Effective Gate Research Articles

Dielectric Constant and Dipole Moment Dependent Hysteresis in Suspended Bilayer Graphene Transistor

Manipulation of transport hysteresis on graphene-based field effect transistors and understanding electron transfer between graphene and organic solution are important for the development of graphene-based sensor device. Several papers regarding to the researches about hysteresis in graphene devices have been published, which are significant to graphene-based device[1 -3 ]. However, there are seldom papers focus on graphene with one-side organic solution which has different relative permittivity and various dipole moment constant. This means that graphene suspended in liquid which eliminates the effect of substrate and leaves graphene and liquid with pure structure. Therefore, we do further researches on the graphene-based device and explore the relationship between graphene and solution.In our research, the structure of the device is shown in Figure1, which includes two gold electrodes used for drain and source separately and the etched area which contains two larger rectangular area used for injecting liquid and one main trench with some pillars used for suspending graphene. When measuring each set of data, we did experiments in ambient environment and used the same suspended-graphene device to control the influence of the fabrication deviation, such as the contact resistance or the sheet resistance of bilayer graphene.Figure2(a) shows the SEM image of suspended graphene on the main trench and the significant differences can be seen between the parts where the graphene exists and does not exist, which proves the presence of suspended graphene. We do the same measurement the transport hysteresis in the device by using several solvent includes isopropanol (IPA), ethonal and dimethylacetamide (DMAC). Figure 2(b) shows the different hysteresis situations of three different solutions observed in this work. In the picture, the solid line illustrates the drain current change with the forward voltage which means voltage swept from -1V to 1V and the dotted line depicts the drain current alter with reverse scanning voltage called backward voltage. The value of hysteresis is defined as the difference between the voltage value corresponding to the lowest value of the forward curve and that of the backward curve，which is equal to the change between Dirac point.As shown in Figure 3(a), the difference between the hysteresis in the organic solution of various permittivity shows an almost curve correlation. Hysteresis value decreases as the dielectric constant drops, which can be explained by less charge trapping will cause smaller hysteresis. At the same time, the variety between the hysteresis of solvent with various dipole moment displays line with more obvious arc, which is shown in Figure3(b). These observations are interesting phenemonon which may related to the change on electrostatic environment of graphene[1] and the process of the competition between charge trapping effect and capacitive gating effect[2].In conclusion, we made several experiments to explore the relationship between graphene-based device and solvent with different electrical characteristics and found some interesting results of the difference between Dirac point regarding to permittivity and dipole moment. This characteristic may be used for judging the purity of organic solvents and other chemical or biological sensing application. Furthermore, it contribute to the fundamental development of relationship between graphene-based devices and different solvents.[1]Philipp Klar and Cinzia Casiraghi. Raman spectroscopy of graphene in different dielectric solvents[J].Phys. Status Solidi C,2010,7:2735-2738.[2]Wang, H.; Wu, Y.; Cong, C.; Shang, J.; Yu, T., Hysteresis of Electronic Transport in Graphene Transistors. ACS Nano 2010,4(12), 7221-8[3]Uysal, A.; Zhou, H.; Feng, G.; Lee, S. S.; Li, S.; Fenter, P.; Cummings, P. T.; Fulvio, P.F.; Dai, S.; McDonough, J. K.; Gogotsi, Y. Structural origins of potential dependent hysteresis at the electrified graphene/ionic liquid interface. J. Phys. Chem. C,2013,118, 569-574. Figure 1

Universal Bacterial Detection Utilizing PEDOT:PSS-Based Organic Electrochemical Transistors

Bacteria are one of the most common sources of illness, responsible for a wide range of infections. Bacterial infections can be caused from a variety of sources, with thousands of deaths attributed to waterborne outbreaks alone [1]. Detection of both infectious and non-infectious bacteria is important to ensure commercial goods and water are safe for consumers. Current detection of bacterial contamination typically uses cell culture plates to measure the number of colony forming bacteria (CFU/ml) in a liquid media. This technique is widely used due to its high sensitivity and easy visual readout. Unfortunately, culture counting technique is time consuming (1-3 days), requires skilled lab technicians, can be contaminated during preparation, and cannot be integrated into the desired testing media directly.To overcome these limitations, many bacterial sensors and detection techniques have been developed over the last few decades [2]. A recent sensor for bacteria detection is utilizing the organic electrochemical transistor (OECT). OECTs are polymer-based transistors that utilize ionic solutions to de-dope and re-dope a conducting channel. These devices are known for the high transconductance, bio-compatibility, low operating voltage, low cost, small size, ease of integration into measurement systems, and ability to function in aqueous environments [3]. Detection of a single bacteria is typically desired and achieved through the capture of bacteria cells onto the OECT channel area [4]. This approach allows for rapid detection of a specific pathogen with high sensitivity. However, for detecting contamination from a variety of bacteria a different approach must be used.We have investigated the OECT response to the presence of non-captured bacteria present within the OECT operating media. In this approach cells are detected both in solution and on the surface of the source-drain channel and on the gate electrode. Presence of bacteria between the gate and channel region will cause a shift in effective gate voltage, leading to a change in source-drain current. Detection and characterization of (non-bacteria) whole cells has previously been reported utilizing this approach [5, 6]. In our work we have focused on the bacteria pseudomonas fluorescens (p. fluorescens) due to its size (~1µm) and potential as a water borne pathogen. P. fluorescens was cultured in Luria-Bertani (LB) and Dey-Engley (D/E) media, diluted to different concentrations in broth, and used as the operating media for OECT. Concentrations of 1.9e5 to 6.8e8 CFU/ml were found to cause a shift in effective gate voltage between 36.8 to 97.5mV. Craun, G.F., Statistics of waterborne outbreaks in the US (1920–1980). Waterborne diseases in the United States, 2018: p. 73-159.Ahmed, A., et al., Biosensors for whole-cell bacterial detection. Clinical microbiology reviews, 2014. 27(3): p. 631-646.Strakosas, X., M. Bongo, and R.M. Owens, The organic electrochemical transistor for biological applications. Journal of Applied Polymer Science, 2015. 132(15).Demuru, S., et al. Flexible Organic Electrochemical Transistor with Functionalized Inkjet-Printed Gold Gate for Bacteria Sensing. 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors, 2019.Liao, J., et al., Organic electrochemical transistor based biosensor for detecting marine diatoms in seawater medium. Sensors and Actuators B: Chemical, 2014. 203: p. 677-682.Ramuz, M., et al., Monitoring of cell layer coverage and differentiation with the organic electrochemical transistor. Journal of Materials Chemistry B, 2015. 3(29): p. 5971-5977. Figure 1

A simple test structure for the electrical characterization of front and back channels for advanced SOI technology development

Pseudo-MOSFET delivers a fast, simple and reliable way of characterizing electrically SOI substrates without the need of full CMOS fabrication. However, the information refers to the back interface. Here, to probe the front interface, we extend the concept to a double-gate pseudo-MOSFET. The structure provides a pertinent test vehicle for the characterization and development of transistors channel and gate stack materials in a configuration similar to fully fabricated transistors. We show that the devices with undoped terminals need specialized modeling development to describe the double gate effect. Devices with doped terminals are immediately exploitable for parameter extraction.

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.

Highly effective gating of graphene on GaN

By using four-layered graphene/gallium nitride (GaN) Schottky diodes with an undoped GaN spacer, we demonstrate highly effective gating of graphene at low bias rendering this type of structure very promising for potential applications. An observed Raman G band position shift larger than 8.5 cm−1 corresponds to an increase in carrier concentration of about 1.2·1013 cm−2. The presence of a distinct G band splitting together with a narrow symmetric 2D band indicates turbostratic layer stacking and suggests the presence of a high potential gradient near the Schottky junction even at zero bias. An analysis based on electroreflectance measurements and a modified Richardson equation confirmed that graphene on n-GaN separated by an undoped GaN spacer behaves like a capacitor at reverse bias. At least 60% of G subband position shifts occur at forward bias, which is related to a rapid reduction of electric field near the Schottky junction. Our studies demonstrate the usefulness of few layer turbostratic graphene deposited on GaN for tracing electron–phonon coupling in graphene. Multilayer graphene also provides uniform and stable electric contacts. Moreover, the observed bias sensitive G band splitting can be used as an indicator of charge transfer in sensor applications in the low bias regime.

P015 Improving the diagnostic performance of ANCA testing: evaluating the use of a gating strategy for ANCA test requests

Abstract Background/Aims Anti-neutrophil cytoplasmic antibody (ANCAs) associated vasculitis (AAV) encompasses: Granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). The 1999 international consensus for ANCA testing recommended the use of indirect immunofluorescence (IIF) to screen for ANCAs, with immunoassays for proteinase-3 (PR3)-ANCAs and myeloperoxidase (MPO)-ANCAs in positive samples. In 2017 this consensus was revised, recommending the implementation of a strict gating strategy for ANCA requests, followed by high-quality immunoassays as the primary screening method, to reduce the volume of tests requested, reducing the false-positive rates, thereby improving the diagnostic performance of ANCA testing. Testing at the Royal Wolverhampton Trust is based on the 1999 consensus. Tests perform poorly when not carried out in the correct setting due to low pre-test probability; we aimed to implement a gating strategy to filter inappropriate ANCA test requests to improve the diagnostic performance of ANCA testing at our centre. We assessed the use of IIF and antigen specific assays in the diagnosis of AAV. Methods We reviewed the records of patients that had ANCA tests requested in June 2019. A gating strategy in the form of an indication selection ‘pop-up box’ directing clinicians to select an appropriate clinical indication for the request was implemented. We re-audited ANCA requests made post-intervention Feburary 2020. ANCA requests were assessed against clinical indications in the 1999 consensus for appropriateness; we assessed the diagnostic performance by the proportion of ANCA tests correctly identifying AAV and calculating the sensitivity and specificity of IIF and immunoassays for MPO/PR3-ANCAs in detecting AAV. Results Post-intervention, 105 fewer ANCA requests were made (298v403). Due to insufficient information, 345 patients pre-gating and 252 patients post-gating-strategy were used for analysis. The proportion of appropriate requests made was greater post-intervention, 215/252 (85.3%) vs 119/345(34.5%). Pre-intervention AAV was identified in 13 (3.8%) patients; AAV was identified in 21 (8.3%) patients following the gating-strategy introduction. IIF was found to have sensitivity of 91.7% pre and 76.2% post-intervention; specificity was 53.0% pre and 58.9% post-intervention. MPO/PR3 immunoassay testing was found to have a sensitivity of 91.7% pre and 57.1% post-intervention; specificity was 97.4% pre and 97.9% post-intervention. Conclusion The introduction of a gating-strategy for ANCA testing at our centre effectively reduced the overall number of ANCA requests by 26.1% over a 1-month period and significantly increased requests with an appropriate recorded indication. The proportion of tests correctly identifying AAV diagnosis increased following the introduction of the gating strategy indicating an improvement in diagnostic performance of ANCA testing. These results indicate antigen specific testing is more specific for a diagnosis of AAV and sensitivity of IIF was reduced following introduction of the gating strategy suggesting IIF is of no additional benefit when an effective gating strategy is employed. Disclosure N. Cleaton: None. N. Barkham: None. T. Adizie: None.

Spatial distribution of multielements including lanthanides in sediments of Iron Gate I Reservoir in the Danube River

Recent studies show that lanthanides (Ln) are becoming emerging pollutants due to their wide application in new technologies, but their environmental fate, transport, and possible accumulation are still relatively unknown. This study aims to determine major and trace elements including Ln in the Danube River sediment which either belong or close to the Iron Gate Reservoir. The Iron Gate Reservoir is characterized by accumulation of sediments as an effect of building hydropower dam Iron Gate I. The surface sediments were collected on the Danube River—1141 to 864 km and three tributaries along this waterway. Two samples of deep sediments were used for comparison. The results indicate the significant upward enrichment of Zn, Sb, Cr, Nd, and Dy in sediments belongs to the Iron Gate Reservoir. The sample 4-Smed is labelled as a hot spot of contamination with Zn, Cr, As, Sb, Nd, and Dy. Also, a trend of increasing concentration in the time period from 1995 to 2016 was found for elements Zn, Cr, and Ni in sediment samples in the Iron Gate Reservoir. Chemometric analysis shows the grouping of sample sites into clusters characterized by the following properties: (i) increased concentration of all measured elements (samples within the Iron Gate Reservoir); (ii) increased Cu concentration (11-Pek); and (iii) lower concentrations of the measured elements (deep sediments). The data presented hereby contribute to the monitoring of pollution of the River Danube sediments and give the first view of Ln profile in the studied sediments.

A Comprehensive Benchmarking Method for the Net Combination of Mobility Enhancement and Density-of-States Bottleneck

In this letter, we propose a comprehensive benchmarking method to simultaneously address mobility enhancement and density-of-states bottleneck in advanced field-effect-transistors (FETs) with novel high-mobility (high-μ) channel materials, where we focused on conventional covalent bonding semiconductors with pure and partially ionic character. This method relies only on the measured extrinsic transconductance of a long-channel FET in the saturation regime together with the source resistance, yielding the product of the effective mobility ( μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> ) and effective gate capacitance ( C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g_eff</sub> ). We tested this method in In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> As quantum-well high-electron-mobility transistors (HEMTs) with various indium mole fractions, such as 0.53, 0.7, 0.8 and 1, as well as in Si n-FETs. We found that the In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> As HEMTs with μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> over 10,000 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s at 300 K provided more than 20 times greater μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> ×C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g_eff</sub> than Si n-FETs. More specifically, the product initially improved as x increased, then showed a peak value of 10,300 μF·V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ·s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at x of around 0.8, and degraded slightly beyond that composition. To verify the validness of the proposed method, we separately measured and analyzed C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g_eff</sub> and μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> using the split-CV technique, showing excellent agreement with the ones from the proposed method.

Formation of ultra-high-resistance Au/Ti/p-GaN junctions and the applications in AlGaN/GaN HEMTs

We report a dramatic current reduction, or a resistance increase, by a few orders of magnitude of two common-anode Au/Ti/p-GaN Schottky junctions annealed within a certain annealing condition window (600–700 °C, 1–4 min). Results from similar common-anode Schottky junctions made of Au/p-GaN, Al/Ti/p-GaN, and Au/Ti/graphene/p-GaN junctions demonstrated that all three layers (Au, Ti, and p-GaN) are essential for the increased resistance. Scanning-transmission electron microscopy, Hall, and Raman measurements have been performed to investigate the mechanisms. Moreover, this high-resistance junction structure was employed in p-GaN gate AlGaN/GaN high electron mobility transistors. It was shown to be an effective gate technology that was capable of boosting the gate breakdown voltage from 9.9 to 12.1 V with a negligible effect on the threshold voltage or the sub-threshold slope.

The Effect of Dual Dummy Gate in the Drift Region on the on-State Performance of SOI-LDMOS Transistor for Power Amplifier Application

The present work proposes a novel dual dummy gate Silicon-on-Insulator Laterally Double Diffused Metal-Oxide-Semiconductor (SOI-LDMOS) transistor. TCAD simulation shows considerable promise to enhance the dc, analog/RF, and switching performance than the single dummy gate and conventional SOI-LDMOS transistor. A strong accumulation region (SAR) forms under the optimum biased dummy gates (at the semiconductor surface in the drift region) that assist in increasing the On-current and, thereby, reducing the On-Resistance. The proposed device exhibits ~93.5% improvement in On-current (ION), ~144% increase in transconductance (gm), ~29% reduction in specific On-resistance (RON,sp), ~360% improvement of intrinsic gain compared to the conventional SOI-LDMOS transistor. The dummy gates, which are in short with the source contact at zero potential, act as a field plate, and minimize the gate to drain capacitance due to the shielding effect. Improvement in the cut-off frequency (fT) and the maximum frequency (fMAX) is reported. The proposed device also offers a decrease of the gate to drain charge (QGD) leading to reduction in Figure of Merit RON,sp × QGD by ~31%. The increase of maximum power per unit area by ~52% is reported for power amplifier applications. It is shown that improving the On-State performance by tuning the dummy gate bias gives a simple, new, and cost-effective technology solution for power electronics applications.

Implementation of nonadiabatic holonomic quantum computation via two blockaded Rydberg atoms

Nonadiabatic holonomic quantum computing has received great attention due to its advantages of avoiding long-term evolution of the system and maintaining the robustness of holonomic gates to control errors. In this paper, we study a scheme for implementing nonadiabatic holonomic computation using two blockaded Rydberg atoms. With the presence of the Rydberg blockade effect, we realized controlled-phase gates, which play an irreplaceable role in quantum computation and quantum information processing. Therefore, the current scheme may open up new prospects for the design of new types of effective Rydberg quantum gate devices.

The impact of data-driven respiratory gating in clinical F-18 FDG PET/CT: comparison of free breathing and deep-expiration breath-hold CT protocol.

Respiratory motion can diminish PET image quality and lead to inaccurate lesion quantifications. Data-driven gating (DDG) was recently introduced as an effective respiratory gating technique for PET. In the current study, we investigated the clinical impact of DDG on respiratory movement in 18F-FDG PET/CT. PET list-mode data were collected for each subject and DDG software was utilized for extracting respiratory waveforms. PET images was reconstructed using Q.clear and Q.clear + DDG, respectively. We evaluated SUVmax, SUVmean, the coefficient of variance (CoV), metabolic tumor volume (MTV), and tumor heterogeneity using the area under the curve of cumulative SUV histogram (AUC-CSH). Metabolic parameter changes were compared between each reconstruction method. The Deep-Expiration Breath Hold (DEBH) protocol was introduced for CT scans to correct spatial misalignment between PET and CT and compared with conventional free breathing. The DEBH and free breathing (FB) protocol comparison was made in a separate matching cohort using propensity core matching rather than the same patient. Total 147 PET/CT scans with excessive respiratory movements were used to study DDG-mediated correction. After DDG application, SUVmax (P < 0.0001; 8.15 ± 4.77 vs. 9.03 ± 5.02) and SUVmean (P < 0.0001; 4.91 ± 2.44 vs. 5.49 ± 2.68) of lung and upper abdomen lesions increased, while MTV significantly decreased (P < 0.0001; 7.07 ± 15.46 vs. 6.58 ± 15.14). In addition, the percent change of SUVs was greater in lower lung lesions compared to upper lobe lesions. Likewise, the MTV reduction was significantly greater in lower lobe lesions. No significant difference dependent on location was observed in liver lesions. DEBH-mediated CT breathing correction did not make a significant difference in lesion metabolic parameters compared to conventional free breathing. These results suggest that DDG correction enables more corrected quantification from respiratory movements for lesions located in the lung and upper abdomen. Therefore, we suggest that DDG is worth using as a standard protocol during 18F-FDG PET/CT imaging.

Manipulating the cross-layer channels in g-C3N4 nanosheet membranes for enhanced molecular transport

Cross-layer channels display ‘gate effect’ to govern molecular selectivity for lamellar membranes. Membranes with hydrophilic/hydrophobic heterostructured channels acquire elevated polar solvent permeance and polar/nonpolar solvents selectivity.

Implementation of the Rydberg double anti-blockade regime and the quantum logic gate based on resonant dipole-dipole interactions

Quantum information science is an emerging field that applies the quantum coherence and correlation to cause the revolutionary advances in computation, communication, and fundamental quantum science. As an irreducible ingredient, Rydberg quantum gate is considered to be a powerful resource with great promises to a wide range of quantum information tasks far beyond the original gate proposals, since the remarkable features characterized by Rydberg atom are long lifetime and giant polarizability. In recent years, the research mainly focused on the properties of Rydberg atom, especially for the case where the effects of Rydberg blockade and antiblockade involving single level for each atom are dominated by van der Waals forces. However, with the variation of interatomic distance, Rydberg interactions can induce more complicated dynamical behavior. This paper studies the implementation of controlled-phase gate and swap gate in one step based on the constructed Rydberg antiblockade (RAB) and double antiblockade (RDAB) regimes when the interatomic distance is less than the characteristic length. Different from the conventional RAB regime that requires weak Rydberg-Rydberg interaction (RRI), our attainable strategy is to compensate the RRI-induced energy shift by properly tuning the detuning between the driving field and atomic transition frequencies. In addition, the proposed RDAB mechanism is a new physical insight that can enable two pairs of Rydberg states belonging to different atoms to be excited, simultaneously. In contrast to other blocking schemes or the schemes without requirements for strong interactions, the merits of our proposal lies in the strong dipole-dipole interaction between two atoms, leading to the population exchange of multiple energy levels. Numerical simulations show that the time evolution of the population for collective double-atom basis obtained from the original Hamiltonian agrees well with the analytical results given by the effective Hamiltonian. In the ideal case, the average fidelity of the controlled-phase (swap) gate can reach 99.35% (99.67%) at final time &lt;inline-formula&gt;&lt;tex-math id="M1"&gt;\begin{document}$t=\sqrt{2}\pi\Delta/\Omega^{2}$\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20210059_M1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20210059_M1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt; (&lt;inline-formula&gt;&lt;tex-math id="M2"&gt;\begin{document}$t=2\pi\Delta/\Omega^{2}$\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20210059_M2.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="13-20210059_M2.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;), and our protocol is robustness against spontaneous emission of high-lying Rydberg states. We believe our present investigation is feasible in upcoming experimental realization and may offer an new venue with respect to on-demand design of new types of effective Rydberg quantum gate devices.

Molecular gate effects observed in fluoroalkylsilane self-assembled monolayers grafted on LiNi0.5Mn1.5O4cathodes: an application to efficient ion-exchange reactions

This work demonstrates the role of fluoroalkylsilane (FAS) self-assembled monolayers in improving the high-voltage durability and C-rate capabilities of spinel LiNi0.5Mn1.5O4(LNMO) cathodes.

A sensitive platform for DNA detection based on organic electrochemical transistor and nucleic acid self-assembly signal amplification.

Highly sensitive detection of DNA is of great importance for the detection of genetic damage and errors for the diagnosis of many diseases. Traditional highly sensitive organic electrochemical transistor (OECT)-based methods mainly rely on good conductivity materials, which may be limited by complex synthesis and modification steps. In this work, DNA biosensor based on OECT and hybridization chain reaction (HCR) signal amplification was demonstrated for the first time. Au nanoparticles were electrochemically deposited on the Au gate electrode to increase the surface area. Then, the HCR products, long negatively charged double-stranded DNA, were connected to the target by hybridization, which can increase the effective gate voltage offset of OECT. This sensor exhibited high sensitivity and even 0.1 pM target DNA could be directly detected with a significant voltage shift. In addition, it could discriminate target DNA from the mismatched DNA with good selectivity. This proposed method based on HCR in DNA detection exhibited an efficient amplification performance on OECT, which provided new opportunities for highly sensitive and selective detection of DNA.

Field Effect and Local Gating in Nitrogen-Terminated Nanopores (NtNP) and Nanogaps (NtNG) in Graphene.

Functionalization of electrodes is a wide-used strategy in various applications ranging from single-molecule sensing and protein sequencing, to ion trapping, to desalination. We demonstrate, employing non-equilibrium Green's function formalism combined with density functional theory, that single-species (N, H, S, Cl, F) termination of graphene nanogap electrodes results in a strong in-gap electrostatic field, induced by species-dependent dipoles formed at the electrode ends. Consequently, the field increases or decreases electronic transport through a molecule (benzene) placed in the nanogap by shifting molecular levels by almost 2 eV in respect to the electrode Fermi level via a field effect akin to the one used for field-effect transistors. We also observed the local gating in graphene nanopores terminated with different single-species atoms. Nitrogen-terminated nanogaps (NtNGs) and nanopores (NtNPs) show the strongest effect. The in-gap potential can be transformed from a plateau-like to a saddle-like shape by tailoring NtNG and NtNP size and termination type. In particular, the saddle-like potential is applicable in single-ion trapping and desalination devices.

Temporal filtering characteristics of gated InGaAs/InP single-photon detectors for coincidence measurement

Semiconductor single-photon avalanche detectors (SPADs) have played an important role in practical quantum communication technology due to their advantages of small size, low cost and easy operation. Among them, InGaAs/InP SPADs have been widely used in fiber-optic quantum key distribution systems due to their response wavelength range in a near-infrared optical communication band. In order to avoid the influence of dark count and afterpulsing on single photon detection, the gated quenching technologies are widely applied to the InGaAs/InP SPADs. Typically, the duration of gate pulse is set to be as short as a few nanoseconds or even less. As the detection of the arrival of single photons depends on the coincidence between the arrival time of gate pulse and the arrival time of photon, the gate pulse duration of the InGaAs/InP SPADs inevitably affects the effective detection of the single photons. Without the influence of dispersion, the temporal width of the transmitted photons is usually on the order of picoseconds or even less, which is much shorter than the gate width of the InGaAs/InP SPAD. Therefore, the gate width normally has no influence on the temporal measurement of the detected photons. However, in quantum systems involving large dispersion, such as the long-distance fiber-optic quantum communication system, the temporal width of the transmitted photons is significantly broadened by the experienced dispersion so that it may approach to or even exceed the gate width of the single-photon detector. As a result, the effect of the gate width on the recording of the arrival time of the dispersed photons should be taken into account. In this paper, the influence of the gate width coupled to the InGaAs/InP single photon detectors on the measurement of the two-photon coincidence time width is studied both theoretically and experimentally. The theoretical analysis and experimental results are in good agreement with each other, showing that the finally measured coincidence time width of the two-photon state after dispersion is not more than half of the effective gate pulses width. The maximum observable coincidence time width based on the gated single photon detector is fundamentally limited by the gate width, which restricts its applications in quantum information processing based on the two-photon temporal correlation measurement.

Performance Comparison of Stacked Dual-Metal Gate Engineered Cylindrical Surrounding Double-Gate MOSFET

In this research work, a Cylindrical Surrounding Double-Gate (CSDG) MOSFET design in a stacked-Dual Metal Gate (DMG) architecture has been proposed to incorporate the ability of gate metal variation in channel field formation. Further, the internal gate's threshold voltage ( V TH1 ) could be reduced compared to the external gate ( V TH2 ) by arranging the gate metal work-function in Double Gate devices. Therefore, a device design of CSDG MOSFET has been realized to instigate the effect of Dual Metal Gate (DMG) stack architecture in the CSDG device. The comparison of device simulation shown optimized electric field and surface potential profile. The gradual decrease of metal work function towards the drain also improves the Drain Induced Barrier Lowering (DIBL) and subthreshold characteristics. The physics-based analysis of gate stack CSDG MOSFET that operates in saturation involving the analogy of cylindrical dual metal gates has been considered to evaluate the performance improvements. The insights obtained from the results using the gate-stack dual metal structure of CSDG are quite promising, which can serve as a guide to further reduce the threshold voltage roll-off, suppress the Hot Carrier Effects (HCEs) and Short Channel Effects (SCEs).

Molecularly Imprinted Polymer for Selective Electrosynthesis of Biphenols

Molecularly imprinted polymers (MIPs) have been widely studied for sensing and separation of compounds selectively. These artificial biomimicking recognition units are highly sensitive and selective to target analytes. Electrochemical preparation of MIPs offers advantages including ease of preparation as well as control over the polymer nucleation and growth, thickness, and film morphology. Moreover, it is possible to follow the formation of cavities electrochemically through the gate effect. Few reports have focussed on selective catalysis by using MIPs. However, the application of these MIPs in the field of electrocatalysis remains unexplored and, therefore, there is a large research scope in this domain.Biphenols are structural motifs of several molecules in nature and for many drugs. They are efficient ligands for catalytic systems and are highly stable under electrochemical condition. In particular, 3,3,5,5-tetramethyl-2,2-biphenol acts as a significant backbone in phosphorus-based ligand systems for calatysis. The oxidation of 2,4-dimethylphenol yields several different products including polycyclic compounds formed by C-H bond activation (Scheme 1). Therefore, designing a scalable process, in which the desired biphenol is selectively produced, is challenging.In the present work, we aim to develop MIPs that can be applied for selective electrosynthesis of the desired C-C coupled biphenol through electro-oxidation of the corresponding phenol. For this purpose, the functional monomer was selected based on the Gibbs free energy of its interaction with the target biphenol template in density functional theory (DFT) simulations. Complexation of the functional monomer with the template was confirmed by spectroscopic titrations. Electroactive monomers can polymerize to form either conducting or nonconducting polymers. In our system, a conductive MIP film was prepared using derivatized thiophene functional monomers. Then, the template extraction process was optimized. Electro-oxidation of 2,4-dimethyl phenol was studied in detail to reach as high yield as possible of the desired biphenol product at a bare platinum electrode. HPLC-MS was used to identify the substrate and products of the electrosynthesis. Then, selectivity of the electrosynthesis study was performed for the MIP film-coated electrode in comparison to a non-imprinted polymer (NIP) film-coated electrode, and a bare electrode. Figure 1