Inversion Mode Research Articles

Direct and Inverse Reduced-Form Models for Reciprocal Calculation of BC Emissions and Atmospheric Concentrations.

Atmospheric black carbon (BC) concentrations are governed by both emissions and meteorological conditions. Distinguishing these effects enables quantification of the effectiveness of emission mitigation actions by excluding meteorological effects. Here, we develop reduced-form models in both direct (RFDMs) and inverse (RFIMs) modes to estimate ambient BC concentrations. The models were developed based on outputs from multiyear simulations under three conditional scenarios with realistic or fixed emissions and meteorological conditions. We established a set of probabilistic functions (PFs) to quantify the meteorological influences. A significant two-way linear relationship between multiyear annual emissions and mean ambient BC concentrations was revealed at the grid cell scale. The correlation between them was more significant at grid cells with high emission densities. The concentrations and emissions at a given grid cell are also significantly correlated with emissions and concentrations of the surrounding areas, respectively, although to a lesser extent. These dependences are anisotropic depending on the prevailing winds and source regions. The meteorologically induced variation at the monthly scale was significantly higher than that at the annual scale. Of the major meteorological parameters, wind vectors, temperature, and relative humidity were found to most significantly affect variation in ambient BC concentrations.

Improved electrical and RF performance of a junctionless vertical super-thin body (VSTB) FET by increased substrate doping

This article focuses on the incorporation of a junctionless (JL) body in a newly invented structure called vertical super-thin body (VSTB) FET and performance evaluation of the JL VSTB FET in terms of different substrate doping (Ns) through a properly calibrated Sentaurus TCAD tool. Compared to the inversion mode device, its JL counterpart significantly decreases off-state leakage current (Ioff) by more than two orders of magnitude and improves subthreshold swing (SS) by 36.69 mV/dec. More importantly, the strong control of Ns on the electrical and radio-frequency (RF) characteristics of the device is explored at a fixed body doping and gate work-function. This study reveals that Ns-increase highly suppresses short channel effects by increasing the body depletion charges and thereby decreasing the channel electron density. An excellent improvement of more than three orders of magnitude is observed in both Ioff and Ion/Ioff ratio for a change of Ns from 1016 to 1019 cm−3. Such an Ns-increase also decreases SS and drain-induced-barrier-lowering by 102.26 mV/dec and 60.34 mV/V, respectively. Various RF parameters such as transconductance, input capacitance, gate-drain capacitance, unity-gain cut-off frequency, and gain-bandwidth-product also exhibit impressive improvement for higher Ns. This study is expected to help future research on such a new device as VSTB FET by revealing the attractive substrate doping control on the device electronics.

DCl-H2O, HCl-D2O, and DCl-D2O Dimers: Inter- and Intramolecular Vibrational States and Frequency Shifts from Fully Coupled Quantum Calculations on a Full-Dimensional Neural Network Potential Energy Surface.

We report full-dimensional and fully coupled quantum calculations of the inter- and intramolecular vibrational states of three isotopologues of the hydrogen chloride-water dimer: DCl-H2O (DH), HCl-D2O (HD), and DCl-D2O (DD). The present study extends our recent theoretical investigation of the nine-dimensional (9D) vibrational level structure of the HCl-H2O (HH) dimer [Liu, Y.; Li, J.; Felker, P. M.; Bačić, Z. Phys. Chem. Chem. Phys. 2021, 23, 7101-7114]. It employs the same accurate 9D permutation invariant polynomial-neural network potential energy surface and the highly efficient bound-state methodology. The objective of this work is to elucidate the isotopologue variations of a range of bound-state properties of the hydrogen chloride-water dimer and compare them to those of the HH dimer. In order to achieve this, for the isotopologues considered, the rigorous 9D quantum calculations performed encompass all intramolecular vibrational fundamentals, and their frequency shifts relative to the isolated monomer values, together with the low-lying intermolecular vibrational states in each of the intramolecular vibrational manifolds of interest. Moreover, for the ground state of each isotopologue, several informative vibrationally averaged intermolecular geometric properties of the dimer are computed, as well as the three rotational constants. The energies of the intermolecular inversion and rock modes, which mainly involve the motions of the water moiety, differ greatly for H2O and D2O, but are much less sensitive to whether the hydrogen chloride isotopologue is HCl or DCl. On the other hand, the excitation of the HCl/DCl stretch changes significantly the energies of the water inversion and rock modes. The DCl stretch frequency shift computed in 9D for the DD dimer, -114.91 cm-1, agrees extremely well with the corresponding experimental value of -115.20 cm-1 measured by Saykally and co-workers.

Overcoming bit loss mechanism in self‐amplified multilevel silicon‐oxide‐nitride‐oxide‐silicon memory cell

AbstractThis work reports on the triple‐level NAND flash cell realized from self‐amplified (SA) double gate (DG) tunneling‐based silicon‐oxide‐nitride‐oxide‐silicon (T‐SONOS) memory device. Through calibrated simulations, we show that capacitive coupling between the front gate and back gate can be used to store eight states (or 3 bits), that is, from “000” to “111,” in a T‐SONOS memory device with the readable difference between each level at lower programming voltages. The performance of the multilevel T‐SONOS cell is compared with the inversion mode SONOS (I‐SONOS) multilevel cell. Results highlight that gate length (Lg) scaling from 100 to 25 nm significantly deteriorates the threshold voltage associated with the lower states in the I‐SONOS multilevel cell. However, highly stable eight states can be achieved in a multi‐level T‐SONOS cell at Lg = 25 nm. The results highlight the potential of SA T‐SONOS cell for designing multilevel memory cell arrays.

Assessment of the resolving power of hydrophobic interaction chromatography for intact protein analysis on non-porous butyl polymethacrylate phases

This study reports on the assessment of the separation performance of hydrophobic interaction chromatography for intact protein analysis using non-porous butyl polymethacrylate phases. The maximum peak capacity in inverse gradient mode was reached at a volumetric flow rate which was significantly (10–20 times) higher than the flow rate yielding the minimum plate height in isocratic mode, as the gradient volume dominates the peak-capacity generation. The flow rate yielding the maximum peak capacity increased with decreasing gradient volume, i.e., steeper gradients, and also depends on the magnitude of the mass-transfer contribution to peak dispersion (affected by particle size and molecular diffusion coefficient of proteins) at these high flow rates. The maximum peak capacity using a 100 mm long column packed with 4 µm particles for steep 7.5 min gradients was determined to be 60. Increasing the column length by coupling columns leads to better gradient performance than increasing the gradient duration for gradients of 60 min and longer. Using a coupled column system (2 × 100 mm long columns packed with 4 µm particles), the maximum peak capacity was determined to be 105, which was 33% higher compared to that of a single column while applying a similar gradient volume. Decreasing the particle size to 2.3 µm leads to higher peak capacities even though the column was operated at lower volumetric flow rate. The maximum peak capacity obtained with the 2.3 µm column was 128% higher than was obtained with the coupled column. Even at suboptimal conditions, the 2.3 µm column yields a higher peak capacity (14%) than when using two coupled columns packed with 4 µm at optimal conditions (gradient time of 120 min and a flow rate of 0.5 mL/min).

Comprehensive Study of Inversion and Junctionless Ge Nanowire Ferroelectric HfZrO Gate-All-Around FETs Featuring Steep Subthreshold Slope with Transient Negative Capacitance

This study reports the ferroelectric (FE) layer of Hf0.5Zr0.5O2 (HZO) film on a Ge gate-all-around field-effect-transistor (GAAFET) with inversion mode (IM) and junctionless (JL) mode, and is the first that discuss the association of the JL field-effect transistor conduction mechanism in the subthreshold region with the transient negative capacitance (TNC) effect of the FE layer are discussed. The IM Ge FE-GAAFET exhibited a minimum subthreshold slope (SSmin) of 55 mV dec−1 and a high ION/IOFF ratio of >106. The sub-60 mV dec−1 SS result demonstrates surface potential amplification, which is attributed to the TNC effect. Furthermore, the Ge JL FE-GAAFETs exhibited an SSmin of 58 mV dec−1, a high ION/IOFF ratio (>105), and reverse drain-induced barrier lowering when compared with baseline HfO2 devices. These IM and JL Ge FE-GAAFETs are highly suitable for low-power integrated circuit applications.

Low frequency noise performance of horizontal, stacked and vertical silicon nanowire MOSFETs

The low frequency noise performance of Gate-All-Around Nanowire (NW) or Nanosheet (NS) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is investigated, taking account of the impact of the device architecture, i.e., junctionless (JL) versus inversion-mode (IM) and process variations for the gate metal. The horizontal devices are characterized by 1/f noise, dominated by the number fluctuation mechanism, so that the power spectral density (PSD) is directly proportional with the trap density in the gate stack. The average 1/f noise PSD is becoming smaller going from single NW transistors on Silicon-on-Insulator substrates, to stacked horizontal NS devices on bulk silicon and, finally, vertical NWFETs with a substrate source contact. At low currents and frequencies below 1 kHz the 1/f noise in the vertical NWs is, in contrast to the horizontal devices, controlled by mobility fluctuations. In these devices white noise is observed above 1 kHz.

Performance improvement of spacer engineered n-type SOI FinFET at 3-nm gate length

In this paper, for the first time, we have investigated the DC and analog/RF performance metrics of 3 nm gate length (LG) silicon-on-insulator (SOI) FinFET using HfxTi1−xO2 high-k material in gate stack to improve subthreshold characteristics. The 3-D device performance of single-k, dual-k, and hybrid spacer is compared without spacer dielectric, and DC characteristics are presented. In this move, it is noticed that the device attains the highest ION/IOFF ratio of ~109 compared to ~105 due to an increase of effective gate length by fringing fields with spacer dielectric. Moreover, to evaluate and understand the nanostructure performance comparison is made between Junctionless (JL), Accumulation (ACC), and Inversion (INV) modes. The device exhibits excellent DC characteristics with ION/IOFF ratio of ~109, subthreshold swing (SS) of ~61.8 mV/dec, drain induced barrier lowering of (DIBL < 25 mV/V), and Vth ~ 0.36 V in all three modes with dual-k spacer. Moreover, the impact of device dimensional and process parameters such as gate length (LG), fin width (FW), fin height (FH), temperature (T), and work function variations on switching characteristics (ION/IOFF) are extracted and studied. The device performance acknowledges that Moore’s law can be validated even in 3 nm nodes to continue further scaling.

Is accumulation or inversion mode dielectric modulated FET better for label-free biosensing?: A comparative investigation

In this paper, we present a comprehensive assessment of dielectric modulated accumulation mode field-effect transistor (AMFET) architecture for label-free biosensing in comparison with inversion mode field-effect transistor (IMFET) architecture. The underlying physics of the AMFET and IMFET biosensors was explored by investigating variation in the conduction band and the electron concentration profile (e−CP) under both ON-state and OFF-state due to charged and neutral bio molecule immobilisation. Subsequently, essential sensitivity parameters are estimated for biosensing. It is observed that the variation in electron concentration profile has a huge impact on the drain current and threshold voltage. Sensitivity evaluation predicts AMFET to have improved ION/IOFF, OFF-current and threshold (VTH) shift. AMFET shows enhanced sensitivity to charged biomolecules over neutral bio molecules. From the investigations done, the AMFET has outperformed at lower bias and fails to predict optimum results at higher bias compared to IMFET. This leaves a choice to use the desired device as per the biasing availability for label-free detection of the biomolecules.

Design of wideband high‐efficiency power amplifier based on continuous inverse modes

This paper presents a wideband high-efficiency power amplifier (PA) based on novel continuous inverse modes (NCIMs). The NCIMs mainly provides a wider impedance design space by introducing freedom factors. More importantly, a combination of two frequency-point harmonic-tuned network and fundamental reactance compensation matching networks is employed simply to design a broadband output matching network for achieving a broadband high-efficiency goal. Eventually, for the sufficient verification, a broadband high-efficiency PA achieves a measured 112.2% bandwidth from 0.9 to 3.2 GHz, while delivering an outstanding performance of 10 to 12.3 dB gain, 60.7% to 84.1% drain efficiency, and 40 to 42.3 dBm output power over the entire frequency band. Furthermore, when driven by a 40 MHz four-carrier OFDM modulation signal, the adjacent channel power ratio (ACPR) is measured better than − 46.3 dBc across the band with digital pre-distortion technology.

An analytical model for a TFET with an n-doped channel operating in accumulation and inversion modes

The tunnel field-effect transistor (TFET) is an ambipolar device that conducts current with the channel in both accumulation and inversion modes. Analytical expressions for the channel potential and current in a TFET with an n-doped channel when operating in the accumulation and inversion modes are proposed herein. The potential model is derived by solving the two-dimensional (2D) Poisson equation using the superposition principle while considering the charges present in the channel due to electron or hole accumulation along with the depletion charges. An expression for the tunneling current corresponding to the maximum tunneling probability is also derived. The tunneling current is obtained by analytically calculating the minimum tunneling length in a TFET when operating in the accumulation or inversion mode. The results of the proposed potential model is compared with technology computer-aided design (TCAD) simulations for TFET with various dimensions, revealing good agreement. The potential and current in an n-type TFET (nTFET) obtained using the proposed models are also analyzed.

Self-adapting automated mode control system of packed absorbers used for selective gas emission treatment

This paper describes the designed self-adapting automated mode control system of packed absorbers used for selective gas emission treatment. It contains the description of automated control chart of the packed absorber and the algorithm of control program of the mass exchange system. The paper covers the principle of self-adapting control and steady maintenance of emulsification (phase inversion) mode depending on existing concentrations to be collected from continuous gas phase flow.

Scaled conjugate gradient ANN for industrial sensors calibration

In this paper, artificial neural network is used to calibrate sensors that are commonly used in industry. Usually, such sensors have nonlinear input output characteristic that makes their calibration process rather inaccurate and unsatisfied. Artificial neural network is utilized in an inverse model learning mode to precisely calibrate such sensors. The scaled conjugate gradient (SCG) algorithm is used in the learning process. Three types of industrial sensors which are gas concentration sensor, force sensors and humidity sensors are considered in this work. It is found that the proposed calibration technique gives fast, robust and satisfactory results.

Orbital‐Angular‐Momentum‐Encrypted Holography Based on Coding Information Metasurface

AbstractMetasurface holography has shown great potentials to reconstruct the full‐wave information of electromagnetic (EM) waves, bringing benefits of high spatial resolution and good precision of reconstructed images. To obtain higher security of the metasurface holography, orbital‐angular‐momentum (OAM) of EM waves is taken into consideration as new freedom of the metasurface holography. The use two coding information metasurfaces is proposed to achieve the OAM‐encrypted holography. One metasurface is used to generate different OAM beams with l = ±1 helical mode indices, which functions as the OAM feed; while the other is used to integrate different OAM helical‐phase wavefronts into the holograms of the transmitted images, forming the OAM‐encrypted holography. The predesigned images are accurately decoded only when the OAM‐encrypted metasurface is illuminated by the incident OAM beams with the inverse helical mode indices (l = ∓1) under the incidence of defined polarization states. Experimental results agree well with the theoretical design and numerical simulations, verifying the feasibility and security of the OAM‐encrypted holography. The proposed method will be a good candidate to enhance the secure communication systems and imaging systems.

Exactly solvable double-well potential in Schrödinger equation for inversion mode of phosphine molecule

The reduced mass of the effective quantum particle for the inversion mode ν2 of phosphine molecule PH3 is known to be a position dependent one. In the present article the inversion spectrum of PH3 is considered with the help of the Schrödinger equation (SE) with position dependent mass and corresponding modified double-well potential. The SE is shown to be exactly solvable. The results are used for the analysis of the pertinent experimental data available in literature. We are based on the reliable value ν2=E2-E0=992.1cm-1 (2ν2=E4-E0=1972.5cm-1; 3ν2=E6-E0=2940.8cm-1; 4ν2=E8-E0=3895.9cm-1) obtained by Špirko et al. Also we use the value for the barrier height Eb=12300cm-1 that seems to be commonly accepted at present and the hypothetical value for the energy splitting of the 11-th doublet of the 10ν2 band s10=E21-E20≈7.2cm-1 suggested in the literature. Definite predictions are derived for the energy splitting of the 4-th doublet of the 3ν2 band s3=E7-E6 that is a test one for the observation in the experiment of Okuda et al. SE with position dependent mass provides self-consistently the required values of {ν2;Eb;s10} yielding s3=6.21·10-12cm-1.

Ground state properties and infrared spectra of anharmonic vibrational polaritons of small molecules in cavities.

Recent experiments and theory suggest that ground state properties and reactivity of molecules can be modified when placed inside a nanoscale cavity, giving rise to strong coupling between vibrational modes and the quantized cavity field. This is commonly thought to be caused either by a cavity-distorted Born-Oppenheimer ground state potential or by the formation of light-matter hybrid states, vibrational polaritons. Here, we systematically study the effect of a cavity on ground state properties and infrared spectra of single molecules, considering vibration-cavity coupling strengths from zero up to the vibrational ultrastrong coupling regime. Using single-mode models for Li-H and O-H stretch modes and for the NH3 inversion mode, respectively, a single cavity mode in resonance with vibrational transitions is coupled to position-dependent molecular dipole functions. We address the influence of the cavity mode on polariton ground state energies, equilibrium bond lengths, dissociation energies, activation energies for isomerization, and on vibro-polaritonic infrared spectra. In agreement with earlier work, we observe all mentioned properties being strongly affected by the cavity, but only if the dipole self-energy contribution in the interaction Hamiltonian is neglected. When this term is included, these properties do not depend significantly on the coupling anymore. Vibro-polaritonic infrared spectra, in contrast, are always affected by the cavity mode due to the formation of excited vibrational polaritons. It is argued that the quantized nature of vibrational polaritons is key to not only interpreting molecular spectra in cavities but also understanding the experimentally observed modification of molecular reactivity in cavities.

Performance evaluation of junctionless double surrounding gate In0.53Ga0.47As nanotube MOSFET using dual material gate engineering

In this paper, the authors present the studies made on drain current (ID) for 5 nm gate length Dual Material (DM) Double Surrounding Gate (DSG) inversion mode (IM) and junctionless (JL) In0.53Ga0.47As nanotube (NT) MOSFET and Silvaco ATLAS 3D TCAD based simulation results are reported. In these studies, the authors have made use of the Non-Equilibrium Green’s Function (NEGF) approach and the self-consistent solution of Poisson’s equation with Schrodinger’s equation. In the case of inversion mode nanotube MOSFET, the channel region is lightly doped. The effect of Dual Material Gate Engineering for In0.53Ga0.47As Nano Tube channel radius 1.5 nm with gate oxide (Al2O3) thickness (0.8 nm) on ID, has also been studied. Further, a comparison of results has been done between IM DM DSG and JL DM DSG NT MOSFET. In the case of JL MOSFET, doping concentrations are optimized for two approaches (i) to get the same ION current as IM device and (ii) to get the same threshold voltage (VTH) as IM device. This results in 10 and 102 times smaller IOFF in matching ION and VTH optimized devices respectively as compared to IM device. It was found that DM Gate Engineering reduces drain induced barrier lowering (DIBL) in IM and JL devices. JL device is found to have much smaller DIBL ~ 21.10 mV/V, almost an ideal SS ~ 60 mV/dec, and a higher ION/IOFF ratio ~ 2.85 × 108 as compared to the results available for CGAA devices in the literature.

Serum Uric Acid Levels and Risk of Eight Site-Specific Cancers: A Mendelian Randomization Study.

The relationship between serum uric acid (UA) levels and cancer risk remains controversial. Here, a two-sample Mendelian randomization analysis was performed to identify a causal effect of serum UA levels on cancer risk. Twenty-six single nucleotide polymorphisms strongly associated with serum UA levels were screened as genetic variants from large-scale meta-analysis data of a genome-wide association study of 110,347 European individuals. Genetic associations with eight common site-specific cancers were subsequently explored. A total of six Mendelian randomization methods were used to estimate the potential effect of serum UA levels on cancer risk, including random effects inverse variance weighting, fix effects inverse variance weighting, MR-Egger, median weighting, mode weighting, and simple mode analysis. Our primary random effects inverse variance weighted analysis revealed that no significant associations with cancers was found (all p > 0.05). Sensitivity analyses and additional analyses also showed similar pooled results. In conclusion, no significant causality between serum UA levels and cancer risk was evidenced.

Has the Tibetan Plateau risen in the Early/Mid-Miocene? Constraints from plate-motion reconstructions and seismicity of the Indian Ocean lithosphere

SUMMARYMagnetization records and seismic stratigraphy of the Indian Ocean lithosphere indicate that the Early/Mid-Miocene onset of diffuse contractional deformation coincided with slowdowns of the Indian and Capricorn plate motions. At present day, such deformation is evidenced by the seismicity of the Indian Ocean floor. Deformation onset and past plate-motion slowdowns have been interpreted as consequences of a sudden uplift of the Tibetan Plateau by 1–2 km, as this—following previous estimates—would generate a tectonically significant force between 4 × 1012 and 8 × 1012 N m−1. However, this view remains at odds with palaeoaltimetry estimates from geological and geochemical data, which indicate no increase in plateau altitude throughout the Miocene. Here, I use well-established models of viscous/brittle dynamics in inverse mode in order to constrain the amount of force that should be delivered by the Tibetan region to the Indian tectonic setting in order to explain the observations above. Results constrain such a force within the range from 4.3 × 1011 to 3.5 × 1012 N m−1. By comparison with previous estimates of the force associated with topography increase, these analyses suggest that the Early/Mid-Miocene onset of contractional deformation and plate-motion slowdowns within the Indian Ocean require minimal uplift of the Tibet Plateau of a few hundred metres. The seemingly contradicting inferences on Early/Mid-Miocene Tibetan uplift that come from geophysical and geological/geochemical observations can be reconciled by noting that the required uplift amount is less than what is resolvable by modern palaeoaltimetry techniques.

Effect of 3 nm gate length scaling in junctionless double surrounding gate SiNT MOSFET by using triple material gate engineering

In this work, drain current ID for 3 nm gate length of triple material (TM) double surrounding gate (DSG) inversion mode (IM) and junctionless (JL) Si nanotube (SiNT) MOSFET has been studied and simulation results are reported using Silvaco ATLAS 3D TCAD. In this device we consider the Non Equilibrium Green’s Function (NEGF) approach and self-consistent solution of Poisson’s equation with Schrodinger’s equation. The channel region is lightly doped in case of IM SiNT MOSFET. The effect of TM Gate Engineering for SiNT channel radius 1.5 nm and gate oxide (SiO2) thickness of 0.8 nm on ID, has been studied. Also comparison of results has been done between IM TM DSG and JL TM DSG SiNT. For a reasonable comparison between Junctionless and Inversion Mode SiNT, in Junctionless SiNT, doping concentration is optimized for two concerns (i) to get the same threshold voltage (VTH) as IM SiNT and (ii) to get the same ION current as IM SiNT MOSFET. This results in 103 times smaller IOFF in both matching VTH and ION optimized device as compared to IM SiNT MOSFET. It was found that TM Gate Engineering reduces drain induced barrier lowering (DIBL) in JL SiNT. JL SiNT MOSFET has a smaller DIBL ~ 61.02 mV/V, almost an ideal SS ~ 60 mV/dec and higher ION/IOFF ratio ~ 2.63 × 109 as compared to available CGAA literature device results.