Enhanced Electron Mobility Research Articles

Preparation of CuCo2O4@NFs nanoflower material with abundant VO/VCo: An excellent catalyst for oxidative breakage of the β-O-4 bond of lignin

A hollow nanoflower material CuCo2O4@NFs with abundant oxygen vacancies (VO) and cobalt vacancies (VCo) was prepared by a simple method. The novel material CuCo2O4@NFs showed excellent oxidation activity, cleaving the β-O-4 bond in lignin model compounds. Conversion of the substrate was as high as 99.02%, and the yield of the main product, phenol, reached 49.50%. Structural analysis showed that the petal and cavity form of the material increased its specific surface area, which facilitated its full contact with O2 molecules. Moreover, the VO generated by lattice oxygen detachment during annealing favor the adsorption of O2, and the VCo generated through lattice distortion induced by Cu-metal doping promoted the detachment of oxygen intermediates. The synergy of these two defects improved the rate of the rate-limiting step. Density functional theory calculations revealed that the synergistic effect of VO and VCo narrowed the gap between the Fermi energy levels and the d-band center, thereby enhancing electron mobility. Finally, excellent recyclability of CuCo2O4@NFs was confirmed through cycling experiments. The application of this material provided technical support for the efficient cracking of lignin into high-value-added chemicals and realized the effective utilization of woody biomass resources.

Hydrogen chloride treated InAs quantum dot thin film phototransistor for ultrahigh responsivity

Indium Arsenide (InAs) colloidal quantum dots (CQDs) are emerging candidates for infrared photodetector applications owing to their excellent optoelectronic properties and low toxicity. However, low electron mobility stemming from its unique surface chemistry hinders its practical application. Through comprehensive structural and chemical analyses, we optimized the one-step HCl treatment to achieve stoichiometric balance, a well-passivated surface with low defect density, and an improved coupling effect by reducing the interparticle distance. Subsequently, a near infrared photodetector at a wavelength of 980 nm was fabricated with the modified InAs QDs in thin film transistor structure by all-solution process, showing remarkable electron mobility enhancement of up to 3.15 cm2/V∙s. The thin film phototransistor exhibited excellent photoresponse with a responsivity of 5.45 × 103 A/W, external quantum efficiency of 6.90 × 105%, and a linear dynamic range of 50 dB. This achievement represents the highest responsivity observed in an InAs QD-based phototransistor device, demonstrating its potential for lead-free infrared (IR) region optoelectronic applications.

Leaf-like MSX/TiN heterojunction photocathodes mimicking plant cell – An effective strategy to enhance photoelectrocatalytic carbon dioxide reduction and systematic mechanism investigation

Semiconductors, such as metal oxides and metal sulfides (MSX), are widely investigated as effectively catalytic materials to convert carbon dioxide (CO2) and water into chemicals under simulated solar light. These valuable investigations might address both the energy crisis and climate change in our modern society. Herein, a novel strategy to construct leaf-like heterojunctions of VS-ZnIn2S4/TiN-x is reported. The new semiconductor heterojunctions were then applied to photoelectrocatalytic CO2 reduction, achieving excellent performance (formate formation rate of 1173.2 μM h−1 cm−2) attributed to the plant cell-like morphology and enhanced electron mobility from the heterojunction interfaces to the active sites on the surface. Our findings suggest that titanium nitride (TiN) with good conductivity can improve the photoelectrocatalytic ability of MSX through heterojunction construction. The photocathode VS-ZnIn2S4/TiN-3 exhibits 81.0 % selectivity toward C2 products by optimizing the material structure and reaction conditions. According to the systematic investigation of operando Fourier transform infrared (FTIR) spectra, common intermediates such as *COO−, *COOH, *CO, *CHO, *COCHO, and *COCH3 reported in the literature were carefully verified. Among these, the carbene specie serve as the key intermediate responsible for generating other intermediates and resulting in all products.

Sludge-derived hydrochar modulates complete nonradical electron transfer in peroxydisulfate activation via pyrrolic-N and carbon defect: Implication for degrading electron-rich ionizable anilines compounds

Nonradical electron transfer process (ETP) is a promising pathway for pollutant degradation in peroxydisulfate-based advanced oxidation processes (PDS-AOPs). However, there is a critical bottleneck to trigger ETP by sludge-derived hydrochar due to its negatively charged surface, inferior porosity and electrical conductivity. Herein, pyrrolic-N doped and carbon defected sludge-derived hydrochar (SDHC-N) was constructed for PDS activation to degrade anilines ionizable organic compounds (IOC) through complete nonradical ETP oxidation. Degradation of anilines IOC was not only affected by the electron-donating capacity but also proton concentration in solution because of the ionizable amino group (−NH2). Diverse effects including proton favor, insusceptible and inhibition were observed. Impressively, addition of HCO3 with strong proton binding capacity boosted aniline degradation nearly 10 times. Moreover, characterizations and theoretical calculations demonstrated that pyrrolic-N increased electron density and created positively charged surface, profoundly promoting generation of SDHC-N-S2O82−* complexes. More delocalized electrons around carbon defect could enhance electron mobility. This work guides a rational design of sludge-derived hydrochar to mediate nonradical ETP oxidation, and provides insights into the impacts of proton on anilines IOC degradation.

Electron Mobility Enhancement of (111)-Oriented Extremely Thin Body Ge-on-Insulator nMOSFETs by Flipped Smart-Cut Substrates

Electron Mobility Enhancement of (111)-Oriented Extremely Thin Body Ge-on-Insulator nMOSFETs by Flipped Smart-Cut Substrates

Ligand-engineered Fe(II)-metallo-supramolecular polymer with benzothiadiazole: Boosting electrochromic energy storage efficiency

The development of intelligent electrochromic energy storage devices that visually display color changes to indicate their charging and discharging status while offering high energy and power densities is gaining interest as a renewable energy solution. Our research engineered a bisterpyridine ligand (BTZ) with a benzothiadiazole spacer and its metallo-supramolecular polymer (Fe-BTZ) via Suzuki coupling and complexation reactions. Spectroscopic, morphological, and structural characterizations revealed nano-rod morphology due to higher aggregation of 1D Fe-BTZ metallo-supramolecular polymer. Quasi-solid-state electrochromic devices with Fe-BTZ as the active layer exhibited significant color changes (matte purple to dirty yellow), an optical contrast of 65.2 % at 567 nm, high coloration efficiency (518.2 cm2/C), quick coloration (0.5 s) and bleaching (1.8 s), and exceptional electrochromic durability compared with commonly used Poly-Fe metallo-supramolecular polymer. Conjugated ridged benzothiadiazole spacers enhanced electron mobility between the Fe-center during electrochemical transitions, increasing coloration efficiency, durability, and electrochromic speed. The Fe-BTZ and Prussian blue (PB)-based quasi-solid-state energy storage device also showed fast response times (1.1 s and 1.9 s), high CE (1077 cm2/C), 6500-cycle durability, high volumetric capacitance (70.1 ± 4 F/cm3) with a specific capacity of 10.96 mAh/g at 0.14 A/g current density and 74 % capacitance retention over 20,000 galvanostatic charge–discharge cycles. The device’s ability to power 18 red LEDs demonstrates its practical applicability.

Enhanced Carrier Transport Performance of Monolayer Hafnium Disulphide by Strain Engineering.

For semiconducting two-dimensional transition metal dichalcogenides (TMDs), the carrier transport properties of the material are affected by strain engineering. In this study, we investigate the carrier mobility of monolayer hafnium disulphide (HfS2) under different biaxial strains by first-principles calculations combined with the Kubo-Greenwood mobility approach and the compact band model. The decrease/increase in the effective mass of the conduction band (CB) of monolayer HfS2 caused by biaxial tensile/compressive strain is the major reason for the enhancement/degradation of its electron mobility. The lower hole effective mass of the valence bands (VB) in monolayer HfS2 under biaxial compressive strain improves its hole transport performance compared to that under biaxial tensile strain. In summary, biaxial compressive strain causes a decrease in both the effective mass and phonon scattering rate of monolayer HfS2, resulting in an increase in its carrier mobility. Under the biaxial compressive strain reaches 4%, the electron mobility enhancement ratio of the CB of monolayer HfS2 is ~90%. For the VB of monolayer HfS2, the maximum hole mobility enhancement ratio appears to be ~13% at a biaxial compressive strain of 4%. Our results indicate that the carrier transport performance of monolayer HfS2 can be greatly improved by strain engineering.

Optimizing dye-sensitized solar cell efficiency through TiO2/CuS doping: effects of internal parameter variations

Dye-sensitized solar cells (DSSC) have attracted significant research interest due to their semi-transparency, ease of fabrication, cost-effectiveness, and environmental friendliness. This research focuses on enhancing dye-sensitized solar cells efficiency by doping titanium dioxide with copper sulfide and varying internal parameters such as concentration, thickness, and temperature. The primary issue addressed is the low electron mobility of titanium dioxide, which limits its performance as a photoanode. Using simulation methods, this study analyzed dye-sensitized solar cells performance under different doping conditions. The results showed that the highest efficiency of 8.18 % was achieved at a TiO2/CuS concentration of 0.3 %. The optimal photoanode thickness was approximately 3 μm, yielding an efficiency of 8.33 %. Temperature variations at room temperature (275 K, 300 K, and 325 K) resulted in efficiency values of 13.94 %, 15.06 %, and 16.18 %, respectively. These findings indicate that targeted doping and precise control of internal parameters can significantly enhance the performance of titanium dioxide-based dye-sensitized solar cells. The improved efficiency is attributed to enhanced electron mobility and better structural and morphological characteristics of the doped titanium dioxide photoanode. This research provides valuable insights into developing more efficient and sustainable dye-sensitized solar cells. The practical implications of these results are significant for advancing dye-sensitized solar cells as a viable alternative to conventional solar cells, contributing to the global effort to address the energy crisis by providing a cost-effective and environmentally friendly energy source.

Investigations on the Recovery of the Electrical Properties of Smart Cut™-Transferred SiC Thin Film Using SiC-on-Insulator Structures

SiC-on-Insulator (SiCOI) structures fabricated using the Smart Cut™ technique can be of great interest in order to probe the properties of a silicon carbide (SiC) transferred layer, by electrically insulating it from the receiver substrate. In this study, we report the fabrication of such a SiCOI structure using a SiC receiver, as well as its electrical and TEM characterization after high temperature annealing. We highlight a decrease of the transferred layer electrical resistivity with increasing annealing temperature, due to doping reactivation and electron mobility enhancement. After low temperature annealing (1200°C to 1400°C), deep acceptor levels, possibly located in a damaged region near the substrate’s surface, might be responsible of a non negligible electrical compensation. Beyond 1400°C however, the transferred SiC crystal is healed and electron transport is only subjected to shallow nitrogen ionization.

Isomers of n-Type Poly(thiophene-alt-co-thiazole) for Organic Thermoelectrics.

n-Type polythiophene represents a promising category of n-type polymer thermoelectric materials known for their straightforward structure and scalable synthesis. However, n-type polythiophene often suffers from a twisted backbone and poor stacking property when introducing high-density electron-withdrawing groups for a lower lowest unoccupied molecular orbital (LUMO) level, which is considered to be beneficial for n-doping efficiency. Herein, we developed two isomers of polythiophene derivatives, PTTz1 and PTTz2, by inserting thiazole units into the polythiophene backbone composed of thieno[3,4-c]pyrrole-4,6-dione (TPD) and thiophene-3,4-dicarbonitrile (2CNT). Although PTTz1 and PTTz2 share a similar polymer skeleton, they differ in thiazole configuration, with the nitrogen atoms of the thiazole units oriented toward TPD and 2CNT, respectively. The insertion of thiazole units significantly planarizes the polythiophene backbone while largely preserving low LUMO levels. Notably, PTTz2 exhibits a more coplanar backbone and closer π-stacking compared to PTTz1, resulting in a greatly enhanced electron mobility. Both PTTz1 and PTTz2 can be easily n-doped due to their deep LUMO levels. PTTz2 demonstrates superior thermoelectric performance, with an electrical conductivity of 50.3 S cm-1 and a power factor of 23.8 μW m-1 K-2, which is approximately double that of PTTz1. This study highlights the impact of the thiazole unit on n-type polythiophene derivatives and provides valuable guidelines for the design of high-performance n-type polymer thermoelectric materials.

Facile fabrication of Mn doped WSe2 as an electrode material for supercapacitor application

The world is currently confronted with major challenges of energy scarcity and environmental deterioration. Prioritising the development and storage of eco-friendly energy sources is imperative given the finite availability of non-renewable resources. Under these circumstances, the production and utilization of environmentally friendly energy have become widely recognized as of utmost significance. Lately, researchers have shown a strong fascination with supercapacitors owing to exceptional energy/power density and prolonged cycle life. In this work, we have fabricated Mn doped WSe2 through the hydrothermal route for supercapacitor applications. Utilization of Mn2+ as a dopant increases the conductivity of the WSe2 lattice by adding charge carriers, hence enhancing electron mobility. The incorporation of Mn2+ enhanced the electrochemical characteristics of Mn-doped WSe2, resulting in an overall improvement in electrochemical efficacy. The Mn doped WSe2 exhibited Cs of 1908 F/g at 1 A g-1, surpassing the Cs of pure WSe2 (593 F/g). This enhancement was attributed to the rise in the quantity of active sites, lower resistance and improved morphology resulting from to successful doping of Mn2+. It enhances the material's conductivity and charge storage capacity, compelling to increase in capacitance. After 5000th cycle at 10 mV/s, the material showed great cyclic stability due to doping. The superior performance of Mn doped WSe2 electrode suggests its potential for supercapacitor electrodes. The widespread implementation of Mn doped WSe2 can considerably enhance the performance, durability, and cost-effectiveness for it to be utilized further in next-generation energy storage processes.

Polyfluorene-poly(ethylene oxide) diblock copolymers: synthesis and electron transport behavior.

Under mild reaction conditions, we synthesized diblock copolymers of poly(9,9-dioctylfluorene)-block-poly(ethylene oxide) (PFO-b-PEO) via end-capping poly(9,9-dioctylfluorene) (PFO) with poly(ethylene oxide) (PEO) on one end. We investigated the thermal, optical, electrochemical and crystalline properties as well as electron transport performance of these polymers. Our results demonstrate that PFO-b-PEO diblock copolymers with short PEO chains (M n = 1000 and 2000 g mol-1) exhibit higher electron mobilities compared to the PFO homopolymer and longer PEO chain (M n = 4000 g mol-1) attached copolymers. This enhanced electron mobility is attributed to the higher crystallinity induced by the shorter PEO chain end-capping.

Analytical modeling of threshold voltage and on-resistance in multi-barrier E-mode MISHEMT with gate-recess and field-plates

This work presents an analytical model for threshold voltage and On-resistance of multi barrier Metal–Insulator–Semiconductor High-Electron-Mobility-Transistor (MISHEMT) with gate-recess and field-plates. The device featuring a high two-dimensional electron-gas (2DEG) density in the channel region. The primary objectives of this device are to achieve a high threshold voltage (Vth) and enhance electron mobility with specific low ON-resistance (Ron_sp) by mitigating the degradation effects arising from scattering and interface-charges. Also, a physics based analytical model for Vth and 2DEG charge density at upper and lower channels is presented. This model is validated by comparing with TCAD numerical simulations and are well matched. The proposed MISHEMT demonstrates improved electron mobility in the lower channel of 1260 cm2/V.s, Vth of ∼2.6 V and Ron_sp is minimized by 33 % in contrast with a conventional MISHEMT. Additionally, the proposed MISHEMT becomes a promising device for achieving both high threshold voltage and mobility which are required for power semiconductor devices.

Weak interlayer interaction and enhanced electron mobility in multilayer WS2 achieved through a layer-by-layer wet transfer approach

Weak interlayer interaction and enhanced electron mobility in multilayer WS2 achieved through a layer-by-layer wet transfer approach

Photo-assisted selective oxidation of monoterpenes by a covalently supported dioxo-molybdenum complex on TiO2: Effect of electron donor ligands

High-valent dioxo-Mo species have demonstrated the ability to catalyze industrially interesting alkene-to-epoxide transformations via oxygen atom transfer (OAT) reactions. The impact of electron donor ligands of dioxo-molybdenum complexes [MoO2Ln] covalently supported on TiO2 nanotubes (MoO2Ln/TiO2NT) on OAT to α-pinene, β-pinene, (R)-limonene and camphene has been investigated through the use of UV–vis radiation and molecular oxygen. Molybdenum complexes with electron donor ligands, such as bipyridine, bispyrazole, and terpyridine, exhibited high conversion and selectivity towards epoxide formation. This suggests that electron donation enhances the efficiency of photostimulated OAT. The photonic efficiency (ξ) demonstrates a linear correlation between the ligand structure and the OAT activity, indicating that the electron donation of the ligands enhances electron mobility towards the Mo=O bond. This correlation is evident in the position of the IR and Raman νsym(O=Mo=O) and vasym(O=Mo=O) vibrations of the complex Mo.

Wide Bandgap SiC-Based Oxide Thickness Optimization by Computation and Simulation using Enhanced Electron Mobility with Regulated Gate Voltage Technique for High-Power 4H-SiC MOSFET

Wide Bandgap SiC-Based Oxide Thickness Optimization by Computation and Simulation using Enhanced Electron Mobility with Regulated Gate Voltage Technique for High-Power 4H-SiC MOSFET

Recent Advances in Metal Oxide Electron Transport Layers for Enhancing the Performance of Perovskite Solar Cells.

Perovskite solar cells (PSCs) have attracted considerable interest owing to their low processing costs and high efficiency. A crucial component of these devices is the electron transport layer (ETL), which plays a key role in extracting and transmitting light-induced electrons, modifying interfaces, and adjusting surface energy levels. This minimizes charge recombination in PSCs, a critical factor in their performance. Among the various ETL materials, titanium dioxide (TiO2) and tin dioxide (SnO2) stand out due to their excellent electron mobility, suitable band alignment, high transparency, and stability. TiO2 is widely used because of its appropriate conduction band position, easy fabrication, and favorable charge extraction properties. SnO2, on the other hand, offers higher electron mobility, better stability under UV illumination, and lower processing temperatures, making it a promising alternative. This paper summarizes the latest advancements in the research of electron transport materials, including material selection and a discussion of electron collection. Additionally, it examines doping techniques that enhance electron mobility and surface modification technologies that improve interface quality and reduce recombination. The impact of these parameters on the performance and passivation behavior of PSCs is also examined. Technological advancements in the ETL, especially those involving TiO2 and SnO2, are currently a prominent research direction for achieving high-efficiency PSCs. This review covers the current state and future directions in ETL research for PSCs, highlighting the crucial role of TiO2 and SnO2 in enhancing device performance.

Optimizing electrical and thermal performance in AlGaN/GaN HEMT devices using dual‐metal gate technology

AbstractThe investigation of aluminum gallium nitride/gallium nitride high electron mobility transistor (AlGaN/GaN HEMT) devices with a dual‐metal gate (DMG) structure encompasses both electrical and thermal characteristics. As efforts to enhance heat dissipation progress, there is a concurrent exploration of novel semiconductor materials boasting high thermal conductivity, like boron arsenide and phosphide. Combining these materials into a model and measuring their interface achieves efficient energy transport. Minimizing the self‐heating impact in AlGaN/GaN HEMTs is essential for enhancing device efficiency. This research exposes the heterogenous combination of boron arsenide and phosphide cooling substrates with metals, GaN semiconductors and HEMT. In this research, the autoencoder deep neural network techniques in GaN HEMT for self‐heat reduction is driven by the ability to effectively analyze and model the thermal behavior of the device. Autoencoders learn complex relationships within temperature data and identify patterns associated with self‐heating. By leveraging these learned representations, the deep neural network optimizes control strategies to mitigate self‐heating effects in GaN HEMT devices, ultimately contributing to improved thermal management and enhanced overall performance. In this research, the use of genetic algorithms in GaN HEMT aims to optimize device parameters systematically, to minimize self‐heating effects and enhance overall thermal performance. The structure also enhances electron mobility within the channel. Results show DMG structures, exhibiting higher saturation output currents and transconductance despite self‐heating. The DMG exhibits a maximum gm value of 0.164 S/mm, which is 10% higher significantly enhancing GaN‐based HEMTs for improved reliability and efficiency in various applications.

Facile fabrication of MgAl2O4/MWCNT nanocomposite for efficient and stable solar-driven degradation of organic dye

This work reports the synthesis and characterization of Magnesium Aluminate (MgAl2O4) and Magnesium Aluminate/Multi Walled Carbon Nanotube (MgAl2O4/MWCNT) nanocomposite by facile chemical co-precipitation method for the dye degradation application. MgAl2O4 and MgAl2O4/MWCNT nanocomposite are characterized by Scanning Electron Microscopy (SEM), x-ray Diffractometry (XRD), Raman Spectrometry, UV–vis Spectrophotometry (UV–vis), Fourier Transform Infrared Spectroscopy(FTIR), and x-ray Photoelectron Spectroscopy (XPS). Surface morphology of MgAl2O4/MWCNT nanocomposite exhibits entangled needle-like structures while MgAl2O4 spinel comprises agglomerated nanoparticles of different sizes. XRD confirms the formation of MgAl2O4. XPS identifies the chemical states and binding energies of constituent elements present in the sample. Optical properties reveal that addition of MWCNTs in MgAl2O4 decreases the optical bandgap energy from 3.02 eV to 2.78 eV. MgAl2O4/MWCNT nanocomposite shows reduced bandgap compared to pristine MgAl2O4 due to increased chemical defects or vacancies in intergranular regions and chemical interaction between MgAl2O4 and MWCNT, leading to the formation of new energy levels in MgAl2O4/MWCNT nanocomposite. Addition of MWCNTs provides a large surface area, more active sites, and enhances electron mobility between energy levels. MgAl2O4/MWCNT nanocomposite proves itself a better photocatalyst due to the fast degradation of Methyl Blue (MB) in 65 min as compared to MgAl2O4 which degrades the dye in 90 min. MgAl2O4/MWCNT nanocomposite also shows good stability and reusability even after performing the six cycles of dye degradation.

Research on intelligent sensor for industrial hazardous gases monitoring based on Tc doped C3N using density functional theory

With the ongoing global industrialization, a considerable amount of hazardous gases is emitted into the atmospheric environment. Achieving intelligent monitoring of industrial hazardous gases is a crucial pathway toward realizing the modernization of electronic information. In this study, the use of Tc doped C3N nanosheet for the intelligent online monitoring of industrial hazardous gases (CO, NO2, O3) is firstly proposed. The doping and modification mechanism of Tc nanoparticle on the C3N surface are revealed. Simultaneously, the adsorption and sensing mechanisms of the three target gases on the surface of pure C3N and Tc doped C3N nanosheet is deeply elucidated through density of states, band structure, and differential charge density analysis. The results indicate that Tc particle can stably bind to the C3N surface, providing numerous active sites for the adsorption of target gases, enabling selective capture and scavenging of hazardous gases. Furthermore, the adsorption type for all three gases shifts from physical adsorption to physicochemical adsorption, with significant changes in the electronic signals during surface reactions, manifested by drastic alterations in the band structure and enhanced electron mobility. The adsorption capacity order for the three gases is O3 > NO2 > CO. The achievements of this work not only provide a theoretical foundation for the design and preparation of Tc doped C3N nanosensors, but also offer a new direction for environmental protection and intelligent detection in industrial applications.