A Review of Diamond Materials and Applications in Power Semiconductor Devices.

Diamond is known as the ultimate semiconductor material for electric devices with excellent properties such as an ultra-wide bandgap (5.47 eV), high carrier mobility (electron mobility 4000 cm2/V·s, hole mobility 3800 cm2/V·s), high critical breakdown electric field (20 MV/cm), and high thermal conductivity (22 W/cm·K), showing good prospects in high-power applications. The lack of n-type diamonds limits the development of bipolar devices; most of the research focuses on p-type Schottky barrier diodes (SBDs) and unipolar field-effect transistors (FETs) based on terminal technology. In recent years, breakthroughs have been made through the introduction of new structures, dielectric materials, heterogeneous epitaxy, etc. Currently, diamond devices have shown promising applications in high-power applications, with a BV of 10 kV, a BFOM of 874.6 MW/cm2, and a current density of 60 kA/cm2 already realized. This review summarizes the research progress of diamond materials, devices, and specific applications, with a particular focus on the development of SBDs and FETs and their use in high-power applications, aiming to provide researchers with the relevant intuitive parametric comparisons. Finally, the paper provides an outlook on the parameters and development directions of diamond power devices.

A Review of ß-Ga2O3 Power Diodes.

As the most stable phase of gallium oxide, ß-Ga2O3 can enable high-quality, large-size, low-cost, and controllably doped wafers by the melt method. It also features a bandgap of 4.7-4.9 eV, a critical electric field strength of 8 MV/cm, and a Baliga's figure of merit (BFOM) of up to 3444, which is 10 and 4 times higher than that of SiC and GaN, respectively, showing great potential for application in power devices. However, the lack of effective p-type Ga2O3 limits the development of bipolar devices. Most research has focused on unipolar devices, with breakthroughs in recent years. This review mainly summarizes the research progress fora different structures of ß-Ga2O3 power diodes and gives a brief introduction to their thermal management and circuit applications.

Carrier tuning of 2D electron gas in field-effect devices based on Al2O3/ZnO heterostructures.

Two-dimensional electron gas (2DEG) formed at oxide heterointerfaces via atomic layer deposition (ALD) has attracted considerable interest toward fascinating electron-related physics and electronic device applications. The employment of oxide-based 2DEG in a confined channel in field-effect transistors (FETs) holds great promise for advanced electronic devices due to its high mobility, spatial confinement, and tunable conductivity. In this work, a 2DEG FET based on the Al2O3/ZnO heterostructure is fabricated with an optimized channel carrier density and oxide thickness. The carrier transport in the bulk and the oxide interface dominantly governed by percolation conduction, optical phonon scattering, and grain boundary scattering is comparatively studied through oxygen annealing and thickness engineering. A tunable carrier density from 4 × 1011 cm-2 to 2 × 1014 cm-2 is achieved with a maximum Hall mobility of ∼62 cm2 V-1 s-1. The electron distribution associated with the annealing process of the ZnO underlayer and the interface reaction during Al2O3 deposition are found to have an impact on the electrical characteristics of the devices. The fabricated Al2O3/ZnO-based 2DEG FET exhibits an on/off ratio over 108, a subthreshold swing of 224 mV dec-1, and a field-effect mobility of 5.7 cm2 V-1 s-1 which can be promising for advanced oxide thin film-containing device and system applications.

Maternal and perinatal outcomes of low-dose aspirin plus low-molecular-weight heparin therapy on antiphospholipid antibody-positive pregnant women with chronic hypertension.

Objectives: Positive antiphospholipid antibodies (aPLs) and chronic hypertension (CH) in pregnancy are important causes of maternal and neonatal morbidity and mortality. However, there are no relevant studies on the treatment of aPL-positive pregnant women with CH. This study aimed to determine the effect of low-dose aspirin (LDA) plus low-molecular-weight heparin (LMWH) on maternal and perinatal outcomes in persistently aPL-positive pregnant women with CH. Methods: This study was performed at the First Affiliated Hospital of Dalian Medical University in Liaoning, China, from January 2018 to December 2021. Pregnant women diagnosed CH and persistently positive aPL who had no autoimmune disease such as systemic lupus erythematosus, antiphospholipid syndrome were recruited and divided into control group (LDA and LWMH were not used), LDA group (LDA was used) and LDA plus LMWH group (both LDA and LMWH were used) according to whether they use LDA and/or LMWH. A total of 81 patients were enrolled, including 40 patients in the control group, 19 patients in the LDA group, and 22 patients in the LDA plus LMWH group. The maternal and perinatal outcomes of LDA plus LMWH therapy were analysed. Results: Compared with control group, the rate of severe preeclampsia in LDA group (65.00% vs. 31.58%, p = 0.016) and LDA plus LMWH group (65.00% vs. 36.36%, p = 0.030) had a statistically significant reduction. Compared with control group, the rate of fetal loss in LDA group (35.00% vs. 10.53%, p = 0.014) and LDA plus LMWH group (35.00% vs. 0.00%, p = 0.002) had a statistically significant reduction. Compared with control group, the rate of live birth in LDA group (65.00% vs. 89.74%, p = 0.048) and LDA plus LMWH group (65.00% vs. 100.00%, p = 0.002) had a statistically significant increased. Compared withcontrol group, the incidence of early-onset preeclampsia (47.50% vs. 36.84%, p = 0.008) and early-onset severe preeclampsia (47.50% vs. 13.64%, p = 0.001) in the LDA plus LMWH group decreased and were statistically different. Furthermore, we also found that LDA or LDA plus LMWH hadn't increase the rate of blood loss and placental abruption. Conclusion: Both LDA and LDA combined with LMWH could decrease the incidence of severe preeclampsia, decrease the rate of foetal loss, increase the rate of live birth. However, LDA plus LWMH could reduce and delay the onset of severe preeclampsia, prolong the gestational age and increase the rate of full-term delivery, improve the maternal and perinatal outcomes.

Ion-Electron Coupling Enables Ionic Thermoelectric Material with New Operation Mode and High Energy Density.

Ionic thermoelectrics (i-TE) possesses great potential in powering distributed electronics because it can generate thermopower up to tens of millivolts per Kelvin. However, as ions cannot enter external circuit, the utilization of i-TE is currently based on capacitive charge/discharge, which results in discontinuous working mode and low energy density. Here, we introduce an ion-electron thermoelectric synergistic (IETS) effect by utilizing an ion-electron conductor. Electrons/holes can drift under the electric field generated by thermodiffusion of ions, thus converting the ionic current into electrical current that can pass through the external circuit. Due to the IETS effect, i-TE is able to operate continuously for over 3000 min. Moreover, our i-TE exhibits a thermopower of 32.7 mV K-1 and an energy density of 553.9 J m-2, which is more than 6.9 times of the highest reported value. Consequently, direct powering of electronics is achieved with i-TE. This work provides a novel strategy for the design of high-performance i-TE materials.

Insights into enhanced removal of Cd2+ from aqueous solutions by attapulgite supported sulfide-modified nanoscale zero-valent iron.

The sulfidation of nanoscale zerovalent iron (nZVI) has received increasing attention for reducing the oxidizability of nZVI and improving its reactivity toward heavy metal ions. Here, a sulfide (S)-modified attapulgite (ATP)-supported nanoscale nZVI composite (S-nZVI@ATP) was rapidly synthesized under acidic conditions and used to alleviate Cd2+ toxicity from an aqueous solution. The degree of oxidation of S-nZVI@ATP was less than that of nZVI@ATP, indicating that the sulfide modification significantly reduced the oxidation of nZVI. The optimal loading ratio was at an S-to-Fe molar ratio of 0.75, and the adsorption performance of S-nZVI@ATP for Cd2+ was significantly improved compared with that of nZVI@ATP. The removal of Cd2+ by S-nZVI@ATP was 100% when the adsorbent addition was 1 g/L, the solution was 30 mL, and the adsorption was performed at 25 °C for 24 h with an initial Cd2+ concentration of 100 mg/L. Kinetics studies showed that the adsorption process of Cd followed the pseudo-second-order model, indicating that chemisorption was the dominant adsorption mechanism. The adsorption of Cd2+ by S-nZVI @ATP is dominated by the complexation between the iron oxide or iron hydroxide shell of S-nZVI and Cd2+ and the formation of Cd(OH)2 and CdS precipitates.

Transcriptome and Metabolome Analysis of Color Changes during Fruit Development of Pepper (Capsicum baccatum).

Fruit color is one of the most critical characteristics of pepper. In this study, pepper (Capsicum baccatum L.) fruits with four trans-coloring periods were used as experimental materials to explore the color conversion mechanism of pepper fruit. By transcriptome and metabolome analysis, we identified a total of 307 flavonoid metabolites, 68 carotenoid metabolites, 29 DEGs associated with flavonoid biosynthesis, and 30 DEGs related to carotenoid biosynthesis. Through WGCNA (weighted gene co-expression network analysis) analysis, positively correlated modules with flavonoids and carotenoids were identified, and hub genes associated with flavonoid and carotenoid synthesis and transport were anticipated. We identified Pinobanksin, Naringenin Chalcone, and Naringenin as key metabolites in the flavonoid biosynthetic pathway catalyzed by the key genes chalcone synthase (CHS CQW23_29123, CQW23_29380, CQW23_12748), cinnamic acid 4-hydroxylase (C4H CQW23_16085, CQW23_16084), cytochrome P450 (CYP450 CQW23_19845, CQW23_24900). In addition, phytoene synthase (PSY CQW23_09483), phytoene dehydrogenase (PDS CQW23_11317), zeta-carotene desaturase (ZDS CQW23_19986), lycopene beta cyclase (LYC CQW23_09027), zeaxanthin epoxidase (ZEP CQW23_05387), 9-cis-epoxycarotenoid dioxygenase (NCED CQW23_17736), capsanthin/capsorubin synthase (CCS CQW23_30321) are key genes in the carotenoid biosynthetic pathway, catalyzing the synthesis of key metabolites such as Phytoene, Lycopene, ß-carotene and ε-carotene. We also found that transcription factor families such as p450 and NBARC could play important roles in the biosynthesis of flavonoids and carotenoids in pepper fruits. These results provide new insights into the interaction mechanisms of genes and metabolites involved in the biosynthesis of flavonoids and carotenoids in pepper fruit leading to color changes in pepper fruit.

Multi-Ionic Hydrogel with Outstanding Heat-to-Electrical Performance for Low-Grade Heat Harvesting.

Ionic thermoelectric (i-TE) materials have attracted much attention due to their ability to generate ionic Seebeck coefficient of tens of millivolts per Kelvin. In this work, we demonstrate that the ionic thermopower can be enhanced by the introduction of multiple ions. The multi-ionic hydrogel possesses a record thermal-to-electrical energy conversion factor (TtoE factor) of 89.6 mV K-1 and an ionic conductivity of 6.8 mS cm-1 , which are both better than single salt control hydrogel. Subsequently we build a model to explain thermal diffusion of the ions in multi-ionic hydrogels. Finally, the possibility of large-scale integrated applications of multi-ionic hydrogels is demonstrated. By connecting 7 i-TEs hydrogels, we obtained an open-circuit voltage of 1.86 V at ΔT=3 K. Our work provides a new pathway for the design of i-TEs and low-grade heat harvesting.

Role of Ions in Hydrogels with an Ionic Seebeck Coefficient of 52.9 mV K-1.

Ionic thermoelectric (i-TE) material with mobile ions as charge carriers has the potential to generate large thermal voltages at low operating temperatures. This study highlights the role of ions in i-TE hydrogels employing a poly(vinyl alcohol) (PVA) polymer matrix and a number of ion providers, e.g., KOH, KNO3, KCl, KBr, NaI, KI, and CsI. The relationship between the intrinsic physical parameters of the ion and the thermoelectric performance is established, indicating the ability to influence the hydrogen bond by the ion is a crucial factor. Among these i-TE hydrogels, the PVA/CsI hydrogel exhibits the largest ionic Seebeck coefficient, reaching 52.9 mV K-1, which is the largest of all i-TE materials reported to date. In addition, our work demonstrates the influence of ions on polymer configuration and provides an avenue for ion selection in the Soret effect in ionic thermoelectrics.

Highly Skin-Compliant Polymeric Electrodes with Synergistically Boosted Conductivity toward Wearable Health Monitoring.

Despite rapid advances in stretchable electrodes, successful examples of polymeric dry electrodes are limited. Especially in wearable health monitoring, it is urgent to develop biocompatible electrodes that possess intrinsic skin-compliance while maintaining a high conductivity. Herein, a strategy is demonstrated to synergistically regulate the interpenetration behavior and molecular crystallinity in the blend via embedding a novel double network, i.e. physically cross-linked poly(vinyl alcohol) (PVA) and covalently cross-linked polyethylene glycol diacrylate (PEGDA), into the PEDOT:PSS matrix. The favorable interaction energy between PVA and PEGDA enables well-distributed microstructure with finer phase separation in the film, affording a low Young's modulus of 16 MPa with a high conductivity of 442 S/cm. Consequently, the optimal polymeric electrode can acquire high-quality electromyogram (EMG) and electrocardiogram (ECG) signals. Our results provide a feasible approach for producing skin-compliant polymeric electrodes toward next-generation health monitors.

Insight into the stability of cross-beta amyloid fibril from molecular dynamics simulation.

Amyloid fibrils are considered to play causal roles in the pathogenesis of amyloid-related degenerative diseases such as Alzheimer's disease, type II diabetes mellitus, the transmissible spongiform encephalopathies, and prion disease. The mechanism of fibril formation is still hotly debated and remains an important open question. In this study, we utilized molecular dynamics (MD) simulation to analyze the stability of hexamer for eight class peptides. The MD results suggest that VEALYL and MVGGVV-1 are the most stable ones, then SNQNNY, followed by LYQLEN, MVGGVV-2, VQIVYK, SSTSAA, and GGVVIA. The statistics result indicates that hydrophobic residues play a key role in stabilizing the zipper interface. Single point and two linkage mutants of MVGGVV-1 confirmed that both Met1 and Val2 are key hydrophobic residues. This is consistent with the statistics analysis. The stability results of oligomer for MVGGVV-1 suggest that the intermediate state should be trimer (3-0) and tetramer (2-2). These methods can be used in stabilization study of other amyloid fibril.

Synthesis and evaluation of phenylalanine-modified hyperbranched poly(amido amine)s as promising gene carriers.

Hyperbranched poly(amido amine) (HPAMAM), which is structurally analogous to PAMAM dendrimers, has been proposed to be an effective agent for gene delivery. The facile synthesis of HPAMAM with scalable productivity by one-pot polymerization of monomers of methyl acrylate (MA) and diethylenetriamine (DETA) has been set up previously. In this study, the HPAMAM was further modified on the terminal amino groups with phenylalanine to various degrees (HPAMAM-PHE30, PHE45, PHE60). We showed that HPAMAM and HPAMAM-PHEs were all able to form complexes with plasmid DNA (pDNA) at various mass ratios. The cytotoxicity and transfection efficiencies of these polymers were evaluated in SMMC-7721 and COS-7 cell lines. The PHE modifications affected the cell transfection efficiency significantly. The HPAMAM-PHE60 was the most efficient, with transfection activities consistently higher than the commercial transfection reagent PEI. Our study demonstrated that HPAMAM-PHEs may be good new materials for gene delivery and other applications because of its large-scale availability, economical cost, and low toxicity.