Gate Potential Research Articles

Influence of electron beam irradiation induced charging-effect on nanoprobing localization of a crystal defect in MOSFET

The paper demonstrates that the electron beam (e-beam) irradiation induced charging-effect has remarkable impact on nanoprobing localization of a crystal defect hidden in metal-oxide-semiconductor field-effect transistor (MOSFET). We present a practical example showing that device characterization at the contact layer (CT) is susceptible to the charging-effect since scanning electron microscopy (SEM) based nanoprobe system running is inevitablely acompanied by e-beam irradiation towards device under test (DUT). The mechanisms is seldomly reported in the past. In our case, the p-n junction at a nMOSFET drain end showed the ohmic current-voltage (I-V) characteristic at the beginning. However, by utilizing the atomic force microscopy (AFM) based nanoprobe system without e-beam, the measurement found previous resistive characteristic of the p-n junctions disappeared. Instead, it exhibited good rectifying characteristic. I-V characteristic discrepancy coming from two analytical methods was attributed to the charging-effect influence. It was experimentally proven that the charging-effect impact at MOSFET gate CT had strong dependance on the e-beam irradiation magnitude corresponding to the SEM scan speed. Charging effect produced distinct consequences at distinct scan speeds. The positive charging-effect occurred under the fast scan while the negative charging-effect occurred under the slow scan. The former mechanism made the potential at gate CT high enough to turn on nMOSFET. Therefore, the nMOSFET channel current merged with the p-n junction current in a closed-loop. In contrast, the slow scan induced negative charging-effect made the gate potential lower than the nMOSFET threshold voltage (VT), so that the nMOSFET stayed off-state. Consequently, the p-n junction resumed its intrinsic rectifying I-V characteristic. Different from the nMOSFET, the charging-effect affected the pMOSFET in the opposite manner. As a result, the initial conclusion of the MOSFET junction leakage was not valid. Next, we ran a optimal flow to narrow down a fault by eliminating the charging-effect impact. Eventually, a crystal defect (pipeline) was isolated in a suspcted nMOSFET relying on nanoprobe and TEM analysis. The article explains the evident influence of charging-effect on the nanoprobe analysis and puts forward an effective way to minimize the side effect of the e-beam irradiation. The work may draw more attention to the analytical methodologies regarding MOSFET reliability improvement.

Omega‐Gate Silicon Nanowire Geometric Diodes with Reconfigurable Self‐Switching Operation and THz Rectification

AbstractGeometric diodes (GDs) represent a relatively unconventional class of diode that produces an asymmetric current response through carrier transport in an asymmetric geometry. Synthesized from the bottom up, Si nanowire‐based GDs are three‐dimensional, cylindrically symmetric nanoscale versions capable of room‐temperature rectification at GHz‐THz frequencies with near zero‐bias turn‐on voltages. Here, by fabricating three‐terminal n‐type Si nanowire GDs with axial contacts and an omega‐gate electrode, a distinct class of reconfigurable self‐switching geometric diodes (SSGDs) is reported. Single‐nanowire SSGD device measurements demonstrate a significant dependence of diode current and polarity on gate potential, where the diode polarity reverses at a gate potential of ≈−1 V under specific grounding conditions. Finite‐element modeling reproduces the experimental results and reveals that the gate potential—in combination with the morphology and dopant profile—produces an asymmetric potential along the nanowire axis that changes asymmetrically with axial bias, altering the effective conductive channel within the nanowire to yield diode behavior. The self‐switching effect is retained in two‐terminal SSGD devices, and modeling demonstrates that both three‐terminal and two‐terminal devices support rectification through THz frequencies. The results reveal a new mechanism of operation for nanowire‐based GDs and characterize a new type of self‐switching diode with reconfigurable polarity.

Mixed‐Halide Perovskite Memristors with Gate‐Tunable Functions Operating at Low‐Switching Electric Fields

AbstractCrossbar circuits based on two terminal (2T) memristors typically require an additional unit such as a transistor for individual node selection. A memristive device with gate‐tunable synaptic functionalities will not only integrate selection functionality at the cell level but can also lead to enriched on‐demand learning schemes. Here, a three‐terminal (3T) mixed‐halide perovskite memristive device with gate‐tunable synaptic functions operating at low potentials is demonstrated. The device operation is controlled by both the drain (VD) and gate (VG) potentials, with an extended endurance of >2000 cycles and a state retention of >5000 s. Applying a voltage (Vset) of 20 V across the 50 µm channel switches its conductance from a high‐resistance state (HRS) to a low‐resistance state (LRS). A memristive switching mechanism is proposed that is supported by current injection models through a Schottky barrier and Kelvin probe force microscopy data. The simultaneous application of a VG potential is found to further modulate the channel conductance and reduce the operating Vset to 2 V, thus requiring a low electric field of 400 V cm−1, which is by a factor of 50× less compared to state‐of‐the‐art literature reports. Gate‐tunable retention, endurance, and synaptic functionalities are demonstrated, further highlighting the beneficial effect of VG on device operation.

A closed-loop catalytic nanoreactor system on a transistor.

Precision chemistry demands miniaturized catalytic systems for sophisticated reactions with well-defined pathways. An ideal solution is to construct a nanoreactor system functioning as a chemistry laboratory to execute a full chemical process with molecular precision. However, existing nanoscale catalytic systems fail to in situ control reaction kinetics in a closed-loop manner, lacking the precision toward ultimate reaction efficiency. We find an inter-electrochemical gating effect when operating DNA framework-constructed enzyme cascade nanoreactors on a transistor, enabling in situ closed-loop reaction monitoring and modulation electrically. Therefore, a comprehensive system is developed, encapsulating nanoreactors, analyzers, and modulators, where the gate potential modulates enzyme activity and switches cascade reaction "ON" or "OFF." Such electric field-effect property enhances catalytic efficiency of enzyme by 343.4-fold and enables sensitive sarcosine assay for prostate cancer diagnoses, with a limit of detection five orders of magnitude lower than methodologies in clinical laboratory. By coupling with solid-state electronics, this work provides a perspective to construct intelligent nano-systems for precision chemistry.

Single-Atom Pt Doping Induced p-Type to n-Type Transition in NiO Nanosheets toward Self-Gating Modulated Electrocatalytic Hydrogen Evolution Reaction.

Exploring highly efficient single atom catalysts with defined active centers and tunable electronic structures is highly desirable. Herein, we developed an efficient hydrogen evolution reaction (HER) electrocatalyst through a self-gating phenomenon induced by Pt single atoms (SAs) supported on ultrathin NiO nanosheets (PtSA-NiO). The Ni atoms in NiO are partially replaced by the atomically dispersed Pt atoms, leading to a transition from p-type NiO into n-type PtSA-NiO. When the n-type PtSA-NiO serves as HER electrocatalyst, the self-gating phenomenon occurs in the ultrathin nanosheets, resulting in a mixture of leakage ("active") and metal-insulator-semiconductor ("inert") regions. The "inert" region induced by the ionic gating and reverse potential is capable of accumulating relatively high surface charge carrier concentration with an ultrahigh electric field, making the PtSA-NiO highly conductive; meanwhile, the HER process occurs at the Pt SAs sites (active region) in the PtSA-NiO nanosheets. As a result, the PtSA-NiO requires only 55 mV to deliver 10 mA/cm2 in an alkaline solution with good stability.

Gated nanoparticle transport in a functional group modified nanopore

Inspired by nature, functionalized nanopores have become an important platform in the field of sensing. In this article, we constructed a mathematical model for the gate-controlled manipulation of nanoparticle motion inside pH-responsive polyelectrolyte-modified nanopores and theoretically studied the synergistic control of gate electrode and polyelectrolyte brush layer on nanoparticle motion. By efficiently modifying the charge density and polarity of the polyelectrolyte brush layer located within the nanopore, the gate electrode is capable of actively regulating the velocity of nanoparticle transport through the nanopore. At a solution pH of 5, the higher the gate potential, the faster the nanoparticle transport through the nanopore, which is significantly different from the solution pH of 6. When the gate potential is negative, the degree of ion current blockage increases with increasing gate potential. These results establish a theoretical foundation for the development of novel functionalized nanopores that can be utilized in the field of nanopore sensing.

(Invited) Non-Enzymatic Glucose Sensor Fabricated By Ni-Nanowires Decorated Graphene Gated FETs

In this study, an innovative non-invasive glucose sensor made of nickel nanowire-decorated graphene-gated field-effect transistors is demonstrated. Due to the redox reaction between nickel nanowires and glucose molecules in weakly alkaline solution, electron exchange occurs when Ni(III) reacts with glucose to form Ni(II) and gluconolactone. In order to improve the sensitivity of the glucose sensor and reduce the detection limit, we compared the characteristics of the glucose sensor fabricated by nickel nanowires on gold surface and graphene/gold surface, respectively. Since the CVD-grown graphene film has excellent electrical conductivity and no defects, the electrons generated by the redox reaction can be quickly and evenly dispersed and are not easily neutralized, resulting in a change on the gate potential, thereby affecting the current between the source and the drain metal, and then the glucose concentration in the solution can be deduced. It can be seen from the experiments that the glucose sensor with graphene film has better current stability, lower detection limit and better linear relationship between current and concentration. The demonstrated nickel wire-decorated graphene-gated FET biosensor can be used for the quantification of glucose with a linear range of 10-50 mM and a detection limit of 51nM. Figure 1

GaN High Electron Mobility Transistor with Floating Gate for Accurate Threshold Voltage Control

Gallium nitride (GaN) high electron mobility transistors (HEMTs) have high electron mobility, high breakdown voltage, and low on-resistance, and are expected to operate as power devices. When GaN HEMTs are normally-on devices, drain current flow even for 0-gate-voltage. Thus, the normally-off operation is essentially required to the power devices from a fail-safe standpoint. Figure A shows a schematic of the structure, which is constructed with GaN HEMT including floating gate and the injection gate. The block oxide and tunnel oxide were formed between control gate and floating gate, and between injection gate and floating gate, respectively. It is impossible to inject electrons from the channel to the floating gate by the applying voltage to the substrate because AlGaN layer is located on the GaN layer. We introduced the injection gate for injecting electrons into the floating gate, and then the normally-off operation is obtained by the injecting electrons into the floating gate. The injecting electrons decrease the floating gate potential and form the depletion region under the gate oxide. Because the channel is the same as that of a conventional GaN HEMTs during on-operation, the high electron mobility of GaN HEMTs can be maintained, and then the on-operation behaviors are the same as conventional GaN HEMTs except threshold voltage. In this study, we demonstrate the normally-off operation of the fabricated GaN HEMTs with floating gate.Figure B shows the microscopy image of the fabricated device where the gate length, gate width and thickness of gate oxide are 2 μm, 110 μm and 20 nm, respectively. In floating gate device, the coupling ratio between the induced voltage of floating gate and the applied voltage of control gate is important. To increase the coupling ratio, we extended the overlap areas of floating gate and control gate to the drain side. The area of the control gate and the thickness of block oxide are set to be 3600 μm2 and 50 nm, respectively. Then, the coupling ratio becomes 91%, and then the induced voltage of floating gate is almost the same as the applied voltage of control gate. High-quality oxides are required in our devices for block oxide, tunnel oxide and gate oxide, however high-quality oxide films cannot be deposited by the thermal oxidation processes for GaN and polycrystalline Si. To form high-quality dielectric films, we used the microwave exited Plasma Enhanced Chemical Vapor Deposition (PECVD) [1][2][3].The Id-Vcg characteristics before and after the electron injection into the floating gate are shown in figure C. To change the threshold voltage in positive value, the voltages of control gate and injection gate are determined for the electron injection. The threshold voltage before the electron injection is -10.7 V and the electron injection increases the threshold voltage, resulting in a positive threshold voltage of 3.2 V. This voltage is sufficiently high voltage for normally-off operation. The Id-Vd characteristics after electron injection are shown in the figure D. It is found that the electron mobility is 2100 cm2/Vs, which is the similar value of 1500~2250 cm2/Vs in the reported conventional GaN HEMT [4][5][6] and this indicates that the device can be maintained high electron mobility as same as the conventional GaN HEMT.We fabricated the GaN HEMTs with floating gate, which realize the normally-off and high electron mobility. The threshold voltage can be controlled to be 3.2 V and the electron mobility of 2100 cm2/Vs is achieved. It is indicated that normally-off GaN HEMT device with high electron mobility can be demonstrated.[1] T. Ohmi, et al., J. Phys. D: Appl. Phys., 39, p.R,2006. [2] H. Tanaka, et al., Jpn. J. Appl. Phys. 42, p. 1911, 2003. [3] H. Kambayashi, et al., Solid-State Electronics, 54, p. 660 [4] J.-T. Chen, et al., Appl. Phys. Lett. 106, 251601, 2015. [5] K. Shinohara et al., IEEE Trans. Electron Devices, 60, p. 2982, 2013. [6] X. Ding et al., CES Transaction on Electrical Machines and Systems, 3, p54. Figure 1

Novel Mixed-Dimensional hBN-Passivated Silicon Nanowire Reconfigurable Field Effect Transistors: Fabrication and Characterization.

This work demonstrates the novel concept of a mixed-dimensional reconfigurable field effect transistor (RFET) by combining a one-dimensional (1D) channel material such as a silicon (Si) nanowire with a two-dimensional (2D) material as a gate dielectric. An RFET is an innovative device that can be dynamically programmed to perform as either an n- or p-FET by applying appropriate gate potentials. In this work, an insulating 2D material, hexagonal boron nitride (hBN), is introduced as a gate dielectric and encapsulation layer around the nanowire in place of a thermally grown or atomic-layer-deposited oxide. hBN flake was mechanically exfoliated and transferred onto a silicon nanowire-based RFET device using the dry viscoelastic stamping transfer technique. The thickness of the hBN flakes was investigated by atomic force microscopy and transmission electron microscopy. The ambipolar transfer characteristics of the Si-hBN RFETs with different gating architectures showed a significant improvement in the device's electrical parameters due to the encapsulation and passivation of the nanowire with the hBN flake. Both n- and p-type characteristics measured through the top gate exhibited a reduction of hysteresis by 10-20 V and an increase in the on-off ratio (ION/IOFF) by 1 order of magnitude (up to 108) compared to the values measured for unpassivated nanowire. Specifically, the hBN encapsulation provided improved electrostatic top gate coupling, which is reflected in the enhanced subthreshold swing values of the devices. For a single nanowire, an improvement up to 0.97 and 0.5 V/dec in the n- and p-conduction, respectively, is observed. Due to their dynamic switching and polarity control, RFETs boast great potential in reducing the device count, lowering power consumption, and playing a crucial role in advanced electronic circuitry. The concept of mixed-dimensional RFET could further strengthen its functionality, opening up new pathways for future electronics.

Dielectric layer modulated nanofluidic transport: Formation of parent–sister vortices

Our analysis, consistent with the induced-charge electrokinetic, aptly discusses the effect of gate potential on the formation of vortices of disparate scales in a nanofluidic channel. The nanochannel considered here is connected with reservoirs at its ends, while a pair of dielectric gate electrodes is also embedded on the outer layer of the channel wall. In this endeavor, we establish that a suitable modulation of the dielectric polarization and inherent surface charge of the channel wall leads to the development of pair of “parent–sister” vortices in the flow field alongside yields a net flow in the channel, as well a unique fluidic functionality achieved at small scale is reported here for the first time. Moreover, we identify for the first time that the critical value of surface charge density (“critical-sigma,” i.e., σc) for two different typical heights of the nanofluidic channel, leading to the formation of maximum strength and size vortices by ceasing the net throughput. Also, we establish a critical range of surface charge density for a window of an arbitrary dimension of the dielectric gate electrode—a range for which optimum vortices are generated in the pathway, simultaneously producing adequate net flow through the channel. Under the present modeling configuration, we obtain that |σc|∼O(1 mC/m2) for a 1 μm long nanochannel having embedded quartz layer gate electrodes with gate potential |Vg|∼O(1 V). We believe that critical-sigma would be a crucial parameter for the design and fabrication of state-of-the-art nanodevices/nanosystems intended for augmented fluidic functionalities, for example, efficient solute mixing.

Multi-neuron connection using multi-terminal floating–gate memristor for unsupervised learning

Multi-terminal memristor and memtransistor (MT-MEMs) has successfully performed complex functions of heterosynaptic plasticity in synapse. However, theses MT-MEMs lack the ability to emulate membrane potential of neuron in multiple neuronal connections. Here, we demonstrate multi-neuron connection using a multi-terminal floating-gate memristor (MT-FGMEM). The variable Fermi level (EF) in graphene allows charging and discharging of MT-FGMEM using horizontally distant multiple electrodes. Our MT-FGMEM demonstrates high on/off ratio over 105 at 1000 s retention about ~10,000 times higher than other MT-MEMs. The linear behavior between current (ID) and floating gate potential (VFG) in triode region of MT-FGMEM allows for accurate spike integration at the neuron membrane. The MT-FGMEM fully mimics the temporal and spatial summation of multi-neuron connections based on leaky-integrate-and-fire (LIF) functionality. Our artificial neuron (150 pJ) significantly reduces the energy consumption by 100,000 times compared to conventional neurons based on silicon integrated circuits (11.7 μJ). By integrating neurons and synapses using MT-FGMEMs, a spiking neurosynaptic training and classification of directional lines functioned in visual area one (V1) is successfully emulated based on neuron’s LIF and synapse’s spike-timing-dependent plasticity (STDP) functions. Simulation of unsupervised learning based on our artificial neuron and synapse achieves a learning accuracy of 83.08% on the unlabeled MNIST handwritten dataset.

Bending Stability of Ferroelectric Gated Graphene Field Effect Transistor for Flexible Electronics.

In this work, we explored the potential of the ferroelectric gate of (Pb0.92La0.08)(Zr0.30Ti0.70)O3 (PLZT(8/30/70)) for flexible graphene field effect transistor (GFET) devices. Based on the deep understanding of the VDirac of PLZT(8/30/70) gate GFET, which determines the application of the flexible GFET devices, the polarization mechanisms of PLZT(8/30/70) under bending deformation were analyzed. It was found that both flexoelectric polarization and piezoelectric polarization exist under bending deformation, and their polarization direction is opposite under the same bending deformation. Thus, a relatively stable of VDirac is obtained due to the combination of these two effects. In contrast to the relatively good linear movement of VDirac under bending deformation of relaxor ferroelectric (Pb0.92La0.08)(Zr0.52Ti0.48)O3 (PLZT(8/52/48)) gated GFET, these stable properties of the PLZT(8/30/70) gate GFETs make them have great potential for applications in flexible devices.

Hot-electron resonant terahertz bolometric detection in the graphene/black-AsP field-effect transistors with a floating gate

We evaluate the terahertz (THz) detectors based on field-effect transistor (FET) with the graphene channel (GC) and a floating metal gate (MG) separated from the GC by a black-phosphorus (b-P) or black-arsenic (b-As) barrier layer. The operation of these GC-FETs is associated with the heating of the two-dimensional electron gas in the GC by impinging THz radiation leading to thermionic emission of the hot electrons from the GC to the MG. This results in the variation of the floating gate potential, which affects the source–drain current. At the THz radiation frequencies close to the plasmonic resonance frequencies in the gated GC, the variation of the source–drain current and, hence, the detector responsivity can be resonantly large.

Wavelength‐Selective, Narrowband Graphene Transistor with a Plasmon‐Enhanced Pyroelectric Gate

Herein, a wavelength‐selective pyroelectric sensor based on a graphene field‐effect transistor (gFET) with a plasmon‐enhanced pyroelectric gate (PG) is reported. The PG gFET (PG‐gFET) uses a poly(vinylidene fluoride‐co‐trifluoroethylene) or PVDF‐TrFE membrane doped with plasmonic nanoparticles as the gate. Gold nanorods (AuNRs) or silver nanoparticles (AgNPs) are incorporated into the PVDF‐TrFE membrane to enhance the photothermal conversion efficiency of PVDF‐TrFE in a specific narrowband wavelength range. The wavelength‐selective photothermal effect can optically modulate the gate potential of the PG‐gFET; this, in turn, leads to a change in current through the graphene film of the transistor. The PG‐gFET with AuNRs exhibits a maximum responsivity of 0.79 μA mW−1 at the wavelength of 660 nm. Replacing AuNRs with AgNPs in the PVDF‐TrFE membrane results in tuning the plasmonic response of the transistor to 488 nm with a maximum responsivity of 0.68 μA mW−1. When plasmonic nanoparticles are absent from the PVDF‐TrFE membrane, the maximum response wavelength of the transistor is shifted to a midinfrared regime at 3125 nm, which is associated with the CC absorption of PVDF‐TrFE. The ability of the PG‐gFET to selectively respond to different light wavelengths will benefit many fields, including pyroelectric sensors, spectroscopy, and imaging.

Modeling of spin decoherence in a Si hole qubit perturbed by a single charge fluctuator

Spin qubits in semiconductor quantum dots are one of the promizing devices to realize a quantum processor. A better knowledge of the noise sources affecting the coherence of such a qubit is therefore of prime importance. In this work, we study the effect of telegraphic noise induced by the fluctuation of a single electric charge. We simulate as realistically as possible a hole spin qubit in a quantum dot defined electrostatically by a set of gates along a silicon nanowire channel. Calculations combining Poisson and time-dependent Schr\"odinger equations allow to simulate the relaxation and the dephasing of the hole spin as a function of time for a classical random telegraph signal. We show that dephasing time $T_2$ is well given by a two-level model in a wide range of frequency. Remarkably, in the most realistic configuration of a low frequency fluctuator, the system has a non-Gaussian behavior in which the phase coherence is lost as soon as the fluctuator has changed state. The Gaussian description becomes valid only beyond a threshold frequency $\omega_{th}$, when the two-level system reacts to the statistical distribution of the fluctuator states. We show that the dephasing time $T_{2}(\omega_{th})$ at this threshold frequency can be considerably increased by playing on the orientation of the magnetic field and the gate potentials, by running the qubit along "sweet" lines. However, $T_{2}(\omega_{th})$ remains bounded due to dephasing induced by the non-diagonal terms of the stochastic perturbation Hamiltonian. Our simulations reveal that the spin relaxation cannot be described cleanly in the two-level model because the coupling to higher energy hole levels impacts very strongly the spin decoherence. This result suggests that multi-level simulations including the coupling to phonons should be necessary to describe the relaxation phenomenon in this type of qubit.

Realization of independent contacts in barrier-separated InAs/GaSb quantum wells

InAs/GaSb double quantum wells separated by a 100 Å AlSb middle barrier are grown by molecular beam epitaxy. We report a nanofabrication technique that utilizes the surface Fermi level pinning position in InAs [Efs(InAs)] for realizing independent electric contacts to each well. In particular, separate Ohmic contacts to the upper InAs quantum well are achieved by selectively etching down to the InAs, while contacts to the lower GaSb quantum well are obtained by the depletion method. For the latter, the upper InAs quantum well is locally pinched off by top etched trenches capped with a remaining 2–3 nm InAs layer. As a result of a relatively low Efs(InAs), applying a negative bias gate potential will create a conducting hole channel in GaSb and, hence, a separate Ohmic contact to the lower quantum well. This method is demonstrated with experiment and the support of a self-consistent band bending calculation. A number of experiments on separately probing Coulomb and tunnel-coupled InAs/GaSb systems now become accessible.

A strain-engineered graphene qubit in a nanobubble

We propose a controllable qubit in a graphene nanobubble (NB) with emergent two-level systems (TLSs) induced by pseudo-magnetic fields (PMFs). We found that double quantum dots can be created by the strain-induced PMFs of a NB, and also that their quantum states can be manipulated by either local gate potentials or the PMFs. Graphene qubits clearly exhibit avoided crossing behavior as electrical detuning, with energy splittings of about few meV. We show a remarkable tunability of our device design that allows a fine control of the Landau–Zener transition probability by strain engineering of the NB, showing half-and-half splitting at the avoided crossing point. Further, we demonstrate that the TLSs in the NB exhibit Rabi oscillations near the avoided crossing point, resulting in very fast Rabi cycles of a few ps.

Potentiation of CNG channel gating by matrix metalloproteinases is governed by the turret region and intracellular disulfide bonds.

Proteolytic modification of cyclic nucleotide gated (CNG) channel subunits by extracellular matrix metalloproteinases (MMP9 or MMP2) enhances the ligand sensitivity of native and recombinant channels. MMP modification of gating produced the sequential appearance of sub-populations having distinct ligand sensitivities, with a reduction in Hill slope consistent with emerging channel heterogeneity. Results demonstrated surprising state dependence: more rapid channel potentiation in sub-saturating ligand concentrations, compared to channels held open or held closed; and greater potentiation if channels were sequentially held closed then open, compared to open then closed. Channel potentiation generated by MMP9 activity was (1) reversed by intracellular DTT; (2) associated with high MW complexes on immunoblots, which were reduced by DTT; (3) absent for Cys-less CNGA1 (all cysteines mutated); (4) enhanced by a disease-associated mutation in CNGB3 (G558C); and (5) regulated by alternative splicing of CNGA3, which can toggle in/out a key cysteine within the N-terminal domain. In the absence of disulfide bonds, MMP9 activity instead reduced CNG channel ligand sensitivity. We have previously shown (Meighan et al., 2013) that CNGA subunit glycosylation can protect a sub-population of channels from MMP modification, but protection depends on the glycan site, which varies among paralogs and orthologs. We introduced an N339C mutation at the predicted cleavage site within the CNGA3 turret; MTSEA-biotin pretreatment of N339C attenuated MMP-dependent potentiation of gating. Furthermore, N339C channels exhibited increased susceptibility to modification by endogenous MMPs, producing subpopulations with different ligand sensitivities, which was prevented by MMP2/9 inhibitor. Together, these results suggest that CNG channel modification in the context of extracellular MMP activity is a multi-step process: sequential subunit proteolysis dependent on the extracellular turret (closed state) antecedent to potentiation resulting from cytoplasmic disulfide bond formation (open state).

Quantum Capacitance and Fermi Level Change in Graphene nanoribbons due to Gas Sensing

Here we used semiempirical computations to examine the property of nanoribbon of Graphene as a gas sensor with interaction of H2O gas molecule for both pure and defective GNRs which has been generated in Atomistix Toolkit (ATK) software. Density of States GNR before and after the interaction is shown in a (DOS) diagram with gas particles was discovered to be different which has been observed in MATLAB software. It's vital to look at the quantum capacitance when examining Graphene’s electrical properties. So, this study looked at change in quantum capacitance and Fermi Level of Graphene before and after gas sensing and the results were produced with necessary equations. Using a three-electrode electrochemical setup, we are able to directly quantify Graphene's quantum capacitance as a function of gate potential. If Graphene is used in a highly sensitive capacitive circuit, the change in Fermi energy was determined from experimental data of changed Density of States (DOS). Although this research has some limitations and future scopes, we can propose that the change in Fermi Energy level can be approximately 9.5 eV with respect to the quantum capacitance of fabricated Graphene interacting with H2O which is used as a MOSFET in this work.

Quantum Capacitance and Fermi Level Change in Graphene nanoribbons due to Gas Sensing

Here we used semiempirical computations to examine the property of nanoribbon of Graphene as a gas sensor with interaction of H2O gas molecule for both pure and defective GNRs which has been generated in Atomistix Toolkit (ATK) software. Density of States GNR before and after the interaction is shown in a (DOS) diagram with gas particles was discovered to be different which has been observed in MATLAB software. It's vital to look at the quantum capacitance when examining Graphene’s electrical properties. So, this study looked at change in quantum capacitance and Fermi Level of Graphene before and after gas sensing and the results were produced with necessary equations. Using a three-electrode electrochemical setup, we are able to directly quantify Graphene's quantum capacitance as a function of gate potential. If Graphene is used in a highly sensitive capacitive circuit, the change in Fermi energy was determined from experimental data of changed Density of States (DOS). Although this research has some limitations and future scopes, we can propose that the change in Fermi Energy level can be approximately 9.5 eV with respect to the quantum capacitance of fabricated Graphene interacting with H2O which is used as a MOSFET in this work.