Number Of Charge Carriers Research Articles

TCAD-based investigation of 1/f noise in advanced 22 nm FDSOI MOSFETs

In this work, the mechanistic insights behind low-frequency noise (LFN) of the advanced ultrathin body and buried oxide fully depleted silicon-on-insulator based metal–oxide–semiconductor field effect transistor (MOSFET) are unveiled. The gate voltage-induced noise power spectral density (SVG) is inversely proportional to frequency f (i.e., SVG∝1/fγ, γ∼ 1 is the frequency exponent) for nMOSFET and pMOSFET. Detailed numerical simulations are performed and well calibrated to reported SVG vs f characteristics. Simulation results are consistent with the reported experimental observations. We demonstrate that LFN is caused by the charge carrier number fluctuation mechanism, which is originated by trapping and de-trapping of channel charge carriers via. bulk traps (from oxygen vacancies) in the hafnium dioxide (HfO2) layer, but not through traps at the silicon dioxide (SiO2)/channel interface. This work therefore explains the similar magnitude of SVG in both nMOSFET and pMOSFET observed experimentally and further suggests that oxygen vacancies inside gate oxides are critical to suppress the low-frequency noise in emerging high-k based MOSFETs.

1/f noise in semiconductors arising from the heterogeneous detrapping process of individual charge carriers

Abstract We propose a model of 1 / f noise in semiconductors based on the drift of individual charge carriers and their interaction with the trapping centers. We assume that the trapping centers are homogeneously distributed in the material. The trapping centers are assumed to be heterogeneous and have unique detrapping rates. We show that uniform detrapping rate distribution emerges as a natural consequence of the vacant trap depths following the Boltzmann distribution, and the detrapping process obeying Arrhenius law. When these laws apply, and if the trapping rate is low in comparison to the maximum detrapping rate, 1 / f noise in the form of Hooge’s relation is recovered. Hooge’s parameter, α H, is shown to be a ratio between the characteristic trapping rate and the maximum detrapping rate. The proposed model implies that 1 / f noise arises from the temporal charge carrier number fluctuations, not from the spatial mobility fluctuations.

Interfacial capacitance in lithium disilicate glass: Experimental factors and charge carrier density

AbstractThe formation of an electric double‐layer (EDL) is an important phenomenon for many research areas, including energy storage technology. Although EDL is well‐known in electrochemistry, most of the studies involve the characterization of liquid electrolyte/electrode interfaces, and only a limited number of studies in solid‐solid contacts, such as solid electrolyte/electrode interface are available. This paper employed electrochemical impedance spectroscopy (EIS) to systematically investigate the influence of experimental factors in the interfacial capacitance arising from the electrode polarization in a lithium disilicate glass/gold electrode interface. It analyzed the influence of a.c. input voltage amplitude, samples' roughness (mechanical and chemomechanical polishing) and thickness, range of applied frequency and temperature, and the number of impedance cycles. In short, it was found that an input voltage range of 15–60 mV is indicated to minimize potential electrochemical processes during electrode polarization, where the data is reproducible from the second measurement cycle onward. Smoother surfaces closely approximated ideal electrode spike behavior, with surface treatment exhibiting influence on interfacial capacitance values. Moreover, as expected, we observed an increase in relative permittivity values with increasing thickness, accompanied by decreased capacitance values. Finally, by employing optimal experimental conditions and analyzing the inflection frequency () of the versus log() curve, we determined that the ratio between effective charge carriers () and the total number of charge carriers () falls within the range of 5–12% between 130°C and 280°C.

Crystallite Size Effects on Electrical Properties of Nickel Chromite (NiCr2O4) Spinel Ceramics: A Study of Structural, Magnetic, and Dielectric Transitions

The effect of sintering temperature on the structural, magnetic, and dielectric properties of NiCr2O4 ceramics was investigated. A powder X-ray analysis indicates that the prepared nanocrystallites effectively inhibit the cooperative Jahn–Teller distortion, thereby stabilizing the high-temperature cubic phase structure with space group Fd-3m. Multiple transitions are confirmed by temperature-dependent magnetization M(T) data. Moreover, the magnetization value decreases and the Curie temperature increases with a decrease in the crystallite size. The low-temperature-dependent real permittivity (ε′-T) for a NiCr2O4 crystallite size of 78 nm exhibits a broad maximum at 40 K that is independent of frequency. This establishes a correlation between electric ordering and the underlying magnetic structure. The temperature dependency of the dielectric constant at fixed frequencies for both NiCr2O4 crystallite sizes rises with temperature for a certain range of frequencies. A significant improvement is evident: the dielectric constant (ε’) at room temperature reaches approximately 5738 for the sample with 28 nm crystallites, while the 78 nm crystallite sample shows a noticeable drop to ε’~174. The frequency-dependent conductivity curves for both types of NiCr2O4 nanocrystallites have different conductivity values. The lower-crystallite-size sample demonstrates higher conductivity values than the 78 nm crystallite size one. This observation is attributed to the decrease in crystallite size, which increases the number of grain boundaries and, consequently, scatters a higher number of charge carriers.

Viscous terahertz photoconductivity of hydrodynamic electrons in graphene.

Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively. Here we report a qualitative deviation from the standard behaviour in doped metallic graphene. We show that Dirac electrons exposed to continuous-wave terahertz (THz) radiation can be thermally decoupled from the lattice, which activates hydrodynamic electron transport. In this regime, the resistance of graphene constrictions experiences a decrease caused by the THz-driven superballistic flow of correlated electrons. We analyse the dependencies of the negative photoresistance on the carrier density, and the radiation power, and show that our superballistic devices operate as sensitive phonon-cooled bolometers and can thus offer, in principle, a picosecond-scale response time. Beyond their fundamental implications, our findings underscore the practicality of electron hydrodynamics in designing ultra-fast THz sensors and electron thermometers.

Electrical Study of Changes in Impedance and Internal Parameters of Nano Structures of Molybdenum Disulfide Semiconductor Type (MoS2-2H/3R) with Changes in Temperature

MoS2 nanostructures were prepared using the hydrothermal method by reacting ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O) with citric acid monohydrate (C6H8O7H2O) in distilled water with the presence of sodium sulfide (Na2S), we have found from the Arenos diagram that the value of the activation energy of (MoS2 -2H/3R) is low and equal to Ea= 0.0505 (e.V). From the atomic force microscope (AFM) images, we found that the size of the surface aggregates of the sample (table - MoS2-2H/3R) ranges between (100-150) n m. From studying the changes in the impedance with different temperatures (T = 15, 30, and 60), we found that impedance is inversely proportional to both the applied frequency and the temperature, and at the frequencies the response corresponding to the temperature reaches a value of (Z = 20 K.Ω, T = 15°C). ) and at temperature (Z = 8.02 K.Ω, T = 30 °C), and at (Z = 17.1 K.Ω, T = 60 °C), It has been shown that the number of electric charge carriers (Nd) increases with increasing temperature. On the contrary, we found a decrease in the number of electronic traps (Ns) and a decrease in the relaxation time τP with increasing temperature.

Bioinspired Flexible and Low-Voltage Organic Synaptic Transistors for UV Light-Driven Vision Systems.

Neuromorphic vision systems, particularly those stimulated by ultraviolet (UV) light, hold great potential applications in portable electronics, wearable technology, biological analysis, military surveillance, etc. Organic artificial synaptic devices hold immense potential in this field due to their ease of processing, flexibility, and biocompatibility. In this work, we have fabricated a flexible organic field-effect transistor (OFET) that utilizes chitosan-silver nanoparticles (AgNPs) composite material as the active dielectric material. During UV light illumination, both silver nanoparticles and the pentacene layer generate a large number of charge carriers. The photogenerated carriers lead to a more significant hole accumulation at the pentacene interface, resulting in a current rise. In the absence of light, the trapped electron in the silver nanoparticles persists for a longer duration, preventing the instant recombination with holes. This extended retention of electrons leads to the observed synaptic performance of the transistor. The use of aluminum oxide (Al2O3) as one of the dielectric layers enables the device to operate effectively at low voltage (<1 V). The device mimics various crucial synaptic properties of the brain, including short-term potentiation and long-term potentiation (STP and LTP), paired-pulse facilitation (PPF), spike-duration dependent plasticity (SDDP), spike-number dependent plasticity (SNDP), and spike-rate dependent plasticity (SRDP), etc. This work introduces an approach to develop flexible organic synaptic transistors that operate efficiently at low voltages, paving the way toward high-performance, UV light-driven neuromorphic vision systems.

Carrier-Carrier Repulsion Limits the Conductivity of N-Doped Organic Semiconductors.

Molecular doping is a key strategy to enhance the electrical conductivity of organic semiconductors. Typically, the electrical conductivity shows a maximum value upon increased doping, after which the conductivity decreases. This decrease in conductivity is commonly attributed to unfavorable changes in the morphology. However, in recent simulation work, has shown, that the conductivity-at high doping-is instead limited by electron-electron repulsion rather than by morphology, at least for some material combinations. Based on the simulations, this limitation is expected to show up in the dependence of the Seebeck coefficient versus carrier density: the Seebeck coefficient will follow Heike's formula if carrier-carrier repulsion limits the conductivity. Here, the electrical conductivity and Seebeck coefficient are measured as a function of doping for a series of n-type organic semiconductors. Additionally, the resulting carrier density is measured using metal-insulator-semiconductor diodes, which link dopant loading and the number of charge carriers. At high carrier densities, the Seebeck coefficient indeed follows Heike's formula, confirming that the conductivity is limited by carrier-carrier repulsion rather than by morphological effects. This study shows that current models of hopping transport in organic semiconductors may be incomplete. As a result, this study offers novel insights in the design of organic semiconductors.

Features of electrical transport and H/D isotope effects in the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

The electrical properties of the proton-conducting electrolyte BaCe0.7Zr0.1Y0.1Yb0.1O3-δ were studied using the 4-probe direct current (DC) method depending on temperature and oxygen partial pressure in the atmospheres, humidified with H2O and D2O. Ionic and electron hole contributions to the electrical conductivity were determined, and the transport numbers of charge carriers were calculated. It is shown that in air conditions BaCe0.7Zr0.1Y0.1Yb0.1O3-δ is a mixed ion-electron hole conductor. The contribution of electron hole conductivity decreases with the decrease of temperature and oxygen partial pressure. A significant isotope H/D effect in the electrical conductivity is observed for all investigated conditions expressed in the decrease in conductivity in D2O-containing atmospheres with the increase of activation energy values. Replacing H2O with D2O leads to decrease in the ion transport numbers and ionic conductivity values, while the electron hole conductivity remains almost the same.

Screening Cobalt-based Catalysts on Multicomponent CdSe@CdS Nanorods for Photocatalytic Hydrogen Evolution in Aqueous Media.

We present CdSe@CdS nanorods coated with a redox-active polydopamine (PDA) layer functionalized with cobaloxime-derived photocatalysts for efficient solar-driven hydrogen evolution in aqueous environments. The PDA-coating provides reactive groups for the functionalization of the nanorods with different molecular catalysts, facilitates charge separation and transfer of electrons from the excited photosensitizer to the catalyst, and reduces photo-oxidation of the photosensitizer. X-ray photoelectron spectroscopy (XPS) confirms the successful functionalization of the nanorods with cobalt-based catalysts, whereas the catalyst loading per nanorod is quantified by total reflection X-ray fluorescence spectrometry (TXRF). A systematic comparison of different types of cobalt-based catalysts was carried out, and their respective performance was analyzed in terms of the number of nanorods and the amount of catalyst in each sample [turnover number, (TON)]. This study shows that the performance of these multicomponent photocatalysts depends strongly on the catalyst loading and less on the specific structure of the molecular catalyst. Lower catalyst loading is advantageous for increasing the TON because the catalysts compete for a limited number of charge carriers at the nanoparticle surface. Therefore, increasing the catalyst loading relative to the absolute amount of hydrogen produced does not lead to a steady increase in the photocatalytic activity. In our work, we provide insights into how the performance of a multicomponent photocatalytic system is determined by the intricate interplay of its components. We identify the stable attachment of the catalyst and the ratio between the catalyst and photosensitizer as critical parameters that must be fine-tuned for optimal performance.

Temperature dependent conductivity, dielectric relaxation, electrical modulus and impedance spectroscopy of Ni substituted Na[formula omitted]Zr[formula omitted]Ni[formula omitted]Si[formula omitted]PO[formula omitted]

We investigate the structural, dielectric relaxation, electric modulus and impedance behavior of Ni-doped NASICON ceramic Na3+2xZr2−xNixSi2PO12 (x=0.05–0.2) prepared using the solid-state reaction method. The increase in dielectric constant with temperature and decrease with frequency is explained on the basis of space charge polarization using the two-layer model of Maxwell–Wagner relaxation. The dielectric loss peak at lower temperatures follows the Arrhenius-type behavior with frequency having activation energy of 0.27 ± 0.01 eV of dipolar relaxation, suggests similar type of defects are responsible for all the doped samples. The real (ϵ′) and imaginary (ϵ′′) permittivity variation with frequency shows the broad relaxation behavior indicates the non-Debye type of relaxation in the measured temperature range. The permittivity values decrease with the amount of doping due to the increased number of charge carriers upon Ni doping at the Zr site. The impedance variation with frequency at various temperatures shows two types of relaxation for all the samples correspond to grain and grain boundary contribution in total impedance. The grain contributions are observed at higher frequencies, while grain-boundary contributions occur at the lower side of frequencies. The imaginary part of the electric modulus also shows two types of relaxation peaks for all the samples indicating similar activation energy at low temperatures and variable activation energy at higher temperatures. The fitting of the imaginary modulus using KWW function shows the non-Debye type of relaxation. We find that all modulus curves merge with each other at low temperatures showing a similar type of relaxation, while curves at high temperatures show the dispersed behavior above the peak frequency. The a.c. conductivity data are fitted using the double power law confirming the grain and grain boundary contributions in total conductivity. The double power law exponent variation with temperature shows the small polaron hopping conduction over the measured temperature range for all the doped samples.

Performance tweaking of Co3O4 UV radiation detector via zirconium dopant microstructural and photo-electronic engineering

Incorporation of dopant impurities in semiconducting metal oxide nanostructures has been presumed to increase the pace at which photo-induced holes and electrons separate due to possible bandgap engineering and oxygen vacancy modulations. In this study, we have adopted an electrodeposition technique using a three-electrode configuration for the preparation of Co3O4 thin film samples and investigated the effect of Zr as a dopant ion on the UV radiation sensing performance of nanostructured Co3O4 host material via energy band engineering and microstructural modulation. Consistency in optical energy band gap measurements of the deposited Zr-doped Co3O4 (Zr@Co3O4) was unveiled with the aid of two models: Tauc’s and absorption spectrum fitting (ASF) methods. Ag/Zr@Co3O4/ITO/glass UV radiation detector was fabricated and a sample with 3 % Zr-dopant content demonstrated high UV-365 nm detector performance: detectivity, 1.2 ×1011 Jones, and responsivity, 1818 mA W−1, with high cycling stability, attributable to the host's dopant microstructural tailoring, and the enhancement in its electronic charge carrier number and their scattering potentials within the host's band structure, thanks to the synergistic impacts of dopant ion incorporation and UV irradiation.

Enhancing the fill factor and power conversion efficiency of n-type TOPCon solar cells by using electron migration technique

Improving the efficiency and performance of the solar cells by enhancing the quality and conductivity of the contacts was studied using electron migration (EM). By using intense light that covers the entire cell area at high current densities, the process of EM creates a huge number of charge carriers and helps for enhancing overall cell performances. This study examined the effects of various parameters, including temperature, voltage, time, incident light, and current, on the enhanced performances of n-type tunnel oxide passivated contact (n-TOPCon) solar cells. According to experimental data, 60 V and 10 s at room temperature are the ideal circumstances for optimising both voltage and time. As compared to before the EM experiment in the n-TOPCon solar cells, the illuminated current–voltage (I-V) characteristics of the optimised condition are Jsc of 39.24 mA/cm2, Voc of 707.45 mV, FF of 69.954 %, and PCE of 19.42 %. After the EM condition, this study shows improvements in PCE (19.04 %) and FF (48.02 %). This work provides insight into optimizing the maximum performance in developing solar technologies.

Changes in Current Transport and Regulation of the Microstructure of Graphene/Polyimide Films under Joule Heating Treatment.

The excellent electrical properties of graphene have received widespread attention. However, the difficulty of electron transfer between layers still restricts the application of graphene composite materials to a large extent. Therefore, in this study, graphene/polyimide films were subjected to a Joule heating treatment to improve the electrical conductivity of the film by ~76.85%. After multiple Joule thermal cycle treatments, the conductivity of the graphene/polyimide film still gradually increased, but the increase in amplitude tended to slow down. Finally, after eight Joule heat treatments, the conductivity of the graphene/polyimide film was improved by ~93.94%. The Joule heating treatment caused the polyimide to undergo atomic rearrangement near the interface bonded to the graphene, forming a new crystalline phase favourable for electron transport with graphene as a template. Accordingly, a model of the bilayer capacitive microstructure of graphene/polyimide was proposed. The experiment suggests that the Joule heating treatment can effectively reduce the distance between graphene electrode plates in the bilayer capacitive micro-nanostructures of graphene/polyimide and greatly increases the number of charge carriers on the electrode plates. The TEM and WAXS characterisation results imply atomic structure changes at the graphene/polyimide bonding interface.

Defect Engineering for SnO2 Improves NO2 Gas Sensitivity by Plasma Spraying.

Large emissions of nitrogen dioxide (NO2) pose a significant threat to human health, Monitoring its content and implementing timely measures are crucial. Utilizing oxide semiconductors, such as tin dioxide (SnO2), has proven to be an effective way to detect and analyze NO2. The design and preparation of sensing materials with high sensitivity and excellent selectivity is the key to improve the detection efficiency. SnO2 nanopowders with small and uniform particle size, large specific surface area, adjustable defect content, and no impurities were prepared by a new plasma spraying method. The SnO2 nanopowders exhibit outstanding performance in detecting NO2 at a low temperature of 100 °C, the response to 5 ppm of NO2 reaches 48, and the material demonstrates rapid response and recovery times, coupled with excellent selectivity. The exceptional gas-sensitive properties can be attributed to the superior morphology and structure of SnO2. It provides more reaction sites for gas sensitive reactions, fast electron transport, a large number of charge carriers, and improved adsorption of the material to the target gas. This study provides valuable insights into nanomaterial preparation and the enhancement of gas-sensitive properties for SnO2.

Investigation of spectroscopic and electrical properties of doped poly(pyrrole-3-carboxylic acid)

The spectroscopic and electrical properties of poly(pyrrole-3-carboxylic acid) doped with p-TSA- (p-toluenesulfonate) and AQS- (anthraquinone sulfonate) were investigated. The variation in electrical conductivity as a function of temperature shows that the systems have semiconductor-like electrical characteristics. The investigated polymers exhibit 3D conductivity and less than 0.6 eV energy gaps. The IR and Raman spectra show that the charge carriers are polarons and bipolarons. Doping the poly(pyrrole-3-carboxylic acid) increases the number of charge carriers. Electron paramagnetic resonance has shown that localized polarons and bipolarons are formed within these polymers.

Copper-Enriched Nanostructured Conductive Thermoelectric Copper(I) Iodide Films Obtained by Chemical Solution Deposition on Flexible Substrates

The objects of our research are flexible thin-film thermoelectric materials with nanostructured CuI layers 0.5–1.0 μm thick, fabricated by the chemical solution method Successive Ionic Layer Adsorption and Reaction (SILAR) on flexible polyethylene terephthalate and polyimide substrates. These cubic γ-CuI films differ from films obtained by other chemical solution methods, such as spin-coating, sputtering, and inject printing, in their low resistivity due to acceptor impurities of sulfur and oxygen introduced into CuI from aqueous precursor solutions during SILAR deposition. Energy barriers at the boundaries of 18–22 nm CuI nanograins and a large number of charge carriers inside the nanograins determine the transport properties in the temperature interval 295–340 K characterized by transitions from semiconductor to metallic behavior with increasing temperature, which are typical of nanostructured degenerate semiconductors. Due to the resistivity of about 0.8 mΩ· m at 310 K and the Seebeck coefficient 101 μV/K, the thermoelectric power factor of the CuI film 1.0 μm thick on the polyimide substrate is 12.3 μW/(m · K2), which corresponds to modern thin-film p-type thermoelectric materials. It confirms the suitability of CuI films obtained by the SILAR method for the fabrication of promising inexpensive non-toxic flexible thermoelectric materials.

Transfer doping of epitaxial graphene on SiC(0001) using Cs

Control of the charge carrier concentration is essential for applications of graphene. Here, we demonstrate the doping of epitaxial graphene on SiC(0001) via charge transfer from an adsorbed layer of Cs atoms with sub-monolayer coverage. The electronic structure of the graphene is analyzed using x-ray and angle-resolved photoelectron spectroscopy. In H-intercalated, quasi-freestanding monolayer graphene (QFMLG), the Dirac point can be tuned continuously from p-type to strong n-type doping. For strong n-type doping, analysis of the core level binding energies implies a deviation from a rigid band shift. This might be explained by an increased screening of the atomic core potential due to the higher number of charge carriers per C atom in the graphene layer. Furthermore, charge transfer into the SiC substrate leads to a change in band bending at the SiC/QFMLG interface, which saturates into a flat band scenario at higher Cs coverage. An analysis of the Fermi surfaces suggests an increasing electron-phonon-coupling in strongly doped QFMLG. In monolayer graphene (MLG), which is intrinsically n-type doped due to the presence of the buffer layer at the SiC interface, n-type doping can be enhanced by Cs evaporation in a similar fashion. In contrast to QFMLG, core level spectra and Dirac cone position in MLG apparently show a rigid band shift even for very high doping, emphasizing the importance of the substrate.

Structure and Electrical Properties of Polymer Electrolyte Based on Plasticized Chitosan Grafted Polymethyl Methacrylate (Ch-g-PMMA)- Magnesium Triflate for Electrochemical Double Layer Capacitor

Polymer electrolytes have received much attention as materials used in batteries, supercapacitors, sensors and solar cells. Most of the polymer electrolytes reported are based on synthetic polymer, therefore it is difficult to recycle as it has poor degradability and ends up being a waste. In recent years, biopolymers gained much interest in replacing environmentally unfriendly polymers. Various studies have been done to accomplish polymer electrolytes with high conductivity and long-term safety. This study’s objective is to prepare plasticized Ch-g-PMMA-based polymer electrolyte by introducing the magnesium triflate salt and glycerol plasticizer. The grafted polymer of Ch-g-PMMA was prepared using gamma (γ) radiation. The grafted polymer of Ch-g-PMMA with 0.4 g of Mg(Tf)2 and different concentrations of glycerol has been prepared by using the solution casting technique. To achieve this study, the prepared plasticized Ch-g-PMMA-Mg(Tf)2 polymer electrolytes are characterized by XRD, FTIR, EIS and LSV techniques. XRD was carried out to determine the change in crystallinity and the amorphous structure of the plasticized Ch-g-PMMA-Mg(Tf)2 polymer. FTIR reveals the occurrence of complexation between Ch-g-PMMA polymer, Mg(Tf)2 salt and glycerol plasticizer. The grafted Ch-g-PMMA-Mg(Tf)2 was added with different concentrations of glycerol from 0 to 50 wt%. The Ch-g-PMMA-Mg(Tf)2 polymer electrolyte with 50 wt% of glycerol shows the highest ionic conductivity of 1.50×10−4 S·cm−1 compared with other samples. The increase in mobility of ions and the number of charge carriers has enhanced ionic conductivity. Based on the LSV analysis, the highest conducting Ch-g-PMMA-Mg(Tf)2 polymer with 50 wt% of glycerol was found electrochemically stable up to 3.2 V. The goal of this study is to determine the structure and electrical properties as well as the window stability of plasticized Ch-g-PMMA-Mg(Tf)2. The best outcome was produced by adding the 50 wt% of glycerol into the Ch-g-PMMA-Mg(Tf)2 which increased further by 1 order of magnitude. HIGHLIGHTS The ionic conductivity of the Ch-g-PMMA increases by introducing magnesium triflate salt and glycerol plasticizer which enhance the amorphous state and decrease the crystallinity The prepared plasticized Ch-g-PMMA-Mg(Tf)2 polymer electrolytes are characterized by XRD, FTIR, EIS and LSV techniques The highest ionic conductivity are obtained by added 50 wt% glycerol to the grafted polymer CH-g-PMMA-Mg(Tf)2 which is 1.50×10−4 S·cm−1 GRAPHICAL ABSTRACT

Sensing behavior of pentagonal two-dimensional noble-metal dichalcogenide PdSeS for NO2 gas: DFT and semiclassical studies

The gas sensing performance of the pentagonal two-dimensional noble-metal dichalcogenide PdSeS for NO2 gas detection has been extensively studied using DFT, the nudged elastic band (NEB) model, and the semiclassical Boltzmann theory. The NEB calculations indicate a highly effective physical NO2 adsorption, implying the potential of the PdSeS monolayer as an excellent material for creating efficient and reusable gas sensors. Additionally, the PdSeS monolayer, characterized as a semiconductor with a band gap of 1.34 eV, demonstrates the emergence of a deep trap in the band structure following the adsorption of NO2 gas. Subsequently, the values of σxx and σyy decrease significantly from 11.41 and 42.82 S/cm to 2.24 and 0.99 S/cm, respectively. The decrease in conductivity can be attributed to several factors, including an increase in effective mass, the formation of deep traps, and a reduction in the number of charge carriers. Furthermore, our calculations demonstrate the potential use of the PdSeS monolayer in work function (WF) type sensors. Consequently, the pentagonal two-dimensional PdSeS monolayer fulfills the demands of portable, affordable, and reusable NO2 gas sensors by exhibiting remarkable sensitivity and short recovery time.