarm optimization (PSO), which targets the net present value for the phased optimization of multi-thermal fluid flooding. A comparison between the phased optimization and non-phased optimization shows that the cumulative oil production increased by 16.74% and the net present value increased by 39.66% with phased optimization. The effectiveness of the phased optimization method was verified using a field model. Optimal injection parameter charts were developed for each phase of the multi-thermal fluid flooding under different reservoir parameter conditions. The charts illustrate that the optimal gas injection rate and chemical mass concentration tend towards zero during the steam flooding initiation phase under varying reservoir parameter conditions. Conversely, all the media injection rates increased during the thermal fluid control and steam breakthrough phases. Additionally, with an increase in the crude oil viscosity, effective formation thickness, and original oil saturation, the optimal injection rate of the various media increases. However, with an increase in the permeability and reservoir depth, the optimal injection rate of the various media decreases.

Survey of tungsten gross erosion from main plasma facing components in WEST during a L-mode high fluence campaign

An initial high fluence campaign was performed in WEST, in 2023, on the newly installed actively cooled tungsten divertor composed of ITER-grade monoblocks. The campaign consisted in the repetition of a 60 s long Deuterium L-mode pulse in attached divertor conditions, cumulating over 10000s of plasma exposure. A maximum deuterium fluence of approximately 5⋅1026m−2 was reached in the outer strike point region, representative of a few high performance ITER pulses. Gross tungsten erosion inferred from visible spectroscopy shows that the most eroded plasma facing component is the inner divertor target with rates ten times larger than on the outer divertor target. The outer midplane tungsten bumpers, located a few centimeters from the plasma, show gross erosion rates two times lower than at the outer divertor. We conclude that the outer midplane bumpers have a negligible contribution to the long range tungsten migration and deposition onto the lower divertor. The cumulated gross erosion rate on the inner divertor translates in an effective gross erosion thickness of about 20μm, while it is about 2μm for the outer divertor. Strikingly, these orderings coincide with the thickness of deposits found locally on the divertor : the exposed surfaces of high field side monoblocks are covered with several tens of μm tungsten deposits, while on the lower field side, few μm thin tungsten deposits are only found on the magnetically shadowed parts of monoblocks. The strong impact of those deposits on WEST operation, namely perturbation of surface temperature measurement with infra-red thermography, and the emission of flakes causing radiative perturbation of the confined plasma, calls for anticipating similar issues in ITER. In particular, the start of research operation shall consider the definition of a divertor erosion budget in order to anticipate the formation of deleterious deposits.

Integrating phase change materials in buildings for heating and cooling demand reduction – A global study

This study aims to analyse the integration of Phase Change Materials (PCMs) in building envelopes globally, focusing on its ability to reduce the energy demand and its economic viability. This study conducted extensive simulations using the DesignBuilder software across 5,684 locations globally and utilising artificial intelligence (AI) models to extend the simulation further to 73,515 locations, evaluating the impacts of PCM properties such as melting temperature (MT) and thickness. The main findings indicate that pronounced annual energy savings, 2500 to 3000 kWh, are observed in equatorial regions including northeast Brazil, central Africa, and the Malay Archipelago. Additionally, the optimal utilisation of increased PCM thickness is contingent upon selecting the correct MT and is most effective in regions with high average maximum temperatures, while the most common effective thickness is 20 mm. The study demonstrates that MT significantly affects energy savings, more than PCM thickness, highlighting the importance of selecting appropriate MT based on climatic conditions. The 25 °C MT is most effective within lower latitude range (−15° to 30°), averaging 743.2 kWh greater savings than the 21 °C option. The 21 °C MT shows superior performance outside of this range, however the advantage is marginal as the average savings is 251.0 kWh. Economically, regions such as the USA, southern Europe (Spain and Italy), Brazil, and northern Australia show the best viability for PCM integration, aligning energy efficiency improvements with substantial economic returns. This comprehensive analysis suggests that tailored PCM integration strategies are essential for maximising energy savings and advancing sustainable building practices.

Calculation Thickness of the Added Flexural Layer on Composite Layer using a Light Weight Deflectometer (LWD) Pusjatan

Calculating the thickness of the flexible overlay needs to consider several factors, such as traffic load, soil characteristics, existing pavement conditions, and planned changes to the road design. This procedure generally uses recognized pavement design methods, such as the AASHTO 1993 method (Guide for Design of Pavement Structures). This research aims to determine the thickness of the added layer using an asphalt layer on composite roads in accordance with the 1993 AASHTO standards. It is hoped that this method can produce an effective overlay design, extend the life of the pavement, and increase the comfort and safety of road users. The data used in this research includes primary and secondary data. The results of this analysis are to calculate the STA 0 segment, for other STAs use the same method. From the Light Weight Deflectometer (LWD) deflection data, the Subgrade Reaction Modulus (k) value was 473 psi/in, the Concrete Elasticity Modulus (Ec) value was 4,843,105 psi and the Rupture Modulus (Sc') value was 699 psi. The traffic load used is 25.000.000, so the result of calculating the plate thickness to serve future traffic (Df) is 10.79 inches or 27.40 cm and the effective plate thickness value (Deff) is 9.13 inches or 23.30 cm, then the result is the added layer thickness (Dol) is 3.30 inches or 8.39 cm

A VERY LOW BANDGAP LINE-TUNNEL FIELD EFFECT TRANSISTOR WITH CHANNEL-BURIED OXIDE AND LATERALLY DOPED POCKET

Low bandgap and line tunneling techniques have demonstrated the most effectiveness in enhancing the on-current of tunnel field-effect transistors (TFETs). This study examines the mechanisms and designs of channel-buried oxide and a laterally doped pocket for a very low bandgap line-TFET. Numerical TCAD simulations show that the channel-buried oxide is needed to prevent off-state lateral tunneling while still maintaining the on-state vertical tunneling. The buried oxide pillar should be high so that the channel is thin, about 10 nm thick, to completely suppress the tunneling leakage. The dopant pocket is required to trigger the line tunneling earlier than the point tunneling to improve the subthreshold swing and on-current. Increasing the pocket concentration or decreasing the pocket thickness both cause an increase not only in the vertical band bending but also in the effective gate-insulator thickness. Because of the trade-off between these two operation parameters, for a given thickness/concentration, there exists an optimal concentration/thickness of the pocket to maximize the on-current. The on-current is optimized using a heavy, thin pocket, for which the band bending is maximized and the effective gate-insulator thickness is minimized. For the fabrication feasibility using existing doping techniques, the pocket concentration and thickness should be 1019 cm-3 and 4 nm, respectively, to maximize the on-current of the InAs line-TFET.

The Crust-Mantle Interaction of the Qiangtang Terrane: New evidence from the Effective Elastic Thickness of the Lithosphere

The crust-mantle interaction in the Qiangtang terrane is significant to study continental rheology and evolution. Its mechanism remains a subject of considerable debate for the reason of lack of sufficient geophysical evidence. The effective elastic thickness (Te) of the lithosphere can provide important constraints on this issue because it is sensitive to the state of mechanical coupling between the crust and the lithospheric mantle. We present new high-resolution Te of the Qiangtang terrane by using the multitaper admittance method with fusion of different window, based on satellite gravity and topographical data. Thus, a detailed study of the lithosphere is conducted, for the first time to utilize the spatial variations of Te and associated parameters, including thermal structures of the lithosphere, uppermost mantle seismic Pn-velocity, and crustal deformation. The results indicate that crust-mantle interaction in the Qiangtang terrane primarily occurs in the middle Qiangtang terrane (87°E ∼ 95°E, 32°N ∼ 34°N), where Te values are lower. In the eastern and western Qiangtang terrane, Te values are higher, implying weaker late-stage modification. Due to Rayleigh-Taylor instability, lithospheric delamination occurred beneath the south Qiangtang terrane. Based on the extent of these low Te values (Te < 50 km), we conclude that the delaminated lithospheric slab sinking into the mantle is ∼400 km in length and elongated in shape. The delamination induces the upwelling of mantle material, upward stress, volcanic activity, extensional faults, and hot springs in the Qiangtang terrane.